Building a new dual personality exhaust for the Coupe!!

[jonesmechanical]

Well, finally getting around to the bucket list, and living the dream for a moment. I have always wanted to fabricate my own exhaust. 3 years ago I purchased a really cool Miller tig welder (dual voltage and very portable). I got pretty good rolling straight lines. I took the class with two very good friends (Jr, AKA "Flexer" and Zach, a local talented Ferrari Technician) and had so much fun hanging out that I never got to aluminum.

I thought about going to aluminum, but figured that since I didn't know how to weld that yet, it just wasn't worth the weight. Also, I don't think aluminum really has been very accepted yet as a reliable exhaust material for a street car.

The goals:

1. More Ground Clearance
2. Make it even quieter
3. But also have it LOUDER (I got addicted to the sound of Carl Pardues Turbo Coupe)
4. Get rid of all of the mild steel tubing
5. All mandrel bends and make it Look pretty (I think that good engineering should look good also).
6. Upsize the piping for more flow (Currently converting to run on Flex Feul pump 91/E85)
7. Get Rid of/replace center magnaflow center muffler that had been damaged, but maintain the dual magnaflow mufflers out rear, as they are a perfect fit, and are a true 3" in, to dual 3.5" stainless tips which fit the bumper nicely.
8. Section it for easier maintenance with vbands.
9. Save some weight.
10. Do it myself, with a bit of tig welding help from Flexer.



So, here goes:

Exhaust as it has been for almost a decade, Built by Active Autowerkes:

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-74.jpg

Damaged center muffler (actually looked good inside), 5" thick by 9" wide muffler. It also turned out, that this mid muffler was 3" in, then dual 2.5" out, and then they sleeved 3" over the 2.5" outlets (a bit ghetto).

So, layout of original exhaust (all mild steel) is 3" mostly mandrel bends, but very messy. Wastegate piping for HKS 60mm is very cool the way it curves around. Its done a good job of maintaining spring pressure of under 11 psi with the boost controller off.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-73.jpg

Now for the new:
Stainless 304 18 Gauge beautifulness. I purchased a lot of cool 3.5" mandrel bends, 3" mandrel bends, a 3"-4" cone, lots of 3" stainless vband kits, a splayed "y" 3.5" to dual 3".

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-75.jpg

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-67.jpg

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-68.jpg

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-69.jpg

So Right off the turbo, I increased from 3" to 3.5". Tricky angles to clear everything. It fits like a glove with good clearance, and a full inch higher than the original 3" down pipe.
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-70.jpg

Now here, I may start to reveal my self. I better post this before my wife notices I have disappeared.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-71.jpg

More to come in a moment about the "more quiet, but also louder" design............

[Sniz]

oh nice! looking good

[jonesmechanical]

Ok, I'm back. 3 boys in soccer, 1st day of school, and the hottest week we have had here in Utah yet makes for a busy HVAC contractor.

So, splitting early to dual 3" pipes allows to create options. One 3" pipe will go straight out to one of the magnaflows. The current design has the straight through side being the passenger side. Then the other 3" goes through first a 22" long 3" resonator, then under the cv axels, then to another 8" long 3" resonator, and then to the other old magnaflow.

Now, here is the trick:

http://ep.yimg.com/ca/I/yhst-15342291949654_2168_105938716 I pad $135 shipped for it online. I originally purchased it at summit racing, but it was much more money at over $200. I thought about going to an electric actuated unit, but they have proven to be unreliable, and they also take up a ton of room. Also, the apexi unit is much more "weld in" friendly and looks like it could be modified to open and close based on load with a wastegate actuator.


oh nice! looking good


I will also be utilizing the crank ventilation design you have on your car!! Looking to tap more ventilation into the valve cover and route it down stream into the exhaust. The current design just made a mess of the intercooler.

Here is the rough layout (still waiting on the valve to ship, and also the small resonator. http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-72.jpg

The valve will be located likely towards the entry of the passenger magnaflow. Shutting it forces all of the exhaust gas through the quiet 3" portion of the exhaust. Opening give for a true straight through and much louder drivers side exhaust, and increased pipe volume.

The wastegate piping will just take a 90 degree bend out of the exit of the wastegate, and then will splice into the spayed 3.5 to dual 3" y. The location of the waste gate tie in will allow for the exhaust flow from the wastegate to blow just past the crotch in the "y" or be forced to go down the quiet side of the "y". http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-75.jpg

Either pathway is pretty ideal, and lots of available volume for the wastegate. If I can fit the actuator sooner, or close to immediately after the "y" then I will, but we will see where it works. I don't think it will make a huge difference in sound or performance where it is located.



I think that with this 3.5" down pipe, and spayed "y" fitting and softer angles than the original AA exhaust, its going to be an improvement, even with the "loud" 3" secion shut off, as the muffler choked it down to 2.5" on both sides after the center section magnaflow.

Now, if I can just get Flexer and Josue to finish accurate testing on their quick spool valve and I will have two "flappers" in my exhaust.

[Z3speed4me]

Lookin good....very interested in following this one.

[biglou911]

So that supposed to be spool valve or cutout? I'm sry if I'm confused :(

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[jonesmechanical]

so that supposed to be spool valve or cutout? I'm sry if i'm confused :(

sent from my iphone using bf.com

no, not a spool valve at all. This is the layout: Single 3.5" down pipe off of turbo, then it divides into two 3" separate exhausts, one for each of the rear mufflers that were already on the coupe. One of the 3" exhausts will be "loud", one will be "quiet", the "loud" one will have a valve in it allows me to shut it down and turn that side off completely, and all of the exhaust gas will only exit out of the quiet side of the exhaust system.

Just like a exhaust cut out, except that the cut out valve on this car doesn't just dump to the atmosphere, it serves a louder side of the exhaust system.

[rukman]

I want to see dyno of loud vs quiet :)

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[NickG]

7. Get Rid of/replace center magnaflow center muffler that had been damaged, but maintain the dual magnaflow mufflers out rear, as they are a perfect fit, and are a true 3" in, to dual 3.5" stainless tips which fit the bumper nicely.


You might want to verify the inlet to those rear mufflers. My experience has been that they come from Magnaflow with a 2 1/4" inlet, which you can hack off to expose the real 2 1/2" internal piping (the internal inlet is 2 1/2", not 3"). Maybe somebody welded a 3" inlet on yours to hide the 2 1/2" piping (similar to what was done on your center muffler).

[Boots]

greg, you should do twin dynomax vt mufflers.

[Z3speed4me]

I am searching for rear mufflers with 3" inlets, magnaflow doesnt have them but I want to check vibrant and some other possible alternatives as well. I have mine hacked to 2.5 but thinking of changin it up.

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[jonesmechanical]

You might want to verify the inlet to those rear mufflers. My experience has been that they come from Magnaflow with a 2 1/4" inlet, which you can hack off to expose the real 2 1/2" internal piping (the internal inlet is 2 1/2", not 3"). Maybe somebody welded a 3" inlet on yours to hide the 2 1/2" piping (similar to what was done on your center muffler).

No, they everything looks factory on them. The modifications on the mid muffler was ugly. Internally also the magnaflow rear mufflers are 3" inlet, with dual outlets to 3.5" tips. Remember, this exhaust was built close to 10 years ago. I am sure magnaflows inventory has changed.

JR (flexer) got about 1/2 of the tig welding done last night, and I finished all of the flanges and about 1/2 of the unfinished passes today. It was so relaxing.

I am very pleased with how everything is turning out. Remember that I am a beginner welder, and other than a night class that was more guy time than anything else, This is by far the most tig welding I have ever done in one sitting.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1202.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1203.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1204.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1205.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1206.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1208.jpg

And my two youngest boys about to put their mouths up to it and make car noises.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1209.jpg

I don't know if JR was just being nice, but he said I did really well, he was very surprised. His pointers were very helpful. Huge props to our friend, teacher, and resident welding guru Gordon Reynolds. Maybe I did learn something from his class!!

[milKt]

I'm more interested in those shin guards laying there (both your boys play?)
and seeing the 3" inlets on the magnaflows?

Did you get them cut open yet?

[jonesmechanical]

I'm more interested in those shin guards laying there (both your boys play?)
and seeing the 3" inlets on the magnaflows?

Did you get them cut open yet?

lol, yes, soccer starts for my 4, 7, and 10 year olds on saturday. the 4 year old had his first practice today. And I will cut open the mag's tomorrow and post pics of these rare boys.

[Z3speed4me]

For limited welding experience I would say that looks pretty good!

[milKt]

lol, yes, soccer starts for my 4, 7, and 10 year olds on saturday. the 4 year old had his first practice today. And I will cut open the mag's tomorrow and post pics of these rare boys.

Nice,
my son and daughter's practice started this week. They will play against each other this year. :evil2


So has anyone else heard of Nick's mention of Magnaflow's "trickery"?

[Z3speed4me]

Yes....that is how the 14815 is that a boatload of mz3 guys use.
If you cut off their 2.25 inlet right to the muffler, the opening is actually 2.5, that is 100% confirmed.

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[jonesmechanical]

Did you get them cut open yet?

Lets take two at this. I did edit the post before the moderators edited this thread. I didn't notice your offence until late tonight. My sincere apology to BFC and milkT. No offense was intended with my little photo fun. Let me know when you are ready to receive my PM's Milkt, and we can communicate and fix this bad turn of sarcasm appropriately.

Yes, I did cut the mufflers today Craig, and this is what I found:

3" internal diameter! Straight from Magnaflow (or as I like to spell it magnflow).
http://i470.photobucket.com/albums/rr68/jonesmechanical/photo-68-1.jpg

Diameter shoots straight through

http://i470.photobucket.com/albums/rr68/jonesmechanical/photo-69-1.jpg
Another thing that is NLA, beveled 3.5" tips.
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-71-1.jpg

I wonder if Omar had these built custom by magnaflow, or if it is just an old style that is just NLA. I will be stripping all of the nasty black sharpie marker off of them along with the worn stove paint and give then a new lease on life.

I got some more done today. I cleaned up the bodies of the mufflers, and painted them with some high temp flat black. They turned out nice. I worked on the piping between the after the "Y". I decided to do 2 vbands right after the Y, and then two vbands right at the mufflers. I'm glad I did because it allows for some fine tuning of the fitment of the mufflers, and also will make working on any part of the car very easy.

Here are some pics, sorry about the poor quality, just iphone pics, once I tig everything together I will take real shots with the nice camera:

I got the straight through side (passenger) of the exhaust fabricated and tacked together. I am waiting on the exhaust valve, it will install when it comes. I also got the first resonator on the quiet side (drivers side) fitted. I am waiting on a short 8" resonator that will fit right after the 18" one you see in the pics.
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-69-1.jpg

I tried to keep the exhaust as straight as possible, but also as high as possible. I am very please with the outcome.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-67-1.jpg

Rear Pic. This is with only 1 hanger! So the muffler needs to rotate a bit on the vband. Ground clearance is going to be improved by 1/2"-1.25" everywhere on the entire exhaust over what AA had. I'm not sure when the exhaust valve will come, and I'm not sure exactly where I am going to put it, but there are at least 3 options.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-68-1.jpg


__________________

[BadBoostedBmwM3]

I really like your "loud and quiet" idea. I think it will sound awesome. I think you will find out that the quiet side will act like a big resonator once the valve is closed. IMO, it will enhance the sound. It will be louder just not as loud without the "quiet side."
SO, is the apexi valve mechanical?


BTW, the welds look awesome. Where are you sourcing your parts from?? Also, Im interested in what Miller unit you own.

[jonesmechanical]

Check out the thread that I am running in parallel over on the Z3 Forum, both topics have been covered. Resident welding guru Randy Forbes chimed in nicely.
I also have listed where I got all the parts.

Explain what you mean in your logic of how the exhaust will sound, I haven't thought of it the way you are and are interested it you idea.


I really like your "loud and quiet" idea. I think it will sound awesome. I think you will find out that the quiet side will act like a big resonator once the valve is closed. IMO, it will enhance the sound. It will be louder just not as loud without the "quiet side."
SO, is the apexi valve mechanical?


The valve will be on the loud side. So, Yes the quiet side will act like a big resonator when the loud side is shut, because it will have 3 mufflers in it. I think you are confused because I haven't installed the valve yet, even thought I complete the loud side. I don't have the apexi valve yet. Yes it is very simple. Cable operated like a the throttles on most BMW's. It has a pull knob that adjusts it. Potentially, I think I will hook up a waste gate actuator to it that operated on vacuum.

[milKt]

Lets take two at this.


Yes,
please.

Thank you.

[jonesmechanical]

There you go!! Sometimes it takes a while for either of us to notice progress in a thread.

Just got the shorty resonator today. I will be fabricating the rest of the quiet side tomorrow. So much fun. Still waiting on the valve. Very popular item.

[GG///M3]

Interesting stuff. Why no DMH cutout great power when needed and very civil for the street?

[dRock13]

beautiful work man :)
come do mine

[jonesmechanical]

Interesting stuff. Why no DMH cutout great power when needed and very civil for the street?

It will have a cutout valve. It will function just like a normal dump cutout, but instead of going straight to the atmosphere after the y, it will go straight out to a single muffler. I have no interest in something that loud and unrefined, and also, having tons of noise emit from under a car just seems very wrong to me. Having dual exhausts stock on the coupe allows me to have a refined loud, and then shut that one down, and have a really quiet style exhaust.

The electric cutouts are more expensive, and every single one I have done research on has major failure issues. I think there is a reason the OEM's don't use an electric actuator on exhaust bypass valves. With this apexi valve, its very simple and mechanical, and it can be easily converted to work automatically off of a wastegate actuator/vacuum.

Summit doesnt even sell a electric cutout any more. Just the Apexi one.

http://apexi-usa.com/shop/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/1/5/155-a019_1.jpg

Power craft seems to be doing a great job on exhausts lately. I think this is the effect I am going for:

http://youtu.be/-A9_rld4Xro

I may even gut out the "loud" side magnaflow for more noise. I am really excited to see what this does, with the valve being totally tunable, it will offer a great range of noise levels.....I think.

[turbo325ii]

I am so confused by your exhuast setup greg... So all your exhaust will flow out 1 single 3.5" side with two mufflers, and when you pull the cable, It will allow some of the flow out another 3.5" side with only 1 muffler for slightly louder exhaust?

Did I tell you about my variable tone muffler I have on my car? Its SOOOOO $$$$$ . Dead quiet on the freeway, and wide open flow, loud as hell and nice tone when I am WOT!

[tlmitf]

I think there is a reason the OEM's don't use an electric actuator on exhaust bypass valves.

Not exactly true.
Here in Australia, HSV (Tuner company for Holden) Run some wanky bloody "bi-modal" exhaust.
Basically its a flapper in the rear mufflers (twin mufflers with twin tips each) that block one of the tips untill triggered (im assuming at WoT, i haven't actually driven one)

Sounds good, but just seems like a bunch of wank to me, because with the valves open, it still needs to be under 85db
Yours, i assume, will be nice a quiet at cruise, and then open up to something a bit more performance orientated - rather than keeping it streetable in BOTH modes.

Cant wait to see the finished product :evil2

[jonesmechanical]

I am so confused by your exhuast setup greg... So all your exhaust will flow out 1 single 3.5" side with two mufflers, and when you pull the cable, It will allow some of the flow out another 3.5" side with only 1 muffler for slightly louder exhaust?

Did I tell you about my variable tone muffler I have on my car? Its SOOOOO $$$$$ . Dead quiet on the freeway, and wide open flow, loud as hell and nice tone when I am WOT!

You got it mostly. Its a 3.5" down pipe and exhaust up to the "Y". From there is split 3" on each side.

Drivers side after "Y":
22" resonator, then to a 10" resonator, then to the magnaflow muffler that was always there that has a 3" inlet with dual 3.5" tips.

Passenger side after "Y":
3" straight back to the other Magnaflow twin tip muffler. Apexi 80mm Valve installed somewhere between the "Y" and the muffler.

I know that there are dual mode mufflers. The issue with all of them that I came across, is that they are single tip round mufflers. One that I liked a lot that comes out of Australia is this one:

http://youtu.be/K7jGYnhbQQU

The dual twin tip mufflers if a design I wanted to keep, so that one was out of the question. Also, to keep ground clearance to a premium, I needed to keep the exhaust height no more than 4" high. Those mufflers are very large in diameter, some as much as 8" round. BAsically with my design, its much like the varex, with a single 3" straight though design, or when shut, a muffled through 3 mufflers/resonators.

The original mid muffler on my car was 5" thick by 8" wide (3" inlet, dual 2.5" outlets). It sustained some significant damage, and wanted to stay higher than that.

The thought is, that even with the passenger side shut off, the exhaust size/capacity will be more than it was before, with the larger down pipe, and with the larger 3" piping back to the muffler. (It actualy was 3" after the mid muffler, but they simply welded 3" over the dual 2.5" outlets of that muffler)

What inspired me to do this exhaust was Steve Coupe. Its was beautifully loud. A head turner as you are coming up on people ahead of you that are walking on the sidewalk. I considered eliminating my mid muffler completely, but asked Steve what it was like to drive home, he said it would have been nice to have it quieter.

I cut out my mid muffler, then the ideas started flowing. And here I am. I figured why not try and make my car both louder, and quieter at the same time with more mufflers that I had one side, and less than I had on the other. With a valve modulating in between the two. Slight Priority is given to the straight though design, but its very equally split air flow wise.

As far as cutout valves on OEM applications, I have been paying attention to them very closely. They are run by an electrical switch, but the actual actuator, including on the newer Vettes, and GTO's (Holden Manaro's) are driven by a wastegate type actuator. Yes, there is an electrical circut that runs them, much like a EBC for a turbo wastegate. I have also looked closely at all of the New Ferrari's and Maserati's, and its the same thing.

[tlmitf]

Ahh, gotchya.

Im going to have to do something like this on the rota (when i eventually get my shed finished, and the damn project started :S)

[turbo325ii]

I have dual 2.5" tips on my variable tone muffler! But my 3.5" pipe does ride low.

I am pumped to see how yours sounds greg!

[rt turbo]

I like the mechanical cutout you are looking into. Where do you get them? maybe have a part number? Also, how does it work?... I mean, is it hard to pull on that tab, or is the spring load somehow allowing it to be an easy pull/push opperation?

I too have been weiry of the failure rates of electronic dumps. It would suck to have it stuck open at the wrong time (like passing a cop). lol

[GG///M3]

I like the mechanical cutout you are looking into. Where do you get them? maybe have a part number? Also, how does it work?... I mean, is it hard to pull on that tab, or is the spring load somehow allowing it to be an easy pull/push opperation?

I too have been weiry of the failure rates of electronic dumps. It would suck to have it stuck open at the wrong time (like passing a cop). lol

I have my button located near my ignition well hidden, and easy to get to. DMH cutout's are awesome. I have mine setup right near the downpipe, and then it stays 3inch to s Y back into the stock muffler. Cutout is 179.99 the rest of the piping can be done pretty cheap. I'm sure less then buying 2-3 mufflers, and will flow much better.

[rt turbo]

I have my button located near my ignition well hidden, and easy to get to. DMH cutout's are awesome. I have mine setup right near the downpipe, and then it stays 3inch to s Y back into the stock muffler. Cutout is 179.99 the rest of the piping can be done pretty cheap. I'm sure less then buying 2-3 mufflers, and will flow much better.
Ive seen a few on ebay that are reasonable and come with flanges. I have an extra 3" bend left over that Im going to use. But worried about reliability.

[GG///M3]

Ive seen a few on ebay that are reasonable and come with flanges. I have an extra 3" bend left over that Im going to use. But worried about reliability.

4 year warranty dude. I would buy directly from them.

Maintainence free design!

CNC Machined 6061-T6 aircraft grade aluminum body

.375 diamiter 316 Stainless Steel Shaft

Torrington Needle Bearings for years of trouble free service

High torque gear motor

Plug and play 16GA. Belden Wiring Harness

Small black rocker switch is only .75" X .50"

Proven Design with over 4 years of real world testing

4 year replacement warranty! feed back link http://www.dmhperformance.com/feedback.htm

[flexer]

Here is a article about exhaust cut-outs and why I love them:

http://www.enginebasics.com/Advanced%20Engine%20Tuning/Exhaust%20Cutout.html

[GG///M3]

Loving them is the only logical thing to do for we earthlings

[jonesmechanical]

I have had 3 friends with electric exhaust cutouts, they all failed, and they were all under warranty. The pain in the ass factor is enough for me to avoid them, and along with the inability to modulate. "lifetime warranty" on cheap checker/autozone replacement parts comes to mind. I can remember replacing 3 starters back to back on one of my Trucks, no compensation for labor of course.

Tommy boy: "I can put a guarantee on the box......"

I purchased the Valve here. Super nice guys, very responsive, and the best price I found online:

http://www.importpartspro.com/155a021.html

[nucci]

Sound Performance has a boost-actuated one which looks an awful lot like the wastegate actuator style. It does cost a little more though.

[jonesmechanical]

Here is a article about exhaust cut-outs and why I love them:

http://www.enginebasics.com/Advanced%20Engine%20Tuning/Exhaust%20Cutout.html


Con not listed: Sounds like you have a catostrophic exhaust leak emitting from under your car. On your turbo s2000, I actually like it, but I would prefer the noise to be coming from the rear of the car.

What was your experience JR with your electric cutout?


Cutout is 179.99 the rest of the piping can be done pretty cheap. I'm sure less then buying 2-3 mufflers, and will flow much better.

The point is not only make it louder than I had it, but also give the option to make it quieter than it was. The combined shipped cost of $109 for both stainless resonators is irrelevant to the exhaust cutout debate. The exhaust cutout, instead of diverting it to the atmosphere directly, is simply diverted to a second exhaust section that already exists on the M coupe. So, in reality, no more expensive than what you are doing.

The fact that I am re piping everything in stainless has more to do with replacing a worn and tattered exhaust system thats 10 years old and gaining more ground clearance than anything else.......and of course, for the pure fabrication pleasure of it also.


Sound Performance has a boost-actuated one which looks an awful lot like the wastegate actuator style. It does cost a little more though.

http://www.spracingonline.com/images/products/3673.jpg

Thats a hot one. At $400, I would say its reasonable. Just case in point, you get what you pay for. This is how the OEM's do variable tone exhaust systems. You never see electric actuated motors in the exhaust on OEM's...at least that I have seen and researched.

My only beef with the way that one works, is that its either on or off. I'm not doing it for the performance, but for the tuning of the sound. There will be plenty of times when I want to leave it open all the time, and all the way closed, and maybe somewhere in between. This Apexi valve, when I came across it was the missing piece to the puzzle.

Another issue with the electric units, is that the orientation and size of the motor and drive made it impossible to fit anywhere there was room on my car. That SP valve, the way it orients the linkage parallel to the exhaust piping makes it compact like the Apexi manual unit.

[GG///M3]

Whatever the kids love. The exhaust you are installing the coupe how much research or testing has gone into it? I mean I have years of trouble free use out of the DMH setup I have on my car. I love it because it can be quieter then a stock car, and sound great and spool up a turbo quicker with the flick of a switch.

[3literheater]

Looks like a great build. I just did my NA car exhaust in all 3" stainless.

I like your idea with the valve. I think the valve would be better off near the Y then really close to the muffler though.

[GG///M3]

The DMH setup is great. Great Warranty 4 years. Not 90 days. You can't go wrong.

[GG///M3]

The DMH setup is great. Great Warranty 4 years. Not 90 days. You can't go wrong.

[chikinhed]

I fabricated a copy of the Sound Performance exhaust cutout (except mine has three screws in the butterfly valve instead of one) a while ago and plan to use it on the 3.5" stainless system that I will be building in the near future. I will install the valve in one of the two outlets of a Magnaflow 12587 at the end of the exhaust. The valve is boost controlled to be fully open at 8 psi. This will create a 2.5" exhaust with a 'Helmholtz resonator' when the valve is closed and a really free flowing exhaust when it's open. With a small single 2.5" exhaust below ~6 psi for driving around town and a large 3.5"/dual 2.5" exhaust when I am above 8 psi that automatically happens would be awesome. In town 6 psi is probably enough, and would be almost silent :D

I understand what you are trying to achieve. When a local 'race car builder' looked at my little single 3" exhaust and said "going to 3.5" will probably get ya another 100 whp" made me motivated to hunt down mo powa :devillook

[jonesmechanical]

Whatever the kids love. The exhaust you are installing the coupe how much research or testing has gone into it? I mean I have years of trouble free use out of the DMH setup I have on my car. I love it because it can be quieter then a stock car, and sound great and spool up a turbo quicker with the flick of a switch.

As far as research, Just me laying down under the car thinking, Hmm, what can I do here? Other than that, I don't know what kind of research would be required to execute a successful project like this. I know the benefits of larger piping, I doubt that at my power level, its going to make much of a benefit. With E85, it just may as I crack 600hp on higher boost levels.

How does the DHM make your car quieter than stock? Are you running stock exhaust, but with the addition of the turbo? Kept the Cat? Have you tested your setup to actually document quicker spool of the turbo when the valve is open. I would put my bet on the placebo effect on that one.


I fabricated a copy of the Sound Performance exhaust cutout (except mine has three screws in the butterfly valve instead of one) a while ago and plan to use it on the 3.5" stainless system that I will be building in the near future. I will install the valve in one of the two outlets of a Magnaflow 12587 at the end of the exhaust. The valve is boost controlled to be fully open at 8 psi. This will create a 2.5" exhaust with a 'Helmholtz resonator' when the valve is closed and a really free flowing exhaust when it's open. With a small single 2.5" exhaust below ~6 psi for driving around town and a large 3.5"/dual 2.5" exhaust when I am above 8 psi that automatically happens would be awesome. In town 6 psi is probably enough, and would be almost silent :D

I understand what you are trying to achieve. When a local 'race car builder' looked at my little single 3" exhaust and said "going to 3.5" will probably get ya another 100 whp" made me motivated to hunt down mo powa :devillook

Thats very interesting. I guess that I will have a very larger version of "Helmholts resonator" with this design. Its just a massive scale version of what you are doing. I would be curious how much sound difference there would be just blocking off one of your tips, without the piping layout being different at all internally in the muffler on one tip vs another. Like on the corvette muffler design, it appears the muffler is like what you are doing but in fact one side is muffled, the other is more straight though. I wouldn't take much to just plug one side and see what the difference is.

[chikinhed]

The idea is that with a 3.5" exhaust at low power levels, ie. city driving, there is no back pressure and the pulses can just go out the exhaust without entering into the chambers of the muffler or resonator so the baffles and or roving does very little to reduce the noise. If you place a restriction at the exit of the system giving some back pressure then the power pulses do enter the chambers and are absorbed by the baffles and or roving. By using the single 3.5" inlet dual 2.5" outlet muffler and puting the valve on one of the 2.5" outlets will keep it plenty quiet. Your system should be quite tolerable as my current 3" exhaust with straight thru resonator and muffler is not overly loud for daily driving. Once your valve is open you should have very little back pressure going from a single 3.5" to dual 3.0" and with that very little muffling.

This is all great testing producing real world data for the rest on BF to use. We want video and backpressure measurements with valve open and closed. ;)

[So Live]

Everything looks great! I like the concept too. Like Chikinhed suggested, look in to helmholtz resonators. Personally i would try my hardest to get the cut out in a spot that gives you a specific size helmholtz resonator. Say to cancel out the ~2500 or 3000 rpm pulses (whatever your cruising rpm is)...

Keep it up!

[GG///M3]

As far as research, Just me laying down under the car thinking, Hmm, what can I do here? Other than that, I don't know what kind of research would be required to execute a successful project like this. I know the benefits of larger piping, I doubt that at my power level, its going to make much of a benefit. With E85, it just may as I crack 600hp on higher boost levels.

How does the DHM make your car quieter than stock? Are you running stock exhaust, but with the addition of the turbo? Kept the Cat? Have you tested your setup to actually document quicker spool of the turbo when the valve is open. I would put my bet on the placebo effect on that one.



Thats very interesting. I guess that I will have a very larger version of "Helmholts resonator" with this design. Its just a massive scale version of what you are doing. I would be curious how much sound difference there would be just blocking off one of your tips, without the piping layout being different at all internally in the muffler on one tip vs another. Like on the corvette muffler design, it appears the muffler is like what you are doing but in fact one side is muffled, the other is more straight though. I wouldn't take much to just plug one side and see what the difference is.

Car has 3 inch downpipe. Then the dhm cutout 3inch(no cats), and then a 3 inch pipe that Y's off to the stock cat-back.

http://www.youtube.com/watch?v=uGeENbXBPtA

That video is a bit dated, but you get the idea.

http://i835.photobucket.com/albums/zz279/gjon777/run3.jpg

psi was reading higher by 2

[chikinhed]

GG, was that dyno chart with the cutout closed? If not, do you have a dyno chart with it closed? Your car would be very quiet with that set up. With it open it would wake the dead. I recently removed the center resonator and installed a cat for emissions and it is noticeably louder, cats don't do a lot for reducing noise but do increase back pressure.

Nice numbers by the way. Are you using the T3 or T4 Steedspeed manifold?

[GG///M3]

GG, was that dyno chart with the cutout closed? If not, do you have a dyno chart with it closed? Your car would be very quiet with that set up. With it open it would wake the dead. I recently removed the center resonator and installed a cat for emissions and it is noticeably louder, cats don't do a lot for reducing noise but do increase back pressure.

Nice numbers by the way. Are you using the T3 or T4 Steedspeed manifold?

That was with it open on the spa t3 manifold. I'm now using the T4 SteedSpeed mani Hta 3586. I haven't gotten a chance to get it on the dyno after working out some boost line issues. I did have it dyno'd with cutout open and closed it did make a difference in power and spool. I do not have those sheets on this computer.

Here is an old vid showing the difference in sound open and closed. Not a great video.

http://www.youtube.com/watch?v=afU3Q88cbk0

[jonesmechanical]

Yea, at one point in my life I would have been a fan of a dump gate. I can't even handle a open wastegate now, let alone a open exhaust.

Rukman has done extensive testing on all of his setups. At one point he even took his exhaust off on his car (3" down pipe) and did testing on the dyno, and at 500 wheel, there were zero gains in power or spooling. He had a very similar magnaflow setup (3" to dual 2.5" to twin mufflers). Maybe its the nature of the coupe exhaust and how its dual setup that makes for no gains.

Today I got the "quiet side" done today (fabricated and tacked together).

Now, just waiting on the cut out valve, and need to figure out where to put it.

Here is a questions. I am about 1/2" away from the cv axel boot with the suspension at full droop, on the road, its more like 3/4". Do you think I will have issues with heat and the boot?

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-67-2.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-68-2.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-70-1.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-69-2.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-71-2.jpg

[chikinhed]

You could wrap the exhaust in that section or make a heat shield that attaches with hose clamps to the exhaust.

Rukman probably saw very little gain because he was still using a 3" down pipe or he was still using the TT manifold that may be the bottle neck above 500 whp. Phillip is at 550 whp with Spa T4 and 3.5" exhaust and down pipe at 17 psi with a GT35r. I think the 3.5" helps a lot.

I just ordered all the parts to put together a 3.5" system. That is going to be a very full days work to build with new waste gate piping as well.

[GG///M3]

You could wrap the exhaust in that section or make a heat shield that attaches with hose clamps to the exhaust.

Rukman probably saw very little gain because he was still using a 3" down pipe or he was still using the TT manifold that may be the bottle neck above 500 whp. Phillip is at 550 whp with Spa T4 and 3.5" exhaust and down pipe at 17 psi with a GT35r. I think the 3.5" helps a lot.

I just ordered all the parts to put together a 3.5" system. That is going to be a very full days work to build with new waste gate piping as well.

Makes sense. We need him to chime in to make sure.

[GG///M3]

You could wrap the exhaust in that section or make a heat shield that attaches with hose clamps to the exhaust.

Rukman probably saw very little gain because he was still using a 3" down pipe or he was still using the TT manifold that may be the bottle neck above 500 whp. Phillip is at 550 whp with Spa T4 and 3.5" exhaust and down pipe at 17 psi with a GT35r. I think the 3.5" helps a lot.

I just ordered all the parts to put together a 3.5" system. That is going to be a very full days work to build with new waste gate piping as well.

Makes sense. We need him to chime in to make sure.

[jonesmechanical]

Well, I finally got the 2" short radius elbow for the wastegate pipe. I had a 2.25" piece of pipe that was long enough to complete it, so I just had a neighbor who has a exhaust shop next door (kind of ironic) let me use his pipe expander. I flared the elboe out to 2.25" and then competed the rest. It was the first time I had to bevel two pieces of pipe together. Very fun grinding and trimming to get the fitment good.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-68-3.jpg

Then I took out the miller portable plasma cutter and waved the magic want and cut out the junction of where the wastegate ties into the exhaust. That machine never ceases to impress me. Amazing!

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-67-3.jpg

A couple of pics of the waste gate setup. Sorry, I didn't get any pics before I pulled it down.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-70-2.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-69-3.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/photo-71-3.jpg

I can't wait to tig it up. Its going to be a fun one to do. Still waiting on the valve for the passenger "loud" side of the exhaust.

[chikinhed]

Nice progress. I wont get the rest of my parts to start my exhaust before the weekend :(

I want to see some dyno results and back pressure readings.

[BadBoostedBmwM3]

Nice work. Those welds look pretty damn good IMO.

[chikinhed]

Update please.

[cmzwirner]

If you dont mind me asking, where do you get the stainless stell piping, and how much does it go for? Im going to need some soon, and need a source!

[chikinhed]

I just got my stainless pieces from ATP turbo and from Verocious Motorsports. ATP has slightly better prices on everything but they don't have 3.5" U bends and they don't have the kind of flex coupling I wanted.

[jonesmechanical]

Sorry about the non updates, but between soccer starting with 3 boys and a sudden change of schools for my oldest, I haven't had any progress. Also, the valve is shipping later this week, so I have been kind of dragging my feet waiting on it.

As far as piping, The BEST deal I have seen anywhere on piping is the seller "boeschbuilt" very high quality stuff, quick shipping, and a very diverse selection of stuff that I have not seen anywhere.


As far as stainless v band flanges, Ebay is great also, like $17 shipped a piece, instead of like $75. Also another good source for stainless piping is columbia river aka www.mandrelbends.com (http://www.mandrelbends.com)


I also have a lot of 3.5" left over from my project, I think I only used 3 of the bends (I think the upper outside two, and one of the lower middle ones in the ebay title pic) I would estimate enough to do two or three more down pipes like the one I did. I'll take photos of everything, It would save you money! I would sell all of the extra tubing I have for $120 shipped, I'll post pics up.

[BadBoostedBmwM3]

Linkies no workie...

[jonesmechanical]

I finished welding up the waste gate recirc and most of the other sections of the exhaust. Still waiting on the valve. Should be here next week.

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1374-1.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1375.jpg

Flexer saved me on this tight section. I couldn't do it this nice. More Practice!!
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1378.jpg

Nice shot of how direct the wastegate blows down both section of the dual exhaust:
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1381.jpg

also pics of left over 3.5" piping (all SS304 .065" thick):

$160 shipped to any one who wants it:

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1385.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1384.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1383.jpg

[pbonsalb]

Very nice looking and creative design. Do you see any need for flex sections, for either or both the downpipe to main exhaust and the wastegate to main exhaust?

I bought a very lightly used Mike Radowski full 3.5 inch exhaust with two mufflers and have no complaints about the noise. It is not silent, but is quieter than my replica supersprint headers to real supersprint midipe to B&B rear exhaust was when supercharged (blame the B&B).

[jonesmechanical]

Yes, I thought about doing some flex connectors in there, but the exhaust on the car didn't have any. They would be easy to install in retrofit. I don't think there will be any issues though.

[pbonsalb]

I put some in mine, but they significantly change the clearance. V Bands seem to add half an inch top and bottom, but the good flex sections with interlock liner add about an inch top and bottom -- a 3.5 flex is at least 5 inches around. In hindsight, I might have tried the stainless interlock flexi truck exhaust like you see for elbows sometimes on 18 wheelers.

[jonesmechanical]

I got the valve finally from APEXI. Very tough to find. Everything in Japan is in turmoil right now getting product imported.

I got the "loud side fabbed up and tig'd today:

http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1396.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1399.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1387.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1395.jpg
http://i470.photobucket.com/albums/rr68/jonesmechanical/M%20coupe/DSC_1394.jpg

[tlmitf]

Looks the goods man :)

[n0n0perational]

how did you guys miss quick time performance, http://www.quicktimeperformance.com/QTEC/index.php

its powered and can be wired to make the car have basically infinity varied adjustment, open it as much or as little as you want like how a power window works

[milKt]

how did you guys miss quick time performance, http://www.quicktimeperformance.com/QTEC/index.php

its powered and can be wired to make the car have basically infinity varied adjustment, open it as much or as little as you want like how a power window works

Greg posted he prefers to not rely on electronics for his flappy valve.

You have how many posts?
http://29.media.tumblr.com/tumblr_kwlvlbjg1c1qaton8o1_500.jpg

[jonesmechanical]

The other issue other than what Craig said is packaging. This little guy takes up a fraction of the space of a electric actuator. The mechanism is super smooth, has a little ball ratchet that holds it It where ever you set it.

Also was only $150 shipped. When this one became hard to locate in stock, I seriously considered the quick time actuator, but it sticks out too much to fit it anywhere in the exhaust.

The interesting thing about this specific valve is that it isadvertised to be used in the exhaust to quiet it down. Like a internal adjustable baffle. Nothing is mentioned about a dump valve. I think in japan the idea is to have a Loud exhaust, but then to avoid a ticket or be stealth, you shut it down.

Crazy.

They even say not to apply full throttle while it is shut down. Leave it to the Japanese to do such a thing!! There is about a 1/16th gap all the was around the valve. Maybe that's enough to keep a little Japanese 4 banger running when idling around. No holes or anything that would let exhaust bypass around the valve. They also instruct to install before the cat (maybe to keep it from getting over heated?? I don't read Japanese very well.

Milkt, maybe you could translate??

[Schitzo]

Top tigging.
Do you purge when welding?

[chikinhed]

Great job! I'll apologize now for the thread jacking. :D

Once you get tired of pulling yer knob you should get one of these......

http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-WGT-011B&Category_Code=WGT

.......and attach it to the valve.

I too was busy on the weekend. I replaced my clutch and built a QUIET 3.5" exhaust. I was amazed when I finally started the car, it's quiet like stock. There is a definite power increase, easily spinning in third rolling into the throttle. I will be measuring back pressure soon and may go to the dyno depending on my AFRs.

I built a 3.5" exhaust from the turbo to a Borla XR-1 'mid muffler' and on back to a 3.5" in / dual 2.5" out huge Magnaflow p/n 12587. The Magnaflow was 28" long over all (22" body length), 11" wide and the dual 2.5" outlets were 5.75" apart. It was too long and the tips needed to be a lot closer together. Nothing a chop saw couldn't fix ;) I removed about 6" from the length, moved the outlets closer and formed a new end cap for it. Then installed the boost actuated valve in one of the outlets. With it installed the tips look stock. :redspot

[black bnr32]

So, I assume it must be open, at least a little, at all times? or else back pressure is through the roof?

[BadBoostedBmwM3]

Great job! I'll apologize now for the thread jacking. :D

Once you get tired of pulling yer knob you should get one of these......

http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-WGT-011B&Category_Code=WGT

.......and attach it to the valve.

I too was busy on the weekend. I replaced my clutch and built a QUIET 3.5" exhaust. I was amazed when I finally started the car, it's quiet like stock. There is a definite power increase, easily spinning in third rolling into the throttle. I will be measuring back pressure soon and may go to the dyno depending on my AFRs.

I built a 3.5" exhaust from the turbo to a Borla XR-1 'mid muffler' and on back to a 3.5" in / dual 2.5" out huge Magnaflow p/n 12587. The Magnaflow was 28" long over all (22" body length), 11" wide and the dual 2.5" outlets were 5.75" apart. It was too long and the tips needed to be a lot closer together. Nothing a chop saw couldn't fix ;) I removed about 6" from the length, moved the outlets closer and formed a new end cap for it. Then installed the boost actuated valve in one of the outlets. With it installed the tips look stock.

I will upload pics in a minute.


Greg, sorry to take away from your thread. I can't wait to see the pics of your new exhaust. Why 3.5" over 4"??

[chikinhed]

Greg, sorry to take away from your thread. I can't wait to see the pics of your new exhaust. Why 3.5" over 4"??

I was concerned about ground clearance and it being too loud. I was using a 3" down pipe that I made going to the AA 3" race exhaust. That exhaust had a decent sound, tolerable for sound levels. After complaining about not enough power pbonsalb sent me a link to a Modified Mag artical about a 500 whp Supra that when from a 3" exhaust to a 3.5" exhaust and gained 100 whp. It is a relatively cheap power gain if you are a DIY guy.

[BadBoostedBmwM3]

I was concerned about ground clearance and it being too loud. I was using a 3" down pipe that I made going to the AA 3" race exhaust. That exhaust had a decent sound, tolerable for sound levels. After complaining about not enough power pbonsalb sent me a link to a Modified Mag artical about a 500 whp Supra that when from a 3" exhaust to a 3.5" exhaust and gained 100 whp. It is a relatively cheap power gain if you are a DIY guy.

What's going on with the AA 3" exhaust? :)

[chikinhed]

What's going on with the AA 3" exhaust? :)

After some more testing with the new exhaust the 3" AA system will be for sale WITH the down pipe for a GT3582R on a TT exhaust manifold. Do you know anyone interested? ;)

[jonesmechanical]

Great job! I'll apologize now for the thread jacking. :D

Once you get tired of pulling yer knob you should get one of these......

http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-WGT-011B&Category_Code=WGT

.......and attach it to the valve.

I too was busy on the weekend. I replaced my clutch and built a QUIET 3.5" exhaust. I was amazed when I finally started the car, it's quiet like stock. There is a definite power increase, easily spinning in third rolling into the throttle. I will be measuring back pressure soon and may go to the dyno depending on my AFRs.

I built a 3.5" exhaust from the turbo to a Borla XR-1 'mid muffler' and on back to a 3.5" in / dual 2.5" out huge Magnaflow p/n 12587. The Magnaflow was 28" long over all (22" body length), 11" wide and the dual 2.5" outlets were 5.75" apart. It was too long and the tips needed to be a lot closer together. Nothing a chop saw couldn't fix ;) I removed about 6" from the length, moved the outlets closer and formed a new end cap for it. Then installed the boost actuated valve in one of the outlets. With it installed the tips look stock. :redspot

That is awesome. I know about that valve. It's expensive, but worth it. I wasn't sure what to do with such a valve though. I want to have quiet or loud, and not boost dependent. I know there would or could be a simple way to simply actuate it on/off. As far as modulating it, that would be very tricky, I doubt you could get it to stay steady at 50% closed. This valve allows for lots of easy simple experimentation.

How much of a sense of power loss do you notice when the valve is shut? How much of a difference in noise by simply cutting out one of the tips?




Greg, sorry to take away from your thread. I can't wait to see the pics of your new exhaust. Why 3.5" over 4"??

No, not at all. This is the stuff I love. Other people's input. 3.5" I didn't even know was an option. Then I found a killer deal on some 304ss bends on eBay, and jumped on it. I wanted ground clearance also. 4" would have been super tight on the down pipe and making it around the waste gate and waste gate piping. Also, knowing that I was only going to go dual 3", and one side was going to be shut down likely more time than not, it seemed to make more sense to do 3.5" all around. If I was dedicated to dual 3", I would have gave 4" a much closer look.

I am so excited to hear the sound of this exhaust!!

About a week ago, in searching for a different valve for this project, I cam across this:
http://www.forcegt.com/wp-content/uploads/2010/10/agency-power-nissan-gtr-7.jpg

http://youtu.be/Jv8SL41BCr4

I think that sums up what I am going for. Little to no power performance difference between open and shut, but with a big sound difference. I can see doing something like this for my 510, and if I could sneak My wifes Volvo XC90 away from her, I would love to hear that Yamaha V8 uncorked.