gt4094r dyno results

[m3boost]

I finally had time to take my car for a dyno tune..

ms3pro
s52 87mm
cp pistons/arrow rods
3" cutout
o-ring block
elring headgasket
8.5 to 1
11mm arp
1050x ID
525 fuel pump

we decided to just leave it at 14 psi due to 91 octane. Started at 14 psi and tapered to 12 psi at the high end. I didn't get the graph since I'll be switching boost controlling through the ms3pro and also retune for e85 ..


453 rwhp
456 rwtq

[pbonsalb]

You definitely want E85. 93 plus meth is OK but 91 is holding you back.

[DSTX17]

Are you planning on e85/meth/or race fuel? Why else would you build the engine if you were going to leave it at 450?

[m3boost]

Are you planning on e85/meth/or race fuel? Why else would you build the engine if you were going to leave it at 450?

yes e85. I just ordered the boost controller valve from diyautotune

[chikinhed]

The stock exhaust is also going to cause low numbers. Also, a 3” cut out is not a great solution as it isn’t big enough and you’re asking the high velocity exhaust gasses to do an abrupt change in direction out the cut out. Is your WG open dump or tied back into the exhaust? A 3.5” or 4” straight through exhaust would be a big improvement over what you have now.

[someguy2800]

Needs E85, two fuel pumps, 3.5" exhaust, a screamer pipe, and 30 lbs of boost!

[Robocop]

that's really not allot of power is 3'' not enough??

[Mklock]

Hmmm, can't wait for a turn't up run.

[someguy2800]

This group is a bad influence

[NOTORIOUS VR]

Was the boost ramping down because of the boost controller used? It shouldn't taper at all at the boost level (my 4094 runs 13.5-14 psi off the gate - no controller) till redline - ~510whp 4th gear on a DJ.

[chikinhed]

At 426 whp with a SC running 13 psi and stock M3 exhaust with track pipe I was measuring 11 psi of exhaust back pressure measured at the O2 sensor bung. On a turbo engine you would ideally see no back pressure to give the greatest delta P across the turbine.

Here is my theory. The 3” cut out will help but you are giving up a lot and restricting how much you can turn up the boost due to higher combustion chamber temps and intake cross contamination from the exhaust having trouble getting out. The boost taper is probably from the high back pressure giving a lower delta P across the turbine.

Many have had similar set ups with similar results and a big exhaust greatly improved the ‘system’.

[Robocop]

interesting I've been reading that 3'' should be good for 600hp.
can you give a real example on how a 3.5'' or 4'' improved on a 3'' on 450/500hp?

[pbonsalb]

Website may not be secure but if it works:

http://www.superstreetonline.com/how...ust-test-tech/

[chikinhed]

Often people say they have a car that has xxx hp has xxx diameter intake or exhaust. Sure stuff may work but if you are trying to optimize a system to be efficient and get the most hp out of it you need to size all the components appropriately.

You can always check to see if the exhaust size/design is an issue by measuring the back pressure at full boost near redline.

I also tested a bunch of different mufflers that were claimed to have high flow rates and was sadly disappointed.

[m3boost]

My cut out dumps below the driver seat.And Yes, I'm think of replacing it with a 3.5" cutout. Down pipe is 3.5" my two wastegate are reverted back into the exhaust. Tuner said I should be at 700 rwhp with e85 at around 25 psi. I also just received the boost controller valve from diyautotune. It will be controlled by the ms3pro.. Tuner could have squeezed out a little more hp but we decided to leave it at that safe zone since I live in the desert where it gets 115-120 degrees. I will be running e85 most of the time anyways. I remember seeing peak torque at 4400rpm and rpm was stopped at 6400rpm.. It was on a dynopack..

[Robocop]

woah

"Our 3-inch exhaust baseline netted 527 whp at 19 psi.
With the 3.5-inch exhaust, it climbed to 567 whp with a peak gain of 66 whp at 6000 rpm in fourth gear.
At 29 psi, we went from a baseline of 699 to 740 whp.
Peak gains here were 52 whp at 6100 rpm.
The icing on the cake is the fact the turbo spools up a 150-200 rpm quicker with the larger-diameter exhaust."

so just from a 3.5'' exhaust 3'' downpipe...


"at 19psi we hit 610 whp with a peak gain of 52 whp at 7000 rpm from the downpipe alone.
Compared to our baseline, at this boost setting, the entire exhaust system is netting a whopping 103-whp gain"

dude. so they gained 100hp just going full 3.5'' from 3''. Even leaving the downpipe at 3'' is amazing. 3.5'' it is!
looks like it gives it acouple hundred rpm too.

[pbonsalb]

I think what is happening is that while the boost remains the same, the reduction in backpressure from the bigger exhaust means the turbo is spinning faster to create the same restriction through the motor (measured as boost). If this was a supercharged car and the pulley ratio remained unchanged, the boost would drop from the bigger exhaust.

[Robocop]

hey sorry for bringing this up again so if it's just less restriction therefore, less pressure but same power.
just up the boost right? The motor will see the same stress i think at 25psi vs 15psi making the same power.
i'm just trying to wrap my head around it because 3.5'' means 0.5 closer to slamming my shit onto a speedbump also, trigger a cops mating call..

but ya 100hp difference is like say.. 7psi? idk the only issue would be higher intake temps perhaps?
which would also lower hp slightly which would lead u to increase boost. hmm.



then u have this thread where he did a 3.5 vs 3 dyno
no change at over 600hp

https://www.evolutionm.net/forums/ev...exhaust-2.html

[pbonsalb]

In addition to the hotter pressurized air there would be hotter exhaust gas. This means greater risk of detonation and the or the need for more octane. There is more heat and thus more stress. E85 would help since it has more octane and tends to reduce exhaust gas temperature. Efficiency is ideal, but if it’s a matter if spending thousands on fancier parts versus turning the boost up 3 psi, I’d turn the boost up 3 psi.

[chikinhed]

The Evolution link did not specify if the WG was open dump or if it recirculates. It’s a factor which could make the difference between no change and a big change depending on turbo size and boost being run.

[m3boost]

UPDATE...

I just tuned it on e85, actually e60..684rwtq and 681rwhp at 24 psi... peak torque at 4400rpm..hp is dropping after 5700 rpm. Tuner stated my exhaust is restrictive. He told me to get the 3.5" cutout and some ID1300's for next time. Tune was done with blend tables VE, Ign, and Boost.

[Robocop]

godam does 680 not satisfy u?

[m3boost]

godam does 680 not satisfy u?

yes it does, just want to fix the top end drop off. Tuner said I would have no problems hitting 700 rwhp as is on a cooler time.

[chikinhed]

godam does 680 not satisfy u?

As with everything, you get use to it. That said, chasing numbers is also fun.

Nice results! Get a bigger exhaust and get back on the dyno.

[pbonsalb]

As with everything, you get use to it. That said, chasing numbers is also fun.
.

Also expensive. The second 200rwhp costs about as much as the first 200rwhp addition.