Upping the Boost on my VF SC'd 540. Testing the Failure Limits of the Stock M62?

[philly98540]

Hey Guys,
New spring project for my 540!! I've been happy with my VF kitted 540, and the car runs very good, but I've been wanting to try some more boost. I can't seem to stop messing with a good thing I guess, and the extra power will add some more fun and hopefully not too much misery.

The issue with the VF kit, and a lot of other supercharger kits, is they are designed for low boost, in the 6-9 psi range typically. One of the limiting factors of these kits, among other things, is the pulley and belt drive set-up. The VF kit comes with a 6 rib drive belt and a 6" dia crank pulley. The easy way to get some more boost is to reduce the SC pulley size. This increases the SC'er RPM's and you get more boost. Most of the VF guys here have all reduced to the 3.25" SC pulley and have had good success. If you reduce your SC pulley size too small, the boost goes up even more, and the belt will slip as it has less belt wrap on that really small SC pulley.

The best way to combat this is to go with a larger diameter crank pulley and an 8 rib belt. This allows you to maintain a larger SC pulley and get plenty of belt wrap and grip. This is the best way, but requires a custom 8 rib crank pulley and the re-location of the radiator expansion tank to allow the belt to fit. Not a horrible amount of work, but I'm going to try something easier first.

My goal is to reduce the SC pulley from 3.25" to 2.87" dia. To get the needed grip on this little pulley, my plan is to fabricate an adapter plate so I can mount an additional idler pulley to get increased belt wrap. To get the idler to fit, I need to relocate a new auto belt tensioner nearer the crank that rotates CCW to tension the belt.

I've been designing and collecting parts for the past couple of weeks, and working on this for a couple of nights. I installed the prototype last night.
Here is a vid of the first start-up.


I did some drives this morning, on the way to work! All I can say is WOW! I was hitting 15 psi, but AFR's were a bit too high, so had to pull off! Still need to do the larger injectors and a re-tune, so this was just a quickie test. So far so good on this step!

I'll be posting up some details later for anyone else that may want to go this route.

[JimLev]

Looks like a good mod. What RPM is that VF good for?
So when ya adding the 7" crank pulley, you know you want to.

[Plattus1000]

Neat mod, mod. Looking forward to injectors and a tune.

[BMW540san]

That ape is really screaming now. Can't leave it alone, can you.

[philly98540]

Looks like a good mod. What RPM is that VF good for?
So when ya adding the 7" crank pulley, you know you want to.

The Vortech V3 Si is rated for 52000 RPMs. With the new 2.87" pulley, I'll be right at that limit at my current 6800 RPM rev limiter setting. Lots of guys over-rev them though without much issue. I talked to Vortech, they say the bearings are what fails early if you over rev them too much. I'll only be hitting the limit for a brief moment, so I hope it will be fine.

If this current set up pans out to be reliable and not slip, (so far so good...) I'll be keeping the 6" crank pulley. I actually bought a 8 rib 6.88" crank pulley made for a Mustang set up, that I was going to machine to mate up with my VF crank pulley, but I decided to take this lazier route. The bigger crank pulley would have been nicer though.

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Neat mod, mod. Looking forward to injectors and a tune.

Thanks. I need to get in touch with TTFS and get a tune scheduled. Bad thing is its busy season for car tuning. I'll be lucky to get in there before summer.

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That ape is really screaming now. Can't leave it alone, can you.

I think I have a problem.

[Mach540]

Why don't they make cogged drive belts for these things, like an NHRA dragster?

Would be pretty simple to modify a timing belt for this purpose.

[jstern]

Very nice mod. Congrats!

I want to install a smaller pulley on my car but haven't had the time for that or to get back to TTFS-a 500 mile one way trip for me.

[joekitch]

interesting
although a solution to the expansion tank clearance issue is to get one of those aluminum welded expansion tanks from zionsville
not sure if they sell that separate from their radiator+electric fan though...

really curious to see if there's such a thing as too much boost on the m62, i've basically never heard of someone blowing their motor but m62 owners tend to baby their stuff for good reason

but if it blows up....hey...s62 swap time!

[dovlet]

Wau, it is amazing and awesome

[ColtonBH]

Looking forward to a dyno pull once this thing is tuned!

[dk500]

I guess all that is left now is to intercool it for even moar powa

[DrCharles]

I guess all that is left now is to intercool it for even moar powa

Plumbing would be simpler (and cheaper) to use water/methanol injection...

So now you have a way of getting just about 100% more air (1 atm boost) into your engine. Sounds great so far. But how are you going to double your fuel?
Is the fuel pump and its wiring, the fuel lines, etc. large enough to supply double the original volume while raising the line pressure by 15 psi?

[mcgnms]

Why don't they make cogged drive belts for these things, like an NHRA dragster?

Would be pretty simple to modify a timing belt for this purpose.

Dangerous.

[philly98540]

Very nice mod. Congrats!

I want to install a smaller pulley on my car but haven't had the time for that or to get back to TTFS-a 500 mile one way trip for me.

Let me know if you passing by if you decide to do it. I'd like to check out your car.

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interesting
although a solution to the expansion tank clearance issue is to get one of those aluminum welded expansion tanks from zionsville
not sure if they sell that separate from their radiator+electric fan though...

really curious to see if there's such a thing as too much boost on the m62, i've basically never heard of someone blowing their motor but m62 owners tend to baby their stuff for good reason

but if it blows up....hey...s62 swap time!

Yeah, one of the aftermarket X-tanks or possibly the E30 that Dinan used seems like a viable choice. Not sure if Zionsville sells theirs separate.

And not hearing of these blowing up either, but I've not seen a stock block M62 at this boost yet, so who knows.

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Looking forward to a dyno pull once this thing is tuned!

I'll be getting one for sure!!

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Plumbing would be simpler (and cheaper) to use water/methanol injection...

So now you have a way of getting just about 100% more air (1 atm boost) into your engine. Sounds great so far. But how are you going to double your fuel?
Is the fuel pump and its wiring, the fuel lines, etc. large enough to supply double the original volume while raising the line pressure by 15 psi?

I have meth injection already, so all set there. I may up the nozzle sizes. I also put in a high volume fuel pump so that should be good for this power.

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Dangerous.

Yup!

[mcgnms]

Have you considered an intake mounted wastegate to bleed out after say 12 PSI? That way you can get better midrange without blowing your manifold potentially. And it would double up as a BPV to prevent spikes on throttle release.

[topaz540i]

in the off chance you find the limits off the stock engine, as the thread title suggests, and it blows up I call dibs on the s.c.'er

[Clark49660]

philly , Nice mod. Sounds wicked. Who makes that belt

[philly98540]

Have you considered an intake mounted wastegate to bleed out after say 12 PSI? That way you can get better midrange without blowing your manifold potentially. And it would double up as a BPV to prevent spikes on throttle release.

I likely need a better valve. We will see how it goes. I would think the mani will be fine at 15 or so psi.

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in the off chance you find the limits off the stock engine, as the thread title suggests, and it blows up I call dibs on the s.c.'er

I'm hoping it will be fine but we will see. You would need a different charge pipe for your TU.

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philly , Nice mod. Sounds wicked. Who makes that belt

Tks. Belt is Gates Fleet liner green stripe. Not a fan of the green really, but it's a very good belt.

[JimLev]

So when you going to slap on an 75 shot of juice?
I've got a spare intake manifold that it drilled and tapped with fitting for 8 injectors.

[mcgnms]

I likely need a better valve. We will see how it goes. I would think the mani will be fine at 15 or so psi.

I hope so. Other kits out there are going with heavy duty metal manifolds at boost levels even before this. You will be the guinea pig of course. I very much would like to go this route, but crank pulley instead. I have calculated the size of crank pulley I need to match the same supercharger RPM I have now back on my 3.8'' pulley which I would gladly reuse.

[philly98540]

So when you going to slap on an 75 shot of juice?
I've got a spare intake manifold that it drilled and tapped with fitting for 8 injectors.

A nice 75 would really fill out the 2-3K rpm range, but I'd just be buying more tires me thinks! With the smaller pulley, I can feel the boost come on sooner, so i think it will be pretty good overall once I get the new injectors and tune.

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I hope so. Other kits out there are going with heavy duty metal manifolds at boost levels even before this. You will be the guinea pig of course. I very much would like to go this route, but crank pulley instead. I have calculated the size of crank pulley I need to match the same supercharger RPM I have now back on my 3.8'' pulley which I would gladly reuse.

I think the mani will be fine. Fingers crossed! Going bigger crank pulley is a better way, but this seems to be doing great and is much less work. Looking forward to what you come up with. I'll be posting some details of the bracket and hardware soon, if you want to copy.

[Zep]

Really like the sound of this and certainly keen for further details.

I only just received the tune file from Frank for the 3.25" pulley but am still anticipating pushing the boost further.

[jstern]

Let me know if you passing by if you decide to do it. I'd like to check out your car

Would be happy to stop by but I don't think it will be til next year. Nancy and I are about to open our Bakery for the last year and then it will be retirement on Dec. 24. We have wanted to take a trip South for a while. Hope I have the $ and time to do it.

[geargrinder]

Lookin good you crazy frakkin whackjob. Can't wait to see it / try it in person. Get on the horn to Frank and get him to shoehorn you in. The longer you wait the longer his spring backlog will be and the more you'll be tempted to hammer it and blow something up by mistake.

interesting
although a solution to the expansion tank clearance issue is to get one of those aluminum welded expansion tanks from zionsville

As Chris said - the way to go that a lot of the S62 blower guys do is an outboard 3er tank mounted on the left (drivers) side fender area. I think you'd still be pretty tight w/ the ZV tank and really it woudl be great to get more room there. That exp tank is the bane of us S/C guys existence.

Have you considered an intake mounted wastegate to bleed out after say 12 PSI? That way you can get better midrange without blowing your manifold potentially. And it would double up as a BPV to prevent spikes on throttle release.

Again macjgrznmf... superchargers DON'T HAVE WASTEGATES. Wastgates BLEED EXHAUST for turbos, not boost.
I know other wrong people use the term wrongly but you'd rather be on the side of actual correctness, right?
What you mean is a controllable BPV or BOV setup. Pedantry out of the way it's an interesting idea. The only way to get 'boost shaping' w/ a S/C is with something like that and some factory S/C setups have them - servo PWM controlled BPV that can pull boost down... of course then you need a boost controller - BUT - if you can sort out actuation, you could probably use an outboard boost controller made for turbo setups - there are some very cool very slick ones out there. Noodling it around I don't htink you can use the existing BPV without tangling in various complications and endangering its "base" function of off-throttle boost recycling so you'd need to rig up a secondary system I think? Plus you'd worry about fail-safe stuff like what happens if you have a failure of the BPV/BOV system and overboost. But a fun thing to noodle about.

I don't think he has anything to worry about re: the manifold - wendell was making turbo grade boost into the OEM setup and never blasted it out... its not like the S62 plenum that's a clamshell with lots and lots of holes in it and lots of places that weren't designed for boost - being a big monoblock of plastic for the most part really is to our advantage I think...

I want to install a smaller pulley on my car but haven't had the time for that or to get back to TTFS-a 500 mile one way trip for me.

Would be happy to stop by but I don't think it will be til next year. Nancy and I are about to open our Bakery for the last year and then it will be retirement on Dec. 24. We have wanted to take a trip South for a while. Hope I have the $ and time to do it.

Hey I still got pie credits in the bank! Can't wait to head up for an early season item. ;^)

If you do think about the roadtrip lemme know would be fun to have New Englander day at TTFS...

[mcgnms]

Again macjgrznmf... superchargers DON'T HAVE WASTEGATES. Wastgates BLEED EXHAUST for turbos, not boost.
I know other wrong people use the term wrongly but you'd rather be on the side of actual correctness, right?
What you mean is a controllable BPV or BOV setup. Pedantry out of the way it's an interesting idea. The only way to get 'boost shaping' w/ a S/C is with something like that and some factory S/C setups have them - servo PWM controlled BPV that can pull boost down... of course then you need a boost controller - BUT - if you can sort out actuation, you could probably use an outboard boost controller made for turbo setups - there are some very cool very slick ones out there. Noodling it around I don't htink you can use the existing BPV without tangling in various complications and endangering its "base" function of off-throttle boost recycling so you'd need to rig up a secondary system I think? Plus you'd worry about fail-safe stuff like what happens if you have a failure of the BPV/BOV system and overboost. But a fun thing to noodle about.

Again, GearGrinder, superchargers CAN use wastegates. Wastegates are typically used to bleed exhaust turbochargers, but you can also mount them intake side. When I said wastegate, I really did mean wastegate such as a Tial MV-R or something of the sort. I'd rather sound exactly how I worded what I said. You can call it whatever in the world suits you. A modified BOV? Fine. Makes no difference.

Mounting a wastegate on the intake side where the discharge is and referencing it just like a normal wastegate setup to you guessed it...the intake discharge would work. It work good and far easier than the concoction you just described.

The wastegate would also double up as an anti-spike BPV. On WOT it would bleed out anything over X PSI and when you drop the throttle it would also open at that X PSI and help prevent spikes.

So for example you can mount the MV-R (Tial, the people who made it call it a wastegate, but I'll call it a BPV for you) and the reference port on it would unlike a normal BPV go infront of the throttle. Then you would obviously need to recirculate it back just like the original BPV. But now you have a pressure-only activated bleed system that will work both on and off throttle.

This has been used before and for the exact same setups, overdriven Centrifugals with amazing success. Its just a giant fuel-pressure regulator except for air never allowing pressure in the discharge to get over a certain PSI regardless of throttle opening.