Question about limiting boost....
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,683
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Question about limiting boost....
on a supercharged Vette. I am starting to see 10+psi now that it's getting colder and I *really* don't want to grenade my motor.... just yet! 
Could a wastegate controller from a turbo system somehow be used to set a limit to boost pressure on my D1-SC blown car?
I have had my oil dipstick go POP two times this week due to excessive boost, I'd really like to correct this over-boosting situation before something seriously bad happens.
Any suggestions??
Could a wastegate controller from a turbo system somehow be used to set a limit to boost pressure on my D1-SC blown car?
I have had my oil dipstick go POP two times this week due to excessive boost, I'd really like to correct this over-boosting situation before something seriously bad happens.
Any suggestions??
Team Owner
Joined: Jul 2002
Posts: 37,048
Likes: 69
From: This city NEVER sleeps! Frank's back yard!
Originally Posted by dads01dream
on a supercharged Vette. I am starting to see 10+psi now that it's getting colder and I *really* don't want to grenade my motor.... just yet!
Could a wastegate controller from a turbo system somehow be used to set a limit to boost pressure on my D1-SC blown car?
I have had my oil dipstick go POP two times this week due to excessive boost, I'd really like to correct this over-boosting situation before something seriously bad happens.
Any suggestions??
Could a wastegate controller from a turbo system somehow be used to set a limit to boost pressure on my D1-SC blown car?
I have had my oil dipstick go POP two times this week due to excessive boost, I'd really like to correct this over-boosting situation before something seriously bad happens.
Any suggestions??
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,683
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I have the A&A kit installed by ECS, we're using the largest available pulley now. During the summer my boost was just fine, but now with the colder air the D1 is simply producing too much boost. :o
Intermediate
Joined: Aug 2004
Posts: 25
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From: AZ
When using this method to limit boost on a supercharger you use a pop off valve. This is a little different from a blow off valve (BOV) in that a BOV is only meant to open when the throttle plate is closed to relieve pressure between TC/SC and throttle plate. A pop off valve you would not run a vacuum source to the top, it's only held closed by spring pressure. You adjust this spring pressure to give you the desired pop off boost level. The advantage to this method on a SC is you can use a smaller pulley to get you more boost sooner in the RPM band but then relieve the excess pressure you don't want on the top end.
Kevin
Kevin
Instructor
Joined: Sep 2004
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Originally Posted by dads01dream
I have the A&A kit installed by ECS, we're using the largest available pulley now. During the summer my boost was just fine, but now with the colder air the D1 is simply producing too much boost. :o
HMMM, I would contact A&A and see what he has to say about that. I am not sure the above idea (BOV) will be in expensive.
Team Owner
Joined: Jul 2003
Posts: 20,474
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From: Detroit
I wouldn't step up the pulley size - as soon as it gets warm again and your boost drops your going to want the smaller pulley back.
We are both in the same situation as far as wanting to at least maintain our current hp levels while running lower boost.
All I've been able to come up with:
-- LT's (which you already have)
-- Reduce your RPM - max it at 5800 instead of 6300 for example.
-- Better flowing heads - larger CC's - lower compression.
Cheers,
Mark
We are both in the same situation as far as wanting to at least maintain our current hp levels while running lower boost.
All I've been able to come up with:
-- LT's (which you already have)
-- Reduce your RPM - max it at 5800 instead of 6300 for example.
-- Better flowing heads - larger CC's - lower compression.
Cheers,
Mark
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Melting Slicks
Joined: Jan 2003
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Originally Posted by blownchevy
The pulley is easy and cheap. Why would you not swap back and forth. 30 min install, MAX. drop it 2 psi and throw some timing at it.
. But you get the drift. The only thing you can do is slow down the blower.
Thread Starter
Melting Slicks
Joined: Apr 2002
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Well, the problem I have is we're already using the LARGEST pulley on there (I believe it's 4.5"). Short of making a custom 4.75" or 5" and absoluting KILLING my power production.... there's got to be a way of rigging up some sort of electronic/progressive wastegate controller??
Unfortunately, I just haven't got a clue how to do it OR if it'll even work for that matter. I've got to think the issues of pressure dissipation whether it be with a turbo or blower are the same... at least I hope! If I'm correct, then maybe some "Ricer kid" out there knows how to make me effectively reduce my boost and then CRANK'ER UP again as desired. Anybody know someone that owns a Supra?
Heck, I may even be able to go with that smaller pulley somebody mentioned above if this can be done?? Any other thoughts? Maybe our TT brothers on this Forum could give me some suggestions?
Thanks guys!
Oh, one more thing.... I like your idea Mark about putting on some different heads!!! Yet another good reason/excuse to modify the Vette.
Unfortunately, I just haven't got a clue how to do it OR if it'll even work for that matter. I've got to think the issues of pressure dissipation whether it be with a turbo or blower are the same... at least I hope! If I'm correct, then maybe some "Ricer kid" out there knows how to make me effectively reduce my boost and then CRANK'ER UP again as desired. Anybody know someone that owns a Supra?
Heck, I may even be able to go with that smaller pulley somebody mentioned above if this can be done?? Any other thoughts? Maybe our TT brothers on this Forum could give me some suggestions?
Thanks guys!
Oh, one more thing.... I like your idea Mark about putting on some different heads!!! Yet another good reason/excuse to modify the Vette.
Last edited by dads01dream; Nov 17, 2004 at 11:56 PM.
Team Owner
Joined: Jul 2003
Posts: 20,474
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From: Detroit
Originally Posted by dads01dream
... I like your idea Mark about putting on some different heads!!! Yet another good reason/excuse to modify the Vette.
. Sounds like you might need the AFR 225's and an ECS alky kit - for safety purposes only . Mark
Last edited by mdhmi; Nov 18, 2004 at 12:56 AM.
Team Owner
Joined: Jul 2002
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From: This city NEVER sleeps! Frank's back yard!
Originally Posted by dads01dream
Gee... how about a useful suggestion? 
Remove the supercharger?
I know, I know - tell your wife how much you've spent, and she'll hammer one of her heels into the intake plumbing, thus limiting the boost indefinitely!!
Drifting
Joined: Nov 2002
Posts: 1,587
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From: Colorado Springs CO
I would say try some 6.0L heads, go with a thicker gasket to decrease compression ratio even further. Plus you dont have to rev it up to redline, maybe short shift the car during the cold days.
Melting Slicks
Joined: Mar 2002
Posts: 2,931
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From: Tx
Originally Posted by DDSLT5
Remove the supercharger?
I know, I know - tell your wife how much you've spent, and she'll hammer one of her heels into the intake plumbing, thus limiting the boost indefinitely!!
I know, I know - tell your wife how much you've spent, and she'll hammer one of her heels into the intake plumbing, thus limiting the boost indefinitely!!
I know it sounds too simple, but I think it will work. I took off my BOV once when I only had a 1.5" or so flange on it and I still made decent boost.
Burning Brakes
Joined: Feb 2001
Posts: 892
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From: Houston Texas
Originally Posted by dads01dream
Well, the problem I have is we're already using the LARGEST pulley on there (I believe it's 4.5"). Short of making a custom 4.75" or 5" ...:
Le Mans Master
Joined: Apr 2000
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The problem with using a BOV/Wastegate type setup with a supercharger is that when you run a small pulley and then let off the boost without using it, you continue to have the parasitic horsepower loss of driving the blower off the crank.
All of the extra power to drive the supercharger is wasted and is a constant drag on the system. Also increases intake temperatures negatively.
Boost leaks may throw your tune off as too rich if the air has been metered by the MAF already.
All of the extra power to drive the supercharger is wasted and is a constant drag on the system. Also increases intake temperatures negatively.
Boost leaks may throw your tune off as too rich if the air has been metered by the MAF already.
Last edited by MelloYellow; Nov 18, 2004 at 02:33 AM.
Thread Starter
Melting Slicks
Joined: Apr 2002
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Thanks Quick.... I'll look into your suggestion & discuss it with Doug or Chris @ ECS (I've got an alky kit to order today!!!).
Thanks Av8ter.... I'll measure my pulley to see *exactly* what's on there. I asked Andy @ A&A for the biggest pulley to really limit boost, I "thought" he mentioned to me it was a 4.5" size.
Thanks Yani & mdhmi.... The idea of using bigger heads and thicker gaskets really makes a TON of sense! Both for increased power production and safety.
To DDSLT5.... The only time that blower is going to come off is to install my new forged motor!!! Of course, then the blower would be put RIGHT BACK ON!!!!
Does anyone have some thoughts about how to stop my oil dipstick popping issues? Thanks!
Thanks Av8ter.... I'll measure my pulley to see *exactly* what's on there. I asked Andy @ A&A for the biggest pulley to really limit boost, I "thought" he mentioned to me it was a 4.5" size.
Thanks Yani & mdhmi.... The idea of using bigger heads and thicker gaskets really makes a TON of sense! Both for increased power production and safety.
To DDSLT5.... The only time that blower is going to come off is to install my new forged motor!!! Of course, then the blower would be put RIGHT BACK ON!!!!
Does anyone have some thoughts about how to stop my oil dipstick popping issues? Thanks!
Pro
Joined: Aug 2002
Posts: 570
Likes: 1
From: Las Colinas, Texas
Thanks Yani & mdhmi.... The idea of using bigger heads and thicker gaskets really makes a TON of sense! Both for increased power production and safety.
Does anyone have some thoughts about how to stop my oil dipstick popping issues? Thanks![/QUOTE]
Do more research before you use thicker gaskets as was done in the OLD days. Different burn pattern and flame front in these motors and added space between top of piston and head is all part of a design marriage.
I am using a spring to hold my dipstick in place with no problems.
Does anyone have some thoughts about how to stop my oil dipstick popping issues? Thanks!
[/QUOTE]Do more research before you use thicker gaskets as was done in the OLD days. Different burn pattern and flame front in these motors and added space between top of piston and head is all part of a design marriage.
I am using a spring to hold my dipstick in place with no problems.