Low Boost?
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Race Director
Joined: Jan 2006
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Low Boost?
Was at a friends garage yesterday, and planned to dyno my car. Turns out, that after we had the car loaded and strapped down, he encountered a software issue and the computer would lock up, without recording any data. Anyway, we had a boost guage hooked up and I was very dissapointed to see only 4 pounds of boost. We thought it might be the guage, tried a different one, same results. We checked all couplers, T-bolt clamps, everything, and could not find any evidence of leakage. Also, no evidence of belt slippage. The installation has about 2k miles on it. The car runs fine, just low boost. I was expecting 6 pounds. Its a PS1 ProCharger. Any ideas from you guys is appreciated.
Racer
Joined: Jan 2006
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From: New York NY
I had the same issue I noticed only 3psi but I really should be making 7psi because i have a smaller pulley. Spoke with procharger and they said if you have exhaust and headers you lose 2-3 pounds of boost. Didn't seem right to me so i had my tuner, tighten everything up, the belt, bolts, move the intercooler back for more airflow and now I make around 5-6 psi at WOT.
If you are running headers, or exhaust you might lose 1-2 pounds of boost that's what I heard. If you are only running 3psi your belt might be slipping at higher rpms..
If you are running headers, or exhaust you might lose 1-2 pounds of boost that's what I heard. If you are only running 3psi your belt might be slipping at higher rpms..
Racer
Joined: Dec 2005
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From: Phoenix AZ
My Procharged car has experienced the same occasional lack of boost at higher power levels (higher rpm). Belt slippage, tightness, is an issue at due to the higher force required to turn the s/c at high rpms. I find I need to monitor belt tightness often because of slip detected during dyno runs. If kept tight the slippage, and consequent loss of power, can be avoided. Gatorback belts seem to hold up well.
Thread Starter
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Didn't think of the headers. I'm running 1 7/8 DynaTech's. Bet that's, at least, part of what's happening here. So, does that mean cars without headers make more boost, thus more horsepower? I think the motor will live with 8 pounds. What size pulley will I need for this level of boost? Could it be that the original BOV (it looks like it is adjustable?) is set to dump boost on anything above 4 pounds? Thanks.
Burning Brakes
Joined: Jul 2005
Posts: 779
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From: Bloomingdale Illinois
Didn't think of the headers. I'm running 1 7/8 DynaTech's. Bet that's, at least, part of what's happening here. So, does that mean cars without headers make more boost, thus more horsepower? I think the motor will live with 8 pounds. What size pulley will I need for this level of boost? Could it be that the original BOV (it looks like it is adjustable?) is set to dump boost on anything above 4 pounds? Thanks.
It's very possible it's your BOV
I just sold my HKS SSQ BOV to a person experiencing the same problem, loosing boost.
That is what it was .The Procharger BOV was leaking .His boost is back up to normal.
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Racer
Joined: Jan 2006
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From: rochester michigan
I also noticed my boost go up after replacing the bov, I went with the hks-ssqv and I'm seeing 5lbs. boost with 1-7/8 headers and big bollas mod #2.
Safety Car
Joined: Aug 2006
Posts: 4,347
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From: Apache Junction AZ
Didn't think of the headers. I'm running 1 7/8 DynaTech's. Bet that's, at least, part of what's happening here. So, does that mean cars without headers make more boost, thus more horsepower? I think the motor will live with 8 pounds. What size pulley will I need for this level of boost? Could it be that the original BOV (it looks like it is adjustable?) is set to dump boost on anything above 4 pounds? Thanks.
BJK
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Racer
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From: Gahanna Ohio
Former Vendor
Joined: May 2006
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From: Houston TX
Your problem is a very simple fix. Change the pulley to get the boost level back up.
Burning Brakes
Joined: Jul 2005
Posts: 779
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From: Bloomingdale Illinois
Didn't think of the headers. I'm running 1 7/8 DynaTech's. Bet that's, at least, part of what's happening here. So, does that mean cars without headers make more boost, thus more horsepower? I think the motor will live with 8 pounds. What size pulley will I need for this level of boost? Could it be that the original BOV (it looks like it is adjustable?) is set to dump boost on anything above 4 pounds? Thanks.
Did you observe your boost level before the dynatech header installation ?
The Procharger BOV's do leak though,keep an eye on it. The butterfly design is not the best way to seal the valve.
I had a boost peak of 13 psi with the Procharger BOV I used for 4 months.
Then I put on the HKS SSQ BOV .The peak boost jumped to 14psi.
I then put the 52mm BOV from Turbo smart boost stayed at 14psi.
I was loosing 1psi with the Procharger BOV at high boost levels.
Like I said in my earlier post ,the forum member I sold my BOV to lost 2psi of boost through his faulty butterfly style Procharger BOV. The HKS unit put his boost back up to 6psi.
If you lost boost due to the header install it's OK as stated in above post by Razrback16.
The engine is just pumping more air out because it has less restriction. It's more efficient.
Now you can raise the boost back up to 6psi with a smaller pulley do a dyno test and see the power gain.
6psi w/o headers = xxx rwhp
6psi w/headers = xxx rwhp
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Thread Starter
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No, I installed the headers actually several months prior to installing the PS1, so I don't have any data. Is the BOV that ProCharger supplies a 52mm unit. I will try another BOV. I'd like to buy it, get it in, then swap them in the same afternoon. Also, could use a suggestion on which one and where to buy. Funds are not an issue, just want a good BOV that I can install and forget. Thanks. 
Safety Car
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From: Apache Junction AZ
No. What you have to understand about forced induction is that theoretically you want to run lower boost, it's better for the motor, but the only way to run less boost and still make tons of power is to make the motor more efficient, ie. better flowing heads/intake/exhaust, etc. These things will allow the motor to make more horsepower but with less boost and this is also healthier for the motor as with less boost you have less cylinder pressure. Think of your entire engine setup as one big air pump -- the more air you can get in and out of it, and the more efficient you can do it, the more power you can make, and if you can do it with less backpressure (because all boost is, is a measure of pressure building up at the intake because the motor can't digest it fast enough; if you get a better flowing set of heads and intake, the boost level drops because the motor is digesting the air faster so the pressure can't build up), it's better for all components.
What he said.
BJK
Safety Car
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From: Kuwait
No. What you have to understand about forced induction is that theoretically you want to run lower boost, it's better for the motor, but the only way to run less boost and still make tons of power is to make the motor more efficient, ie. better flowing heads/intake/exhaust, etc. These things will allow the motor to make more horsepower but with less boost and this is also healthier for the motor as with less boost you have less cylinder pressure. Think of your entire engine setup as one big air pump -- the more air you can get in and out of it, and the more efficient you can do it, the more power you can make, and if you can do it with less backpressure (because all boost is, is a measure of pressure building up at the intake because the motor can't digest it fast enough; if you get a better flowing set of heads and intake, the boost level drops because the motor is digesting the air faster so the pressure can't build up), it's better for all components.
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Hmmm. So, if pressure in the manifold is a measure of boosted air that the engine can't digest, then why does increasing that pressure, beyond that of which the engine can use, increase power? I think pressure in the manifold is a measure of the air avilable to the cylinders, when the intake valve opens. The more pressure (avilable air), the more power. More pressure in the intake, more is forced into the cylinder.
Racer
Joined: Aug 2005
Posts: 297
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From: Gahanna Ohio
Hmmm. So, if pressure in the manifold is a measure of boosted air that the engine can't digest, then why does increasing that pressure, beyond that of which the engine can use, increase power? I think pressure in the manifold is a measure of the air avilable to the cylinders, when the intake valve opens. The more pressure (avilable air), the more power. More pressure in the intake, more is forced into the cylinder.
If you take "Car X" which has a stock exhaust and say a 4.00'' pulley on the blower and it makes 15lbs of boost and it makes XXXrwhp then add a set of really well flowing longtube headers, the boost levels may drop a few psi but your horsepower is going to go up because it's flowing more air with less heat in the cylinders, and less heat = less timing pulled which results in more power. The key here is that it's not the amount of boost/pressure that makes the power in your setup, it's the volume of air. By adding longtubes you're not decreasing the volume of air processed, you're just allowing the motor to get rid of it quicker out the exhaust valves which is resulting in less back pressure. It's just that normally boost (psi) coincides with volume since most people just swap to a smaller pulley to make more boost which pumps more air which makes more power due to more volume of air.
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I'm really having a hard time understanding why my car is down on HP. The engine is ProCharged with a PS-1 and 4.25" pulley, Dynatech 1 7/8" headers, X-pipe, Corsa Sport, Miezere electric water pump, Typhoon intake manifold, 55 pound Marren injectors (flowed and balanced), Ron Davis 57mm radiator, oil cooler and a good tune. Yet it's only making 450 rwhp at 5 psi. These are supposedly corrected figures. It was very hot the other day. IAT were over 100. A/F was at 11.7 @ WOT and the engine enjoy full timing advance thru the entire pull. Other cars are pushing over 525 hp with basically the same set-up. I think I'm snake-bit!
j/k
Racer
Joined: Aug 2005
Posts: 297
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From: Gahanna Ohio
I'm really having a hard time understanding why my car is down on HP. The engine is ProCharged with a PS-1 and 4.25" pulley, Dynatech 1 7/8" headers, X-pipe, Corsa Sport, Miezere electric water pump, Typhoon intake manifold, 55 pound Marren injectors (flowed and balanced), Ron Davis 57mm radiator, oil cooler and a good tune. Yet it's only making 450 rwhp at 5 psi. These are supposedly corrected figures. It was very hot the other day. IAT were over 100. A/F was at 11.7 @ WOT and the engine enjoy full timing advance thru the entire pull. Other cars are pushing over 525 hp with basically the same set-up. I think I'm snake-bit!
Safety Car
Joined: Aug 2006
Posts: 4,347
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From: Apache Junction AZ
Hmmm. So, if pressure in the manifold is a measure of boosted air that the engine can't digest, then why does increasing that pressure, beyond that of which the engine can use, increase power? I think pressure in the manifold is a measure of the air avilable to the cylinders, when the intake valve opens. The more pressure (avilable air), the more power. More pressure in the intake, more is forced into the cylinder.
BJK
