lost 60 WHP !!!!
Thread Starter
Racer
Joined: Jun 2008
Posts: 370
Likes: 0
From: Somewhere in Portland,OR
lost 60 WHP !!!!
Alright guys i don't know whats going on but i lost somewhere around 60 WHP !!!
My car used to be 570 whp with 8.9 psi thru an A&A kit.
Now i got my car on the dyno and i got little over 500 whp and 7.4 psi which less than i used to be
But i did couple of changes that might caused this problem.
1. I installed A&A bigger supercharger inlet ( Dongle )
2. Changed and moved the Blow off valve on top of the intercooler.
Blow off valve is Tial 50mm with 7 psi spring used to be 3 psi but it idle better with 7 psi spring
I went to Tom at Wung performance shop and he said that my fuel is off and he tweaked it so its not as bad as it used to be and he added more timing to get it back to where is used to be.
He said that that my fuel doesn't want to stay stable at idle and blow off valve might be the reason and i still have a surge but not as bad as it was before.
But still how did i lose 2 psi is cause of the blow off valve
My car used to be 570 whp with 8.9 psi thru an A&A kit.
Now i got my car on the dyno and i got little over 500 whp and 7.4 psi which less than i used to be
But i did couple of changes that might caused this problem.
1. I installed A&A bigger supercharger inlet ( Dongle )
2. Changed and moved the Blow off valve on top of the intercooler.
Blow off valve is Tial 50mm with 7 psi spring used to be 3 psi but it idle better with 7 psi spring
I went to Tom at Wung performance shop and he said that my fuel is off and he tweaked it so its not as bad as it used to be and he added more timing to get it back to where is used to be.
He said that that my fuel doesn't want to stay stable at idle and blow off valve might be the reason and i still have a surge but not as bad as it was before.
But still how did i lose 2 psi is cause of the blow off valve
Thread Starter
Racer
Joined: Jun 2008
Posts: 370
Likes: 0
From: Somewhere in Portland,OR
Thread Starter
Racer
Joined: Jun 2008
Posts: 370
Likes: 0
From: Somewhere in Portland,OR
But i do a compression test.
I checked and to be exactly accurate its 1.1 psi is what i lost and the shop thinks that the blow off valve is disturbing the airflow cause i didn't have this problem before i did the change
This new blow off setup
Former Vendor
Joined: Jul 2008
Posts: 4,327
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From: Oxnard SoCal www.aacorvette.com www.superchargersuperstore.com
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Racer
Joined: Jul 2009
Posts: 431
Likes: 0
From: Long Island NY
keep something in mind. Boost is just a level of restriction, so by changing some parts, especially with a better flowing part, can reduce boost. With such a change, you should be near the same power levels, if not better, with lower boost.
as far as the power, as mentioned, was it the same dyno? were the correction factors applied? so many variables from dyno to dyno, even on the same dyno, that the best test would be ET & MPH at the track.
as far as the power, as mentioned, was it the same dyno? were the correction factors applied? so many variables from dyno to dyno, even on the same dyno, that the best test would be ET & MPH at the track.
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
If he made an exhaust or even cam change then I could see losing boost bust still gaining power but increasing the efficiency of the intake should only serve to increase boost if anything.
I'd pressurize the intake (disconnect the BOV and give it some RPM's) and spray some soapy water around any couplings, the new BOV flange and piston, etc.
I'd pressurize the intake (disconnect the BOV and give it some RPM's) and spray some soapy water around any couplings, the new BOV flange and piston, etc.
Thread Starter
Racer
Joined: Jun 2008
Posts: 370
Likes: 0
From: Somewhere in Portland,OR
keep something in mind. Boost is just a level of restriction, so by changing some parts, especially with a better flowing part, can reduce boost. With such a change, you should be near the same power levels, if not better, with lower boost.
as far as the power, as mentioned, was it the same dyno? were the correction factors applied? so many variables from dyno to dyno, even on the same dyno, that the best test would be ET & MPH at the track.
as far as the power, as mentioned, was it the same dyno? were the correction factors applied? so many variables from dyno to dyno, even on the same dyno, that the best test would be ET & MPH at the track.
He thinks it the blow off valve. I like to know what guys with Tial blow off valve do or did or if they why faced the same problem.
I thinking that the i am bleeding boost cuz of the blow off valve and i already tried 3 different spring setup.
3 psi was recommended by Tial which was the worst surggge at idle.
9 psi was good but the blow off vale didnt bleed at idle at all but better idle.
7 psi installed now but open half way at idle still surgges and thats when dynoed the car with the results.
11 psi spring which i never tried yet but i think it too much but might try cutting that till the blow off starts bleeding only at idle.
Burning Brakes
Joined: Dec 2006
Posts: 1,165
Likes: 1
From: Houston TX
I would not think the BOV on the intercooler would have an effect on the idle. It's a good distance from the MAF. Now if it were on the charge pipe, that's a different story.
I would run the -3psi or -6psi. I run the -6psi spring (black) for the Tial Q and have no issues.
It is not the spring or BOV itself that is causing the loss of power. At WOT, the BOV will be closed shut.
I would check all sources for leaks, including around the area where the BOV was welded.
The new dongle should have picked up psi if anything, but may not be much at all.
Do you have any dyno graphs? Maybe belt slip?
I would run the -3psi or -6psi. I run the -6psi spring (black) for the Tial Q and have no issues.
It is not the spring or BOV itself that is causing the loss of power. At WOT, the BOV will be closed shut.
I would check all sources for leaks, including around the area where the BOV was welded.
The new dongle should have picked up psi if anything, but may not be much at all.
Do you have any dyno graphs? Maybe belt slip?
Thread Starter
Racer
Joined: Jun 2008
Posts: 370
Likes: 0
From: Somewhere in Portland,OR
I would not think the BOV on the intercooler would have an effect on the idle. It's a good distance from the MAF. Now if it were on the charge pipe, that's a different story.
I would run the -3psi or -6psi. I run the -6psi spring (black) for the Tial Q and have no issues.
It is not the spring or BOV itself that is causing the loss of power. At WOT, the BOV will be closed shut.
I would check all sources for leaks, including around the area where the BOV was welded.
The new dongle should have picked up psi if anything, but may not be much at all.
Do you have any dyno graphs? Maybe belt slip?
I would run the -3psi or -6psi. I run the -6psi spring (black) for the Tial Q and have no issues.
It is not the spring or BOV itself that is causing the loss of power. At WOT, the BOV will be closed shut.
I would check all sources for leaks, including around the area where the BOV was welded.
The new dongle should have picked up psi if anything, but may not be much at all.
Do you have any dyno graphs? Maybe belt slip?
I get the dyno graph today i going to shop right now so i be back with results.
Melting Slicks
Joined: May 2008
Posts: 2,121
Likes: 2
From: CT
Alright guys i don't know whats going on but i lost somewhere around 60 WHP !!!
My car used to be 570 whp with 8.9 psi thru an A&A kit.
Now i got my car on the dyno and i got little over 500 whp and 7.4 psi which less than i used to be
But i did couple of changes that might caused this problem.
1. I installed A&A bigger supercharger inlet ( Dongle )
2. Changed and moved the Blow off valve on top of the intercooler.
Blow off valve is Tial 50mm with 7 psi spring used to be 3 psi but it idle better with 7 psi spring
I went to Tom at Wung performance shop and he said that my fuel is off and he tweaked it so its not as bad as it used to be and he added more timing to get it back to where is used to be.
He said that that my fuel doesn't want to stay stable at idle and blow off valve might be the reason and i still have a surge but not as bad as it was before.
But still how did i lose 2 psi is cause of the blow off valve
My car used to be 570 whp with 8.9 psi thru an A&A kit.
Now i got my car on the dyno and i got little over 500 whp and 7.4 psi which less than i used to be
But i did couple of changes that might caused this problem.
1. I installed A&A bigger supercharger inlet ( Dongle )
2. Changed and moved the Blow off valve on top of the intercooler.
Blow off valve is Tial 50mm with 7 psi spring used to be 3 psi but it idle better with 7 psi spring
I went to Tom at Wung performance shop and he said that my fuel is off and he tweaked it so its not as bad as it used to be and he added more timing to get it back to where is used to be.
He said that that my fuel doesn't want to stay stable at idle and blow off valve might be the reason and i still have a surge but not as bad as it was before.
But still how did i lose 2 psi is cause of the blow off valve
you need to start eliminating items. Do a boost leak test and pressure the system with compressed air and see if it holds, if not find out where its leaking, check the plugs, make sure all injectors are firing properly, make sure BOV is not defective and have a ripped diaphram internally. Im sure youll figure it out. If fuel isnt stable at idle more than likely its because the air flow isnt stable either. Is you car Maf tuned? Idle is one thing but WOT is another. Start with that and report back
Drifting
Joined: Aug 2009
Posts: 1,412
Likes: 0
From: Texas 1,002rwhp/928rwtq
St. Jude Donor '09-'10
I doubt it is BOV placement or brand. I run a Tial Q and it is in the same position. Time of year, heat and humidity will all play a part in your numbers and boost. SAE correction is not as scientific as you may think and is much less accurate on FI cars than NA.
Safety Car
Joined: Feb 2008
Posts: 3,712
Likes: 3
From: TEXOMA
St. Jude Donor '08-'09
when i was messing with my maf. i had the car running with out the charpip connected.
the bov was closed and it was MOOOOOOVIng LOTS of air! like a giant leaf blower at just idle
when your on the dyno, just swap out the springs. i bet its gonna need the 9 or 11 psi spring. deff a boost leak
-carl
the bov was closed and it was MOOOOOOVIng LOTS of air! like a giant leaf blower at just idle
when your on the dyno, just swap out the springs. i bet its gonna need the 9 or 11 psi spring. deff a boost leak
-carl
