Boost Question
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Race Director
Joined: Mar 2004
Posts: 12,466
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From: Fort Wayne IN
2025 C5 of the Year Finalist - Modified
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Boost Question
Using my car as an example, I currently am pushing 8 lbs of boost on the stock 8lb wastegate springs in the APS TT kit.
I'm in the process of purchasing Lowboost's Patriot 317's and GT2-3 cam. I'm not planning on putting this on to the stock shortblock, but a question sprang to mind.....
As you increase the motor's VE, the boost should see a relative drop. But, being that the only thing controlling the boost is the wastegate springs, if I was to install the stuff on the stock shortblock, would it still come up to the 8lbs boost because that's what the wastegate springs are looking/waiting for? I really don't know the answer to this one, which is why I'm asking.
I'm in the process of purchasing Lowboost's Patriot 317's and GT2-3 cam. I'm not planning on putting this on to the stock shortblock, but a question sprang to mind.....
As you increase the motor's VE, the boost should see a relative drop. But, being that the only thing controlling the boost is the wastegate springs, if I was to install the stuff on the stock shortblock, would it still come up to the 8lbs boost because that's what the wastegate springs are looking/waiting for? I really don't know the answer to this one, which is why I'm asking.
Melting Slicks
Joined: May 2002
Posts: 3,210
Likes: 1
Using my car as an example, I currently am pushing 8 lbs of boost on the stock 8lb wastegate springs in the APS TT kit.
I'm in the process of purchasing Lowboost's Patriot 317's and GT2-3 cam. I'm not planning on putting this on to the stock shortblock, but a question sprang to mind.....
As you increase the motor's VE, the boost should see a relative drop. But, being that the only thing controlling the boost is the wastegate springs, if I was to install the stuff on the stock shortblock, would it still come up to the 8lbs boost because that's what the wastegate springs are looking/waiting for? I really don't know the answer to this one, which is why I'm asking.
I'm in the process of purchasing Lowboost's Patriot 317's and GT2-3 cam. I'm not planning on putting this on to the stock shortblock, but a question sprang to mind.....
As you increase the motor's VE, the boost should see a relative drop. But, being that the only thing controlling the boost is the wastegate springs, if I was to install the stuff on the stock shortblock, would it still come up to the 8lbs boost because that's what the wastegate springs are looking/waiting for? I really don't know the answer to this one, which is why I'm asking.
the difference with the better flowing heads/cam, as you pointed out already, is that your VE will increase so you will flow more air threw the motor w/less restriction. Thats all boost is after all, a restriction. If you can move the same amount of air with less pressure you are moving in the right direction.
Thread Starter
Race Director
Joined: Mar 2004
Posts: 12,466
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From: Fort Wayne IN
2025 C5 of the Year Finalist - Modified
C5 of Year Finalist (performance mods) 2019
2017 C5 of the Year Finalist
2016 C5 of the Year Finalist
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Thanks! I just wasn't sure if I was thinking straight on that one or not. Of course, leaving it at 8lbs might not be the smartest idea because even though the boost is still only at 8 PSI, the cylinder pressures are still going to be increased via the extra airflow.
Safety Car
Joined: Jul 2005
Posts: 4,275
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From: Vancouver WA
Turbos don't change, because the boost is control by spring pressure.
Blower cars change, because there boost in controlled by pully size.
And the GT2-3 cam is a little cam. It is comaprable to a stock Z06 (LS6) cam.
Blower cars change, because there boost in controlled by pully size.
And the GT2-3 cam is a little cam. It is comaprable to a stock Z06 (LS6) cam.
Thread Starter
Race Director
Joined: Mar 2004
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From: Fort Wayne IN
2025 C5 of the Year Finalist - Modified
C5 of Year Finalist (performance mods) 2019
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I realize that. But coupled with come Patriot CNC'd 317's it opens things up quite nicely. Plus, I'm sure there's some pretty noticeable differences in a stock LS6 cam when compared to a GT2-3 if you dig deeper into the specs past the standard duration @ .050, lift, and LSA.
Team Owner
Joined: Jul 2003
Posts: 20,474
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From: Detroit
I also ran a GT2-3 cam and worked over stock heads with my TT kit on a stock lower end. You can definitely make good power, the only issue is potential longevity.
To answer your question you'll still make 8 psi but generate more hp.
To answer your question you'll still make 8 psi but generate more hp.
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Thread Starter
Race Director
Joined: Mar 2004
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From: Fort Wayne IN
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Former Vendor
Joined: Jun 2002
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From: Bridgewater Ma
Since the stock (weak) lowerend is still being used I wouldn't bother with the H/C and just turn the boost up to 12lbs instead. Either setup is going to stress the lower end more.I would save the $$ and do a forged motor in the future instead.
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Race Director
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From: Fort Wayne IN
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That's already the plan. I bought the heads/cam setup to sit on while I locate a stock block and crank and get some forged rods/pistons and do a budget short block. I posed the question here because I really wasn't sure if those wastegate springs would give 8 lbs boost on any setup or not. Newb to turbo's still.
Le Mans Master
Joined: Sep 2003
Posts: 6,272
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From: Farmington CT
Cruise-In VII Veteran
Sean, you will have some fun getting those twins out of there, I worked my azz off on that car for weeks to get things to fit
seperate the turbo housings, not in the APS tech data for rem'l or install, but I see no other way
Hope your having fun with the car, that was quite a project, I would've have really like to see how the tuned result was
seperate the turbo housings, not in the APS tech data for rem'l or install, but I see no other way
Hope your having fun with the car, that was quite a project, I would've have really like to see how the tuned result was
Thread Starter
Race Director
Joined: Mar 2004
Posts: 12,466
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From: Fort Wayne IN
2025 C5 of the Year Finalist - Modified
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Sean, you will have some fun getting those twins out of there, I worked my azz off on that car for weeks to get things to fit
seperate the turbo housings, not in the APS tech data for rem'l or install, but I see no other way
Hope your having fun with the car, that was quite a project, I would've have really like to see how the tuned result was
seperate the turbo housings, not in the APS tech data for rem'l or install, but I see no other way
Hope your having fun with the car, that was quite a project, I would've have really like to see how the tuned result was
I'm having a blast with the car. The smoothness of the powerband coupled with how quiet it is overall is just awesome. It's so beautifully deceptive. I think if you'd have gotten to run in it fully tuned you'd probably have one on your FRC by now!
