How do you check a wastegate for boost leaks ?
07-11-2005, 10:48 PM
#1
Melting Slicks
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How do you check a wastegate for boost leaks ?
There's a boost leak somewhere, check all connections everything else seemed OK. Don't know how to check if the wastegate is the problem.
07-11-2005, 11:50 PM
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Originally Posted by brokesupra
a waste gate cannot cause a boost leak...
07-12-2005, 09:17 AM
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In an attempt to answer your question...this is how we "bench test" wastegates:
Assuming that you can unbolt the wastegate at the mounting flange, you can fab a jig/base on which to mount the wastegate, with a fitting that allows you to apply compressed air pressure to the wastegate valve. Using a regulated/metered air pressure source (air compressor) to replicate exhaust boost to the wastegate and reference (manifold) boost, you can visually observe the "boost" pressure at which the wastegate opens.
If you're using any type of progressive boost controller with a multiple port wastegate, you can also apply (or bleed) boost controller air pressure at the wastegate control port(s) to mimic the signals from your boost controller and thus observe the action of your boost controller.
Most often, we discover the source of boost leaks to be cracked headers/manifolds or leaky boost tube connections...generally not the wastegate at fault.
Assuming that you can unbolt the wastegate at the mounting flange, you can fab a jig/base on which to mount the wastegate, with a fitting that allows you to apply compressed air pressure to the wastegate valve. Using a regulated/metered air pressure source (air compressor) to replicate exhaust boost to the wastegate and reference (manifold) boost, you can visually observe the "boost" pressure at which the wastegate opens.
If you're using any type of progressive boost controller with a multiple port wastegate, you can also apply (or bleed) boost controller air pressure at the wastegate control port(s) to mimic the signals from your boost controller and thus observe the action of your boost controller.
Most often, we discover the source of boost leaks to be cracked headers/manifolds or leaky boost tube connections...generally not the wastegate at fault.
Last edited by xracerz06; 07-12-2005 at 02:09 PM.
07-12-2005, 10:33 PM
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Originally Posted by DDSLT5
Well.........of course it can.
jerry
07-12-2005, 10:36 PM
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Originally Posted by xracerz06
In an attempt to answer your question...this is how we "bench test" wastegates:
Most often, we discover the source of boost leaks to be cracked headers/manifolds or leaky boost tube connections...generally not the wastegate at fault.
Most often, we discover the source of boost leaks to be cracked headers/manifolds or leaky boost tube connections...generally not the wastegate at fault.
07-13-2005, 12:25 AM
#12
Melting Slicks
Thread Starter
Going to drop the car off friday, this is a lot more than I would want to tackle it myself.
At least I would have some idea as to the diff. options used to investigate this problem. Learning as I go along
At least I would have some idea as to the diff. options used to investigate this problem. Learning as I go along
07-13-2005, 12:32 AM
#13
Team Owner
Originally Posted by brokesupra
ok. here is the deal. a wastegate cant cause a boost leak. but it can cause boost related issues. the waste gate allows exhaust gasses to bypass the the turbo in order to regulate boost pressure. so for you to have a boost leak you must be leaking boost somewhere between the turbo outlet and the intake port. the wastegate is lacated on the exhaust side of the engine. it never sees boost so it cant leak it. the exception is if one of the vac/boost lines going to the ports on the waste gate are leaking. trust me on this. i work on turbo cars every day.
jerry
jerry
You are 100% correct - but, you're also playing with semantics - you know as well as I do, that the original post obviously was asking about a drop in boost pressure, which a leaking waste-gate could cause. Technically though - you're on the money - what would have helped, is this explanation instead of "can't happen", know what I mean?
07-13-2005, 07:00 PM
#16
Melting Slicks
Thread Starter
Hey guys that's exactly what I mean a drop in boost, 5lbs to be exact.
Don't hate me but this question concern my Evo8 & not the C5. I have not had a lot of response on the Evo board.
Supposed to be running 20lbs boost w/ power around 400whp, now I'm at 15lbs w/ AFR in the 10.7, power down considerably to 226whp and 160+wtq, pathetic.
This is the first hickup in 14,000miles since the mods. Car drive OK still, just NO power.
Don't hate me but this question concern my Evo8 & not the C5. I have not had a lot of response on the Evo board.
Supposed to be running 20lbs boost w/ power around 400whp, now I'm at 15lbs w/ AFR in the 10.7, power down considerably to 226whp and 160+wtq, pathetic.
This is the first hickup in 14,000miles since the mods. Car drive OK still, just NO power.
07-13-2005, 07:01 PM
#17
Drifting
Originally Posted by boblackhardtop
There's a boost leak somewhere, check all connections everything else seemed OK. Don't know how to check if the wastegate is the problem.
One way to test is to plug the ends (at say blower outlet and throtle body) of your intake plumbing. Pressurize and see if/where she leaks. All you need is an air tank or compressor, and some pipe plugs from the Home Depot.
07-13-2005, 07:02 PM
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Originally Posted by boblackhardtop
Hey guys that's exactly what I mean a drop in boost, 5lbs to be exact.
Don't hate me but this question concern my Evo8 & not the C5. I have not had a lot of response on the Evo board.
Supposed to be running 20lbs boost w/ power around 400whp, now I'm at 15lbs w/ AFR in the 10.7, power down considerably to 226whp and 160+wtq, pathetic.
This is the first hickup in 14,000miles since the mods. Car drive OK still, just NO power.
Don't hate me but this question concern my Evo8 & not the C5. I have not had a lot of response on the Evo board.
Supposed to be running 20lbs boost w/ power around 400whp, now I'm at 15lbs w/ AFR in the 10.7, power down considerably to 226whp and 160+wtq, pathetic.
This is the first hickup in 14,000miles since the mods. Car drive OK still, just NO power.
07-13-2005, 08:19 PM
#19
Melting Slicks
You might also look for a disconnected vacum hose hidden somewhere.
I've wondered how to make some sort of quiet pressure tester for FI intakes...Can of artificial smoke and Compressed air can...A fitting on a rubber blower inlet bung/exhaust pipe caps...
I've wondered how to make some sort of quiet pressure tester for FI intakes...Can of artificial smoke and Compressed air can...A fitting on a rubber blower inlet bung/exhaust pipe caps...
07-13-2005, 10:07 PM
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Originally Posted by Stock FRC
It sounds to me that he is referring to a blow off valve. Hey brokesupra, you sound as if you assembled the "Fastest Street Supra in the World". 
BTW... your junk aint stock 
Last edited by brokesupra; 07-13-2005 at 10:11 PM.