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how much of a loss in power does a boost leak cause?

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Old Jul 11, 2005, 09:44 AM
  #16  
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Maybe someone can answer this.....

I noticed that the AMS LICP bolts up to the turbo via a black flanged pipe with a small nipple coming out from it. I always thought that this was a stock pipe. Is it not?

I obviously did not buy or install this part. It was on the car when i bought it.
Old Jul 11, 2005, 10:04 AM
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Yes it is the stock pipe. The AMS pipe has a silicone sleave that slides onto the stock black pipe coming off the turbo. Mine AMS lower IC is coming this week.

I have noticed that you can tighten down a clamp and then come back several weeks later and you can tighten it more. I have t-clamps for my IC piping.

I have come to the conclusion that the number one power robbing issue with the EVO is boost leaks. I am changing out some of the stock clamps near the intake and also get those little metal clamps for all the vacuum hoses. I have blown off the vacuum hose to the left of the TB several times. I am hoping this will cure 99% of the leaks. I have had leaks at the TB, intake and IC pipes.
Old Jul 11, 2005, 10:18 AM
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Much of whether or not your car loses boost due to a leak depends on where the boost source for the boost controller is located.

Alot of guys tap in to a feed coming off of the manifold. Tapping into the manifold for this signal will work fine but the effect is that the boost controller will compensate for any leaks that there may be between the compressor discharge and the manifold. The net result is that you may not see the leak manifest itself as a drop in boost (up until a point) and instead you'll push the turbo out of its efficiency island more quickly. Charge temps will go up and if the charge temp is high enough, knock will occur and timing will get pulled resulting in a loss in power.

Tapping into the compressor discharge for boost signal won't get you the rock solid boost that everyone craves if you've got any sort of leak however the pressure at the compressor discharge will remain constant and the turbo will remain in it's efficiency island and will be less prone to blowing hot air.

What I'm trying to get at with my long winded response is that the amount of power lost due to a boost leak depends on alot of factors. Some folks may have a boost leak and not even realize it since their boost guages don't register any taper but in reality they may be losing power due to timing getting pulled.
Old Jul 11, 2005, 12:00 PM
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so if i were to do a pressure check from the turbo inlet and not get a single leak, would that mean that there are no chances for a boost leak?
Old Jul 11, 2005, 01:52 PM
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Originally Posted by titaniumkingpin
so if i were to do a pressure check from the turbo inlet and not get a single leak, would that mean that there are no chances for a boost leak?
If you can pressurize your entire intake tract to you target boost level and detect no leaks, you should be good to go. The only area that I can think of that might be inconsistant would be the BOV/BPV. In my experience that is the place that I have the most trouble curing leaks.
Old Jul 11, 2005, 08:08 PM
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Originally Posted by redevo58
I have a boost leak at the flange where the turbo compressor side bolts up to the intercooler piping. I know the cause is my greddy I/C pipe since i just found out after having it on for a year and always having a leak. even after trying several different gaskets . the lower i/c pipe flange was was welded wrong and when trying tpo lay the pipe on a flat surface is does not lie flat but rocks back and forth thus causing the leak. But how much power could i be losing because of this? i already ordered a helix i/c pipe kit to fit the problem.
It's hard to say exactly how much power you're losing, but can be very significant even from a small leak, especially on a mass-airflow sensor equipped car. Not only is there the obvious loss in air volume, but you also have an inaccurate reading in the amount of air entering the engine because the leak will be behind the mass airflow sensor. Also, your air temps will typically be higher because (assuming you're not beyond the limits of your turbo), your turbo will spin faster, compressing more air than your motor is actually consuming.

I have the Buschur Upper IC pipe and it came with a warped flange. After I put the flange on a belt sander to flatten it and reassembled it made a HUGE difference, enough that I could obviously feel it.
Old Jul 11, 2005, 08:12 PM
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Why live with the leak? Just put some high temp silicon seal on the both sides of the gasket and make sure everything is tight and dry before driving. This should solve your leaking prob.

Thanks,
Tom
Old Jul 12, 2005, 01:33 PM
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I tried that and it still leaked . the actual flange is bents and does not lay flat when placing it on a level surface but rocks back and forth. so there will always be some form of a leak. it always leaks from the same spot since all the gaskets that i've tried always blow out the gasket form the same spot. thats why i just ordered a new intercooler pipe kit form you guys.
Old Jul 12, 2005, 01:54 PM
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Originally Posted by redevo58
I tried that and it still leaked . the actual flange is bents and does not lay flat when placing it on a level surface but rocks back and forth. so there will always be some form of a leak. it always leaks from the same spot since all the gaskets that i've tried always blow out the gasket form the same spot. thats why i just ordered a new intercooler pipe kit form you guys.
You may have to put it on a belt sander if it's minor, or if it's major take it to a machine shop and have the flange milled flat.
Old Jul 12, 2005, 02:17 PM
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i got the AMS LICP and it didn't come with the part with the flange.
Does the Helix one come with the flange pipe also? (the one that bolts directly to the turbo)
Old Jul 12, 2005, 02:38 PM
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yes it does.
Old Jul 16, 2005, 10:40 AM
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my turbo spools up slower than before. I hit max boost at like 4300rpms. Now what kind of leak would cause this. Also would my wastgate cause this type of problem.
Old Jul 16, 2005, 05:19 PM
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I have the 3076r AMS kit running stock 20lbs boost w/ AEM, 272/272, etc... tuned by Martin at AMS, supposed to be making about 400whp & did feel like it before the leak. It pulled like a freight train.
Right now it can only muster 15lbs, AFR at 10.7 likely from the boost leak w/ a sad 226whp/160 ft lbs .
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