Re: stock exhaust vs open down pipe at 600plus awhp
The biggest restriction is the turbo itself, not suprized the stock catback off made much difference
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Re: stock exhaust vs open down pipe at 600plus awhp
Quote:
Originally Posted by eengler2
Wow. My IPS exhaust was not worth it! It's probably as heavy as stock too.
i don't think so. the stock is heavy as hell. the exhaust shop has to drag it on the floor it was so heavy. i like single exhaust better though. lighter, flow better and sounds better.
Re: stock exhaust vs open down pipe at 600plus awhp
yea i wouldnt say aftermarket exhaust like the IPS isnt worth it. if it flows as good as open downpipe... 16hp is 16hp.. there theres the weight, look and sound for whatever your into
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Re: stock exhaust vs open down pipe at 600plus awhp
Love the real world data! I would have easily guessed at least 20WHP at that power level. My assumption is that backpressure in the turbine and manifold is already so high that relieving the restriction downstream nets little benefit. I don't think an aftermarket TD04 manifold would net any gains as a result; I maintain the bottleneck is in the turbine/housing.
Now what would be really interesting is to see the gains from on open-dump wastegate. Back in the day the butt dyno and roll-racing told me 30-40WHP gains at pump gas levels with the JPDC "Widgets" -- I absolutely HATED the sound of them, though. Gains diminished as boost increased, but when the gates opened it pulled much harder up top.
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Re: stock exhaust vs open down pipe at 600plus awhp
Quote:
Originally Posted by HellBringer
Love the real world data! I would have easily guessed at least 20WHP at that power level. My assumption is that backpressure in the turbine and manifold is already so high that relieving the restriction downstream nets little benefit. I don't think an aftermarket TD04 manifold would net any gains as a result; I maintain the bottleneck is in the turbine/housing.
Re: stock exhaust vs open down pipe at 600plus awhp
Quote:
Originally Posted by HellBringer
Love the real world data! I would have easily guessed at least 20WHP at that power level. My assumption is that backpressure in the turbine and manifold is already so high that relieving the restriction downstream nets little benefit. I don't think an aftermarket TD04 manifold would net any gains as a result; I maintain the bottleneck is in the turbine/housing.
Now what would be really interesting is to see the gains from on open-dump wastegate. Back in the day the butt dyno and roll-racing told me 30-40WHP gains at pump gas levels with the JPDC "Widgets" -- I absolutely HATED the sound of them, though. Gains diminished as boost increased, but when the gates opened it pulled much harder up top.
I respectfully disagree, and the only way to find out is sending Ray a set of my manifolds to test. I do not think the gains will be high at that power level but definitely will give gains and spool.
A open dump tube will reduce back pressure on the 02 housings and will give little gains.
Re: stock exhaust vs open down pipe at 600plus awhp
Quote:
Originally Posted by GCtech Industries
I respectfully disagree, and the only way to find out is sending Ray a set of my manifolds to test. I do not think the gains will be high at that power level but definitely will give gains and spool.
A open dump tube will reduce back pressure on the 02 housings and will give little gains.
You've got it backwards... The manifolds themselves are not the issue and don't pose a tangible restriction relative to the TD04 hotside. The best engineered tubular TD04 manifold is still corked by the turbine, so no matter how well the manifold flows the turbine still can't move any more exhaust gasses through it than before. Further, a nice high-flowing tubular manifold will like introduce "lag", not mitigate it. On the other hand, dumping the exhaust that exits the wastegate flapper will provide significant gains; gains however are diminished as boost increases as a result of the gate staying shut longer. This is not conjecture; I've had TD04 car with an open-dump O2 housing. I've also had a TD04 car with a Titan front tubular manifold. The ONLY benefit of said manifold is it doesn't crack like the OEM, and it looks a little nicer under the hood..
Re: stock exhaust vs open down pipe at 600plus awhp
Quote:
Originally Posted by HellBringer
You've got it backwards... The manifolds themselves are not the issue and don't pose a tangible restriction relative to the TD04 hotside. The best engineered tubular TD04 manifold is still corked by the turbine, so no matter how well the manifold flows the turbine still can't move any more exhaust gasses through it than before. Further, a nice high-flowing tubular manifold will like introduce "lag", not mitigate it. On the other hand, dumping the exhaust that exits the wastegate flapper will provide significant gains; gains however are diminished as boost increases as a result of the gate staying shut longer. This is not conjecture; I've had TD04 car with an open-dump O2 housing. I've also had a TD04 car with a Titan front tubular manifold. The ONLY benefit of said manifold is it doesn't crack like the OEM, and it looks a little nicer under the hood..
There is only one way to find out, when we tested the first set in one of our cars we could feel the difference, then again did not have an AWD dyno near by to test them.
Dutch was able to dyno his VR4 with our V1 kit but did not made any before and after runs.
I have a set laying around is just a matter if Ray want to do the test.
You've got it backwards... The manifolds themselves are not the issue and don't pose a tangible restriction relative to the TD04 hotside. The best engineered tubular TD04 manifold is still corked by the turbine,
Fact. The hotside is more narrow than my thumb. And it houses an appropriately small turbine wheel. The internal wastegate flapper is MICROSCOPIC and does a horrible job at letting out any kind of exhaust gasses out
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Re: stock exhaust vs open down pipe at 600plus awhp
I would have easily guessed at least 20WHP at that power level. My assumption is that backpressure in the turbine and manifold is already so high that relieving the restriction downstream nets little benefit. I don't think an aftermarket TD04 manifold would net any gains as a result; I maintain the bottleneck is in the turbine/housing. 
Gains diminished as boost increased, but when the gates opened it pulled much harder up top.
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