Helix downpipe and uppipe spool up?
#17
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[QUOTE]Originally posted by 02silversuby
[B]
It depends on your definition of increased flow. When you increase the volume of the pipes, you then normally decrease exhaust gas velocity. I'm not sure if you know what the inside of a turbo looks like, but there is an injector like opening that 'spits' the exhaust gases right into the turbine blades which get it to spin. On smaller turbos, this 'injector' is pretty small to gain fast spool up. This fast spool up in caused by the opening being small which causes the gas velocity to pretty fast. On larger turbos, this 'injector' is larger which allows more volume of gas to enter. While this is good at high rpm's where you are shooting out a lot of exhaust gas from the engine, it doesn't do quite well at low rpm's which is why you have a lot of lag with these. THe same principle goes with exhaust piping such as headers. With the dyno charts, you have to read the fine print. There are so many variables that can change what the output on the car is. Such as, what other mods the car has, the ambient temp., octane of fuel, the tuning of the car, etc. Personally, I never take what a dyno chart says to heart. Just because something worked on one person's car, doesn't mean it will work on another. No two cars are the same. Even if two identical cars stock were to race one another with as many conditions kept the same as you could...one would be faster then the other.
[B]
Originally posted by 03blauWRX
That is why it isn't always good to get headers.
wouldnt headers also increase the exhaust flow? how come gruppe-s dyno sheet states what u will get 15hp more to the wheel.
-Adam
That is why it isn't always good to get headers.
wouldnt headers also increase the exhaust flow? how come gruppe-s dyno sheet states what u will get 15hp more to the wheel.
-Adam
#18
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The biggest problem with aftermarket headers is the heat loss more than the change in flow, because the actual volume of gas flowing through is the same. The heat loss is lost energy however, and energy is what the turbine needs to spin the compressor wheel. From what has been observed on the Vishnu dyno, aftermarket headers can help midrange torque a little, but they lose top end because they can't provide enough heat and pressure to power the turbine. This goes with what Mike Shields has to say on www.spdusa.com about the engine in a turbo car being nothing mroe than a 'hot gas generator' for the turbo, so that it can pump more air.
#19
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Originally posted by BAN SUVS
The biggest problem with aftermarket headers is the heat loss more than the change in flow, because the actual volume of gas flowing through is the same. The heat loss is lost energy however, and energy is what the turbine needs to spin the compressor wheel. From what has been observed on the Vishnu dyno, aftermarket headers can help midrange torque a little, but they lose top end because they can't provide enough heat and pressure to power the turbine. This goes with what Mike Shields has to say on www.spdusa.com about the engine in a turbo car being nothing mroe than a 'hot gas generator' for the turbo, so that it can pump more air.
The biggest problem with aftermarket headers is the heat loss more than the change in flow, because the actual volume of gas flowing through is the same. The heat loss is lost energy however, and energy is what the turbine needs to spin the compressor wheel. From what has been observed on the Vishnu dyno, aftermarket headers can help midrange torque a little, but they lose top end because they can't provide enough heat and pressure to power the turbine. This goes with what Mike Shields has to say on www.spdusa.com about the engine in a turbo car being nothing mroe than a 'hot gas generator' for the turbo, so that it can pump more air.
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