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YOUR RESEARCHexhaust project for my 4S
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engine) and keep only the helm-holtz portion of the line that I will adapt after the fabspeed headers I installed today.
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These discussions about exhaust gave me some ideas (and envies).
I want to unleash Hell
I took an "old" GT2 street exhaust line out of the box it was sleeping into and am going to adapt it on the 4S.
This line had the most astonishing sound I ever heard on a street P-car. I didn't have a GT2 but was so impressed by it that I bought it when the owner decided to turn the car into a track car. I thought I would keep it for an eventual turbo conversion, but I think it is time do to something with it.
It's using the helm-holtz principle: counter pressure created in the pipe by the echo at the end of the pipe into the cans soften the sound under 3000 rpm, but it sounds like a track beast about 4000 on WOT. Hilarous.
The cats are 300 cells high flow catalytic converters (given for 620+ HP).
Well, you will probably react and state that this is like throwing raspberry jam to pigs and you are right!
This is why the plan is to save the cats and keep the GT2 headers (that anyway don't fit the N.A. engine) and keep only the helm-holtz portion of the line that I will adapt after the fabspeed headers I installed today.
This way I keep the whole OEM line that I can put back in place if needed.
The only thing I need to find is a pair of good quality cats, made of stainless steel, big flow.
Does someone have a source for that (I don't trust ebay and the crap we can get their for less than $200) ?
The painful stuff is to find an elegant solution to fit the cats between the collector/header and the 'silencer'.
It would be perfect not to have cats, and the tips perfectly fits the 4S bumper, since it's the same than the turbo.
The idea is to put the header into the reversed direction (outlet to front instead of rear) then a gentle ~145 deg pipe to the cat then 35 deg to the pipe that goes to the muffler, where the second sensor is.
A lot of work, and I'm not a specialist, but that's the only good solution I see to keep the spirit of the helm-holtz effect and two independent lines.
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