Cheap easy HP gains?

[Johnny Danger]

Originally Posted by shadrach74

Easy Danger, I made no sweeping assumptions other than the factory header/cat arrangement is sub-optimal. When you were running with out cats, did you have the ECU reflashed to match your new exhaust set up? Certainly opening the exhaust may cost some low end power, but that would depend on the diameter of the pipes, not the the cats.

Are you of the opinion that the back pressure from your cats is "enhancing" torque/power at lower RPM?

I think an easy way to gain a few pony's is to leave the stock headers in place and remove the secondaries. $250 buys a 2-3% hp increase on an S plus a loss of ~35lbs. If you then opened the intake with a better set up, reflashed the ECU and added an underdrive pulley. I think you'd get gains that you could feel for about $1200-1500. Earth shattering? No. However, if properly fettled, there is no reason why the 3.2 can not make around the same BHP/liter as the 3.4 996.

Sorry for taking such a hard line. However, before dissecting and removing parts from the oem exhaust system with hopes of improving power and performance, one needs to first have a methodical plan in mind. For example, the removal of the oem headers/precats requires either an improved custom version of the original design, wherein headers/precats are fabricated in such a way that they incorporate longer, equal length primaries with larger diameter specs followed by a high flow merge collector and high quality low cell cats. Or, a single header design based on similar specs along with relocation of the cats further "down stream" . In my experience, these are the only two ways that one can gain "real" performance as it relates to street applications without the concern for triggering CEL's and the need for re-mapping the ECU . Neither of these two approaches are inexpensive undertakings. Having said that, if one has a limited budget, my recommendation would be to leave the oem headers/precats in place and simply delete the secondary cats for the purposes of weight reduction and elimination of some unnecessary back pressure, along with a good quality cat back that will further eliminate unnecessary back pressure and weight, and perhaps result in better sound .

[shadrach74]

Originally Posted by shadrach74

I think an easy way to gain a few pony's is to leave the stock headers in place and remove the secondaries. $250 buys a 2-3% hp increase on an S plus a loss of ~35lbs. If you then opened the intake with a better set up, reflashed the ECU and added an underdrive pulley. I think you'd get gains that you could feel for about $1200-1500. Earth shattering? No. However, if properly fettled, there is no reason why the 3.2 can not make around the same BHP/liter as the 3.4 996.

Originally Posted by Johnny Danger

Having said that, if one has a limited budget, my recommendation would be to leave the oem headers/precats in place and simply delete the secondary cats for the purposes of weight reduction and elimination of some unnecessary back pressure, along with a good quality cat back that will further eliminate unnecessary back pressure and weight, and perhaps result in better sound .

So much for sweeping assumptions. Great minds think alike...

[Johnny Danger]

Originally Posted by shadrach74

So much for sweeping assumptions. Great minds think alike...

As long as we're not talking about using cheap eBay headers, or going catless I guess so.

p.s. By the way, if you have a source for high quality mandrel bent cat delete pipes for only $250, by all means let the forum know where they can get them ! Most aftermarket companies charge $500 plus for them .

[shadrach74]

Originally Posted by Johnny Danger

As long as we're not talking about using cheap eBay headers, or going catless I guess so.

p.s. By the way, if you have a source for high quality mandrel bent cat delete pipes for only $250, by all means let the forum know where they can get them ! Most aftermarket companies charge $500 plus for them .

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I'm on the wait list now...

As for the cheap eBay, that would be on a case by case basis. I've heard some are pretty good, others are complete crap. All other mechanical things being equal, going catless will make more power.