Cheap easy HP gains?

[Johnny Danger]

Originally Posted by shadowprincess25

Woah that is a great deal. I might consider doing some headers especially for that price!

Not only will a cheap set of eBay headers fail to give you any power or performance gains, there'll render your vehicle non emissions/OBDII compliant .

[shadrach74]

Originally Posted by Johnny Danger

Not only will a cheap set of eBay headers fail to give you any power or performance gains, there'll render your vehicle non emissions/OBDII compliant .

You cannot say that all of the cheap eBay headers will not give additional power. Porche's stock set up is awful from a flow standpoint. Eliminating the catalyst that is shaped like a coffee can with a port on the side would most certainly allow the motor to breath better.

[Johnny Danger]

Originally Posted by shadrach74

You cannot say that all of the cheap eBay headers will not give additional power. Porche's stock set up is awful from a flow standpoint. Eliminating the catalyst that is shaped like a coffee can with a port on the side would most certainly allow the motor to breath better.

True. But, once you've removed the headers/pre-cats and replaced them with a cheap set of headers that have primaries that are probably no larger than 1 5/8 in diameter along with the even more restrictive 600 cell secondary cats still in place, what do think you'll gain ?

[shadrach74]

Originally Posted by Johnny Danger

True. But, once you've removed the headers/pre-cats and replaced them with a cheap set of headers that have primaries that are probably no larger than 1 5/8 in diameter along with the even more restrictive 600 cell secondary cats still in place, what do think you'll gain ?

There is no reason to keep the secondary cats. Mandrel bent cat delete pipes can be had for under $250; the install should take about 2 hours. There is a lot of unrealized potential in the 3.2 that was deliberately left untapped by the factory. Porsche's marketing dept likely did not want the lowly roadster beating up on it's older more expensive brother.

[JAAY]

PM Sent. Sorry I did not post here.

[Johnny Danger]

Originally Posted by shadrach74

There is no reason to keep the secondary cats. Mandrel bent cat delete pipes can be had for under $250; the install should take about 2 hours. There is a lot of unrealized potential in the 3.2 that was deliberately left untapped by the factory. Porsche's marketing dept likely did not want the lowly roadster beating up on it's older more expensive brother.

Have you ever tried going completely catless ? I have. There was a significant loss of low end power, not to mention CEL"s galore, along with the fact that the vehicle would not pass emissions/inspection testing.. I've spent considerable time (and money) over the years experimenting and testing various exhaust configurations for the 986 boxster. And, I can assure you that there is no easy or inexpensive way to improve upon and gain power over the oem system . I suggest that you gather some actual experience on the topic before making any more sweeping assumptions

[shadrach74]

Originally Posted by Johnny Danger

Have you ever tried going completely catless ? I have. There was a significant loss of low end power, not to mention CEL"s galore, along with the fact that the vehicle would not pass emissions/inspection testing.. I've spent considerable time (and money) over the years experimenting and testing various exhaust configurations for the 986 boxster. And, I can assure you that there is no easy or inexpensive way to improve upon and gain power over the oem system . I suggest that you gather some actual experience on the topic before making any more sweeping assumptions

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.

[JAAY]

Has anyone here dyno'd any of their mods? If so please post some graphs as well as A/F's. I am not looking for the end number but the difference. Anyone?

[Topless]

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.

It all sounds good on paper Shad but in 7 years of looking I have seen very few examples of success with this. None were inexpensive. The best example was a few years ago when a guy had quality headers, racing exhaust, well thought-out custom one-off intake, larger TB, plenum, ported intake runners, and a custom dyno tune to make the most out of his changes. He did find about 25 hp at 6500rpm but it cost him $6k to get it done and the torque curve was significantly narrowed. Lap times after all this... no measurable improvement. He gained paper hp but sacrificed a broad torque curve and driveability in the process. The car was also no longer street legal.

Ultimately it is your car and your dough so if you think you can find the magic bullet here, have a go and let us all know how it turns out. A cool dyno slip doesn't really interest me. Until I actually see a car turning faster laps by making these changes, I'll be on the sidelines. Compare this to dropping in a 3.4L, the difference in performance is instant and measurable in significant improvement in lap times.

[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 .