Performance Upgrade

I have a 99 C4 completely stock. I would like to boost the HP a bit... What is the best way to go about it? Are there performance chips available for these cars? How about air intakes and free flowing exhaust? I don't want the car to be really loud though... Thanks! SPT

headers and chip

My 99 was also completly stock when I got it. I added the Fabspeed 996 Maxflo Performance Airbox Enhancement Cold-Air Kit and The K & N Filter which means that I: Took out the muffler inside the lid of the stock air box and installed the carbon fiber block off plug. Removed the black hose that goes to the throttle body and installed the smooth red silicon hose. Removed the plastic screen and the metal screen in front of the Mass Airflow Sensor in the air box and installed the carbon fiber ring in its place. Removed the stock air cleaner amd used the K & N air cleaner. Fabspeed says this gives 25% more air flow and .42 seconds faster acceleration. I installed the 996 Fabspeed Maxflo Free Flo Mufflers with the Chrome sport oval tips. Fabspeed says this gives +10 HP I think this combo did give me more power as it sure feels like it and the intake sounds great and the exhaust sounds awesome. Installed the B & M Short Shift also bob

I guess SPT has a question regarding headers. I don't know why he chose to send a moderator alert for it, though. Here it is: --------------------- A user (SPT at IP 24.62.72.145) has requested that you review the following post by SPR in a forum you moderate: --------------------- headers and chip --------------------- The user's reason for this request is: Don't I already have headers??? I thought all 911's had headers... You may view the topic at the following URL: <a href="http://forums.rennlist.com/cgibin/rennforums/ultimatebb.cgiubb=get_topic;f=5;t=004393;p=1#000001" target="_blank">http://forums.rennlist.com/cgibin/rennforums/ultimatebb.cgiubb=get_topic;f=5;t=004393;p=1#000001</a>

No - they do not have equal-length headers. You can get a set from Fabspeed. Add their Piggy-back computer. My 99 996 gained 26.5HP neasured before/after on the same dyno/same day. I have to admit I'm thinking of purchasing a 2003 but if I do, I'll transfer the headers and computer. Dealer had no problem at all with the headers - the computer is electronically undetectable. I highly recommend these two items.

I have an 01 C4 with GHL stainless steel exhaust and headers. Air flow and heat transfer are improved for increased torque. Sounds great. I hear that chips do not offer much. I had the ecu reprogrammed to ROW which makes the torque band more linear. A light flywheel would also increase torque. Regards, Mike

giac and gemballa chips give 23 hp, not much? dunno also high flow cats give some also but the best bang for the buck, after reaearch would entail headers and chip. other stuff is afterwards, cats, bmc, mufflers, throttle body, etc.

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by MikeP Long Island: [QB]No - they do not have equal-length headers. You can get a set from Fabspeed. Add their Piggy-back computer. My 99 996 gained 26.5HP neasured before/after on the same dyno/same day.QB]</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Did you purchase a preprogrammed piggy-back or custom tuning at Fabspeed? Could you comment on the piggy-back setup (i.e. where does it mount, how many wires are attached to the car, etc). Thanks

A lighter flywheel should be more free-revving at the expense of low-end punch.

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by NMoore: <strong>A lighter flywheel should be more free-revving at the expense of low-end punch.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Why would you loose any low-end punch with a lighter flywheel?

I had the Piggy-back installed/programmed by the Dyno facility used by Fabspeed. This was nearly 4 years ago. I was there during the entire process. The computer is installed adjacent to the car's OBDII computer which is underneath a panel in the back seat area of the car. The computer is wired into the car's harness - probably 10 wires or thereabouts - so cutting/soldering is required. As I mentioned, the piggy-back is not detectable electronically. However, if, for some reason, the dealer had to physically access the OBDII computer, the Piggy would be obvious. Of course, since my 99 is out of warranty, this doesn't matter at all. And it didn't matter to me then, obviously. The car wasn't more than 6-8 months old when the piggy/headers were installed. (I installed the headers and posted all the pics on this site way back then.) This is my first visit to the Rennlist in nearly 2 years! After dyno programming, the car was tweaked in actual driving on the street by the dyno operator. He sat in the passenger seat with the laptop still connected to the piggyback and made minor adjustments at all driving ranges from idle to acclerating at WOT. I was/am still extremely happy with the results. Consider that the 26.5 HP and additional torque through the rev range means your 99 will have more power than an unmodified 2000-2003 996.

You get more low end punch with a lighter flywheel less rotating weight for the crank to turn so it turns(Revs faster)

Bottom line is that on a naturally aspirated Porsche engine, there is not a whole lot you can do to tweak extra power without spending $10K+. You can do the chip, exhaust, headers, and air intake, but you will have spent $5,000+ and gained only about 25-40 HP (aka not noticeable). The law of diminishing returns certainly applies early on with these engines. You can supercharge the engine, but that will be at least $6K-$8K by itself. Now the 996TT on the other hand...$500 for an Upsolute Chip, $1500 for a custom exhaust, and $100 for a K&N - BAM! You've got an easy 80-100HP+.

Don't throw away your money. Trade the car in for a newer model.

Hey RR.. I think there is some value in spending $5K for 40 extra horse..... no? just the money you will save from buying a used 996 vs new is huge.... regards, Peter

I guess I'm confused. What good is 25-30 more hp? As I understand physics increased hp gives you a higher top speed, but not necessarily any more torque. Isn't torque improvement what you really want, either more or improvement at lower rpm. Why not change the gear ratios. That will certainly pic up speed. Have no idea what the cost is but the improvement must be significant. Of course, you may lose top speed, but other than for track purposes what does greater top speed give you o/t bragging rights.

DonW: If I can jump in here for just a second,........ I'd offer three points here in this thread: 1) A properly programmed chip (EPROM or Unichip) will increase torque to almost the same degree as HP and the gains are found from 3500 RPM to the rev limiter. If its done right, the gains are not just at the top end and its VERY worthwhile. 2) Anyone can feel and measure (dyno or stopwatch) a 20-40 HP increase and if a person can't feel that, it might be time to seek a physican to get a full physical. 3) Unfortunately, there are no gear ratios being made for the 996's transmission. Porsche does not race these tranny's and engines and they share nothing with the GT-3's powertrain. There are some differerent ring & pinions being made for the 996 tranny but that does nothing to address the prime problem; the ratios are too far apart.

Steve, thanks for straightening this out for me. Re the eprom and unicip increases...I assume that's for a 3.4 and not a 3.6 ???

So then who makes the best chip? Does any company make a good package? I would like to buy an air intake, exhaust and chip that have been matched for max performance... Thanks!

unichip if you want the tuning or giac if you want out of the box. Stephen aka PHD also tweaks the giac one and makes it put out more for a very respectable price. I would go that route. another thing however I spoke to Heinz the distributor for gemballa and they offer an ecu mod and they said that it would give the most hp out of any tuner period. Other tuners could only match exactly what it put out. That then sold me there and from reading posts about gemballa ecu's on 993tt's I was impressed, but then again there's the track record with giac and the 996tt which is currently the hottest deal. tough decision. Air intake is whatever get bmc and if you want do the fabspeed mod. Exhaust aka mufflers is whatever as well I loved my gemballas. there are also fabspeed, fvd, techart, ghl, etc. the best headers it seems are the fvd/ghl's/fabspeeds they are equal length and have a nice collector. The gemballas are pretty weak in this area. techart are the same as the fvd/ghl fabs for the most part also with design but of course cost much more. so there you go for mufflers it's personal choice for the other stuff it's output proven numbers I would go steven's giac modded ecu or the gemballa for the ecu and fvd/ghl for the headers- also fvd makes both high flow cats and straight pipes for the cats- another cool deal overlooked that should give 5-10 or something.! I do agree that it is coslty to mod the cars. As for rear end ratios don I believe that I saw gears for the rear end on IMEC's web site. however the problem with agressive rear end gears much lower- higher numerically is that top speed is shortened - whatever - but that it is more difficult to drive for most off the line and all day very punchy and that the gas mileage goes to sh*t.

oh yeah and regarding the lightened flywheel look at my other post about the clutch in the current threads I found some neat info out of a magazine.

Are we talking only 3.4L here? Any suggestions for 3.6L?

Woops sorry those ghl headers have a terrible design. Sorry I would go fvd/fabspeed/tehcart only as they have equal and long length runners and a nice collector. the ghl's look like the old sbc ram headers. Not the best deisgn for sure.

both 3.4 and 3.6 just different numbers on the chip really the exhuast and intanke is the same

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