Good info. I can't wait to see how my car reacts. I've been saving for a while so I can make these mods. My car is stock right now other than Cross coilovers and seems to run well. My plan is to baseline dyno Mon or Tues and install the plenum afterwards, give the ecu a couple of days to adapt, and return to the dyno over the weekend.
I'll follow suit with other mods after that and be happy to post results. I have ordered a semi-ti Cross exhaust, but think I'll wait and install headers first...kinda see if there are any gains to be realized ahead of the intake and before the mufflers. Then I'll do the mufflers, intake, and finish up in 4K miles (at my 60K service) with a lw flywheel/clutch and tune last.

I'm still torn about headers, cat-pipes and intake. I've been told to modify/clean up the stock headers, not to worry about losing a power with the stock cats and to use a dry filter setup.. But I'm a little too thick-headed to believe equal length runners won't be a benefit. I have no opinion of the cat pipes other than I'd like to change them at least to lose some lbs..same with the intake.
Anyone with experience please chime in about the mods and let me know if you think the order I plan to make these mods will shed some light on which stock parts are worth replacing... I know some don't care about hp gains and will change the intake and exhaust at least for sound or weight reduction...but I have always been curious about how much power can be realized without forced induction and stand-alone management, and which parts are actually restrictive.

 

....good point nine9six....you can have a faster car without peak gains.
I'm off for a bit to watch the checkered flag..hopefully Dumas can get it done in the #7...

 

Rush...I hate to tell ya...but pretty much the consensus around the campfire is the N/A Porsche motors are pretty "maxed out" from the factory. Whatever little mods you do here will give you gains that are pretty much negligible. It is NOT worth it to extensively mod a N/A motor.

now if you have a TT that is a whole different animal and you get a whole new car with mods...the TT literally wakes up after exh and chip and so on.

Now back to the NA. As stated before the ONLY major HP mod is the super charger. That is the painful truth. You can have the plenum, intake, headers, cats, exh, chip, the list goes on...and you know what? YOU MAY LOSE POWER! Yes...after spending tons of money adding this and that in the end you MAY LOSE POWER. So be careful with everything you are planning. One thing may cancel out the other.

I also agree that the weight reduction stuff really helps. I personally have the Evo stage II clutch and LWFW and that makes a difference. Super responsive, the revs are zippy and the car feels great.

Hate to tell you..but mod sparingly on the N/A motors. Your car is maxed out!

 

Thanks AI.. I really have no expectations..I'm going to make the weight reducing mods regardless. The only mod that has had positive performance reviews from everyone I've talked to that has it is the plenum. I hope to install a supercharger kit by year's end..I figure what might not make power now may make a difference with forced induction. But part of the fun is finding out..

I did talk to a guy that was involved with a 996 Grand Am Cup effort..he was strictly going by memory, though, so his info was approximate. On 1 race car, which is very stock, the plenum made a huge difference in low end and measurable across the range, modded stock headers about 5hp, house-made exhaust 5hp and they tuned for an extra 4hp after that. (wheel numbers) Couldn't offer numbers on a CAI. Stock cats retained. But he also said car#2 realized substantially more on the header and tune..only difference was it had a Boxster MAF... They used a SPEC clutch/flywheel combo and, like you said, enjoyed much more spirited revs, which would be expected from dropping that kind of weight from the crank. He didn't remember any specific numbers from the wheel, but said it was substantial. The MAF is interesting..they had MAF issues from an oiled filter and somehow they ended up trying a Boxster unit..

 

if i can do it all over again, i'd only do a muffler for better sound (i doubt it'll add any hp), pss10 or KW3 and GT3 sways/drop links. keep the rest of your mod money in the bank and start saving for a tt.

 

Do you have dyno to back up your statement or did you only "hear" on the forums from other people with no dyno that said so?

 

Me too plus a BMC filter

 

Talk to greg at RSS, nice guy they developed the plenum and they have done LOTS of research and development. I heard the same thing AI said from greg when I visited the facility. They are VERY knowledgeable.....

 

Ill second that... ive got them all on mine,(except my dream.. a SC) and according to my extremely accurate butt dyno, my car can take a Turbo

but in real life? Sounds great, tons of fun to drive, way faster then i really need it to be, and is a AWESOME canyon carver, but any more HP? i doubt it.... but have fun pouring money into it! I really enjoyed the exercise.

Realistically, 996's arnt drag cars. I dont try to outrun every car on the freeway, or off street lights. I rather enjoy waiting till we hit the twistys.. then lets play. Spend the money on brakes, suspension, tires and exhaust. Much more bang for your buck.

 

Hi, I did the mods you list. LTFW stage2 ,full exhaust 100 cel cats, EVOMS V-flow, EVOMS flash, and last was the plenum. Never did I dnyo the car along the way. I did feel something so I keep on going! My brother in law has a stock 03 cab 6spd he would get me out the hole every time and stay there. Now I pass him in 2nd and in 3rd I am 4-5 cars out. The plenum made it all feel better. The hp increase is based on stock plus that one mod. The plenum however just works with or with out mods. you really feel it. I did put the car on the dyno at full temp(1hour driving) and pulled a 286 rwhp on a dynojet. My car is an 02 C2 with 65000m on it at that time.
Tim

 

Well...no sir. No dyno sheets. But I am a fairly good researcher and based on NUMEROUS experiences from people on this board and others, I feel my statements are a good "GENERAL" consensus.

"Most" people agree that the N/A motor is pretty tuned maxed out from the factory.

"Most" people agree that most mods to a N/A motor is for appearance, or sounds or NON HP type mods like brakes and suspension.

"Most" people agree that after they did "everything you can" to a N/A motor, they did NOT experience huge super gains. Yes maybe a hair faster, a tad more responsive, but some have experienced the opposite and lost power or car felt slower.

in the end...YMMV.

 

What about those people who do have factual data to backup their claims? There was a few guys who dyno'd a 3.4 with dyno graph stating 25ish hp peak gains. To me, how most people "feel" about the mod is subjective. Those who did before and after dyno, now thats fact.

Have you tried any of these mods? Or do you go around these forum preaching what you have read of others opinion but never have experience for yourself?

 

IMHO, for MOST of us, modding is very little about performance and more about enjoyment of customization...making it yours and having fun doing it. It can get expensive, but it's your money...so go do what you want.....just don't expect to get any serious performance improvement...the other senses may feel good though.

Also, regarding posting hp gains as a result of a dyno...this can be very misleading as dynos are known to vary quite a bit (and can be manipulated quite easily).

 

I cannot agree with you more about teh enjoyment of customization because to many people, it is not worth it to fork up thousands of dollars for 10hp. But for some, 10hp gains is 10hp gains and they are happy about it.

Dyno can be misleading and dyno can be manipulated but if you try and keep similar weather and condition with the same dyno, I believe that you can get a good estimated power gains or loss. It is also better than the seat of pants estimate.

My main point is that I am sick of people who never had any experience with any of these mods then going on these forum preaching about something they have only heard.

 

would it be better to mod a 99-01 or 02-04 996?