Every N/A mod seems to claim a 10-20 horse boost. For example:
cold air filter: claim 26 hp
exhaust: claim 10 hp
plenum: claim 30 hp
chip: claim 15 hp

the list goes on... My question: Does a combination of these mods "stack" the claims? Or is 20 extra hp all you can expect to get without force-feeding the engine? Please respond with your thoughts and/or experiences. R

 

The motor is pretty much maxed out from the factory. You might get some HP gains but nothing worth bragging about. Turbo/SC is the only way to go unless you buy a TT.

 

dont believe the hype... reducing weight is the best way to make the car quicker. Getting an additional 20 hp isnt going to happen without spending thousands.

 

how to install a turbo or SC on 997S ? Thanks

 

light forged wheels probably made the biggest difference to me

 

1. Improving driving skills.
2. Reducing weight.
3. Turbo or SC (TPC, EVO, list goes on...)

 

+1 on weight reduction , including unsprung, suspension upgrade is best mod for my money and as Deskjob1 says improve your driving skills, PCA DEs and Autocross are the best for the money. Highly unlikely many of us can actually use the power behind the axel anyway so what's the use in getting more pizza after you finished eating just to leave it in the box.

 

Alex at Fabspeed estimated 28-35 extra hp on my 996 3,4 with the following mods:
-Headers
-Fab 200 cells x-pipe cats
-Fab exhaust
-EVOMS intake
-Plenum
-EVOMSit chip

So clearly the individually claimed hp gains does not add up. However, one point which is often overlooked is that the claimed hp gains might not be at peak power. The the plenum for the 3,4 is claiming 26 hp gain, but when looking at the dyno plot this is at about 5000 rpm, while the gain at 6800 rpm is about 8 hp. From what I can rememeber, the same applies to the Fabspeed x-pipes.

Of the mods on my car I think the: X-pipes, plenum and chip made the biggest difference.

On the other hand exchanging my Sportdesign "GT3" wheels with some 5-spoke Carrera lightweights gave the best value for money, as the 20lb weight saving gave noticable improvemenet and the exchange cost was very low .

 

Thanx for all your replies. I called on some real lightweight wheels. (AMT? ATM?) cant remember. but i do remember they were $4800. And specifically designed for racing.