I was just wondering about peak HP numbers, Spool up and A/R ratios on a stock S4 or S5 turbocharger...



What HP and spool up changes can I expect from most common modifications like: A cone filter and 3 inch Downpipe. maybe a boost controller..



What modifications will give me the fastest spool up???

 

What about Porting the stock wastegate on a S5. Will that help spool up?? or even help me get more HP??

 

Peak hp numbers are generally around 250rwhp. More can be done, but you're asking for it running the engine that lean.

Turbine housing a/r is 1.0 I believe. However thats dependent upon the turbine. Stock turbine is a small t3. What I mean is a 1.0 stock turbine housing does not equal a 1.0 P trim housing. Porting the wastegate doesn't give you more power, it will just help control boost pressures better. If you open up your exhaust and intake you must port the wastegate or the car will overboost in 4/5th gears. 15-20psi in my experience. Exhaust upgrades will yield the most bang for your buck in spool time.

 

Porting the stock wastegate will do only one thing: Make it flow better.



Since the wastegate's function is to bypass the impeller once a preset boost limit is reached, porting it will neither hasten spool-up or increase HP. Porting the wastegate will however help to prevent blowing up your engine if you do reduce exhaust system backpressure and/or increase intake efficiency, say by removing the stock airbox.



Increasing power with these cars is easy, but you'll want to do your homework, or it's a short trip to Blown Engineville.



Good reading here: http://fc3spro.com/TECH/FM2W/power.htm

 

Wow!! That site is the ****!! thanks for the info!!!



this might be a stupid question but,.... do you have to take the exhaust housing off the turbo charger to port it??



Thanks again guys!!!

 

Oh yeah I forgot, What RPM does the stock turbo spool up on a S5..?



And what is the fastest you can get one to spool up at.....????



I have a knight sport hybrid turbo that uses the stock hot side but a larger compressor side.. And I was just wondering what to expect from it... From what I get form the FC site with the setup I plan on going with ill be looking at 300-320 HP...