I've been told to expect 40-50 hp gains with the full turbo back exhaust

 

its because of higher boost being on tap

 

probably more hp than that on an otherwise stock s4 turbo...

3" exhaust and a stock s4 wastegate............................. add in the fact the rb exhaust kicks butt and the stock exhaust is ~~~~~~~~~~~~~~~~~~~

 

60 is the figure I've heard claimed.

 

Racing Beat claims that it will give you 59 horses. Thats whats on my t2 and its because there is no cat. Also when buying the exhaust you will need to get a fuel cut defencer because if you dont, fuel will not go to the rear rotor because of the higher boost this exhaust allows.

 

Its more like 100 hp to the flywheel or close to 250 to the wheels........ with the right setup.

 

Hes asking about what the exhaust alone does. A gain of 100 is with a good bit of other stuff done to it like fuel mods to keep from blowing up your engine.

 

could I bug you to explain why this exhaust woudl cause fuel to not go to the rear rotor? and what exactly a FCD does...sorry im noob

 

due to the face that this exhaust causes ummmm boost creep you could say the stock limit on the turboII if im correct is 10psi well the racing beat fuel cut defenser (FCD) allows you to boost more than 10psi but if you dont install this fuel stops going into the rear rotor when the computer senses the motor receiving more than 10 pounds... so to really notice the power in this exhaust system you would need the Racing Beat FCD and the Racing Beat Exhaust
TwEaK

 

I thought the4 boost limit on the s4 was 5.5psi

 

If you dont upgrade your wastegate and have a exhaust, such as a RB, your boost will creep up. the ECU will start cutting fuel to the rear rotor once i reaches a certain psi. then you go kaboom.thats why you need a fuel cut defencer.

 

<---noob is it the same for the cat back exhaust?

 

nope...the full exhaust thats being mentioned replaces down pipe, main cat ,and cat back .... thas the whole shabang

 

http://fc3spro.com/TECH/FAQ/fuelcut.html


-Ted

 

stock psi on an S4 TII is 6.2 PSI. you will hit fuel cut around 8.5 PSI. this is only from what i have read on the forum so if im wrong...blame those fools over there

 

ok i just read the FC3S article and i guess im wrong...forget that last post...

 

thnx for the explinations...makes sense now

 

stock boost is 5.5 and 7.5 on S4s and S5s respectivly. just memorize ReTed's website and all you noobs will know everything it's an amazing site.

as for the turbo back, I have one, it's deffinitly a really awesome exhaust. I'm not sure how much hp you can expect, I replaced my stock exhaust which had clogged cats but it's a good bit

 

Most of the gain is not simply from the boost increase. At stock boost with a 2.5" single exhaust my car made an extra 30hp+. It stands to reason that a properly designed 3" exhaust should gain even more. http://www.geocities.com/jeffguilfoil/dynoresults.html

 

so if i get a cat back exhaust set up would i need to go thur all that too?

 

Yes it is, but that info is still wrong.

From the 88 FSM: Boost pressure 45.2kPa (6.56psi)

From the 89 FSM: Boost pressure 57.0kPa (8.25psi)