Msp Exhaust

[PHILLY-ORANGE]

I have a friend that does exhaust is it better to do from the cat back or turbo back and what should I get 2.5" or 3" will this create back flow is it poss. to 3" turbo back custom or am I going to need parts

 

[Vulcanon]

well if you want to pass emissions you may want to keep your cats

 

[changedman]

3" will be good for turbo applications. 2.5" would be ok if you are N/A

 

[Torco-MSP]

i would say turbo-back catless 2.5".
3" just seems way too big for an engine that only produces 170 at the crank.

 

[changedman]

well down the road, 3" would allow for higher output, say he cranks the boost...

 

[Torco-MSP]

i still dont think that 3" will ever be needed with the stock internals.
the msp cant even boost that much any how compared to gs-t and wrx's. even v8 dont really use 3".

 

[ARD MP5]

According to several books published by turbo designers I would definitely say 2.5 or 2.75 is definitely more than enough for the power output that the MSP power and drivetrain can withstand. There maybe some initial loss in response with the bigger exhaust.

I would go 2.5 turbo back. This will allow for better clearances as well in the rear of the protege.

Rishie

 

[jonnydoe48]

yeah, out of all the debates i have seen on this board, the conclusion is always that the 2.5 is all that is needed..even with turbo application.

 

[KyRaceFan]

2.5in turbo back, with high flow cat, will be plenty for this car, even when upping the boost to 9 or 10.
Expect faster spool, possibly even upping the boost a little, so if you have a BC, be sure to check your gauge, you may need to adjust it a little.

 

[PaulMP3]

i have 2.5" turbo back w/ high flowcats and my turbo is a lot bigger. I would think you would loose some low end torque with 3".

 

[Notorious]

3" is too big for a turbo our size. With a 2.5 or 2.75 hot gases will flow better.

 

[PHILLY-ORANGE]

will I get alot off back flow from what I understand the backflow reduces low end torque will this happen with a 2.5 or 2.75

 

[iON Performance]

PHILLY-ORANGE - Ok, there's two sides of the coin here. If you go with 3", in N/A mode (ie: before boost comes on) you will loose torque b/c of pumping losses. However since you have a turbo car, the larger the pressure differential there is, the quicker your turbo will spool up. It also allow for higher flow rates @ higher boost levels.

With 2.5" or 2.75" piping, in N/A mode (off boost) your car will retain more torque, however your turbo will spool slightly slower, and the flow rate will be lower then a 3" system.

 

[changedman]

Ion, how much for your exhausts?

 

[EvilMSP]

That is some good info ion, but what do you think persoanlly. I can see the benefits of both systems but what do you think is better? Having a little less torque at the start? Or getting that turbo working faster??

 

[iON Performance]

pdhaudio - there's all the info you need ->
http://www.protege5.com/vbb230/showthread.php?threadid=28915

Wilsman00 - well, it all depends on what you want to achieve in the end. Different types of driving/racing have different requirements. ie: Road Racing in a turbo car, you're going to usually be on boost, so no need to worry about loss of torque. Drag racing, you usually try to "pre-load" the car and by revving your motor you help create boost, so loss of torque here isn't too much of an issue either.

The only place it becomes an issue is on the street. The torque loss however from a 3" system is quite minimal vs. decrease in lag and extra power on boost that it can be easily over come by just down-shifting to the next lower gear.

 

[PHILLY-ORANGE]

Ok that cool thank you I'm going to put on a boost control on and hope to kepp it at 8 or 9 psi and add a high flow cat.

 

[PHILLY-ORANGE]

thanks so much 4 the info im printing it out and using it thanks again

 

[DiscreetSpeed]

if your just doing it from the down pipe then there is no point in getting 3 inches, 2 1/2 will flow the same, reason being the s pipe after the turbo has an outlet size of 2 1/4 so 3 is point-less.