I have a 2.5" catback exhaust for my Mitsuibishi Eclipse RS. I am unsure what size testpipe I should buy.
Is the 2.5 straightpipe going to allow too much free airflow for my 4 cylinder non turbo Eclipse?
Will the 2.25 straightpipe be quieter than the 2.5?

There are a lot of threads based on this question. Use the search command to find one of them.

Most people say you lose more low end torque than you gain in high end HP and it's not worth it to buy one at all.

for non turbos, you need backpressure, to produce torque, when you got that nice exhaust, you eliminate back pressure, slap a turbo on there and it'll be able to breathe in and out really well and be able to FLY

What they ^^^^ said.


AEM CIA|SpiralMax|NGK Plugs|Magnecor Wires|GST Exhaust|Mirror Tint|Grillcraft grill|EBC brakes|Brembo Crossdrill/slotted rotors|Front/Rear strut bars|
Coming:55mmTB

ahem, backpressure is a myth.............

my NT with a full catback Apexi N1 and Greddy header definitly lost some low end and gained a little bit in the top end...It's a little bit faster than before but i was dissapointed with the gains....When i had my older turbo, after installing a highflow exhaust and downpipe, there was a huge boost in power....Id say in NT trim, catbacks arent really worth it.

Why don't race cars use a catalytic converter?

Get either size - they'll both do the trick. :thumbsup


ride__________95 Eclipse RS : 5 speed
power________Gude cams : AFX UDP : ram air : test pipe : Thrush glasspack
suspention___BOMZ F/R upper strut bars : ES inserts
shizzle_______AutoCommand remote start : Dual air horns : Kenwood KDC 5000 : Rampage sub
incomming___lower strut bars

The same reason why people take them off or guy them.

>Why don't race cars use a catalytic converter?

Race cars don't have them because their engines are built totally different. They are built to use the least restrictive intake and exhaust possible. The engines would run even better on those cars if they could just be released to the engine bay, but we all know that isn't a realistic possibility.

'98 Talon Esi

Mods:
System:Alpine CD Deck w/ 6d Changer|2 10" C2 Precision Power Subs|Fosgate 360a2 Amp
Engine:helmut.idlegames.com/sounds/tal_cdb.mp3|Bosch Platinum +4 Plugs|K&N Drop-in Air Cleaner
Suspension:Upper Front & Rear Strut Bars
Exterior:15% Tint All Around

Next Purchases:
Symborski Shifter Kit
Short Shifter

"Power is the ultimate aphrodisiac!!"

Why don't race cars use cats???

Why don't race cars use mufflers either?...duh...

How often is a racecar at 1000-3000 rpm's?

You definately notice a loss of torque. To be honest my car is more fun to drive around town with the stock intake on because it has so much torque and just feels "zippy" around town.

>How often is a racecar at 1000-3000 rpm's?
>
>You definately notice a loss of torque. To be honest my car
>is more fun to drive around town with the stock intake on
>because it has so much torque and just feels "zippy" around
>town.

stock intake and exhaust OWNZ JOO!! around town that is ;)

i've been experimenting with different exhaust and intake setups...from what i have seen the loss is torque from having a catback is minimal...i can deffinatly tell there is more power with the catback on...and the top end is very very nice...

I have the Apex n1 cat-back exhaust also but mines for a GS. I'm going to buy a turbo kit soon . What will happen to the back pressure that I have now will it be to much that I will have to buy a cat-back exhaust for a gs-t or will it just be fine?





99 GS OZ EDITION
MODS- Apexi N1 Catback
Progress Sport Springs
Audio- JVC CD/TAPE/MP3 Player
Pioneer XM Radio
2 Alpine type R 12s
MTX-775 Watt Amp

Future Mods-
Hahns Stage 2 Turbo Kit
17in Rims
JSP Carbon Fiber Blade or Arospeed Carbon Fiber ST wing
Carbon Fiber Vented Hood
Sparco Racing Seats
AEM Big Brake Kit
Final Drive Mod
Tansco Shift Kit
Bottom End Kit
More to come......

just my .02 (drag cars dont use cats or mufflers because there using methanol + gas, or racing fuel as most people call it. using this in your cat'd car, the exhaust would melt that honeycomb inside of your cat or muff. and suddenly block it, and everyone knows, with no exit for exhaust to go what happens......boooooom.