3in turbo back good or bad

[SherbertRocket]

Is three in to much flow for stock psi? Would I lose power?

[Maniac0301]

I don't know specifically on the MSP but for most turbo cars the turbo produces more than enough back pressure for the motor. After the turbo the exhaust systems main job is to get the exhaust gases away from the turbo as fast as it can so that it won't put pressure on the blades. For this job the bigger the better.

[jersey_emt]

3" turbo back is good. You MAY lose a bit of power compared to a 2.5", but if you turn up the boost later on, you'll be glad you got the 3".

[jred321]

there is no such thing as too much flow. the motor won't produce enough gas though to see much of a gain over 2.5", but 3" won't hurt anything

[kwiktsi]

Originally posted by jred321
there is no such thing as too much flow. the motor won't produce enough gas though to see much of a gain over 2.5", but 3" won't hurt anything

Take all three answers, put them together and there is your complete answer :). They are all right. You may not "need" it now, but it doesn't hurt for down the road. It will not affect mid range in the least (at least nothing noticeable) due to the turbo itself providing the back pressure and will only help it breathe after the turbo.
Joe

[SherbertRocket]

So out of Apex 3in turbo back, insidious 3in turbo back, or ion 3in turbo back which would sound and perform the best?

[AutoBox]

whatever is catless and the less retrictive :) IMO anything slowly the exhaust gas up hurts performance and gives the exhaust a more raspy tone...aka ricey....of course this IMO

[SherbertRocket]

anyone have power gains

[SherbertRocket]

like dyno charts of powergains from the different exhaust systems

[AutoBox]

i got a baseline dyno done on my stoc msp last week and will have my turbo back put on this week or next..then another dyno done....ill post a thread when it happens

[^tyrant^]

im planning on getting the apex 2.5 with 1 hi-flow cat

[SherbertRocket]

Ya i have the 2.5 apex catless which kick ass. But im thinking about going bigger

[AutoBox]

i recommend 3" if u plan to boost past stock....like stated....turbos like to breath

[SherbertRocket]

how much boost you talking about? 8 or 9?

[AutoBox]

yeh honestly i think a 3" is better if u plan to turn up the boost at all

[jred321]

you won't outflow the exhaust capabilities of 2.5" until you get to the 400hp mark. it won't hurt to go bigger, and you may see very minimal gains, but basically all you'll get is more noise

[AutoBox]

where is this information from??? i never heard a 400hp car runnin a 2.5" exhaust

[jred321]

http://buschurracing.com/faq_dsm_int_ex.html
among others

[hukster00]

it realy depends on what you planing to do,

this is what i found when i was looking wich one to get




Consider this: John S. ran 11.3 on HKS 2.38” cat back and BR2.5” press bend DP. He swapped that system in favor of BR 3” system and went 11.2.

Clearly, 3” will flow more, but you will not notice any difference between 2.5” and 3” systems on a 12 sec car. I have seen it first hand...

dsmtuners.com

[AutoBox]

ahh boost creep makes sense...the turbo would be flowin so much....cool info....still runnin a 3" though.......

[jred321]

yea our o2 housing should help prevent that as nobody with 3" has suffered from it yet, but it could be a concern if people start to push more power

[hukster00]

hmm but we dont have o2 housing, our o2 is in the mani :p , i gess you mean the spipe :D

[SherbertRocket]

so 3in is the way to go even if i were to leave it stock for a while would i loose torque and gain hp or gain both?

[jred321]

Originally posted by hukster00
hmm but we dont have o2 housing, our o2 is in the mani :p , i gess you mean the spipe :D
yea that's what i was talkin about, the equivalent of the o2 housing on a dsm :)

[hukster00]

ye hehe dame dsm's, its like every one had one :D

[hukster00]

Originally posted by SherbertRocket
so 3in is the way to go even if i were to leave it stock for a while would i loose torque and gain hp or gain both?

what ever you decide you will make hp/torque

[BinaryRotary]

Originally posted by SherbertRocket
so 3in is the way to go even if i were to leave it stock for a while would i loose torque and gain hp or gain both?

The size of the motor and the size of the turbo are whats going to determine how much back pressure you produce in the xhaust system. With the smalll 2.0 liter engine and the output of the turbo, you're not going to see any gains from a 2.5 to 3.0 exhaust. Go with 2.5 inch. You have more room to drop the car also, if you AutoX.

[iON Performance]

SherbertRocket - The biggest advantage with our system is that it's a TRUE full turbo-back system. A 3" exhaust will maximize the pressure difference throught the turbo, thus minimizing lag.

[Maniac0301]

Not sure where you get the 400hp numbers but an unmodified 1.8t GTI gains an extra 5hp between the same brand 2.5" and 3" exhaust systems. A chipped GTI gains and extra 10hp between the two. These dyno runs were done back to back.

[03MSPRO]

I have a 2.5" Apex DP and 3" Thermal exhaust. I like the setup.

[hukster00]

i have TRUE full 2.5 turbo back and i like it to :D

[gcotton]

I have a 3in dp and exhaust with no cats. I suggest 3in.
Bigger is always better

[03MSPRO]

Originally posted by gcotton
I have a 3in dp and exhaust with no cats. I suggest 3in.
Bigger is always better

Sometimes too big hurts....;)

[BinaryRotary]

Originally posted by gcotton
I have a 3in dp and exhaust with no cats. I suggest 3in.
Bigger is always better

Wells lets throw a 4 inch on than.

[Glowmunkey]

Originally posted by BinaryRotary
Wells lets throw a 4 inch on than.

If it don't fit, push harder.

[SherbertRocket]

what about the new insidious 3 in back or apex 3in back

[gcotton]

This aint no damn SUPRA

[Spicy1390]

I am having a custom 2.5 leaving the turbo, then it tapers into a 3" inside a hi flow cat. Then the 3" the rest of the way back. Makes for easier fitment..