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3l turbo bottle neck???

SicSE said:
I know others may disagree, but I'd bet he would see AND feel some nice gains from a larger exhaust.


Wouldn't you have said the same thing about your current setup before you upped the pipe size?
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thats why i said seemed.;) its my opinion that if its blown, a 3inch is in order. i probably wouldve said the same, u're right. but the thing is that i never knew what size it was like i said. soon as i found out, it had to go.
 
bagged FI car was running on open downpipe the weeknd of SZ, because he didnt havetime to hook it up. i'm willing to bet he just left the exhaust off it....
 
BrApple said:
iirc baggeds svt still has stock exhaust and it put down 260 hp ....
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It's not all about the HP.

The bigger the exhaust the less backpressure the turbo has to deal with, aka the faster it will spool and the less boost lag you will have to deal with, aka the better your torque curve will be and consequently the faster your car will be.

Any boosted car, no matter what size engine should have at least a 3" exhaust imo.

I built my entire (zx2 - 3" mandrel bent mild steel) exhaust for about $120 + muffler, no resonator. If you have a little know how you don't have to pay the ludarcris price for a trubendz.
 
Beans said:
Sound clip?
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here's a picture and a couple of clips. didnt feel like taking quality pix or anything. just figured all u'd want to hear is the sound.

HPIM4438.jpg







by the way, for my tips to stick out as far as i wanted them, i had to scrape quite a bit of the rear lower black fascia at the bottom. only visible from the bottom:cool:
 
FYI, I'm running a 2.25" Borla catback, but I was thinking of upgrading eventually for the reasons posted. Here's what the experts have to say:

Maximum Boost by Corky Bell said:
It is easy to get overeager on fitting large-diameter pipes into an exhaust system. 'The larger the better' is not the case... [To calculate the ideal pipe size, use a maximum velocity of 250 ft/sec for the exhaust side rather than the 450 ft/sec maximum we used for the intake side.] The tubes for the hot gas on the exhaust side should therefore be larger than the tubes for the cooler intake side. To size a tailpipe you can [compute it using gas velocity or simply select] a tube diameter approximately 10% larger than the turbine outlet diameter.
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In the chart appearing in his book, 2.25" is appropriate for 200 bhp, 2.5" is appropriate for 400 bhp, and 3.0" is appropriate for 700 bhp. If running a "true dual" exhaust, then 2.0" is appropriate for 650 bhp. Now, in the chart appearing in "Street Turbocharging" by Mark Warner, his chart shows that 2.0" is appropriate for 200 hp and 3.0" is appropriate for 400 hp and 600 hp requires a 4.0" exhaust.

From what I've read, it's more important to minimize restrictions after the turbine than after the cat.
 
SoopaCooga said:
In the chart appearing in his book, 2.25" is appropriate for 200 bhp (e.g. 0 psi 3L), 2.5" is appropriate for 400 bhp (e.g. 16 psi 3L), and 3.0" is appropriate for 700 bhp. If running a "true dual" exhaust, then 2.0" is appropriate for 650 bhp. Now, in the chart appearing in "Street Turbocharging" by Mark Warner, his chart shows that 2.0" is appropriate for 200 hp and 3.0" is appropriate for 400 hp and 600 hp requires a 4.0" exhaust.
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This is where the problem lies on this topic. For every "expert" that says one thing, you can find another "expert" that disagrees. Throw in the fact that "appropriate" is a subjective term, and you might as well roll some dice to decide your exhaust size.

SoopaCooga said:
From what I've read, it's more important to minimize restrictions after the turbine than after the cat.
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Agreed. This is why a larger downpipe is often one of the first performance mods that people do to a factory-turbo'd car. What good is an adequately sized cat-back exhaust if there's a bottleneck betwen the turbo & CAT? Not very much good.
 
SicSE said:
This is where the problem lies on this topic. For every "expert" that says one thing, you can find another "expert" that disagrees. Throw in the fact that "appropriate" is a subjective term, and you might as well roll some dice to decide your exhaust size.
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Okay, but expert opinions are at least a place to start, if not the be-all-end-all. Seems to me the best way to determine whether or not your exhaust is restrictive is to drop the cat-back and go for a ride or dyno.
 
Pipe size is not always the problem here on many cars. It is the restrictions on the pipes that makes the cars exhaust not flow enough. Which is why many people upgrade their exhaust tubes to a larger DIA, but additionally add high flow mufflers etc which over does it for certain cars. I'm speaking for all cars here.

You must find a balance and it is done so by the cfm flow your car puts out!!!

Each car produces different wave lengths which is created by many things, CR, cams, rockers, CI etc. Those crucial elements will help find the amount of exhaust gases that are releasing into the exhaust. Those will help make a proper assessment on exhaust flow needed on a specific car.

Measuring hp to find an accurate exhaust pipe is wrong.:help:
 
SicSE said:
Agreed. This is why a larger downpipe is often one of the first performance mods that people do to a factory-turbo'd car. What good is an adequately sized cat-back exhaust if there's a bottleneck betwen the turbo & CAT? Not very much good.
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true. as much as i think exhaust size is important, the cat is of even more importance. i do not believe the cat i had was a highflow one. it was a cheapo installed by some hack of a shop here in vegas a few years ago. if the exhaust gases flowed effectively through the cat, the exhaust size would be of little consequence. and by that, i dont mean like an inch piping or sumthn. it is of my opinion that i would've been fine with a 2.5 inch piping and highflow cat. thats why i was having problems with the dpfe hose blowing off under WOT due to an ineffective cat converter. but i'll tell u this much... a 3inch certainly doesnt hurt:)
 
Some may differ, but I think it sounds like a bassani or at least my bassani. TX00SVT who has the SAME EXACT exhaust as me from headers on back, his exhaust is much quieter than mine...mmm
 
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