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Fore!
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Discussion Starter #1
I don't care about sound or appearance.

I want to know what performance gains may occur, how much, and why.

I have heard some opinions that there are minimal gains and a lot of hype.

Also, what is the benefit of an aftermarket exhaust together with a supercharger on the V6. Is there something special about this combination that makes it better?

I am not talking about headers, but if you want to chime in about the benefits of headers and why, that's cool too.
 

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i say around 10HP....anytime the flow of air is increased in a car..it run's more efficient and increases HP...most stock exhaust are very restrictive...

check out the search function..get alot of answers.
 

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aldolicious77 said:
i say around 10HP....anytime the flow of air is increased in a car..it run's more efficient and increases HP...most stock exhaust are very restrictive...

check out the saecr function..get alot of answers.
Not necessarily, remember our turbos need some exhaust to help spool the turbo. Too much air flow could cause a decrease in both HP and torque especially in the low range where we need the most HP and torque.

However, I can really think of any exhaust vendors that have negative effects. Some have no benefits other than cosmetics and sound.

Editted because my wording was misleading.
 

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Fore!
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Discussion Starter #6
Julian,

Thanks for the numbers, but I am always skeptical of manufacturers claims regarding performance. From this forum I have gotten the sense that most manufacturer's claims of performance increase are usually overstated. Does anyone have any before and after dyno numbers?
 

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...remember our turbos need some back pressure to help spool the turbo. Too much air flow could cause a decrease in both HP and torque.

However, I can really think of any exhaust vendors that have negative effects. Some have no benefits other than cosmetics and sound.
Backpressure to spool the turbo?...exactly how and why?

The gas turbine will turn faster with the least possible back pressure. We're not talking about air flow, we're talking about hot gas flow. On a naturally aspirated engine an exhaust system too large in diameter will allow the hot gases to expand and cool, and the sound pressure waves, which travel at the speed of sound (which is temperature related) to slow. This hurts low end power. There may be a somewhat similar condition with the exhaust from a turbocharger, but certainly backpressure is always bad. Look at ads for large truck mufflers...5" diameter off the turbocharger, and advertising 30% backpressure reduction. http://www.walkerheavyduty.com/walkerHDdetail.asp?sec=prd&page=muf_megaflow


Ken
 

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Also, what is the benefit of an aftermarket exhaust together with a supercharger on the V6. Is there something special about this combination that makes it better?
You will see more of a benefit under forced induction than NA. Some systems can weigh less, some will flow better. More air out means more air in. Your engine is a big air pump, and an efficient system will always produce more power. Of course designing an efficient system takes many variables into consideration, and I would look for a system that is designed for your application (supercharged or na).

If you are suspicious of claims, then ask the manufacturer to guarantee them. Tell them you will take a before and after dyno, and if the gains are not within 10% of the stipulated gains, then you want a full refund.

Of course most exhaust systems are IMHO kind of like wheels, a way to individualize your mass marketed ride. That being said, I have one (but OEM wheels), go figure.
 

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When I said back pressure, I meant recirculated exhaust. Forgetting that back pressure in the true sense is part of the exhaust dictionary of terms and would be confusing.

What I meant to say, IIRC, is too large of an exhaust can cause the turbo to spool slower when compared to the base amount of exhaust. It will take a longer time to build enough exhaust pressure (or gas) to cause the turbo to spool effectively. Causing a large lag and hurting performance.

If you are increasing air in, it is always good to increase air out. I was speaking more for a stock engine. A 3" turbo back might hurt more than help. With chipping and or bigger turbo, this is a different story.
 

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NYC4Ever, the numbers from SuperSprint are dead on the $$$ because I provided them back in 2002. I think my 2K 4 Motion was one of the first header back systems in the United States. I did the tests at Curry's Automotive before installing my Supercharger and intake on the V6. Julian, run some dyno's on your car because with the right plugs you should be close to 280HP at the wheel and real close to 300 at the crank with the BMC Intake.

The reason you want to include an upgraded exhaust system with major performance mods; especially forced-induction, is to decrease the amount of restriction after combustion. The more your car can breathe in good air and spew out exhaust increases efficiency. PES will not install a G2 unit unless you have an upgraded system. I first installed the Remus Dual Muffler/Resonator system on my 4 Motion and I noticed better throttle response on the low-end. When I installed the headers and full cat-back exhaust from SuperSprint, the powerband changed dramatically without the PES unit being installed. You will honestly see about a 25-35HP difference depending on the setup!!
 

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NYC4ever - if my schedule allows, I'm going to dyno the car at www.pruvenperformance.com this friday afternoon. I'd like to see where things are right now.

Granted my system consists of:

Left and Right exhaust
Evo Intake
G2
NGK iridiums

so it's not a complete system that I'm dyno'ing.

It will be at least a few more weeks/months before SS sends me the center exhaust and headers. I also haven't decided whether or not I'll be switching to the BMC intake. Everything will be done just prior to waterfest, so I probably won't have the complete numbers till then.
 
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