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I am planning on getting my 90 eagle talon tsi awd to around 350-400 horses.. and was wondering what size of exhaust I should use? 2 1/2 or 3? I keep hearing people say that 3 inch would cause me to lose power because there wouldnt be enough back pressure, and heard people say that 2 1/2 inch is to much of a restriction? I am lost.. and what kind of power increases could I expect running at around 15-16 psi, until I do some work on the fuel system.. my engine has 169,000 miles still runs great.. I need to do a leak down test, should I plan on getting a new motor first or what? thanks
 

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The bigger the better with turbo cars. A turbo does not need any back pressure like a NA car. With that much HP you'll want the 3" system.

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Chris Holmes
'91 Plymouth Laser RS Turbo
www.geocities.com/motorcity/speedway/5051
Turbo + Intercooler = The Replacement For Displacement
 

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definitly get a full 3 inch system, downpipe and exhaust and make sure if the one you get necks down to bolt to the stock cat you have that cut off and a 3 inch piece of pipe put in there. oh yeah get rid of the cat to ;)

bill

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95 tsi-awd
91 tsi-fwd
95 civic turbo
82 gti
 

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I disagree.
Until you exceed 500 hp a 2 1/2 in exhaust will provide optimum flow. If you plan on going beyond 500 hp the 2 1/2 exhaust will become a restriction.

The 3 in system will definetly be louder.

11's can and have been run on 2 1/2.

Thats all i have to say.
 

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gsxalex, are you sure it's 500hp and not like 350hp, i mean i just couldn't see a 2.5 inch exhaust on a 495hp dsm not being a restriction. maybe a n/a car but a turbocharged engine at 500hp is pushing alot more air than a n/a car at 500hp. i'm not saying you are wrong but is there a website that has this kind of info.

bill

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95 tsi-awd w/full 3 inch exhaust
91 tsi-fwd
95 civic turbo w/full 2.5 inch exhaust
82 gti

[This message has been edited by 4npower (edited September 01, 2000).]

[This message has been edited by 4npower (edited September 01, 2000).]
 

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also remember, the easier it is to get air in and out of the engine the easier it is to make more hp....i think it's called pumping loss, anybody???

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95 tsi-awd
91 tsi-fwd
95 civic turbo
82 gti
 

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500hp with 2.5in exhaust? damn.... What a claim! And how would know this? have you ran 11's with 2.5 in exhaust? or are u just repeating what other have said like a parrot?

This is like saying 20g turbos are good for 10's. Yes, it has been done, but only by those rare & exceptional people..(those racers with $ and shops) Others do 10's with Frank series turbo or Garrett turbos b/c 20g turbos are too damn hard to do 10's (but we all know it's not impossible)

So why tell someone 2.5in exhaust is good for 11's when we all know its impossible for average Joes like AWDturbo?
 

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I am also in the market for a downpipe and cat. I got the same answers. I was planning on getting the 2.5," everybody said 3". I still haven't decided though. I have read that 2.5" is good for 350+, but you gotta believe the real people here on the street. Maybe, do a little research on some cars, same kinda mods you're planning, what kinda times they get and then decide. That's what I'm currently doing.

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'91 Talon Tsi AWD
 

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Hi! I just picked up the "new" Extreme 3" cat-back (w/out resonator) last week. Their Web site claims that it is slightly quiter than the Thermal and the price is slightly cheaper as well. Anyway, I was going to get the 2 1/2 inch model, but I opted for the 3" as my sales person told me it is a better exhaust for our turbo cars. Well, I am almost done installing it and will post my results in a couple days. I ran into a couple problems during the install. As a side note, the system is VERY well constructed, very light, and looks very strong. However, the hanger next to the drive shaft (GSX) needed to be bent so it wouldn't rub. The sensor wire is rubbing against the floor board, which has me scared. The two support brackets at the "cat" don't line up very well with the rubber hangers. I am thinking that if I buy the DP and high flow cat, these things would line up a little better, but don't know for sure. Anyway, looking at the rear of the car, the exaust looks very nice.

I have heard it's better to go with a 2 1/2" DP and cat, then open it up with the 3" cat-back. I say this because I've heard hotter gasses move quicker, and to keep them hot just after combustion, they should go through a 2 1/2" DP. If released straight into a 3" DP, they'd cool too quickly. As a result, they'd slow down and be "tougher" to push out. Anyone heard of this?

Has anyone else bought this new system yet?

Troy
'99 GSX
 

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I have *read* that the 2.5 dp to a 3" cat-back is the optimal set up for a mostly street driven dsm because it offers more low end when at low and no boost but still flow good for the average guy at high boost. I would say that if you plan on running more than 350 hp save yourself the time and do the 3 inch all the way the first time. No matter how you look at it, when you plan on running fast (12 and better) I don't see how it can't be beneficial to run the full 3 inch system.
 

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greenstreak is absolutley right! If anyone needs more info on exhaust go here http://z31.com/board/archives/view.pl?129
This site explains everything that you need to know about exhaust systems and what size to go with
Good Luck!
Mike
RalliArt
 

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ChosunDSM,
Have you ever heard of a guy by the name Corky Bell? didn't think so.
Read his book, and you will learn. It's called "maximum boost".

Anyways, i did make the mistake of posting those figures as "hp" when they are actually "bhp" which is *british* horse power. I honestly don't know the differance between the two, and if someone does, would they please post it.
 

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As far as I know (not much really) BHP means Brake Horsepower which is horsepower measured at the wheels instead of regular HP which is horsepower measured at the crank.

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95GSX
 

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Corky Bell owns Bell engineering. I know they have Miata turbo kits, and NSX kits. Although I haven't read that book, I can imagine someone like him saying that. Buschur also said that 2.5 exhaust is good for 11's.

Like I said,
"this is like saying 20g turbos are good for 10's. Yes, it has been done, but only by those rare & exceptional people..(those racers with $ and shops) Others do 10's with Frank series turbo or Garrett turbos b/c 20g turbos are too damn hard to do 10's (but we all know it's not impossible)"

So let me ask, if you were to run 11's and have 500hp (or bhp), would you buy 2.5 exhaust to reach that goal? I figure you would go with 3 inch. It seems like what you are saying isn't very practical. I guess all the DSM owners w/ full 3 inch systems and stuck running 12's are just idiots b/c they could have done that w/ 2.5 exhaust.....=)



[This message has been edited by ChosunDSM (edited September 03, 2000).]
 

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
I guess all the DSM owners w/ full 3 inch systems and stuck running 12's are just idiots b/c they could have done that w/ 2.5 exhaust.....=)<HR></BLOCKQUOTE>

I'm certainly not saying anyone is an idiot for have a 3 in exhaust.
I am, however, saying that unless you plan on comitting your car to drag racing you can save your money and buy a quieter exhaust because a 2.5 in system should give you similar performance all the way to low 12's or high 11's.


[This message has been edited by gsxalex (edited September 04, 2000).]
 

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Jesse, what type/size of exhaust do you have? What are you thoughts of your system? Thanks!

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Troy
'99 GSX
 

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AWDTurbo,
You might be alittle confused by now with all this debate going back and forth about 2.5" vs a 3" exhaust system. If you are planning on pushing the car to around 400hp, save yourself the cost of two exhaust systems and buy a 3 inch first. Now, could you hit 400 hp on a 2.5 inch system? Maybe. The main goal is to have a nice smooth path for the exh, to travel (read mandrel bends, str8 through muffler and test pipe). I would be willing to bet less than 5% of all DSMs running 11.99 and quicker are using 2.5" pipes. Good luck!

Jesse
99 GSX
 

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I have a 2.5 inch Archer Racing SS downpipe,
2.5 inch cat-con, and 3 inch HKS turbo exh.
The sound level is moderate at the loudest. Idle is whisper quiet. WOT is a smooth tuned sound. I love the exh and would recommend it :eek:)

Jesse
99 GSX
 

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>I guess all the DSM owners w/ full 3 inch systems and stuck running 12's are just idiots b/c they could have done that w/ 2.5 exhaust.....=)<HR></BLOCKQUOTE>Unquestionably, the general consensus is... bigger is better when you are talking moderate to major build-up. Personally, I agree with that consensus. Free-flowing exaust and intake are what turbo systems love.

I am not defending Alex - he does a fine job of it himself, :) but I will say he is VERY aware of the general consensus and has balls to offer an opposing view point. I have heard others as well say that too large an exhaust pipe may under certain circumstances slow the exhaust gases.

BTW, using sarcasm to express your viewpoint, even with the "be cool, I'm not pickin a fight" smiley after it, definately reduces the effectiveness of your argument. :)

I have a full 3" turbo back, no cat. I would not step down to anything less than 3". And it is loud, very loud.

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Ted - 95 GSX
[email protected] MPH
 
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