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3.5" exhaust?

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Old Dec 8, 2005 | 08:42 PM
  #16  
Gott des Kriege's Avatar
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From: Alexandria
^^ Do you have any sound clips of youexhaust. I would like to here as would many others wanting to spend that amount of money for one.
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Old Dec 8, 2005 | 08:53 PM
  #17  
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Here is mac_05evo's evo when it was basicly stock http://videos.streetfire.net/Player....652B&kw=4&p=13 .
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Old Dec 8, 2005 | 10:16 PM
  #18  
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Originally Posted by dubbleugly01
your lower tie bars may not fit with a 3.5" exhaust. I can only fit one of two lower tie bars with a 3" dp/cat delete combo. I think my issue is with the dp. Fitment may be an issue if you want to keep the lower tie bars in tact.
the RMR lower subframe brace not only stiffens up the front of the car but also has a depression for aftermarket DP's. www.rmrproducts.com
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Old Dec 9, 2005 | 05:25 AM
  #19  
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Originally Posted by alloyic_rs
wow that article is well written but a bit too well for my brain... what i got from it is that turbo engines should have the least restrictive turbo back exhaust, the headers should have the most back pressure, but i didnt understand the part about a downpipe and wastegate, so the bellmouth inlet is good or bad? what should be done about the wastegate outlet?
Well, in the ideal case, you would have a separate wastegate dump tube (like you would find with an external wastegate). The next best thing is to have a dividing wall between the wastegate and turbine discharge. As far as a bellmouth inlet, he says it may be better than a stock setup, depending on what stock is. To be honest I haven't really looked at the Evo's stock turbine discharge or at any aftermarket downpipes that are currently available, so I am not sure how those fit the situation.
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Old Dec 9, 2005 | 08:58 AM
  #20  
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I think 3 to 3.5 inch is good. 4 inch is over kill..
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Old Dec 9, 2005 | 09:03 AM
  #21  
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Originally Posted by andrew20195
I always thought the scavenging effects were negligible in a turbo-back exhaust. Doesn't the turbo basically interrupt whatever scavenging is going on in the header?

I always thought the whole idea when designing a turbo exhaust system was to have as little back pressure as possible in order to increase the pressure differential between turbine inlet and outlet, thereby having the highest turbine velocity.

Just out of curiosity, did you read the article I linked? Since you seem to disagree with it, can you explain why? (I'm not trying to be a jerk here, I am genuinely curious)
It was taken out of context due to my speedy, and poorly worded statement... you are correct. I've not read your article, but when I misused "scavenging", it was meant to apply to the layman's ideal of exhaust gases and pipe diameter. Not in the respect of actual down stream "scavenging" as that would naturally cause a certain amount of back pressure in and of itself. I've been beating myself up trying to convince the public at large that back pressure after the turbo "...is the devil" since the early 90's. However the concept is so ingrained in the American psyche, that even the old Garrett article dispelling the back pressure myth found reticule from people you would think knew better (a while back). So I publicly apologize for the misleading statement... maybe we are coming out of the dark ages, and people are willing to accept the fact that there not only is no need what so ever for "back pressure" after the turbine, but that it is actually utterly detrimental.
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Old Dec 9, 2005 | 09:15 AM
  #22  
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Thank you for your response, Zeus. I appreciate your clarification.
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Old Dec 17, 2006 | 01:25 AM
  #23  
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are you interested in a full 3.5" tbe exhaust? PM me
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Old Dec 17, 2006 | 01:26 AM
  #24  
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Originally Posted by Soon2BEVO
Depending on what size turbo you plan on running, a 3.5inch is slight overkill for the application. Many people run 28psi with GT35Rs (LARGE turbos!) and 3" is fine.

Do not worry about backpressure. Turbo cars dont need any backpressure at all, in fact you want NONE possible. Remember that guy Corky Bell said ... "best exhaust for a turbo is NO exhaust!" ... something of that sort!
+1
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Old Dec 17, 2006 | 01:27 AM
  #25  
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they make a 5inch supra exhaust! now thats overkill haha
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Old Dec 17, 2006 | 10:14 AM
  #26  
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i have a 3.5" for sale, PM me and I can get you pics and try and get sound clips.
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Old Dec 17, 2006 | 01:42 PM
  #27  
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Originally Posted by andrew20195

Also check this out:

http://www.tantrumwerks.com/html/Spl...t%20theory.pdf

It basically explains all about ideal turbosystem exhaust design.
That article is a very good read. Thanks.
It also goes with the saying "the best turbo exhaust is no exhaust"



Originally Posted by diablo2184
i have a 3.5" for sale, PM me and I can get you pics and try and get sound clips.
Send me some pics i wanna see it.
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Old Dec 17, 2006 | 05:01 PM
  #28  
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yeah, the best turbo exhaust is none because you dont want any backpressure whatsoever, so in this case, bigger is better. yeah 3 inch maybe ok, but then you max that out, you have to add wastegates on the exhaust. to me, whats the point of doing that? why not just do it right the first time and leave it? i have a 3.5" now, yes on stock turbo, but i will be ready for my GT series turbo that my friend has at his house. [that bad boy is huge, but i cant release any info now (for all the haters) ]. thats how i look at it.

just remember you dont want any backpressure after your turbo, and some turbo guys still dont understand this concept. N/A guys are a different story, but thats none of us here!
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Old Dec 17, 2006 | 05:15 PM
  #29  
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More than likely you absolutely do not need a 3.5" exhaust. We build them so I am not telling you this because it is something we don't sell. I am telling you this because the 3.5" is just over kill and extra weight. We do have the lightest 3.5" exhaust available.

My car ran 9.97 at 142.32 mph with our 3" exhaust on the car. My brothers car has trapped 144+ at full weight and made 647 whp to the wheels through our 3" exhaust. Etc., etc., Point is a 3" exhaust if designed properly like ours is going to flow enough for just about any application.

We install the 3.5" systems on cars we put GT42's on as the turbine housing outlet requires something that large.

Have a good day.
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Old Dec 17, 2006 | 05:25 PM
  #30  
ries's Avatar
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^ listen to the man...he'd know best
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