How much HP will a single 3 inch exhaust support?

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Thread: How much HP will a single 3 inch exhaust support?

  1. #1
    Turbo351
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    How much HP will a single 3 inch exhaust support?

    How much HP will a single 3 inch exhaust support?

    How big of exhaust are you 800+ hp guys running?

    My target is to make 800 engine HP.

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  3. #2
    iSketch Master! AlxRSPTT's Avatar
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    The bigger the better. I think if you have the cash to get up to 800hp you can afford a bigger exhaust. Having a smaller exhaust just makes it harder to make the power, but you can still make it. Try searching around a bit i'm sure its been covered many times before.

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  4. #3
    SupraForums Member sadil's Avatar
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    Son made 817hp with 3" exhaust . Correct me if I am wrong.

  5. #4
    Addiction Giggs's Avatar
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    I think alot of the high horsepwer guys use around 4inch exhaust, I know Ryan Woon uses a 5inch exhaust though.
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  6. #5
    AEM Nutkase BLKMGK's Avatar
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    I made 623RWHP with a T78, Greddy DP, Blitz mid, HKS Carbon/Ti on pump w/meth injection - 1.7BAR. This was a 3inch setup although the Carbon/Ti has a spot where it necks down some. Race gas I'd have hit 700RWHP easily IMO but I've NOT ever done it. If you're going for 800HP (why that number exactly?) you will likely need cams or alot of boost. Around 750RWHP I'm told the stock cams begin to become a bottleneck.

    I am now running a 4inch exhaust ALL the way back - WOTMs 4inch cat back, BLs DP/Mid. Ever been in a Mustang with 2chamber Flowmasters? I can't say it's quite that loud but I'd expect I'll get some unwanted attention from the local police if I'm not careful. Unfortunatly I couldn't put this DP on my T78 to check power increase - bummer! 4inch exhaust does allow the turbo to spool more easily but without back to back testing it's impossible to say how much easier. I can hear that sucker spooling EASILY and on light shifts I can hear it slowing down - it's wild! A silencer WILL slow spool, I found that out on my T78 setup - the effect was noticable for sure.
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  7. #6
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    From what ive heard the WOTM doesnt fit all that well and needs some work to make it line up perfect. And dont you need some back preasure to help spool the turbo?
    -Dan

  8. #7
    AEM Nutkase BLKMGK's Avatar
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    The 4inch system from WOTM fit pretty well. It would've helped if there had been something in the box to tell us where the hangers were supposed to go but we got it. It's poretty rigid and I wish it weren't but it did fit without us beating on it or making mods.

    Backpressure to spool a turbo? You're kidding right? Hell NO you don't want ANY backpressure in the exhaust if you can help it!

  9. #8
    Shawn Davis Ubermensch's Avatar
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    Originally posted by BLKMGK

    Backpressure to spool a turbo? You're kidding right? Hell NO you don't want ANY backpressure in the exhaust if you can help it!
    But you do want to maintain exhaust gas velocity...which requires some pressure differential.

  10. #9
    SupraForums Member Einsti3n's Avatar
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    Sorry, Off topic. With the WOTM 4in cat back do you have to welf up new hangers or dose it slide into the existing?

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