Problems With Exhaust Size

Discussion in 'Exhaust System' started by odelarosa, Feb 8, 2018.

  1. odelarosa

    odelarosa New Member

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    Hello, i'am new here and i'am a no native english speaker xD, i have a Toyota Altezza with a 1UZ VVT-I Engine and W58 manual transmission, my friends say me that my exhaust is very small, from Headers to Y pipe is 2.50 but half way, before reaching the Y pipe is 2.0, from Y pipe to rear bumper is 3.0 (this is not done yet, this is in process).

    My car for now is for daily and some drift day in my country, so, i want the (almost impossible) balance between a good sound and not loose HP/Torque.

    PD: i want more or less 300+HP

    Please, Teach Me.
     
    Last edited: Feb 8, 2018
  2. 016UCH

    016UCH New Member

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    Hey man,

    I'm not an expert but I've read lots of posts that say the smaller the pipe the better for low end torque/power. In fact most people swear that the stock 1uz Y-pipe is hard to beat. Ideally, since your engine is stock, you're better off with the stock Y-pipe set-up.

    Look around for posts by JBrady. I think he's the subject matter expert.

    Good luck .
     
  3. gloverman

    gloverman Well-Known Member

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    On 1uz and 3uz use headers where i can then from headers to merge (y pipe if i can) use twin 2 1/4. From join single 2 1/2. One big packed muffler. There will either be a resonator or converter in the system too. Ive done 3 inch but they make more noise and less torque. If im doing an LS1 which is 5.7 litres then i go up to 3 inch.
     
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  4. Zuffen

    Zuffen Super Moderator Staff Member

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    Tell me about 3"and torque loss.

    I have twin 3"left over from my Supercharged engine and I'm too lazy and mean (the system cost $5,000.00 over ten years ago) and whilst its not to noisy it does rob the torque.

    Too big a pipe is the commonest error most people make.
     
  5. gloverman

    gloverman Well-Known Member

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    It was really interesting comparing setups when I had a dyno. Max power was always the similar between systems. One memorable comparison was two utes both built to the same spec, same gearboxes, both early series 1 engines, same flywheel and clutch, same diffs, same exhaust manifolds and same ecu with exactly the same tune loaded. Difference was one customer listened to me a had 2 1/2 system other thought exhausts theory was bigger the better like cocks and wanted it noisey so insisted on a 3 inch system. Test drive on a corner close to workshop 2 1/2 barked tyres on hard acceleration upon exit, 3inch didnt. And I tried it a few times. Ok quite a few times haha. Even after the tune was personalized the result was the same.

    Did the builder of your twin 3 inch system expect you to make around 750ish HP?
     
  6. Zuffen

    Zuffen Super Moderator Staff Member

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    We were chasing better than 750.

    The engine was probably the most complete twin screw Supercharged attempt at huge power and it gave around 600 at the end but was undriveable due to wheelspin and fuel economy.

    I'm over fighting with it and couldn't be bothered replacing the whole system.

    If i did it would have an LS3 hanging off the front of it.
     
  7. melvinmelvin

    melvinmelvin Member

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    I take it that this means that you lose the pump/suction effect in the pipes if they are too large.

    I have 4 pipes (2 cylinders/pipe) start with a small piece of 2 inch then 2.5 inch then finally 3 inch.

    Do you have to maintain the "smaller size" all the way to the end in order not to loose power,
    or would it suffice to have 2 inch/2.5 inch for "most" of the distance?

    (my interest, now, is more for lower end torque than top end hp)
     
  8. Zuffen

    Zuffen Super Moderator Staff Member

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    The further the gases get from the exhaust valve the cooler they get so the pipe can theoretically get smaller as the gas compresses as it cools.

    If running 4 pipes I would think anything over 2"would be way overkill.

    John Cribb will have good advice so wait on his reply.
     
  9. melvinmelvin

    melvinmelvin Member

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    thats a personality defect of mine, opting for overkill solutions


    yep,
    eagerly awaiting Mr Cribb
     
  10. Zuffen

    Zuffen Super Moderator Staff Member

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    There's a bit of Tim Allen (Tim the Toolman) in all of us who modify cars!
     

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