Phreak

Will going from 1 and 3/4 to 2 and 1/4 exaust pipe give me too little backpressure?

I got a new exaust from the cat back and went from stock 1 and 3/4 to 2 and 1/4 pipe today, I thought it would give me some gain but it is almost as though I lost some horsepower instead. I am wondering if it is just me or if the bigger pipe reduced the backpressure too much.

Anybody got an opinion on this?

Phreak

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Ummm...
Am I there yet??
93 Prelude with H23A

93VTECLude

With a larger exhaust you may lose some low end torque but you should make up for it in the higher rpms. For a N/A engine smaller than 2.5 liters the 2.25 inch piping is what you should be using.

94SiSQO

you're probably feeling loss of low end... try going past 3000 rpms and higher and u'll feel a better gain.

dont worry, 2.25" is the best balance of backpressure and mid-range+ gains for your n/a car.. you've chosen the right one.

i had 2.25" when i was n/a.. u get used to it after a while, except going up hills..

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turbocharged 93 prelude si

brendon2k

Just to clarify backpressure is never a good thing. The reason you lose low end torque is becuase the exhaust gas is flowing out slower which makes the engine lose some of the vaccum effect of sucking out exhuast gas out of the combustion chamber. More exhaust in the chamber causes a loss of power.

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-Brendon-
09 - Subaru Impreza
07 - Honda CBR 600RR

luder4lyfe

brendon2k is right. its a missconception that some backpressure is a good thing. couldnt have said it better myself

brendon2k

Thanks, I try to enlighten all who allow.

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-Brendon-
09 - Subaru Impreza
07 - Honda CBR 600RR

VeeTec

You should be safe up to a 2.5 inch exhaust.

I had a 2.5 inch custom exhaust, with a Dynomax muffler on my 93 and it worked great with the Jackson Racing header and Random Tech cat.

I wouldn't go beyond that though, without forced induction.

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2007 Honda Odyssey EX-L w/RES (Taffeta White/Ivory Leather) 8 Passenger Family Hauler! *stock*
2009 GTI 4D United Grey Metallic (Black Leather) 6 speed *stock* (For now)
Warren