backpressure - good or bad?
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Joined: Jul 2001
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From: Ewing, NJ, USA
Re: backpressure - good or bad? (Leo95SE)
I wasn't referring to turbos. I was talking about your idea of VEC.
Ferrari has what you called a VEC in many of its road cars. Ferrari incorporates "variable exhaust backpressure control" to maintain the ideal volume no matter what the engine speed. The Ferrari F50 has one and so does the F355. The mid 90's mazda 929 had a crude one. There is a valve in the muffler which opens during certain rpm and load of the engine for better breathing. The technology is already there.
Ferrari has what you called a VEC in many of its road cars. Ferrari incorporates "variable exhaust backpressure control" to maintain the ideal volume no matter what the engine speed. The Ferrari F50 has one and so does the F355. The mid 90's mazda 929 had a crude one. There is a valve in the muffler which opens during certain rpm and load of the engine for better breathing. The technology is already there.
bonus lesson - someone develop that VEC 
oh, and CivicV10@18000rpm, im guessing your referring to turbos.. the theoretical means of creating efficiency in a otto cycle.. yes?
oh, and CivicV10@18000rpm, im guessing your referring to turbos.. the theoretical means of creating efficiency in a otto cycle.. yes?
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Joined: Apr 2001
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From: Spring, Tx, US
Re: backpressure - good or bad? (CivicV10@18000rpm)
There is a valve device in autospeed.com, I think their reason for it is noise control, but it could be used to open the exhaust direct to the atm at WOT....
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Joined: Jul 2001
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From: Ewing, NJ, USA
Re: backpressure - good or bad? (G)
Thats because at a certain amount of RPM and load, that restrictive long exhaust is free flowing. Its all about flow. That is why Ferrari uses a variable exhaust.
[Modified by CivicV10@18000rpm, 11:36 AM 3/3/2002]
Does anyone know why a more restrictive or long exhaust system makes more torque than a free flowing one (given the engine is the same with only exhausts being changed)? Or is this poppycock?
[Modified by CivicV10@18000rpm, 11:36 AM 3/3/2002]
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Joined: Feb 2004
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From: Canada
Re: backpressure - good or bad? (CivicV10@18000rpm)
Question, bear with me.
I am running a built B18A LSVTEC, compression 12.2:1. I'm running a JDM ITR 4-1, with a 2.25" straight back to a small straight through design canister muffler. Thinking I might have too MUCH backpressure, but not all that sure.. Backpressure issue is confusing me. I thought about upsizing exhaust to 2.5" with a resonator and a better flowing 2.5" straight through muffler.
What do you all think would be the best setup for my engine?
I am running a built B18A LSVTEC, compression 12.2:1. I'm running a JDM ITR 4-1, with a 2.25" straight back to a small straight through design canister muffler. Thinking I might have too MUCH backpressure, but not all that sure.. Backpressure issue is confusing me. I thought about upsizing exhaust to 2.5" with a resonator and a better flowing 2.5" straight through muffler.
What do you all think would be the best setup for my engine?
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