i am going to have some custom piping done but im not sure what kind of muffler i sholud get. maybe flowmasters or an imeco i just dont know because that kinda stuff is for v8s. I am also not sure if i want 3" or 2.75" piping this will be from the headers back there will be no cat
custom exhaust 2.75" or 3.00"
- Thread starter mkIII2jz
- Start date
http://supraforums.com/forum/showpost.php?p=4086344&postcount=8
3"
Is your car 5spd? Why does ur info say 6spd 2jz?
3"
Is your car 5spd? Why does ur info say 6spd 2jz?
I went from 2-1/4" to 2-1/2" on my auto N/A. The slightly larger pipe made the engine lazier until I really pushed the pedal. Peak power at high RPM did increase but low end responsiveness took a hit. If you are driving an automatic, I would not recommend anything larger than 2-1/2" because the auto likes to keep the Rpm's down.
For a stick driven N/A, up to 2-3/4" may be fine since you have better control over your normal operating RPM. For most drivers, 2-1/4" to 2-1/2" is still probably the best choice. The smaller exhaust will also sound more aggressive (more like a sports car and less like a old worn out truck). If you are a racer and keep the rpm between 4,000 and 6,000 much of the time 2-3/4 may be better.
My recommendation is 2-1/2". A 3" exhaust is simply too big for our N/A.
For a stick driven N/A, up to 2-3/4" may be fine since you have better control over your normal operating RPM. For most drivers, 2-1/4" to 2-1/2" is still probably the best choice. The smaller exhaust will also sound more aggressive (more like a sports car and less like a old worn out truck). If you are a racer and keep the rpm between 4,000 and 6,000 much of the time 2-3/4 may be better.
My recommendation is 2-1/2". A 3" exhaust is simply too big for our N/A.
I just posted about this in another thread. The discussion is about a turbo car, but the basic theory about exhaust velocity and temperature is the same.
http://www.supramania.com/forums/showpost.php?p=950217&postcount=4
For N/A, I wouldn't go over 2.75" until you are over 300 rwhp. I wouldn't go 3" until you are over 350 RWHP.
http://www.supramania.com/forums/showpost.php?p=950217&postcount=4
For N/A, I wouldn't go over 2.75" until you are over 300 rwhp. I wouldn't go 3" until you are over 350 RWHP.
I run 3" on my NA,
and I have yet to find a faster non-turbo that will out run it.
In fact, I have out run Every stock Turbo Mk3 that I have ever come up against.
The only place velocity is beneficial is in the header primaries.
Smaller pipe will only 'Look' better if the car isn't tuned properly.
When you run a more free-flowing exhaust,
you have less exhaust diluting your incoming charge.
This means you must have more fuel going in, or the engine runs Lean,
and makes Less HP.
It isn't the slower moving exhaust flow in the pipe,
or the reduced Back Pressure,
that causes people to have less power when they go to a large pipe.
It is the fact that they didn't add more fuel to deal with the reduced exhaust contamination in the next charge.
If your not willing to add a good A/F meter,
and something basic like a S-AFC to address the increased fuel requirements,
Then yes,
stick with a pinched-off exhaust........
and I have yet to find a faster non-turbo that will out run it.
In fact, I have out run Every stock Turbo Mk3 that I have ever come up against.
The only place velocity is beneficial is in the header primaries.
Smaller pipe will only 'Look' better if the car isn't tuned properly.
When you run a more free-flowing exhaust,
you have less exhaust diluting your incoming charge.
This means you must have more fuel going in, or the engine runs Lean,
and makes Less HP.
It isn't the slower moving exhaust flow in the pipe,
or the reduced Back Pressure,
that causes people to have less power when they go to a large pipe.
It is the fact that they didn't add more fuel to deal with the reduced exhaust contamination in the next charge.
If your not willing to add a good A/F meter,
and something basic like a S-AFC to address the increased fuel requirements,
Then yes,
stick with a pinched-off exhaust........