On an LS i always though 2.25 would be better than 2.50 ? what are your thoughts on the diameter of the piping ? whats better ?

 

exhaust diameter shouldn't be calculated purely off the size of the collector. also, "some bolt ons and fuel tuning" do not necessitate the need for a 2.5 exhaust on on LS. a 2.25 is fine on an LS unless you were to go forced induction, ls/vtec.

 

thats what i was thinking so a 2.25 would be good for say i/h/e and maybe down the line some nitrouse ? also how do you do fuel tuning ?

 

yes 2.25 would be fine. u can tune the fuel w/ a fuel pressure regulator,vafc. if you decide to do some serious mods you can get rid of the fpr, then add some bigger injectors and do tuning via standalone (aem ems, hondata).

 

2.5 is better but if you can find 3.0 that is the best

 

youre an idiot.

 

The 2.5 would be better, the back pressure is released smoother,I guess you would say.

 

hmm some mixed things here .. i always heard the 2.25 would be best now i'm hearing 2.5 doh what to do ? and 3inch is for turbo isnt it

 

*cough*specify mandrel or crushed


[Modified by XDEep, 3:34 AM 1/2/2003]

 

2.25 mandrel .. 2.5 crush ? does it equal the same ?

 

i wouldnt buy nor make anything less than a 2.5.

 

i had 2.25" on my car when i first got it, then had 2.5 inch put on, all the way down, it makes a nice difference, go with 2.5", trust me

 

my friend has I/H/E. when he first dyno'd his car.. he had a 2.25in exhaust. he swapped it out with a 2.5in exhaust and gained 2-3 hp from it. it actually was better to go with a 2.5in exhaust.

when i first got my car.. i got a 2.5in exhaust... everything else i left stock because i was puttin in a turbo kit. i raced my friend who has the I/H/E and 2.25in at the time and i always beat him... 8 out of 8 races. better driver? nope. we switched cars and he would beat me. 2 out of 2. thats what gave him the idea to go with a 2.5in exhaust. he has the dyno papers to prove that a 2.5in exhaust benefitted his LS.

funny thing... if you noticed.. he had an intake and header... i didnt... and he would always lose. maybe its cause i got a RS?


[Modified by dlplayboy, 12:44 AM 1/2/2003]

 

dude, what's your wheel/tire setup? and what has that chip done for you?

 

i think the figure is a crushed bend reduces the cross-sectional area 15-20%. i wouldnt necessarily consider it the same since our engines rely on exhaust velocity, not volume. so a 2.25 mandrel would have a quick, smooth exit path while a 2.5 crushed will be bigger, but then it gets choked at the bend.. kinda reminds me of squeezing a straw in the middle. as to whether or not mandrel bending is worth it i dont know..

again, could you guys please specify whether or not your 2.5 is crushed or mandrel bent, as a 2.25 crushed vs 2.5 mandrel is a lot more significant than 2.25 mandrel and 2.5 crushed.

 

This thread's kinda convincing me to go with 2.5 inch piping. I have 2.25 inch as of now. So the 2.5 is really better for topend oppposed to the 2.25? But I assume it loses some low end at the same time right?

 

It aalllll depends on your specific setup. There is no right or wrong, and there is no better or worse. It all depends on what youre running. For an LS with boltons, a 2.5" exhaust is overkill.

Ill say one thing, unless youre FI or have a decent amount of NA work done, if you already have 2.25" or 60mm piping, I definitely wouldnt spend the money on a 2.5" exhaust "upgrade".

Only a few manufacturers (DC & Comptech if I remember right) include true 2.25" piping with their setups. Most use 60mm, or 2.34" piping...so there is a happy medium for you. That .16" in piping is going to make FAR less of a difference than a bottleneck or resonator or canister design. You may have a 2.5" crush bent exhaust with a 2" bottleneck at the muffler that flows worse than your stock exhaust.

Piping is an issue, but since most here would debate between 2.34" and 2.5", it isnt as big of a deal as most would think. You also have to take into consideration a number of other things that would make a bigger difference.

 

so the bigger question is mendrel bent or crush ... 2.25 or 2.50 really doesnt matter ?

 

It depends on what you are going to do to your car. If all you are going to stay basically stock and just doing the typical I/H/E, I would just stick to the 2.25 system.

If your're planning to mod your car past I/H/E, then 2.25" may not be big enough for you. If you plan on doing some serious modification it would be best to purchase the 2.5 now, to get the adequate exaust diameter for what your future HP goals are.