300zxls1

iTrader: (13)

I am changing the setup on my 93 Rx7 Ls1. I will be going with a JTR long tube setup and a new exhaust. I am looking for your opinion if I should go with the 1 7/8" headers or 1 3/4" and if you think it will pay off to go with dual 3" exhaust over a single 3" for my power goals.

Current Mods:
Stock 00 Ls1 shortblock
FMS F5 Cam 224"/228" .588"/.576" on a 112LSA
SLP CNC LS1 heads 260CFM @ .600 lift
Typhoon Intake 85mm throttle body
Direct Port Nitrous setup (will either jet for 150 or 200hp)
3.5" cold air intake system
LS7 Clutch and flywheel
Walbro 255, Aeromotive FPR, Billet rails and stock injectors
EFI Live wideband tune when completed

I am looking to break 400rwhp on motor.

I am on a budget so I wont be doing the 1 7/8" headers or true 3" dual exhaust unless it will be worth it with my other mods. I will be running this setup for a long time and have no plans to boost or anything else in the future. I know on most instances the 1 7/8" and true duals will make a big difference but for my current setup will it pay off.

I already have a 3" stainless catback exhaust I had planned to use. But if you guys think it will be a bottle neck. I might get a true dual 3" setup made. So I already got quoted to have a 3" y-pipe to run the longtubes and also mod the stainless catback to work. It will cost $300 to be made. If I go with the true duals it will be $850. So for the potential gains will it be worth the extra $550 for the gains.

On the headers the 1 7/8" cost $75 more. So its not really the cost on them I care. But I know bigger is not always better.

Thanks for your help.

-Joe

Smartass6885

iTrader: (3)

if you do duals. go with 2.5" with an x pipe. will give you the most power. i have read about people losing power with 3" duals on stock cube ls1's. not sure about the headers. 1 7/8" might be overkill again. i wouldnt expect to see any gains over the 1 3/4".

joker machine

Bigger cam would get u to 400hp for alot less.

DVS99TRANS

iTrader: (7)

I wouldn't necessarily use the 1 7/8". There are posts where people have picked up a few extra ponies with massive cams with awesome heads on the stock motor. But would only really use them on a 400ci motor or bigger in my honest opinion.