DaSkinnyGuy

If there is already a thread on this post it here

For the most part i know 1 3/4 lontubes add a great amount of power to a stock LS1 motor. But my questions is would 1 7/8" really be overkill. I feel they wont. I remember seeing a article somewhere and on a lsx motor the 1 7/8" longtubes actually achevied hp and tq gains at all rpms over the 1 3/4" longtubes. But i could be wrong that it was improved in all rpm ranges.

If you dont got facts with proof dont answer. Anyone can just post any answer. Please post any articles or info on this to show how 1 3/4" longtubes compare to 1 7/8".

At least once you have the 1 7/8" your set for when you want to do bigger heads.

I just saw a article in i think hot rod magazine and they did this test on a 572 and every time they went to a bigger primary the power gains improved. They went from 1 3/4", 1 7/8", 2", 2 1/4" and i think as big as 2 1/2". They gained i think 20hp from the biggest over the 1 3/4". Now i know this is a whole different motor. But the concept is the same. Bigger size primary seems to really help.

But the one thing is the way the exhaust flows out of stock ls1 heads into a 1 7/8" primary. Yea the 1 7/8" primary is bigger than the exhaust port on the heads but would it really affect the flow.

conan

iTrader: (5)

https://ls1tech.com/forums/generation-iii-external-engine/981229-stock-motor-1-3-4-vs-1-7-8-engine-dyno-results.html

DaSkinnyGuy

perfect. I kind of figured the 1 7/8" would be better. And they are, equal blow 3,000rpm but gain like 10hp above that

jrob56

iTrader: (39)

ya this has been beaten to death in multiple threads with a lot of heated debate, even that thread ended in argument since it wasnt brand specific and a newly designed header versus an old we really still dont know but thats the closest thing on here to proving anything

blown03mustang