U240

I see alot of carbed cars running a tighter lsa than F.I. cars ,is there a reason why , I know that a tighter lsa affects idle but what else does it affect, I just see most lt1 cams with around 112-114 lsa and other cams around 106- 108 this is just something i`m not familiar with

seawolf06

Some light reading:

http://www.ls1tech.com/forums/showthread.php?t=394947

JoeliusZ28

EFI doesnt tend to like a lot of overlap or LSA.

im still going with a 110 LSA cam when i do mine cause i dont mind a little side-effect

Joe B

Honestly, 99% of the reason the majority of cam companys put out wide lobe seperation cam's (IE:112-114) for the LT1 and many of the other late model computer controlled Fuel Injection cars of today, is just for the smoother idle and higher manifold vacuum... which usually equates to less chance of having issues with cam surge and sensor related issues from the lower manifold vacuum & additional cam overlap .......But, in nearly ALL cases(especially with the commonly built and sized LT1 engines), more power and torque would have been made if the cam was ground on a narrower LSA "more" twords what the engine actually needed.......In twenty years, I've personally yet to see a similar spec'd 116-112 LSA cam perform on par with a narrower 106-110 LSA cam......and EVERY test I've ever read about over the years where they took several cams, all with similar specs, but each ranging in lobe seperation from the wide LSA's down to the narrow LSA's..... the narrow cams (untill they went too narrow for that particular engine combo) made considerably more horsepower, "and" torque usually peaked at a lower RPM......................Joe

rskrause

I was writing up my reply, Joe beat me to it. FWIW, I am running a SR cam in my EFI alcohol BBC and the cam has 90 degrees of overlap. Idles at 1,200rpm and could be street driven. So, I don't buy the idea that you need more overlap to run EFI. When the car has a SR cam with less overlap and a carb, it didn't idle and drive as well.

Rich