Simple question, does a cammed LS need premium gas? I seem to be running fine on 87 with stock timing, but I would like to know that people think.

BTW 87 is $1.15 /gal and falling here for mobil.


[Modified by brinks, 12:14 PM 10/2/2001]

 

i'm pretty sure cams wouldn't require you to run higher octane

only if you advance the timing or raise the compression

 

not if you only did cams, what other mods have you done?

 

damn thats cheap!!!!

 

I would say no because octane is a measure of resistance to detonation. Higher compression and advanced timing causes an increased risk of detonation that is why higher compression cars need higher octane. When you upgrade the cams your dynamic compression will probably go down, especially wild cams, so this reduces the risk of detonation. The flip side is that since your dynamic compression is lower you won't see the full benefits of the cams unless you raise the compression back up.

This is why people that are running Toda C's need and can have really high compression running on street gas.

 

Oh god hell yeah, its like 1.80 here.

 

He is exactly right. Dynamic compression will go down.

 

You should be fine, unless you advance the timing.... which would be unwise... very little power gains vs. cost of gas (premium)...

Just chill with 87 oct. till you get higher comp pistons....

ps... milling the head slightly will regain any lost compression......

Can someone explain why there will be a reduction in compression from adding aftermarket cams?


[Modified by X2BOARD, 6:12 AM 10/3/2001]

 

I have to run 93+ in my LS< ITR pistons, and race head.

 

i would like to know also, im running the crower 404's in my ls. thanks

 

The reason that you "lose" compression is because the increased duration "bleeds off" compression on each stroke.

Think about it. If the valves are opening earlier and closing later then when the piston is going up to compress the gases(compression) some of the gas will be pushed out of the cylinder so the gases are not compressed as much as they were before with less duration. That is why even though the static(no motion using and compression formula) compression stays the same the dynamic(moving) compression will be lower.

Hope this helps if not let me know