cam comparison
 

here ya go kids. the only thing that has changed is the cams, and the air temp/humidity. they are in std for this reason. SAE numbers are sorts of wacky. this is simply a cam stand off.

https://www.cobaltss.net/gallery/fil...comparison.jpg

colors, cams, date that it was done. street numbers, not OMG dyno numbers.
red - gmr - 7/5/08
green - 272 - 2/10/08
blue - stock - 10/27/07

red was 11.6 afr. 20 degree's of timing
green was 12.0 afr 24 degree's.
blue was 12.4 25 degree's of timing.

im aware of the torque differences. there is a reason behind it. timing has a part of it, but the bigger part of it is compression ratio.

will it be possible to achieve an AFR as lean as your stock cams along with the 25 degrees of timing?

would that account for some of the loss torque as well?

and what do you mean by referring to the compression ratio? i assume you have changed static compression so could you explain that? (always looking to expand my knowledge)

looks good area...thanks for the comparison and taking the time to do this.

so what ur saying is stock cams with adjustable cam gears is better than the cams available for the lsj...cool

lol u dynoed the stock cams 3 months from now and have the results


i'm done thanks 4 the info area

Nice job b, very nice comparsion for us.

there ya go, i fixed it for ya.

raven. you don't gain the same lift, nor duration with stock cams. these were all done on the same stock cam gears.

yes i can push it hard enough to get the same afr numbers and still rn the same timing as well. the lower compression itself stems from the cam design itself. it has more to do with lift and duration than timing down low.
stock cams are designed to give low to midrange power. when you start adding more lift and duration, something has to suffer. either torque or horsepower.

i understand that..but ur tq numbers are not that much different other than a flatter powerband line...which u can adjust with adjustable cam gears.

time attack cobalt used stock cams retimed fyi you are on the right track i think

Finally something that is straight from you and not in riddles

Area do you have cam gears?

no he doesnt josh

Click

idk in my experience ur power difference on the cams arent that crazy...and ur stock cams provided more tq down low but fell off up high which caused ur hp to fall off...adjustable cam gears will allow u to adjust ur power band which seems like a better upgrade since the stock cams provided to most tq


but this like everything else is all IMO

no, no their not.

i have the cams used in the time attack car. gm-racing. check chapter 6 of the build book.

newp. stock cam gears. i never bought them like i had planned on doing to fix the issue with the 272's.

flat is good.
:)

less low end torque=better traction

I bet with more timing and a little leaner afr the gmr cams would be the same if not better then the stock cams.....

bryans downloaded the new driver mod..he doesnt need low end torque to be limited

possibly if cams allow..ive only known bryan for so long but ive known him long enough to know that this is prolly the best tune for those cams in his opinion...but i may be wrong..he might have not pushed them

from my understanding the stock cams are retarded from the factory.... Ive been pondering if adjustable cam gears and zeroing out the cam retard would benefit.... thanks for the info im going to look into it more and do some math

winna winna:cool:

i didn't feel like pushing them to be honest. my daily is what those numbers made. nothing more right now. i could lean it out and put the timing back in it. im just lazy.

i know i can pick the torque back up down low and again. i just have to get the urge to do it, and right now. i don't feel the urge
:)

Advancing the stock cams would make them peak even earlier.

yea but hes displaying this information for other peoples reference and im pretty sure plenty of other people havent ordered driver mod yet lol

depends..tightening up the lsa between the intake and exhaust cams will cause more overlap which will move ur powerband up in the rpm range which by bryans power band would be a huge gain in traps

u dont have to adjust the cam gears in the same rotation thats the benefit of having adjustable cam gears

you can argue the fact about the stock cams all you want. what you're not seeing is. i didn't give all the info on the tune. here lies the info that people do not know.

there is a reason why the torque was lower, which really resulted in the timing itself and afr. the peak timing on the gmr cams was what i posted. peak timing on the stockers was much higher. THIS is what you're not seeing. along with a leaner afr on the stock cams vs gmr cams.