katie

I'm looking for a stock dyno chart for a 2.0 SC. Any help?

katie

bump

Or any help on where people shift at and launch at.

I'm having problems with my 60' times being terrible. And everytime I rev before launch, I lose traction, and can't get it back the rest of the track. And right now I'm shifting at 6500 (right before redline) and topping out 3rd at the end of the track, and I'm wondering if maybe when I'm getting into the 6000 range I'm out of my power band and it may be better to shift earlier rather than later.

an0malous

a 7k redline will help that problem bigtime.
stage 2 is one way to get it.

Launch technique is dependant on track stickyness.
if its just a normal track.....not that tacky....try launching just above idle. about 1800-2k
and feather in throttle as you get out of the clutch. its a tricky dance.
if the track is sticky, you can get away with more RPM.

definately shift at redline.
these cars make power all the way up.

zinner

Here you go. 3rd and 4th gears pulls. 3rd gear is the higher number.

RJSS

I don't have my dynograph on the computer, but anyone on the site will tell you that the SS/SC in stock trim (and pretty much any other trim) makes power all the way to redline. It's crazy looking at my dynograph because its just like a dead straight line for HP all the way to 6500rpm. So your shifting at the right spot, just before redline. As far as launching goes, I have not been to the track with mine but most people agree that the easiest way to launch is without revving much at all. A lot of people actually say that they treat it like pulling away from a stoplight on the street with just a little more gusto. Most who have been successful at the track launch at like 2000-2500rpm (depending on track conditions) and feather all the way through first (you might not have to worry about this as much, being stock). If you try to go higher than that all you get is spin, like you said in your post. Plus, if you are too aggressive you will get the dreaded wheel hop and bust an axle.

EDIT: My post was too long, you guys both beat me to it

katie

Thanks guys. I think part of my problem is that everytime I go to the track someone always breaks and there is oil all over one of the lanes...and I always end up in that lane. My best run so far was right when I got to the track before anyone broke, then after that, my times were ****. But I may try revving next time only to 2K and see how that helps. I've been feathering it a lot at the launch....my perfect run so far was that one run, and everything was done perfectly...other than my r/t.

DaREDss

dont launch your car so much and act like your at a stop like and just hit you should catch at like 3-4 and then hit it dont short shift the superchrger never stops making boost theoretically only reason our cars redline at 6450 (if you want to get technical) is the injector duty cycle gets maxed out over that. Hope that helps!

8cd03gro

why do i see alot of people dyno in third gear? you will get much more realistic numbers in fourth. WAAAY closer to 1:1

katie

I wouldn't want to see a dyno run for 4th gear....since I never hit 4th when I'm racing it.

Thanks for the tips daREDss.

My biggest problem, that I noticed on my last run, was that I tend to really baby it through 1st gear because I'm afraid to lose traction...so I'm only at like 1/2 throttle through 1st and then when I shift to 2nd, I get on it full throttle. I think if I get over that whole thing. I may get much better times.

8cd03gro

well that's pretty interesting. you should always dyno as close to 1:1 as possible or you will get inflated/deflated numbers. no wonder we see 220whp stock from some and 200whp from others. The ss/sc is under-rated, but no wonder people have an unrealistic idea of how underrated it is...people are dynoing in third and calling it a day.

RJSS

You're right in the fact that 4th is closer to 1:1 than 3rd, but not by much.

overall ratio 3rd - 1.18
overall ratio 4th - 0.89

So both of them kind of suck. In the dynos I have seen of mostly stock vehicles doing back to back pulls with 3rd and 4th the difference is like 5whp either way.

Mikey851

Yeah, dynos need to be run as close to 1:1 as possible for tuning purposes. The goal is to see how much power the ENGINE is providing to the ground and if you dyno in a gear which is farther away from 1:1 then gearing will affect your ability to read the engine's output. Consistency is key.

Hmm, not too big of a difference. Still if I were tuning for max power I would try to use the one which is closest to 1:1.

8cd03gro

yea but look at the tranny gearing.

MM5
Gear ratios
First gear 4.05
Second gear 2.02
Third gear 1.35
Fourth gear 0.98
Fifth gear 0.69
Reverse 3.31
Final drive ratios 3.94

RJSS

You got the wrong numbers if we're talking about the SS/SC

Here are the numbers

1st - 3.38
2nd - 1.76
3rd - 1.18
4th - 0.89
5th - 0.70
final- 4.05

8cd03gro

http://www.chevrolet.com/cobalt/specifications/


like i said....that was tranny gearing. You are talking axle right now. different.

RJSS

I checked out chevy.com before I posted but those numbers aren't right. The SS/SC has the F35 transmission, not the MM5. I think the MM5 is the tranny for the ss non s/c. Their website is messed up. And the numbers I posted are the tranny gear ratios. If you want axle numbers just multiply it by the final.

tcolli17

If you guys looked at the dyno graph and read the passage he said one was in third and one run was in fourth.

RJSS

We knew that. We were discussing what the proper gear ratios for the SS/SC were.

8cd03gro

my point is that 4th is closer to 1:1 either way...whether your numbers are right or mine, and if you look at the spike in the run in third, there is a variation of a good 15whp.

DaREDss

eh higher in rpm more gas you should give it get it going then almost mash it like anamolous or whoever said its a touchy dance lol

SlayeR36987

Well idk bout all of yall but when im on the track im shifting into 4th a lil b4 the line. And that's redlin'n all the way. And when i went to dyno my car i dyno'd it in 4th since in a dyno u want to be able to see what your engine has all the way to 140 mph. Cant get there in 3rd gear. :/
Plus 3rd gear is much shorter then 4th which doesn't give you as accurate reading as 4th would.

DaREDss

dam 3rd ends like 115-120

SlayeR36987

Well mayb i didnt shift at redline then. lol O yea thats rite i went to the track a week after i bought the car and didnt kno it got power all the way to the redline so i was told to shift at 5500rpm. :/ mayb thats y my run suckd ass, that and wheel hop. lol O well im goin to go again soon w/ all ive done and hopefully get mid - low 13's.

EDIT: O and another thing i only crossed the line at 102mph since i spun tires through 1st.

zinner

3rd is 1.18 to 1
4th is 0.89 to 1