JMHZ2401

Friend of mine on here has a Coablt SS/SC with the Gm stage 2kit and reflash. The dealer has reflashed it twice. Car was running really bad, and injector duty cycle was at times 123%. He got it tuned yesterday. Here is a video http://www.youtube.com/watch?v=HBTQubczUFE

YOu will see his numbers started off bad. The car was running off the chart rich. Running great now.

DaREDss

typical gm tune nothing new except the 123 duty cycle

campo165

158whp? wtf? then to 216 just by your tuning? hmm.... both numbers a complete garbage, but a s2 making 158whp is just dumb.

bryce712

must have been hott as ***** down there with a lot of humidity as well.

JMHZ2401

It was hot. The tuner could have gotten more, but he said this tune was safe to go beat the **** out of it and not have any problems. He has tuned a few SS/SC and said this was the worse he had seen.

Don't understand how you say both numbers are complete garbage.

L.P.

well 158 hp with stage 2 is garbage because most stage 2 cars hve about 240 hp or so...so even the 2nd number is really low that is what a stock ss/sc should be making.

JMHZ2401

That 240 number GM gives is at the crank, not the wheels. If you do some math of drivetrain loss. Say 14%. 240 minus 14% is 206.4 at the wheel. 205 minus 14% is 176.3 at the wheels. You take this 216 and add the 14% you get 244.7 crank. I think this is pretty much right on to what it should be.

Also want to add the injector duty cycle is now in the mid 40% range. Plenty of room to grow. He has a Cobra H/E to go in which should help drop the intake temps which can free up some room.

campo165

mm, you havent been around here much, have you.

Theres been PLENTY of dynoes to prove the thoery of 240...to the wheels. Granted our Florida weather sucks, but still. 216 sounds like a mustang dyno number, i guess. But 158 is my main concern, thats horrific. Mustve been SOO slow before.

KillerBee

wow those are some low number what kind of dyno was it on cause those number are way garbage there was a guy i know who had a custome tune on a stock ss/sc and was in the 200 whp range so there is something wrong very wrong

distillion

when i had gm stage 2 i hit about 240 on the dyno.

JMHZ2401

The dyno was a dynojet (says it at the end of the video). I have been around and I have heard of stock SS doing 200+ stock. Some more info on the first pass it was not taken all the way to redline because the air/fuel dropped off the chart. Lowest the gauge would go was 10.0 and it hit that quick. The tuner (who has tuned a few SS/SC off this site) has gotten 2.8whp on a stock SS/SC. His words was it was a aggressive tune in 40 degree weather. With the IAT temps up he did not want to push it anymore. Honestly a dyno is best used as a tuning tool. Too many factors when comparing numbers. Based off how you set-up a dyno you can make the numbers higher or lower. With the 1/4 numbers that most SS/SC run in stock form (and I realize many factors at the track as well) I feel the numbers are fairly close.

distillion

So you got tuned on the dyno.
i suggest geting an a/f gauge.

JMHZ2401

My friend did (Bruski06). I myself plan to get a wideband for my own fun, but dyno is the only real way to tune.

distillion

NO
it is not, sorry to burst your bubble.
STREET tuning is the ONLY way to tune, plain and simple.

JMHZ2401

Yeah ok. Street tuning is a good start, but you can not tune spark safely on the street. Just because you do not see KR does not mean you aren't losing power. You can lose power way before you ever see KR. Everyone think that more timing more timing is always best. Not always so. I'm in no way saying a SS/SC would not gain power from more timing, but you would not know this unless on a dyno.

distillion

umm
what the hell are you talkin about?
i can see if my car knocks on the street, my LC-1 is calibrated in conjunction with hpt.
and with your tuning of the spark comment, well funny thing is i was having spark blow out on the streets due my boost setup and in coming air at high rpms, on the dyno it was non existant.
guess what, on the dyno my car did not knock when i was tuned on one last year.
got my wide band, and i was knocking like a **** and very lean.
you have it backwards., if you have a serious build and need to car to start moving, a dyno is a good start, but finishing it off on the streets is essentially what you want to do.
also a fan cant simualte outside weather conditions.
but what do i know....................


by the way, i know too well about the effects of timing/KR
i run a 2.7, boosting at 18-19 pounds and i run about 23 degrees timing with no knock thanks to a street tune and water injection.
Heat will also cause knock, since ive added the dual pass kit option b from gm and my water kit, the knock is gone and temps are at a decent level at wot.

JMHZ2401

I see that you are way out of my league and know everything. Spark blow out is not knock. Also no reason for spark blow out to not happen on the dyno if it is going to happen. Still spark blow out has nothing to do with timing. I'm aware you can see knock on HPT, but you did not understand what I was saying. Let me see if I can make it a little more clear.

Stock Gm reflash has X amount of timing (safe, very safe). Let's say with your street tune you added 10 degree's advance (just making up numbers here), what if at 5 degree's advance you got the most power your going to get from adding timing?? So after the first 5 degree's you could start dropping power. You would not know this unless on the dyno.

Besides street tuning is more or less illegal (same as drag racing). I'm in no way saying street tuning does not have it's place. It does. I have street tuned my own cars. Still plan to get the on a dyno for the final tuning.

distillion

i never said i knew everything, just talking from experience.
i know spark blow out it not knock, i was just pointing out the differences with the car on the dyno then on to the streets.
and if there is too much timing in certain spots you just have to take some out.
all i can tell you is ive gone both routes, my car has never ran better after street tuning.
much better than stock and much better than my old dyno tune.
i wasnt trying to be an ass, like i said earlier, talkin from expierience here.

Bruski06

Yeah whatever I like the car the way it is (still plan to add more) but yeah the temp was 96.01 F and the intake temp was above 160 so yeah for the 4th run in those temps within 2 hours it was very good. The car is alot more alive and I have no issues with bogging out anymore in 2nd or 3rd gear. Thanks John for the vid!

distillion

as long as your happy with it, thats all that matters

an0malous

so your telling me that you trust the tiny fluctuations that 1-2 degrees of timing would give, to back off your timing....

when generally a dyno could give you 230hp one pull, and 240 the very next pull with no changes?

sorry man. but dynos arent nearly accurate enough to know when that extra degree or 2 of timing is starting to take away power. the margin of error is way larger than the degree of change you are talking about.

cobaltsscoupe

when i was stage2 mine was 241 HP 218 TQ most cobaltsssc here make that or close in the big MO at 97 d & 85% h

distillion

if dynos are so accurate, that DYNO JET woulda read about 240/218 ish
this is wat i mean.
tune it right the first time, hit the streets.
ok speeding is illegal
ever here of the track"test and tune"
i leaned my car out a tad at the track once cuz i noticed is was a tad rich at the top of third.
im not a tuner by any means, my cars been through it all and ive talked to all the right people around my area, and on this very site, they all share the same views as me.
peace.
if you want logs of a dyno tune then a test run outside to show how huge the difference is id be more than happy to dig them up.

SJSchafer

Street tuning FTW!!!

Area47

if i can get over 240 out of a stage 2 car with simple tweeks here and there, in 100 degree heat. it's not hard.

simple rule of thumb. a car will run leaner on the street than it will on a dyno. you dial the afr in on the street, and get the timing close. then within three pulls on the dyno. you have it set. if it takes more than three pulls. you need to re-think you way of tuning.

a box stock stage 2 car i did here. in that same heat. put down 226 when it hit the rollers. in three pulls i got the car to 240 without doing anything major to it. just minor things here and there.