I have

1. 2.85" Pulley
2. 60# Injectors
3. ZZP 3" Intake
4. ZZP Long Tube Header
5. ZZP 3" Catted Downpipe to stock exhaust
6. ZZP Canned Tune

Even with a canned tune shouldn't I be makeing more then a GM Stage II

1. 3" Pulley
2. 42# Injectors
3. Stock Intake
4. Stock Exhaust Manifold
5. Stock catted downpipe
6. GM Stg II Canned Tune

GM Stg II = 241 HP
Me = 239 HP

I can bring in more air
I can bring in more fuel
I can let out more air
What am I missing??





Don't get me wrong, I'm happy with my car and tune, its fun to drive. ZZP said they can dial my tune in abit, lean me out some and get some more power out of me, but it just seems with a smaller then GM Stg II pulley, larger injectors, intake and exhaust, id be makeing more then Stg II power even with a caned tune.

What am I overlooking/missing? My cylinder compression is good, I posted the results a while back forgot what they were.
Edit: Dyno IAT2 = 114, I do have cooling mods. OTTP Stg1 HE/ Dual Pass Endplate/ Pheonalic Sapcer

 

maybe: bhp vs whp

pretty big difference between the two.

 

You're running a canned tune

 

Don't stock ss/sc's dyno at 215? LOL

Not sure what your problem is.. Canned tune being one of them, elevation, temperatures
how much are you boosting?

 

GMS2 cars on avg dyno 230-235 whp.

I wouldn't get caught up on your dyno numbers man....

So many factors can skew a dyno reading.

What kind of airflow are you seeing? Ever take the car to the track?

I'm sure you would be a bit quicker than a GMS2 car.

 

Do you have a wideband? What does it read at WOT?

You could either be running way too rich or not have enough timing.

 

I bet its all in the tune. Get a custom tune

maintenance is up to par?

 

Was the GMSTG2 dynoed at the same dyno as you? Your Air fuel has room for improvements. I would find a local tuner to adjust.

Marco

 

Custom tune but dyno numbers are usually skewed depending on heat soak and ect .

 

Marco - those are GM's bHP numbers ~ and he's comparing them to his wHP numbers...

 

The bhp numbers from GM can be thrown right out the window due to the SS/SC being underrated from the start.

If the stock SS/SC was rated correctly from GM it would have been around 230bhp stock.

You're right though, the OP is comparing "rated" bhp numbers to his actual whp output. Not a good comparison.

Like I mentioned earlier....

A 100% GMS2 car on avg. will make 230-235whp. Slightly more with exhaust work.

Pyros makes a good point about checking the actual AFR.

 

You know why GM picked the 205 number right?

It had to do with the racing series the car was targeted at to begin with;
I believe that the GM stage kit numbers would be legitimate ~ but the cited horsepower increase over stock is the misleading part ~ since the increase would be observed as numerically lower than you would get from subtracting stock rating versus the stage kit numbers.

I figured it was worth pointing out again, because others seemed to have totally missed this fact.

stock rating: 205bhp
Stage 1 rating: 236bhp
Stage 2 rating: 241bhp
Stage 3 rating (on 93 octane gasoline): 248bhp
Stage 3 rating (on 100 octane gasoline): 260bhp
Stage 3 rating (with integrated nitrous shot): 310bhp (not official?)

 

canned tune and you're comparing apples to oranges...

 

My responses are within your quoted post.

 

insylem
You need to have high octane fuel to take advantage of your setup. If you are running on 91 octane fuel, you will be limited by your car pulling timing at the higher rpms. I have done dyno pulls on my car after every modification, and I have documented this quite well on the forums in my threads. Try running some higher octane fuel by adding about a gallon of xylene (from Lowes or Home Depot) to a tank that is about 5/8ths full.
Here is one of the threads: https://www.cobaltss.net/forums/gene...ge-3-a-264296/

 

chassy dynos arent an accurate way of measuring

 

Thank you for your awnsers. They have given me some insight and stuff to think about. Also I run 93 Octane in my car. I did notice that it pulled timing a few times in a few places durning the dyno runs (I set up interceptor to record KR) This Dyno run didnt heat soak, my IAT2s at idle were 114, as aposed to last time my idle IAT2 (Before my cooling mods) was 150.


As for octane boosters, I'm VERY hesitant in adding anything like that to my car's fuel. Some of them Ive looked at even say for off road use only.