Dyno results of our 05 SS, Video of car on dyno !!

We installed a drop in style filter into the airbox of our 05 Cobalt SS, and dyno tested our car before and after. We didnt expect anymore than 2-3 hp at most, but regardless, because we had never dyno tested the car before we wanted to see how much power it would put down.

The dyno tests were done at Carboy in Houston Texas, 3rd gear runs for both dyno results. We gained a consistent 1.5 - 2 hp across the board, even more for torque on the lower end. The peak numbers are a little off for hp after though as the dyno operator bounced off the rev limiter and created a spike which gave higher than normal dyno numbers.

Anyways, heres the dyno result :


Want to check out a video of our car on the dyno and hear the supercharger whine ?

http://www.modernperformance.com/gm/...altss_dyno.wmv

We are very pleased with the dyno results, especially with GM rating the Cobalt SS at 205hp / 195 tq and we put down a solid 217 hp and 185 torque at the wheels. Definitely underrated for HP !!

We will continue working on the Cobalt to increase its performance and will have plenty of pictures of the new items, and dyno results to show the differences before and after.



Cory Haines
Operations Manager
Modern Performance Racing Products LLC
www.modernperformance.com

Proud to be an American four cylinder tuner since 1997, servicing the Cobalt, SRT-4, Neon, Focus, Cavalier, Pt Cruiser and more.

Phone 713-270-8520
Fax 713-270-8890

 

That is very interesting. A simple K&N drop in helps a little it seems. I'd rather get a true cold air kit installed. My SS Supercharger sounds louder then that , nice dyno video

 

THAT IS FREAKIN AWSOME!!!! 217 at the wheels. I'm the happiest guy right now. I was expecting them to be like the redlines at around 205 to 210 but 217? Now that is amazing. This makes waiting for the car even harder for me

 

Correct me If im wrong

Chevy claims

205hp and 200 torque

Your chart shows

217.4hp and 185.5 torque
221.3hp and 187.1 torque

So you get more HP than chevy says but a bunch less torque?

 

Yeah, that's what I was looking at...the low torque. I expected at least the 200 advertised.

 

remember gentlemen the 205hp and 200 tq that gm claims are at the flywheel, that is what the engine produces, at the wheels is a different story. the cobalt atleat that cobalt is producing numbers close to the 240-250hp range and tq around the 215-220 range. so the car is underated. the numbers gm states are not at the wheels. so both numbers are underated, hp mostly.

 

Now you say the cobalt does 240-250 hp and 215-220 torque... Im confused???

 

also looking at the graph its nice to see that the car is producing well over 150 ftlbs tq at the wheels, and over 100 hp at the wheels at 3200 rpm. very good. all we need is a cam profile for some more tq, to get the tq and hp numbers closer. also curious to see how much more hp at the wheel the car will achieve past the rev limiter.

 

curious, how come you dont do 4th gear runs? isnt it closer to 1:1 ratio? thats what i'm used to seeing is 4th gear dyno pulls? shed some light on it please?

 

The Torque curve or rather lack of curve is awesome. Glad to see we are putting out over the stated amount of power.

 

I think someone figured it out an 4th gear was closest 1:1.

 

was that a typo? did u mean 3rd gear is closer? if not, then why dont they dyno it in 4th gear?

 

yes theorettically the car is pushing around 240-250 hp that is what the motor is developing, producing. multiply 217 by around 15%.

15% is due to drive train loss, how much hp is lost from engine to the wheels, ie. transmission, cv axels, brakes, tire size. so if the car is producing 217hp at the wheels, what it uses to accelerate.

217hp, multiply an extra 15% and you get 249.55 so about 250hp that the engine produces.

217x15%=32.55
32.55 is the amount of hp lost in the drive train.
32.55+217=249.55hp

do the same for tq. 185whp x 15% comes out to be 212.75tq. does that make since?
185x15%=27.75
27.75 is drive train loss
27.75+185=212.75tq

the numbers provided on the dynosheet is whp, not engine horse power (flywheel hp). those are two seperate things. gm's 205hp and 200tq are engine horsepower. so both numbers are underated significantly.

so the real numbers that gm should be saying are approximatly

249.55hp and 212.75tq. make since?

 

Thanks now I get it... I'm better at doing the driving not the explaining

 

i explaned it even more. he he. glad it makes since, i started getting confused as i was typing. lol

 

Gotcha. I did notice it was WHP though, which was confusing because it was higher for the HP so I figured the same for torque, or at least 200. By the way, the car sounds awesome. It whines good

 

Well Eddie you got close. you have 9%-15% power loss in the drivetrain. Your math is a little off. you have to take the 15% from the Hp at the engine. if you have the Hp at the tires you have to multiply that number by 1.1764705 and that will give you the Hp at the engine (this is a 15% loss multiplier), and 1.098901 for 9%

Horsepower:
So, if their is a 15% loss in the drive line and 217Hp rating at the wheels that gives you 255.29 Hp at the engine (15%) and 238.46 Hp (9%)

Torque:
15% loss of 185whp at the wheels gives you 217.64 whp (15%) and 203.30 (9%)

summary:
Hp at engine between 238.46 and 255.29, depending on percentage of loss thru driveline
Torque would be between 203.30 and 217.64, depending on percentage of loss thru driveline

 

no, they underrate the numbers to save us all money on insurance, arent u glad?

 

i know theres any way between 9-15% drive train loss. and 1.1764.... isnt that like 17%?? 15% is .15? isnt it? dunno i allways sucked at math so, and like i said approximatly, lol.

also i know chevy underated the car because of insurance, theyve been known to do that with their v8's.

 

15% is high for a FWD car, its more around 12-13%. 15% is about right for a RWD application, but you don't have a driveshaft to turn, so that saves you some.

 

Dynos are not a reliable source for actual absolute power outputs. There are many variables that effect the output on a dynamometer; the results will varry from run to run , and from dyno to dyno. The best you can do is take another car, say a WRX, SRT RSX whatever and run it before or after the cobalt. This way you can see if the other car is over of under by comparison. Gearing is another problem, in order to compensate a correction factor is made by the computer; this is also a source of error.
Dynos are most useful for tuning, and evaluating mods and that is what these guys used it for.
Bottom line... this states a 4 HP gain from a filter.

 

Eddie, those numbers are right.... it's difficult to understand because you already have the answer (at the tires) you just need to work the numbers and percentages backwards. 15% loss is .15 (multiplier) to get a loss. BUT when you start with a loss you can't take 15% of the loss number and add the two together. I'm just going to stop now, I'll have everyone scatching their heads soon. Just trust me those numbers are correct.

255.29 (at the engine) - 15% (38.2935, drive tran loss) =217Hp at wheels.



Nocturn,
for 12% loss= (1.1363636 multiplier) 217 Hp at wheels = 246.59 Hp at engine
185whp at wheels = 210.23 whp at engine

 

oh i believe you, i just didnt know it was different if you start with whp. thought it was the same. so i'm a little off sue me. lol

 

just clarifing the math, you know we would end up with some other person with another type of car flamming the number.

 

oh so true. good job keeping the math straight. i've failed math all through out highschool, and gotten c's in math all through out college. so shows you how good i am.