Saki XL

Well you guys, I went and had my car Dyno'd this weekend along with a few SRT-4's another Cobalt SS (TXLonghorn) and a Mustang GT.

The pulls were all 4th Gear, and they were all calculated by BHP.

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Summary

Maximum Power speed: 6029 RPM (123.4 Mph in gear used)
Power at flywheel (corrected): 270.0 Bhp (DIN 70020)
Power at flywheel (measured): 263.8 Bhp
Power at wheels: 227.8 Bhp
Power Loss: 36.0 Bhp

Maximum Torque Speed: 4964 Rpm (101.6 Mph in gear used)
Maximum Engine Torque
(corrected): 245.7 lb ft

Maximum road speed tested: 125.2 Mph
Maximum engine speed tested: 6117 RPM


Min. Ambient Temperature: 19 Deg C
Max. Ambient Temperature: 26 Deg C
Barometric Pressure: 1000 mb
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My engine modifications at the testing were the following:

2.6" Pulley
3" Tensioner Pulley
42.5 lb Injectors
Autolite 1 Range Colder Spark Plugs (Gapped at .035)
Injen Cold Air Intake
MAF Translator Set at [ On/Off/Off/Off ~ C/1 ]

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Horsepower Graph


Torque Graph



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If you want to see the comparisons against the SRT-4's that went and another nearly stock Cobalt SS, you can view that Here.....


Let me know what you guys think!

~Saki

Tomtwtwtw

Nice numbers...why didn't you take it to redline though? Or is the dyno off?

Saki XL

I honestly don't know what he was doing. I'm unsure of how they test here in the UK... I just know that the criteria was set for 2 pulls in 4th gear.

Any idea of what this would be WHP or Crank wise?

GSoccer24

subtract 15%

Tomtwtwtw

I admit, I'm a little confused by your question, as you seem to have all the info in your first post...what exactly are you looking for? Did the dyno really measure kW, and you're looking to convert that into hp?

roccityroller

i always though bhp and whp were the same just different words.

Saki XL

No. I was actually wondering if there was a difference in Brake Horse Power and Wheel Horse Power... According to this I'm making 227 whp (bhp at the wheels, rather)... That can't be right; not with those mods, right?

I guess what I'm saying here is that I'm a little disappointed with the numbers I'm producing.. Especially after seeing what the other guys ran, (The mustang had 197 whp - wtf?). Any insight? I read the other post about Subtracting 15%.. But what is that from the 270 BHP at the flywheel or something else?


~Saki

Tomtwtwtw

I believe brake horsepower *is* crank horsepower. See here. Your wheel horsepower is the power measured at your wheels, taking into consideration what's lost after the bhp travels through all your drivetrain components to the ground. Loss usually ranges from 10-20%, and I've heard the Cobalt is 17%, which your dyno test seems to confirm.

Also, mustang dynos tend to give lower numbers than other ones...don't read too much into them. Take it to the track, and the number there is more representative of how fast your car is than anything a dyno will print out.

roccityroller

idk, what did your a/f look like? do any tuning on it before running those numbers? that could make a BIG difference.

Saki XL

Ah, alright. Sorry for the newbish reactions here - it's my first real encounter with a personal dyno rather than glancing at everyone elses from time to time. I guess the numbers might seem a little low to me in this case because it's a 4th gear pull, then?

What's a better 1:1 ratio anyhow, 3rd Gear or 4th gear? I see alot of people do 3rd and a handful do 4th.

roccityroller

4th gear should be closer to a 1:1 ratio but what i'm thinking is, that if you didn't go any sort of tuning you could be running very lean, in which case that would cause the numbers you got. I know a lot of the guys running in the 250+ range are running HPtuners

Saki XL

I unfortunately don't have access to a Wideband yet. I'm still waiting on the funds for that one to arrive so I can purchase it. I had been running really really shitty at C-1 on the MAF Translator that day as well.. I realized today that running at C-1 was the reccomended setting for the Stock Air Box - so I'm going to have to change it sometime in the morning when I wake up, because I'm guessing I'm leaning out.




~Saki

Saki XL

Ah hah. There we go. I don't have any sort of tuning - other than the MAF Translator. That's the only way I've been modifying anything since I got everything installed (last Thursday).

roccityroller

that could def be your issue, i would reccomend a wideband and HPTuners so that you have some idea what's going on.

Tomtwtwtw

I'd have to agree that you're getting too lean...our cars to tend to lose a little at the top end, but not as much or as early as yours.

Saki XL

....You know. This could explain the reason I've been going into LIMP mode on hard WOT driving down a few times lately -- the unexplainable smoke pumes coming from my exhaust, a few other things here and there. I'll probably set the settings 1 or 2 notches richer until I can get my hands on a wideband at both BASE and WOT.

Tomtwtwtw

That may help, but also looking at your list of mods, I think running a 2.6" may be overwhelming the 42.5lb injectors. I'm not 100% on that, but I know a lot of the guys going to 2.6" and 2.5" pullies are switching out to 60 lb injectors.

NightmareRacing

how cares about hp at the motor, it is what you're puting at the wheels that truly matters anyway....bhp and hp I to belive are the same (hp at the flywheel = bhp)

Xenozx

BHP = Base Horse Power
WHP = Wheel **** Power


Base HP is the HP at the flywheel/crank that the manufacturer advertises the car at. So our stock BHP is 205 hp at 6500 RPM.

Our cars keep making HP the higher up you go, so had you went to redline you would have seen higher #'s. Alot of dyno operators dont know your redline and guess and let off early which sucks

Saki XL

I plan on switching to the 60's sometime in the next 2 months. The only thing I'm waiting on is INTENSE to start doing tunes with CAI's... My stock air box is screwed and I don't intend on going back ever again. Once that happens, I'll get the PCM, the 60's, and continue the quest for 300 whp.

On the other hand, I believe that once I receive the PCM from Intense and go up to 60lb injectors, these numbers will drastically change... So this will be great to keep for reference.


~Saki

Saki XL

That makes a hell of a lot of sense.. I thought it would have been the way the UK operators worked, but now that I think of it that way - yeah - he could have been weary about the redline. I should have told him. =/ That was an hour and a half drive for these results.

Tomtwtwtw

Awesome! Well keep us updated on that project.

Blown 4-banger

BHP accually stands for Brake Horse Power. If you ever watch top gear on discovery channel, they'll show a caption thats says for example 250bhp and the guy says "this car has 250 brake horse power." Also chevy adertizes our cars at 205 hp at 5600 rpm, stupid why they would say such a low rpm.

Xenozx

my bad, atleast I know for future reference.

Brake horsepower (bhp) is the measure of horsepower at maximum engine output, minus power lost from heat, friction, expansion of the engine, etc. This is commonly called net horsepower. Since each measuring system requires different conditions, there can be no correct conversion factor for the systems. An engine would have to be retested to obtain a rating in another system.

Matty

Brake Horsepower is a measure of the engines power without the additional loss of power due to the alternator, water pump, differential etc.