Dissapointing dyno today

[BanditSRT8]

So from the info I have gathered here on the forums (and I admit, I may have missed a few posts) I believed that a stock GT500 should be throwing down about 440 at the wheels.

 

SO we strapped mine to a Mustang dyno today and pulled a measly 379rwhp out of it.

 

This after beating myself to death since it delivered Tuesday to get at least 500 miles on her. So when we strapped her down today, she had 540 miles.

 

T/C off, pulled in 4th gear (then pulled in 3rd to make sure I wasn't wrong) and that was the result. Engine temp was about 185 when the pull began, so I should not been sunk by heat-soak.

 

Any ideas?

[COBRA SCOTTY]

So from the info I have gathered here on the forums (and I admit, I may have missed a few posts) I believed that a stock GT500 should be throwing down about 440 at the wheels.

 

SO we strapped mine to a Mustang dyno today and pulled a measly 379rwhp out of it.

 

This after beating myself to death since it delivered Tuesday to get at least 500 miles on her. So when we strapped her down today, she had 540 miles.

 

T/C off, pulled in 4th gear (then pulled in 3rd to make sure I wasn't wrong) and that was the result. Engine temp was about 185 when the pull began, so I should not been sunk by heat-soak.

 

Any ideas?

 

 

GO TO ANOTHER SHOP WITH A DYNO AND GET A FEW MORE PULLS. THOSE NUMBERS SEEM A BIT LOW AND I HAVE SEEN AT LEAST 30 TO 40 SETS OF DYNO NUMBERS FOR 07 N 08 GT500'S.

[srk1959]

Yes, take it to another shop. All the stock GT500's I have personally seen dynoed between 425 and 450. Make sure if you use a Dynojet have them use S.A.E. correction factor, a lot of people on the boards use standard c/f and that does read a little higher. Oh by the way don't feel bad, a friend of mine had a 572 cid Hemi Charger which dynoed 480 on a dynojet locally and got an invitation to another shop to be the first car to dyno on their new Mustang dyno......long story short the guy didn't know what he was doing or something was not calibrated correctly and after beating the car up with 6 pulls could only come up with about 385hp. He beat the Hemi up so bad on the dyno that it used a whole quart of oil! My friend was not happy and the dyno guy thought we were lying about the 480hp on the other dyno so everyone was pissed! Long story short.....try someone else before getting bummed out!

[sprint200]

So from the info I have gathered here on the forums (and I admit, I may have missed a few posts) I believed that a stock GT500 should be throwing down about 440 at the wheels.

 

SO we strapped mine to a Mustang dyno today and pulled a measly 379rwhp out of it.

 

This after beating myself to death since it delivered Tuesday to get at least 500 miles on her. So when we strapped her down today, she had 540 miles.

 

T/C off, pulled in 4th gear (then pulled in 3rd to make sure I wasn't wrong) and that was the result. Engine temp was about 185 when the pull began, so I should not been sunk by heat-soak.

 

Any ideas?

Mustang dyno's typically will read lower then Dynojet dyno's which is what most people are posting. If my math is correct (based on my mustang dyno vs. dynojet #'s) your 379 rwhp would probably correspond to about a 435 rwhp reading on a dynojet.

 

I don't think you have anything to worry about. Remember, dyno's are just a tool to keep you safe where it matters.........on the track :car:

 

 

 

edit: for the guys that posted just before me; You missed the KEY word in his first post..... "Mustang" dynamometer.............. WAY different readings than the typical Dynojet dynamometer........ :beerchug:

[kaylan1521]

Was the coil pack cover on when you did the pulls? Once the tach lead is on if you don't re attach the "Powered by SVT" cover back on you will get hp readings in the 3's as well

[cobraracing]

Dynoed 404 RWHP with 100 miles on it

Hit 546 RWHP with only 17 degrees timing, we were going to add meth and timing but had a few trigger issues with the meth controller and never added any more timing.

Going back for round 2 next week

[Oddball]

Was the coil pack cover on when you did the pulls? Once the tach lead is on if you don't re attach the "Powered by SVT" cover back on you will get hp readings in the 3's as well

 

Would you please explain in layman's terms why a simple cover makes such a difference?

I'm technically challenged.

[sprint200]

Would you please explain in layman's terms why a simple cover makes such a difference?

I'm technically challenged.

If the coil packs are allowed to vibrate you will lose power. The covers hold them in place.

 

But that is NOT BanditSRT8's problem..........in fact he doesn't HAVE a problem. His rwhp reading is a normal reaading for a "Mustang" dynamometer.................

 

That was my first thought too, until I read his post more carefully.

[GT500FLYBOY]

I dyno'd only 340-370 RWHP my first time on a Mustang dyno. Do a search on my posts for more info. It was a warm day - not hot, but I was disappointed. The way I understand it, the stock tune is very conservative. If you do a quick run with the car cool - you should get good numbers. But the engine will quickly heat up and the stock tune will dump fuel to keep the cats cool. That ruins the a/f mixture and lowers the power output. I fixed this with the Evo/JCL Stage II CAI/tune. I have dyno'd from 550-570 RWHP since. It's that simple. Really woke the car up. Best bang for the buck you'll ever get.

[68fastback]

+1

 

 

fwiw ...when we were in Romeo they told us when they occasionally dyno one they consistently see 511-517 at the crank (low-mid 440s at the wheels).

 

There's a lot of things that can affect HP ...hi temps will pull timing and drop HP, low barometric pressures (when bad weather is appraoching and/or at higher elevations) will reduce effective cylinder pressure and drop power too. Ditto for high humidity since every grain of H2O reduced available O2 to oxidize (burn) the charge.

 

Dan

[Willie]

....Once the tach lead is on if you don't re attach the "Powered by SVT" cover back on you will get hp readings in the 3's as well

 

My dyno experience from a couple of weeks ago contradict this. My coil pack cover was not reinstalled during the pull. You guys are not going to believe my results on my bone stock drivetrained 2008:

 

Run Conditions:

97.65 deg F

28.54 in-Hg

5 percent Humidity

 

Dynojet - Phoenix, Arizona

Stock tune

15.5 degrees advance

Pig rich 10.2 to 1 A/F ratio

Run only to 5750 rpm

 

Result:

SAE Corrected

459.7 hp

446.3 ft-lbs

 

Again: Coil pack cover not reinstalled.

 

Willie

[GT500FLYBOY]

....Once the tach lead is on if you don't re attach the "Powered by SVT" cover back on you will get hp readings in the 3's as well

 

My dyno experience from a couple of weeks ago contradict this. My coil pack cover was not reinstalled during the pull. You guys are not going to believe my results on my bone stock drivetrained 2008:

 

Run Conditions:

97.65 deg F

28.54 in-Hg

5 percent Humidity

 

Dynojet - Phoenix, Arizona

Stock tune

15.5 degrees advance

Pig rich 10.2 to 1 A/F ratio

Run only to 5750 rpm

 

Result:

SAE Corrected

459.7 hp

446.3 ft-lbs

 

Again: Coil pack cover not reinstalled.

 

Willie

 

You're right. I don't believe it. Especially at 97 deg and only 5750 rpm. That just tells me Dynojets can show way high numbers. Don't kid yourself. Get on a Mustang dyno and get real.

[sprint200]

I agree with 'FLYBOY on this one.

 

I have seen a few stock cars in the 450's; but not with those atmospheric conditions

 

I would take it to another dyno shop to verify the results...............

[Willie]

Some background info: Doug from Bamachips ran the dyno and he did not believe it either. We waited about 20 minutes and ran it again. Result: 3 hp more. Also, two other S197s were dynoed before me. The first was a Procharged '06 GT and he pulled only 383 hp. He said this car had issues. MAF needs an extender and the stock FP was at 98 percent duty cycle. Then another '06 GT with bolt-ons only was dynoed. Result: 292 hp. The owner said he dynoed before with a result of 290 hp so he believed this was realistic. Then came me.

 

After Doug dynoed my car twice, he made several phone calls. He told me the highest stock GT500 dyno known by his "circle" was 470. So although my pulls seem difficult to believe, maybe there is substance in what he said, which might be somewhat verified by the two prior car's results.

 

All in all, I don't care what the numbers are. They're only used for bragging rights, which don't mean much to me. I was just curious, Doug was in town from Alabama so I just had to go.

 

Willie

[GT500FLYBOY]

Some background info: Doug from Bamachips ran the dyno and he did not believe it either. We waited about 20 minutes and ran it again. Result: 3 hp more. Also, two other S197s were dynoed before me. The first was a Procharged '06 GT and he pulled only 383 hp. He said this car had issues. MAF needs an extender and the stock FP was at 98 percent duty cycle. Then another '06 GT with bolt-ons only was dynoed. Result: 292 hp. The owner said he dynoed before with a result of 290 hp so he believed this was realistic. Then came me.

 

After Doug dynoed my car twice, he made several phone calls. He told me the highest stock GT500 dyno known by his "circle" was 470. So although my pulls seem difficult to believe, maybe there is substance in what he said, which might be somewhat verified by the two prior car's results.

 

All in all, I don't care what the numbers are. They're only used for bragging rights, which don't mean much to me. I was just curious, Doug was in town from Alabama so I just had to go.

 

Willie

 

That's a good attitude to have - that's all these numbers are about. 'mine is bigger than yours'...

 

Though they can prove a good reference point for yourself and can prove results after you make changes, or indications of possible problems when you've made none. That's why I like numbers that I can rely on.

 

...and all those numbers above seem consistently high, which would make sense.

[Willie]

Don't get me wrong, I totally agree that an accurate baseline is necessary. But without going to countless dynos and spending countless dollars, how is one supposed to know the accuracy of one and only one? Are Dynojet dynos recalibrated on a regular basis? (I doubt it.)

 

As for the other's results, there's no way to know for sure if the ProCharged GT's numbers are good, simply because there are too many unknowns. The second car that was dynoed may give us an indication of the dyno's accuracy. The '06 GT typically makes around 265 rwhp in stock trim. Add bolt-ons such as a CAI / tune, mufflers, and maybe headers can easily see 290 rwhp. This confirms the second car's numbers because the 292 result is "reasonable".

 

In any case, according to Doug (assuming my car's results are realistic), I'm still within the bell curve, albeit the 98th percentile. Maybe it's the Castrol...... or maybe my car was built on Wednesday (at least until I get my certificate)..... who knows for sure.... All in all, we're talking about a 15-20 hp variance from the 50th percentile. Maybe once it cools down a little (October), I'll hit another dyno....

 

Willie