Surprising HP on Dyno

[Dawg2Snake]

Had my 06 coupe dyno'd on Friday. Went to Dyno-Comp in Scottsdale, AZ. They use a tuning dynamometer with electromagnetic retarders - so there is resistance throughout the power band (as opposed to a rolling drum type). They told me the drive train loss on this type of dyno is 22-25%, compared with 12-15% on a dyno-jet.

I never dyno'd the car stock. I have Belanger headers, single hi flow cats, and Belanger 3" exhaust with no crossover. I also have K&N air filters.

Numbers while engine relatively cold (car sat for 30 min before hand):
456 rwhp, and 495 rw torque. Using the conservative value of 22% drivetrain loss, this equates to 585 HP at the crank, and 635 ft-lbs of torque.

Numbers while the engine was hot:
442 rwhp, 456 rwtq - or 567 hp and 585 tq at the crank.

Temp was 86 degrees although figures are corrected by the computer for temp.

I didn't expect that much HP!

 

[rcl4668]

Congrats on those numbers. I plan on installing virtually identical mods (Belanger headers, sidepipe kit and high flow cats) on a 2008 Viper I have on order. If I had those types of gains I would be very pleased.

/Rich

 

[Flyntgr]

My car on a dynojet tested at 486rwhp and 507 rwt, which I figured produced another 12-15% at the flywheel. I don't know about this different dyno, however.

 

[SylvanSRT]

is this the Dyna-Pac type where they take the wheels off the car and bolt a part of the dyno directly to you cars hubs? Regardless of the loss they say on this type of dyno the mostly accepted loss in the real world through your wheels to the real ground is the 12-15% approx.

 

[GR8_ASP]

Do not believe their claims of a 22-25% loss. That is pure balderdash. But if it makes you think you have a supernatural car then go for it

 

[Bobpantax]

Had my 06 coupe dyno'd on Friday. Went to Dyno-Comp in Scottsdale, AZ. They use a tuning dynamometer with electromagnetic retarders - so there is resistance throughout the power band (as opposed to a rolling drum type). They told me the drive train loss on this type of dyno is 22-25%, compared with 12-15% on a dyno-jet.

I never dyno'd the car stock. I have Belanger headers, single hi flow cats, and Belanger 3" exhaust with no crossover. I also have K&N air filters.

Numbers while engine relatively cold (car sat for 30 min before hand):
456 rwhp, and 495 rw torque. Using the conservative value of 22% drivetrain loss, this equates to 585 HP at the crank, and 635 ft-lbs of torque.

Numbers while the engine was hot:
442 rwhp, 456 rwtq - or 567 hp and 585 tq at the crank.

Temp was 86 degrees although figures are corrected by the computer for temp.

I didn't expect that much HP!

It sounds like they are using a Dyno Dynamics dynamometer. If so, the resistance factor is set by the person using the machine. It can be from zero to 100% based on the Dyno Dynamics website. I do not believe that the 22% figure is correct. With the mods you listed, the 12 to 15% driveline loss numbers put you at about where you should be. I do not think that you would pick up 75 HP from the mods listed.

 

[DMan]

Best double checker would be to do some runs at a drag strip and check your mph. I've never heard of drive train loss that high, but no one knows everything. The Viper's drive train loss is close to 12%, according to feedback from a couple of years ago from a race team that dyno'd the engine, installed it & then chassis dyno'd - they got 12% drivetrain loss. But with variance in dynos and correction factors, I always like to go do a couple of runs and chekc mph, ETs vary on traction greatly, but mph is pretty consistant: checking mph before a mod & then after has worked well for me thru the years.

 

[MikeR]

456 rwhp sounds low for having headers and exhaust. The drivetrain loss as everyone said is not anywhere near 22% , but maybe with that dyno it reads low. Most have dyno'd on a dynojet stock around 440rwhp, some lower , some higher. And with Bellanger headers, exhaust if seen #'s around 470-480rwhp.
At any rate, it doesnt matter, as long as after each mod you go to same place and continue to see gains each time you change something.

 

[PhoenixGTS]

It sounds like they are using a Dyno Dynamics dynamometer. If so, the resistance factor is set by the person using the machine. It can be from zero to 100% based on the Dyno Dynamics website.

And Rich the owner/operator over at Dynocomp can dial in whatever power result he wants to show on that machine. If I recall correctly, when the AZ Club had a dyno day there no stock Gen III could spin 390 to the wheels. Hopefully Marv or someone else from AZ will comment.

 

[SixFootSix]

Is this a mustang dyno? I thought the general rule was 15% up to 50 hp max???

 

[BlueGTS]

22-25 % loss... You must have an AWD Viper, which is rather rare. I think what the dyno operator was trying to convey is that his type of dyno needs to use a 22% correction factor to equal the crank numbers from a dynojet. IE, that his dyno produces lower numbers than that of a dynojet. However, telling you that you have 22% drivetrain loss it ridiculous. Bottom line, if you want to compare with others get to a Dynojet.

 

[Dawg2Snake]

22-25 % loss... You must have an AWD Viper, which is rather rare. I think what the dyno operator was trying to convey is that his type of dyno needs to use a 22% correction factor to equal the crank numbers from a dynojet. IE, that his dyno produces lower numbers than that of a dynojet. However, telling you that you have 22% drivetrain loss it ridiculous. Bottom line, if you want to compare with others get to a Dynojet.

Yes, this was essentially how he explained it. Makes more sense to call it a correction factor than drivetrain loss. Being unfamiliar with this type of dyno, I am still unsure if what he is telling me is true though...