So 4th Gen Hemi Dyno is Depressing Claims 390 Hp Reality is maybe 330 hp

[Ryan12]

So has anyone here had a Dyno of there truck and it was higher then 330 whp stock? All the videos I have seen were right under that its a major bummer considering my bolt on 96 Cobra dynoed 350 whp.

 

[MADDOG]

The rated HP is always an SAE measurement at the crankshaft. The SAE test doesn't always assume all accessory drives are being driven by the crankshaft.

Lastly, since a dyno measures RWHP, you have to expect drivetrain losses.

330 sounds about normal within a small range to account for ambient conditions.

 

[Stangshcky12]

Your 96 cobra had 305hp at the flywheel stock and didn't have a trans/transfer case like your muh heavier ram does

I've never seen it advertised as whp

 

[AF_Hemi]

If you have a stock 4th gen dyno'ing at 330 thats freakin impressive. That means there is only a 15% drivetrain loss with an auto tranny? Typically autos have about 20-25% loss which would put it around 300 rwhp.

 

[Stangshcky12]

The rated HP is always an SAE measurement at the crankshaft. The SAE test doesn't always assume all accessory drives are being driven by the crankshaft.

Lastly, since a dyno measures RWHP, you have to expect drivetrain losses.

330 sounds about normal within a small range to account for ambient conditions.

Mustang dynos and dyno jets each use different correction factors for temp, humidity, elevation etc.
You can run on a mustang and get one number and a dyno jet and hit another

 

[Ryan12]

I understand how crank horse works, i just really thought our hemi's would have alot higher output.

 

[Stangshcky12]

Trup has had his dynod at around 305hp
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[Ryan12]

Ya i was being really generous when i said 330 whp for our trucks most vids are between 305-310, and ya thats when my car was dyoned in central texas at 700ft elevation.

 

[MADDOG]

I understand how crank horse works, i just really thought our hemi's would have alot higher output.

If you do understand how the test is conducted and ratings determined, why would you be surprised at the drivetrain losses or disappointed in the RWHP results?

And yeah, different types of dynos work differently. I've seen as much as a 20 HP difference from one unit to another on the same day, with the same conditions and the same car.

 

[Ryan12]

Very true, and it would just be nice if our trucks actually put down 390 whp.

 

[Trupiano]

Mine dyno'd at 306/331. You have to understand a big ass truck like ours, has a heavy duty tranny and gear-set. So your going to have a significant drivetrain loss. The Srt-10 trucks (for example) have a viper tranny, that's why there's not much drivetrain loss, but they can't tow or haul for ****.

 

[garner]

390 hp is at the motor not the wheels. These rams have around a 22% drivetrain loss so 305 rwhp is 390 hp at the motor

 

[a_guerrajr]

that's why they make bolt ons

 

[HKkid]

This thread confuses me...hes mad/disappointed, but he knew? Hmm...

 

[Graygoose]

shoot, 300+ at the rear is great, put 300+ at the rear on a Mustang, that's in the 11's!

 

[quietpeen]

i moved this over to the engine and performance section.

i agree it would be awesome to actually get 390 to the rear wheels...lol

 

[Ryan12]

No i was more trying to gauge if any other people had dynoed their trucks see what kind of numbers people were getting. Then it became a tech thread about drivetrain and power loss.

 

[Stangshcky12]

Welp since you can't tune them, it's gonna be awfully hard to crest over 330...

 

[garner]

Welp since you can't tune them, it's gonna be awfully hard to crest over 330...

Not really. Flaco got 329 rwhp with longtube headers and cats, cai, and throttle body in 100+ degree heat untuned and 410 rwhp with a 100 shot untuned on his R/T

 

[ncgrl1]

If your Cobra has a manual transmission you will not show as much loss as with an automatic. Thats just the nature of the beast. See what a Challenger with automatic dyno's verses a manual Challenger!!!