I scaned this from the December issue of Petersen's 4 Wheel magazine. I belive they used a Fx4 for the test.

 

Can i assume that these numbers are at the rear wheels.
If so this is not to bad for a stock 300 HP engine.

Mike

 

That does not look to bad to me either, if those are rear wheel numbers, which I assume they are.

Am I doing the math right by calculating about a 22% drive train loss of HP? If so that is pretty good in my opinion.

 

A 22% loss through the drivetrain sounds about right. 20% would be better though. Maybe with some break-in the numbers would be slightly better.

For comparison sake, my Tremec (5-speed manual) loses about 15-16% of power.

E

 

I have been reading on some of the Dodge websites that the dyno results for the new Hemi for example are resulting in close to a 30-34% drive trane loss. So I am glad to see some early numbers to show that there is a little more efficiency with the Ford transmissions.

Whether those numbers from both sides hold up or not only time will tell.

 

Hey I've been waiting to see this. Thanks for posting the numbers

 

I honestly don't know a whole lot about this, but this dyno seems to tell a different story.

http://www.airaid.com/images/400-140-dyno.jpg

 

Is it possible for the rear gear ratio to change those numbers?

3.55, 3.73, or 4.10?

I just reviewed the Airaid dyno numbers again. That is a ton of low end torque the Airaid adds. I would like to see some real world dyno numbers (not vendor sponsored).

 

From the Airaid website - they claim a 20HP increase & 46 ft/lb of torque with their intake system. This seems a bit bold. I am a bit taken back by the amount of dampening passages the OEM intake tube has, but at least the fender whole is larger than a quarter!

Airaid Dyno

 

What I want to know is how the magazine got a stock peak HP of 235, while the airaid dyno peaked at 200????? One of these is just flat out wrong

 

That Airaid dnyo looks odd to me. It actually makes less power over 4000rpm and less peak horsepower.

 

I can bet you that the final gear ratio compared between these two dyno charts provided in this link are wildly different. I am betting that the gear ratio for the airraid is probably 3.08 or 3.55 and those from the magazine article are gears like 3.55 or 3.73, respectively. There is just no way that yu would have that much variance between two identically built engines. Also you have to consider that the 4x4 has additional power loss caused by the transfer case although not much it is still relevant and good for a few percent.

 

Correction,

I should have mentioned. You could have those kind of variances but they would be caused by wildy different air temp, engine temp, humidity.

Either way, the dyno results are absolutely worthless to compare to each other unless engine temp, air temp, humidity, gear ratio, tire sizes and a few other things are also provided.

 

Re: any vendor's (e.g. Airaid) dyno "results"...CAVEAT EMPTOR!

 

look at the RPMs on each dyno. they are comparing different points, which is pretty useless for comparison.