Sam I am

All I know is this. I had my F-bodies dynoed at the DynoJet office here in Vegas, where they make the things. I was told by them time and again 1.1 gave the most accurate results. If that's changed in the last 5-7 years, then I stand corrected.

Gene K

Im now even more confused because the 2011 Mustang GT does have SAE J1349 certification which should make it very difficult to fudge the numbers.

One thing thats very strange is the SAE Paper states that it was certifiied on 98 RON Fuel which should be 93 AKI not the 91 AKI that Ford specifies.

After a little research actual output on the SAE J1349 test appears to have been:

91 RON - 406/381
98 RON - 416/394

Ford appears to have taken advantage of the +/- 1% rule to derate the engines to:

87 AKI (91 RON) - 402/377
91 AKI (96 RON?) - 412/390

Nuke

Now you guys have raised a question mark over my woody for the 5.0...

Gene K

I agree. That does give the most accurate results. However the point was that more gear like a 1.32 vs 1.00 in the trans has the same effect as 4.10 vs 3.55 in the axle... It results in a lower rwhp mumber not higher.

That said I am now leaning toward a happy dyno. After reviewing the results of the SAE J1349 Test and the results of the test on the GT500 on the same dyno.

Xcelsius

This puts a period under mine to make it a nice "!"

iDance

Not an engine dyno

howarmat

dynos lie all the time....so why are we surprised that this one lied to give better numbers than most would expect when they are promoting a car

Kona6Stang10

Slap it on a mustang dyno and see what it REALLY makes

Driver72

Well if you want to know what it "really" makes, you'd have to put it on an engine dyno.

Or you could care less about the dyno numbers and just take it to a track and get the numbers that really matter.

Dyno numbers don't really mean a whole lot, other than knowing what mods and tunes did for you, and removing any "driver" faults.
But what Inside Line should have done is brought a new LS3 Camaro SS along for comparison to dyno the cars on the same dyno, same day.

For the record, when I was dynoing one of my 335i's at a local dynojet once back in 2008, a new LS3 Corvette with 2000 miles on it dynoed and got the same 395 rwhp stock.

Sooo, if owner 5.0's show the same 390-395 rwhp on other dynojets, it would seem that the 5.0 really is making 20+ hp more than Ford is marketing it as.

Last note: As far as I know, the SAE allows manufacturers to "claim" whatever they want as long as it's equal to or LESS than what the engine actually makes.
It's not lying, it's marketing.
To claim it had MORE power than it really does would be criminal. To underrate, well, nothing wrong with that, and breaking no rules.
The 300 hp rating of the N54 engine in the BMW is clearly also proven many times over to be underrated by 20+ hp too.

Snakebite64

I have 1800hp???????????????????????????????????????????? ?????????????????????