That may be true but Reb definitely knows his stuff... I'll hit up a Dynojet at some point and see what it says. Its just nice cause this place is 1/4 mile from my house and if I break down I trust them to work on it..

I think I have heard that the Mustangs do tend to read a little low.. 20% seems like ALOT low though.

 

Hey Reb,

Whats your opnion on running the dyno.. 1:1, or in O/D? I'd like to hear some other people opinions on the matter. Everybody seems to have a different way of getting it done.

 

you need to dyno in O/D. You add the most load. Some mustangs I've seen 20% high and 20% low and in between. Seen and dynoed on them. The mustang IS an Inertia Dyno, it also has a load eddy current on it too. A super flow is a true load dyno. It takes you up to X rpm and then pulls you down to XY rpm. This is a great dyno as long as the truck owner doesn't mind if his truck blows up. The mustang runs just like an inertia, but it adds load to it. Ya, its harder to spin and work the turbo more, but its too hard to calculate HP when you have two things working against themselves. The DynoJet uses slugs of inertia (weight) to put resistence on the truck. I can make 100 PSI boost on the dyno, so it has enough resistence to get the motor to work. The DynoJet 248 is the most reliable dyno on the market. All you need to do is put a stock truck on and you should be 15-18% lower than advertised HP. Now the DynoJet 248 is not the same as the DynoJet 224. The 224 has less weight on the rolls and some have a load eddy current motor on them, BS in my opinion.
So Dyno jet 248, dyno in O/D, and put a lock switch in so that it stays locked. On 47re trucks you should put a wire between the lockup switch and the O/D wire so it won't downshift. If you haveww a 48RE valve body it will not pop out of O/D if the lockup switch is on.

 

Good info Reb, thanks alot. I have a towloc on the rig in question so shouldn't be a problem keeping it locked up.

Just gotta track down a local dynojet 248 I can hit.

 

go to DynoJets website and they will have a list of 248 dynos in WA