Here is a Dyno. slip that shows my stock vs. Gibson 4" catback.

Don't the H.P. and TQ. figures seem kinda low since we're supposed to have 325 HP stock? I mean, I know there is some loss in the drivetrane, but Dang!

 

I'd be more concerned with the torque than the HP. Geez-you're supposed to have flywheel 560lb-ft @2000rpms and the graph is at 275lb-ft!! Something must be wrong.

I have a Truck Trend article where the dynoed a Chevy Silverado 1500 with 5.3L and it put down 266lb-ft @ 3000rpms!

I'd take it to a different shop and see if you get a different result. Maybe the operator didn't know what he was doing. I'd be mad as a hornet if any new diesel pickup I bought was putting down under 375lb-ft with the exception of maybe the non-HO Cummins.

 

Bikenut, The 7.3 stock will dyno right at 200hp...On the 7.3 all the power in the exhaust is in the downpipe..But only about 10-15 dyno...You are attacking the right place first..Guages are not a bad idea first, to set up baseline..And as diagnostic devices..I am thinking my should hit 400hp...I had it dynoed at 260 wo propane or exhaust, or a serious chip...The Fords dont dyno well and you have to have someone who knows the trucks to get them to dyno well...

 

Im sure its something like that Mach, Beastie mentioned that the 1-1 ratio is 4th gear and I dont know if they knew that. I just dont want them putting this dyno. sheet on their website!! All those damn duramax and cummins guys will laugh at us!!


I'll update after a talk with them.