Quote:
Originally posted by andy669
You need a load bearing chassis dyno to accurately read horsepwer and torque on a car with a stall convertor. Like you mentioned, with an inertia dyno they will show low horsepower numbers, but they will also show high torque numbers. If the inertia dyno is operated correctly they can still be used as a tuning tool, but comparing horsepower numbers is silly.
On a manual transmission car, its a different story. The Dynojet 248 I have access to is very repeatable. I have been on 3 different 248's and the corrected numbers are usually within 5-7 horsepower of each other. To me, thats close enough for me to quote what my car makes and feel confident that I'm not mis-representing.
Andy
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Hey andy I checked into this and found that I was using and still using a dyno which is called (mustang dynamometer). Which is quite different from a Dynojet 248! This Mustang dyno can simulate elapsed time tests (1/4 mile pass)!
You can use the transbrake and launch the car off of 6000 rpms and simulate a full pass!!! This dyno is not an inertia dyno. You can make a pass and hold the car at a predetermined rpm and check your wide band o2 and make the adjustment right there while under load!!! The only thing is that it gives a much lower h.p #.The more h.p you make, the more it will vary from a dyno jet (it"s on a percentage).
Example: Fact
My friends down south dynoed a car with 650 rear wheel horse power and could barely keep it tied down. (auto-with a loose converter) Went to the track and gave the car 5psi more boost and blew off a low 8 second pass.! Now on a dyno-jet it would of probably made some where in the 900-1000 hp+ but it would of taken a lot longer to dail in.