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Old 09-17-2001, 10:17 AM
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In the US we generally list horsepower in two different ways, flywheel hp and brake hp. The old way of doing it is by flywheel hp which is the same way that the Dyno 2000 does it. Here in the southeast, around NASCAR country, there are plenty of engine dynos available to run up and tune just your engine (very expensive). A more common type of dyno, and less expensive, is the rear wheel dyno which you simply drive your car onto, strap it down, and do a run up. This, of course only gives you the rear wheel hp which is about 25% less than flywheel hp because of the drivetrain drag. A close friend of mine who builds drag racing engines says that the Dyno 2000 software is within about + or - 5% of what he actually gets on an engine dyno. This isn't good enough for a professional racing program, but for us guys who just want to compare some engine changes and different cams, compression, heads, carbs., etc. it seems to do all we need through good comparative numbers. They tell you up front that the biggest unknown in the program is cylinder heads and the flow numbers because the biggest flow may not give you the most hp. There are some large hp gains and losses to be had in cylinder head design as far as airflow and burn rates and I guess their software isn't capable of handling all of the possible combinations.
I have no problem with Chevy's. Certainly the most horsepower for the dollar here in the US. I just couldn't bring myself to put one in a Cobra.
My question relating to the rollers kind of got back to the fact that the 5.0 HO came with rollers from the factory which worked real well and were reliable as far as I know, but the block was designed for rollers. The aftermarket rollers have to work in blocks which aren't designed for them and That's where I don't have enough experience. My friend who builds the drag engines says "no problem". But he does his driving a 1/4 mile at the time.
H Dog
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