I'm looking for the flow numbers of a stock U20 head. I have a dyno program for the computer that is very accurate (+/- 5 Hp). I haven't had my head on a flow bench so I'm looking to find some numbers to feed into this thing.
Thanks,
Will
Has anyone done a U20 head flowbench test?
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SLOroadster
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Has anyone done a U20 head flowbench test?
Sorry, I find modern engine swaps revolting. Keep your G, R, or U series in your Roadster!
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SLOroadster
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Alvin, I have a copy of Dyno 2000, its a desktop dyno and basicly you build your engine in the program. You enter the dimentions of EVERYTHING. The valve sizes, bore, stroke, cam specs, compression ratio (it will calculate it for you, mine was a big surprise, 10.75:1! It doesn't ping on pump gas either. I double checked on a few other compression ratio calculators as well and they were about the same.) Type of exhaust (a basic thing, havent figured out if I can be specific.) It asks for the type of intake (in my case, an independent runner). it also asks for the combustion chamber volume and type.
The guy I got it from went to an auto tech school in AZ where they built a SBC using this program and when they tested the engine, it was 3 hp off, and it was carburated.
I did a test run with a stock U20 with a B cam, found 151 hp at 6300 rpm and 138 lb ft of torque 9.6:1 compression ratio. This was at standard bore and the came was a 280 degree .456 lift) Using the same constants, did my engine and discovered that I potentially have a torque monster, 195 hp at 6500 rpm, and 179 ft lbs torque at 5000. NOW WEATHER OR NOT THIS IS TRUE, ONLY TIME WILL TELL. I WON'T BELEVE IT UNTIL I DO AN ACTUAL DYNO RUN. The figures are at the flywheel as well.
I need an accurate flowbench result to find out what the head will actually flow and yes Alvin your guess was correct, I'm trying to find the CFM for the ports. I guessed on the CFM, but used the same for the stock U20 run, a Weber 45 DCOE will flow about 215 CFM per barrel, a Mikuni 44 is around 211, times 4 is 844 cfm, thats what I used.
Its a cool program, you can build the biggest monster you want, in reallity who knows if your monster will even run, but its fun to play with
I SO wish I had a tranny that I could trust on a dyno.
Will
The guy I got it from went to an auto tech school in AZ where they built a SBC using this program and when they tested the engine, it was 3 hp off, and it was carburated.
I did a test run with a stock U20 with a B cam, found 151 hp at 6300 rpm and 138 lb ft of torque 9.6:1 compression ratio. This was at standard bore and the came was a 280 degree .456 lift) Using the same constants, did my engine and discovered that I potentially have a torque monster, 195 hp at 6500 rpm, and 179 ft lbs torque at 5000. NOW WEATHER OR NOT THIS IS TRUE, ONLY TIME WILL TELL. I WON'T BELEVE IT UNTIL I DO AN ACTUAL DYNO RUN. The figures are at the flywheel as well.
I need an accurate flowbench result to find out what the head will actually flow and yes Alvin your guess was correct, I'm trying to find the CFM for the ports. I guessed on the CFM, but used the same for the stock U20 run, a Weber 45 DCOE will flow about 215 CFM per barrel, a Mikuni 44 is around 211, times 4 is 844 cfm, thats what I used.
Its a cool program, you can build the biggest monster you want, in reallity who knows if your monster will even run, but its fun to play with
I SO wish I had a tranny that I could trust on a dyno.
Will
Sorry, I find modern engine swaps revolting. Keep your G, R, or U series in your Roadster!
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ambradley
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SLOroadster
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SLOroadster
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Mark,
I used Bob sharps prep manual when I built this thing. He was also limited to .040 and no larger in the displacement, and he was using the stock B cam. He also didn't have many of the performance upgrades that are now out. I don't know what I will show at the wheels, as I stated, that was a projected simulation. I don't know what I actually have, I had to guess on a few things, mainly the airflow # for the head (the reason I started this thread.) Evidently I posted to the wrong site because no one has even tried to answer the question. I did however use the same numbers when I did the base run with the specs (straight out of the Claymer manual, or found else where.)
Will
I used Bob sharps prep manual when I built this thing. He was also limited to .040 and no larger in the displacement, and he was using the stock B cam. He also didn't have many of the performance upgrades that are now out. I don't know what I will show at the wheels, as I stated, that was a projected simulation. I don't know what I actually have, I had to guess on a few things, mainly the airflow # for the head (the reason I started this thread.) Evidently I posted to the wrong site because no one has even tried to answer the question. I did however use the same numbers when I did the base run with the specs (straight out of the Claymer manual, or found else where.)
Will
Sorry, I find modern engine swaps revolting. Keep your G, R, or U series in your Roadster!