Dynoed an engine running rx8 rotors
02-17-2006, 05:19 AM
#1
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Join Date: Nov 2005
Posts: 93
S4 block with rx8 rotors, Haltech fuel only ecu (12 years old!), 50mm TB, electronic dist.
Initial tune on 91 octane fuel gave 255rwhp @ 7900rpm and 420rw ft/lb @ 6900rpm. Spark is breaking down at high rpm so I'll fit an MSD box and should get a fair bit more power. I need to bring oil temps down also, for every 10deg increase in oil temp above 190F about 7 or 8rwhp is lost. I belive this is due to the rotors being thinner walled than earlier items and transferring more heat to the oil. Oil temps are getting as high as 240F at the mo.
Inlet manifold is too long but it seems to give a lot of useable torque. Engine does not need to be revved above 8500rpm. It feels like driving a v8 rather than a rotary! I'll try an IDA style mani later on.
Initial tune on 91 octane fuel gave 255rwhp @ 7900rpm and 420rw ft/lb @ 6900rpm. Spark is breaking down at high rpm so I'll fit an MSD box and should get a fair bit more power. I need to bring oil temps down also, for every 10deg increase in oil temp above 190F about 7 or 8rwhp is lost. I belive this is due to the rotors being thinner walled than earlier items and transferring more heat to the oil. Oil temps are getting as high as 240F at the mo.
Inlet manifold is too long but it seems to give a lot of useable torque. Engine does not need to be revved above 8500rpm. It feels like driving a v8 rather than a rotary! I'll try an IDA style mani later on.
02-17-2006, 05:34 AM
#2
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Originally Posted by PDF' post='802385' date='Feb 17 2006, 03:19 AM
Initial tune on 91 octane fuel gave 255rwhp @ 7900rpm and 420rw ft/lb @ 6900rpm.
Read this then have a word with the guys who's dyno you got those numbers from:
http://www.epi-eng.com/BAS-PwrTrq.htm
02-17-2006, 06:36 AM
#3
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Originally Posted by 20b_boy' post='802386' date='Feb 17 2006, 03:34 AM
Think your numbers are a little out mate, 400ft/lb at 6900rpm should produce more like 550hp - just dont stack up...
Read this then have a word with the guys who's dyno you got those numbers from:
http://www.epi-eng.com/BAS-PwrTrq.htm
I was wondering about the torque reading, its according to the dyno sheet but I'll have to ask the dyno operator what its actually a measurement of. This is the first engine I've dynoed so its all new to me.
Working backward and calculating torque from hp gives 194ft/lb @ 6900rpm(peak torque) and 169ft/lb @ 7900rpm (peak hp).
02-17-2006, 10:00 AM
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Originally Posted by PDF' post='802394' date='Feb 17 2006, 04:36 AM
I was wondering about the torque reading, its according to the dyno sheet but I'll have to ask the dyno operator what its actually a measurement of. This is the first engine I've dynoed so its all new to me.
Working backward and calculating torque from hp gives 194ft/lb @ 6900rpm(peak torque) and 169ft/lb @ 7900rpm (peak hp).
Is that wheel torque maybe? what gear was the pull done in?
