Pro Street Import, 2004: Ethanol(E100) to 110 octane Unocal 76.
Horse power should be calculated per cylinder, with each cylinder making the same horse power as the next.
The engine was first tuned for maximum power gain(which had the same a/f), and was then set to have the fuel delivery for a 9.5 a/f reading. (as we were advised to do).
Equipment used for measurement of power gains/losses: Dynojet 248 Chassis Dynamometer.
Fuel Management: Hondata S200 w/P72 Disabled Knock Sensor.
PLX Meter with NGK NTK Air / Fuel Sensor was used for measuring oxygen content compared to each one part of fuel.
Engine used for study: Naturally Aspirated 1.6L B16A 1989 CRX-Sir, Arias custom 85mm stroker piston, 89mm stroke, 1.54 rod ratio. 12.8:1 compression.
Fuel used for comparison: The engine was first tuned on 110 octane Unocal 76 Racing Fuel, then flushed and converted to E100.
Effective fuel pressure comparison from C16 to E100 was the same, 65psi at WOT(wide open throttle) without fuel pressure drop in all rpm.
Individual port fuel injection.
Fuel delivery comparison: E100 approx. 136% to each 1 part of 110 octane Unocal 76.
TUNING TOLERANCE / STOICHIOMETRIC :
110 octane Unocal 76 : 14.7 +/- .1, at idle
E100 (ETHANOL) : 14.6 +/- .1, at idle
Other then the NGK NTK Air / Fuel Meter, we have no other way for measuring oxygen content after the combustion process. Thus, leaving us with the theory of a 14.7 stoichiometric reading, for both E100 and Unocal 76 110 octane, means the same amount of readable oxygen particles are left unburnt in the exhaust after a proper combustion process has ended. For every 1 part race fuel at a stoichiometric reading of 14.7, it will take approx. 136% of Ethanol(E100) to reach the same proper stoichiometric reading.
Removed multiple cylinder heads in other tests. Cylinder head removal/inspection after a 500 mile break-in period and again after a hard driven 5k miles..
Findings: Stoichiometric is the same. ( -.1 variation is the added safety precaution when tuning with E100, making it 14.6 +/- .1, at idle.)
Horse Power Gain From Unocal 76 to E100: approx. 6hp / 1.5hp per cylinder
Torque Gain from 110 octane Unocal 76 Race Fuel to E100: approx. 18 lbs / 4.5lbs per cylinder
Intake air temperature readings didn't differentiate enough to see the cooling benefits that come by using ethanol.
It was a surprise to find optimal gains were made at the same ignition timing settings for both fuels. Losses from detonation were more with E100 then the race fuel. Safe tuning window for ethanol is smaller then fuels that use fossil fuel as a main part of its product.
Fuel Ratios : Air / Fuel Ratios in the 9's dilute the oil, causing engine failure. Ethanol left as the unburnt residual after the combustion process has ended, seeps past the piston rings and into the crankcase. Stoichiometric for 110 octane Unocal 76 Race Fuel is identical to E100. Engines with their engine oil services done on schedule, when using ethanol, have not experienced failure due to fatigue of lubrication since after this study was conducted in the year 2004.
This is all based on findings from 2004 to current.
Pro Street Import
Mike(Skinhead) Schwichow, thanks for letting us use your car.
Jerry(Built) Guzman, thank you for helping us with the study.
ARIAS PISTONS, I know I can always depend on your products.
Hondata (Javier Loraca), you have always been there for us.
Clutch Masters (Luis), you guys never fail. Happy client since 1996
Castillos Crankshafts, if you need .0002" machined off the crank journal when setting up proper engine bearing clearances, talk to Rudy. I LOVE YOU GUYS!
If you find this interesting, read what we found out during our research when converting from pump gas 91 octane to Flex Fuel, E85(85% Ethanol/15% Petrol).... on boosted configurations.
Dec. 12, 2021
edited for grammar correction: 5/28/2022
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