Dyno'ed an FRS with 104 octane in the tank!

[TheRipler]

Originally Posted by 2forme

I understand this, but he was tuning 104....

That seems odd, but I haven't had a chance to try myself.

I was going more off the OP. From the top post, they didn't tune the 104.

[BerkTechnology]

Originally Posted by ABQautoxer

Did you, out of curiosity, pull the battery ground? Only asking because I did this on the dyno and made 11whp more though I was low on the pulls done before this.

I did not pull the ground strap or reset the ECU. Just dumped the fuel and made a few passes.

why does this surprise you??

There is a lot of headroom on this car for more timing advance, but the ECU seems to target a specific torque value and sticks to it. Its more for curiosity than anything to see what can and can't be done so we can all learn more about the car. This certainly isn't the first direction injection car we've worked with, but the first dual fuel system car we've gotten our hands on.

[uspspro]

Originally Posted by BerkTechnology

There is a lot of headroom on this car for more timing advance, but the ECU seems to target a specific torque value and sticks to it.

There were some previous threads about this, and it appears to be true. The ECU targets a certain "projected torque" value. A flash tune, will raise those limits.

[OrbitalEllipses]

Originally Posted by 2forme

I've talked to John about this. He mentioned that race gas didn't do squat as well.

It's surprising given the gains on E85.

Those gains are likely from running crazy timing that's only possible on E85 (compared to pumpgas).

[Mars2]

Originally Posted by OrbitalEllipses

Those gains are likely from running crazy timing that's only possible on E85 (compared to pumpgas).

Remenber that E85 will make more power even if you don't use map with more advance timing. just because you burn more of it at stochio than Pump 93 gas.

thsi guy expalin better than me:


Many sources make a big deal about E85 having less thermal energy per gallon that a gallon of gas. They frequently draw the false conclusion that you cannot make more power on E85 than you can on gasoline. E85 actually has a higher specific energy at stoichiometric fuel air mixtures than gasoline, and at proper max power mixtures releases more thermal energy in the cylinder for a given amount of air to burn. Since an internal combustion engines power output is primarily air supply limited this means you can make 5% to nearly 30% more power on E85 than you can on gasoline.

(edit 6/10/08) Current experience shows turbocharged cars like the WRX and DSM families can run upwards of 30 psi boost on E85 tunes without knock. The only case I know of where knock was logged was on a 500+ whp DSM running 35-39 psi boost!

Ethanol specific energy at stoichiometric fuel air mixtures is actually higher than gasoline allowing a higher release of energy per lb of air burned than gasoline.

Typical gasoline Thermal energy 19,000 BTU/lb max power fuel air mixture 12.5:1
Typical E85 Thermal energy 13,475 BTU/lb max power fuel air mixture 6.975:1
Typical ethanol Thermal energy 12,500 BTU/lb 6.429:1

If you are consuming 100 lbs of air, lets see how much fuel energy you release for each of these fuels using gasoline as the base 100% reference.
100/12.5 = 8 lbs of gasoline @ 19,000 BTU/lb = 152,000 BTU = 100%
100/6.975 = 14.337 lbs of E85 @ 13,475 BTU/lb = 193,189.9 BTU = 127% more heat energy
100/6.429 = 15.555 lbs of Ethanol @ 12,500 BTU/lb = 194431.5 BTU = 128.9% more heat energy

Typical fuel energy contents:
gallon of gasoline = 125,000 Btu
1 gallon of ethanol = 84,400 Btu

[SkullWorks]

The only reason more power wasn't made is the ECU didn't have enough time to learn and advance fueling, I have seen 9 out of 10 FA20 dyno's on 91 cali swill crop in torque up top sharply due to timing retard (presumably from knock detection)

Just the increase to 93 should realistically show some improvement in knock prone areas of the map, but the ECU needs some cycles to determine fuel quality/knock resistance.

that being said, I'd doubt the ECU has much timing to give beyond it's threshold for 93.

[Illusive]

you need to reset the ecu first, do 3 pulls,
pour in new gas, let car run for a bit to let the new fuel get to the injectors,
reset ecu, do 3 pulls
then compare.

http://www.ft86club.com/forums/showt...highlight=DDPR

[brufleth]

For a production ECU flash I would bet money that they didn't run the schedules out much beyond timing for 93 octane. There is no reason to do so and it would otherwise lead to customers using higher octane gas and maybe squeezing more performance out of the engines but at the cost of fuel economy and engine life.

Plus, if there's a sensor (maybe a dual) fault they have to worry about the timings changing such that your engine blows up. If they stop the maps at 93 octane settings they can at least be sure it isn't their fault that you blew your engine up or got a knocking rev mode.

[arghx7]

The engine is certified on 97RON in the USA, which is about 93 AKI. Don't expect more timing advance if you are higher than that. I find it funny that California certification fuel is 97RON but you can't even get that kind of gas in California...

OP would have been better off if he had reset the ECU and given the ECU time to learn.

[soros151]

Watching.