E85 dyno tune

Discussion in 'High Performance Modifications' started by Rick WI, Jul 14, 2008.

  1. Rick WI

    Rick WI Veteran Member

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    Did a E85 dyno tune the other day and if that fuel is available it's a nice way to go.

    Used a Quick Fuel 850 which is "kind of" like a 850 DP Holley. Not a bad carb but not as nice of castings as you tyically see from Holley.

    A few things on dialing in after first start. Float levels for E85 need to be well above 1/2 up the sight glass, at least in a 600 horse applilcation. We needed to set the float level at the top of the sight glass to keep floats near the 1/2 point during a pull. With E85 float level has a PROFOUND affect on the fuel curve.

    Setting up the 4 corner idle was somewhat time consuming. Lots of playing around on the secondaries to get all 4 to respond equal. This carb never did quite fuel at idle, or through the power band, as well as a stock style Holley 750 HP. Small idle adjustments seemed to make big changes so think tic turn here not quarter turns. Once in the car will want to fine tune the idle in for sure.

    Overall power curve was exactly the same. Maybe lost a tad of torque low and mid but HP was basically the same up top and after peak.

    There is no doubt, lots of fuel flow is required with E85.

    NO doubt though with high compression, 12:1 and if it's available, it is a very effective way to lower fuel costs versus race gas.
     
  2. ccrider

    ccrider Veteran Member

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    i've thought about that for my car since i work at an ethanol plant. i wonder if that carb would work with straight 200 proof?
     
  3. Rick WI

    Rick WI Veteran Member

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    It would work but the jetting and airbleeds would be off if it was tuned to E85.
     
  4. ccrider

    ccrider Veteran Member

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    did the motor run cooler ,like on methanol?
     
  5. Rick WI

    Rick WI Veteran Member

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    The top of the intake was cool to the touch. It's not unlike methanol, although we didn't see frost. Since the dyno controls water flow through the engine no way to say how it affects that aspect. Oil temps ran the same as well as EGT's responding basically the same when dialed in for best power.

    One other thing that was interesting is on gasoline this engine liked a 2" spacer A LOT. On E85 it seemed to like a 1/2. We didn't spend a whole lot of time dialing in the E85. We started tuning this fresh motor at 7:00AM on gasoline and finshed that ritual around 4:30 in the afternoon. After swapping the E85 carb on we only made a handful of pulls and by that time it was close to 7:00 in the evening. Could have spent a whole lot more time fine tuning.
     
  6. 79supergasdriver

    79supergasdriver A Scholar and a Gentleman

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    I've read that you have to increase the entire fuel delivery volume capacity about 40% at the same pressure to keep it alive. I've been looking into E85 A LOT since it's supposedly 105 octane, cools the engine, and costs close to a dollar less a gallon here. Switching from 91 octane pump gas would allow my smaller chamber aluminuim heads, more agressive timing, and hpefully put me a lot closer to the 400 hp marks...
     
  7. Doug Jaynes

    Doug Jaynes Veteran Member

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    It is cheaper per gal but you end up using about 30% more fuel . so It isnt cheaper to run but the 105 octane is nice. When I get back on my twin turbo project I am wanting to experiment with it.

    Doug
     
  8. Rick WI

    Rick WI Veteran Member

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    We will run a 170 GPH pump on this engine with -10 feed. Yes, fuel flow is quite a bit higher. Gas jets 78 secondary 74 primary. E85 96 and I think 89 in the primaries or something like that. 96's for sure in the secondaries is where it ended up.

    It's A LOT cheaper than race gas. Pump gas, if you can run it, don't know if I'd go this route. Sooner or later ethanol is going to go up in price, has to as inputs to the plant are WAY up. Either they will all go out of business or the price will meet the production cost. They can't all go out of business since it's a mandate and a huge economic investment at this time. Off topic, but the basis for why the cost for ethanol will be going up in the not too distant future.
     
  9. Kamikaze

    Kamikaze Veteran Member Lifetime Gold Member

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    rick,

    I was curious if you ran a wide band O2 sensor on the dyno and if you saw any differences in the stoichiometry with E85 compared to regular race fuel?
     
  10. Rick WI

    Rick WI Veteran Member

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    We don't have a wideband, use EGT's. EGT's are the same but the A/F is MUCH richer on E85, about 10:1. Sooner rather than later we will be doing an E85 application with a FAST EFI system. That will have the wideband and this fall we are replacing the data aquisition system and going to 8 widebands plus EGT's.
     
    Last edited: Jul 16, 2008

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