Re: I have never used ethanol, - Saab 900 Bulletin Board -
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Re: I have never used ethanol,
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Posted by oldsaab [Email] (more from oldsaab) on Mon, 13 Jul 2009 21:09:32 Share Post by Email
In Reply to: Re: I have never used ethanol,, Landjet [Profile/Gallery] , Mon, 13 Jul 2009 17:13:50
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So my question was:

"If you run E85 does the engine make more horsepower? What is the octane of E85 (I was told in Texas it was 105 - maybe it's like everything in Texas - bigger)? Does an ethanol Octane rating equate to an octane rating for typical gasoline? Would you get more horsepower like you do with 87 vs 91 vs 93 gasoline if the engine were setup to continue to boost higher if the knock sensor was happy?

If the engine does produce more horsepower, and mileage is not my goal, would running E85 be a good thing to do, and are there any other side effects, aka do I have to do any ajustments to the vehicle to avoid issues?"

...I don't think I saw the answer (or I certainly didn't understand it) other than it doesn't have as many BTU's per measure of volume. Some cool figures about the relative energy per volume in various fluids, didn't see anything about gasoline in it's various Octane flavors which I know you know can and does make a HP difference in an engine designed and/or setup to take advantage of that Octane difference. You also mentioned that they are ripping us off and we'd need another continent to grow the stuff that makes it and make it worthwhile or something like that... These points may all be true (and you already know I agree with the economics of the stuff point), but right now none of that answers the question thought I asked. It was most likely me so I'll do it again.

To restate:

If the octane displayed at the pump is XX+15 can I extract more horsepower than using a value of XX ??? Are Octane figures equal irregardless of the fuel despensed? Does it matter that it's E85 or not? Yes Octane is the ability to resist knock and thereby for us Turbocharger guys we can squeeze more fuel and air together for more horse power, right?

I know that I can setup my turbocharger, Injectors and ECU and all the other TLAs get MORE WHP running pump 93 over pump 87 IF THE CAR is setup to take advantage of it, which I specifically asked, AND even MORE if using racing fuel of around 100 Octane at $9 plus per gallon.

My question did say 1) what changes to the engine to make it get the benefit of the fuel and 2) are Octane ratings the same no matter the fuels being measured? Like Watts in an amplifier, which are *not* because there is Music Power, Peak, Peak to Peak, and RMS at 4 ohm, or at 8 ohms... Basically you have to know the measurements that you are dealing with. I know that Octane has both a "Research" and a "Measured" metric and that for some time, at least in California, they go to great lengths to let you know that the octane rating they are claiming is the *average* of R+M printed right on the pump.

If the E85 Octane allows higher boost, but you get a lesser amount of energy per unit measure compared to good old *pump* gasoline... is there a point on the curve that a turbocharged car can make a case for using E85???

Somewhere out in the middle earth people are saying that E85 is 105 octane... is it Gallons and/or Imperial Gallons? Is a 105 Octane 105 Octane???

You know why I want to know this, I race a car and don't want to pay $9 and change for race fuel to get "more power Scotty". If I can put bigger injectors in (We can go plumper...) or something... and get more power, I want to try it out. As above, mileage is not my goal... HP per Dollar of fuel spent is the metric here. If it takes 33% more by volume for miles traveled... but the fuel costs 1/3 of the highest test stuff.. It's a win for my requirements.

Easy math example:

Race Fuel at $9.00 a gallon. WHP 300. Mileage 15 MPG Boost 22 PSI
E85 or?? at $3.00 a gallon. WHP 300. Mileage 10 MPG Boost 29 PSI

150 miles later... 150/15mpg = 10 * $9 = $90.00
150 miles later... 150/10mpg = 15 * $3 = $45.00

Now as to the rest of it... will the engine run cooler? Does anyone actually Know? I understand the science behind this, but has anyone actually Done it? Seems like they run some interesting fuels in NASCAR, Formula anything and others. Since I'm not *always* hard in the boost, with the off boost performance be good, bad, or ugly?

As to the water pump and fan overhead on the HP... It can't be that different between these two, especially since once the engine is up to temperature the thermostat is going to be open about all the time and the back pressure that the water pump has to deal with should be approximately the same. Will higher boost with E85 make more heat? How much more heat if so?

There are many other factors in the car that rob effective horsepower, including rolling resistance with the tires, air flow/resistance, total weight, gearing, flywheel inertia, rotor amd wheel/tire inertia, driving style and sure something else too, I'm sure you guys know this.

Yes, maybe one could spend hundreds or thousands of dollars on the engine to do really cool porting and extra injectors and all kinds of other engineering marvels (install a DI setup, or other really cool stuff) to get to a high WHP figure with pump premium gas... but as Justin and Landjet both know... that is not allowed in the 24HOL...

Again, my questions are not with a street car in mind, but for a play car.

Thanks for any and all information, I learn more everyday here!

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