Fuel these days...

[blue2000s]

Originally Posted by pk2

---------------------------------------------------------------------
I have forced induction and a piggyback AIC (or call it a DME-lite) that leaves whatever Porches intent was as far as induction & ignition goes, somewhere back along the road.

Your right I suppose that more energy might create more heat but, a blower adds alot more though, an easy 125+ degrees to the intake temp. The hotter the charge the more it is likely to detonate.. Knock sensors will solve that by retarding the timing but, start Kissing performance away to.

The setup as designed is really pushing the limit on 93 octane (probably pre ethanol 93). We only have 91 oct. (except for 2 or 3 places across town) So, just to get it to that minimal 93, I have to brew my own from 91 and 100. I can't pretend to notice the dif between 93 or 91. I've been leed to beleive higher octane it a cooler burn. Keeping my piston from burning (they can) is my only concern. This thread complicates things a bit.

PK

Adding a forced induction system to a high compression engine will certainly require an increase in octane rating in the fuel you use for safety. Compression pressure is higher, mixture temp is higher, cylinder temps are higher, the potential for hot pieces of residual carbon setting off the mixture prematurely is higher. Everything is there to allow for an unintended ignition. You would want the increase in octane to resist the chances. Actually, it's popular within the tuners of turbo engines to use E85 (speaking of E85) because it's octane rating is very high, which allows for high boost levels beyond what you can do on pump gas.

[pk2]

Originally Posted by blue2000s

Adding a forced induction system to a high compression engine will certainly require an increase in octane rating in the fuel you use for safety. Compression pressure is higher, ...You would want the increase in octane to resist the chances.

-----------------------------------------------------------------------------------------------------
All very true. Pistons can come to look like Swiss cheese fondue on a connecting rod to.
------------------------------------------------------------------------------------------------------

Originally Posted by blue2000s

Actually, it's popular within the tuners of turbo engines to use E85 (speaking of E85) because it's octane rating is very high, which allows for high boost levels beyond what you can do on pump gas.

-------------------------------------------------------------------------------------------------------
So what you seem to be saying is rating (burn starter energy), by whatever means (ethanol, whatever), is more important and the actual energy content doesn't matter much with a blower. In fact, the rational for the 91 oct. sects belief system is opposite to that which you are suggesting for this app.

Interesting about e-gas. I've not seen it...but I haven't looked either. What is it likely to dissolve?

Regards, PK

[blue2000s]

Originally Posted by pk2

So what you seem to be saying is rating (burn starter energy), by whatever means (ethanol, whatever), is more important and the actual energy content doesn't matter much with a blower. In fact, the rational for the 91 oct. sects belief system is opposite to that which you are suggesting for this app.

Interesting about e-gas. I've not seen it...but I haven't looked either. What is it likely to dissolve?

Regards, PK

Apparently, high boost and more fuel more than makes up for the difference in energy content.

[pk2]

Originally Posted by blue2000s

Apparently, high boost and more fuel more than makes up for the difference in energy content.

----------------------------------------------------------------------------------------
Patience must be running dry but, my options now that I know of for 93 oct (what the cblower was set up for) are

100 oct race fuel ------------------------------------------------$5-6 per gal

114 oct. toulene (already about 15% in pump fuel)------$20/gallon

115 (?) ethanol---------------------------------------------------$10/gallon

Bang for buck aside, I wonder what is easiest on the motor. And, what exactly is susceptible to deterioration with ethanol.

Regards, PK

[blue2000s]

Originally Posted by pk2

----------------------------------------------------------------------------------------
Patience must be running dry but, my options now that I know of for 93 oct (what the cblower was set up for) are

100 oct race fuel ------------------------------------------------$5-6 per gal

114 oct. toulene (already about 15% in pump fuel)------$20/gallon

115 (?) ethanol---------------------------------------------------$10/gallon

Bang for buck aside, I wonder what is easiest on the motor. And, what exactly is susceptible to deterioration with ethanol.

Regards, PK

E100 is about 113 octane. If your goal is to hit 93 octane, using 22/78 race/pump gas your cost is at about 3.70/gal if you assume pump 91 is 3.00/gal.

9/91 toulene/pump is 4.50/gal

9/91 E100/pump is about 3.63/gal

This is just to get you to a safe octane rating. As we noted before, race gas will have more energy content than E100, so you'll make more power (and wear) on the race gas.

[pk2]

Originally Posted by blue2000s

E100 is about 113 octane. If your goal is to hit 93 octane, using 22/78 race/pump gas your cost is at about 3.70/gal if you assume pump 91 is 3.00/gal.

9/91 toulene/pump is 4.50/gal

9/91 E100/pump is about 3.63/gal

This is just to get you to a safe octane rating. As we noted before, race gas will have more energy content than E100, so you'll make more power (and wear) on the race gas.

------------------------------------------------------------------
Thanks as always BLUE200OS,

Nice of you doing the arithmetic, I flunked that class. Pretty much my how I've been running it the majority of the time (8:2 piump). I usually wind up using toluene in pinch. It's a lot easier to find, in most hardware stores, than race fuel.

Ive got a custom made h2o/methanol injection sittimg on a shelf. Sure to relieve any angst with an effective octane well over 100 oct. on any grade pf fuel(from what I understand). Dont quite understand it but, Ive heard of people claiming the equivalent.118 on a 50/50 meth h20 mix, a little less with straight h20.

Regards. PK

[edevlin]

Does it make any sense to put in a gallon or two of race fuel with with every tank of high test? I have also noted that my mileage goes down (and maybe performance, hard to tell) with ethanol in the mix. BTW, I did a couple of dyno runs with my 2.7L and picked up a few HP running straight race fuel, that was an expensive, but fun experiement....

Ed