E85 and straight 93 blend

[tbaumann]

A question regarding mixing E85 and 93 Premium. Would it be a good idea to mix e85 and straight 93 premium. Where I live I can straight 93 which contains no ethanol. I would like to try to fill up with about 30% E85 and 70% straight 93. Would this increase the octane to 98 give or take a point? What would I need to adjust from a tuning stand-point?

 

[Razor]

I think its not a good idea to mix the two.. tune.. and then try to get your mix to where it was before. Each one of the fuels has a different burn and stoich.. if its just to drive around its a non issue, but for racing.. whole other story.

You need constants when racing. Your fuel should be one. You cannot guarantee that every time you'll have 72% 93 and 28% E85 foer example. And once you tune the 72% 93.. if you change the concentration.. you threw your tuneup off.

This is the same with alcohol injection where water is mixed in. Or different types of alcohol are used.

Hope this helps.

 

[bsdlinux]

I think its not a good idea to mix the two.. tune.. and then try to get your mix to where it was before. Each one of the fuels has a different burn and stoich.. if its just to drive around its a non issue, but for racing.. whole other story.

You need constants when racing. Your fuel should be one. You cannot guarantee that every time you'll have 72% 93 and 28% E85 foer example. And once you tune the 72% 93.. if you change the concentration.. you threw your tuneup off.

This is the same with alcohol injection where water is mixed in. Or different types of alcohol are used.

Hope this helps.

Yep Julio got it right even though I do this all the time with a 50/50 mix. If you have a WB setup with correctional fueling then you'd be all set. Eric and I have been talking about just that so you can overcome the different mixtures even when running pure E-85 or E-75.

 

[tbaumann]

Thanks for the feedback. I am a little green when it comes to these GN’s, but I am learning quickly. I have an 87 GN I just purchased. I did the basic spring cleaning. I have just ordered a Walbro 340 and hot wire from Racetronix today.

What I am looking to do is increase the boost. Right now I can not go above 12 psi without knock on the scanmaster. I am thinking this could be due to the original fuel pump. I figure it is good idea to upgrade this anyway.

I understand that the goal is consistency and you might need to adjust your tune for varied amounts of E85 though I could keep the ratio close since the same station sells E85 and 93 (just a pump a part).

Don’t you need to adjust your tune anyway for outside air temperature? My car seems to really change with air temperature.

Can you elaborate on “WB setup with correctional fueling”? What is needed?

I was looking for an inexpensive way of getting 100 octane and upping the boost without race gas or alkly.