no, E-85 requires a smaller restrictor because it makes more power then 93 oct. thus to even the playing field they require a smaller restrictor for the e-85 cars.

e-85 has less power density then gasoline, but because so much more of it is needed for stoic operation, it edges out gasoline.

 

Did you guys ever try it on a turbo F4i?

d

 

no, turbo f4i is so big and heavy and doesn't make any more power then a non turbo f4i on 93. weight is the name of the game in formula sae. cost, complexity, reliability, weight are all worse when you turbo the 4fi. the f4i on 93 will already max out the restrictor, so if your drivers can shift theres no need for a wider power band.

our 06 car was super light with the 250 turbo. the car weighed 395 pounds without the wings, not using any titanium, and a steel tubeframe. and it made 73 hp (which generally the other sub 400 pound cars were all single cylinder cars making 40hp at best. with the wings and other last second bull**** it weighed 450lbs.

the 06 wings were much more effective then any other years, with the car being able to pull 1.8g's in a 200 ft skidpad. previous years were significantly slower.

the problem with the 250 is it is really unreliable and only myself and our engine lead had any idea what was going on with that engine package. dr. bob the self claimed "king of the world" at engine tuning had no idea what was going on, as shown by his poor showing of the 06 car at the texas autocross weekend. and yes, he was the one telling the team what to do, and the one tuning the car after california (also a week before california while i was at a friends wedding... thats why our engines all blew when i was gone, and thats why we never had a running car in cali... but thats another story)

 

After a little more tuning I'm very happy with the results. I still think there is more power to be found in this fuel, but it takes a while because the only time I have to datalog is during my drives to/from work. Below is a Data Log Lab dyno graph comparing a very strong 93 octane pull I did earlier this month to a pull on the same road tonight.

-Paul

 

E85 also requires more timing so dont be afraid to go to an aggressive timing curve. Heck even the infamous sea of 8's would work, but the point is it has a slower flame front speed so thusly more advance is needed.

 

I've decided to start playing with the boost first and then will work with the timing. As of right now I just log my drives to and from work and retune between each drive. It takes a while to get things fine-tuned but unfortunately I don't have time to do a lot of tuning runs during the week. Tomorrow morning I'm going to bump the boost up another couple of pounds and see how that works, although I'm supposed to get 3-5" of snow tonight so if it's still snowing for my drive to work I won't get to do any WOT pulls. After this boost jump I'll start playing with the timing.

-Paul

 

One more thing regarding flame front speed: E85 actually has a faster flame front speed but has a longer light-off time. This is just based on some reading I have done, but if it is true it means that more timing will increase power but will have rapidly diminishing returns after a certain point.

-Paul

 

I think I would run stock timing map ..... picking up a few extra degrees from the leaner AFR. Then just run whatever boost you feel comfortable at.

Running stock timing on a cammed car should be good for about 4* more than what 93 is capable of.

 

Thats what it was. I knew it needed more advance but I couldnt remember what it was exactly that precipitated the advance. Thanks for the clarification.

 

I did a little playing with the timing, adding a couple of degrees in the middle and top. Mitsulogger picked up 3 counts of knock near peak torque so I think I may have reached my limit there, but there might be a little more left at the top end. Below is a comparison between my best pull from this morning and my best run from tonight with a little more timing. For people that may be questioning my numbers, the speed graph shows that it takes me 2.93 seconds to go from 40-80. Also, other than any weight savings from replacing parts, I have not pulled any weight out of the car.

-Paul

 

Be careful with adding timing. Its possible to have bad things happen and not see knock.

 

I'm still at only 7 degrees at 3500 RPM and gradually increase to 20 deg right around 7000 RPM. I chose to start off very conservative with my timing so I still have a bit of headroom before I run into any trouble.

-Paul

 

Would this be on a FSAE car

i did a honda on e-85 3 years ago and so far it has been good with no problems

10.5:1 and 10psi boost

which is really low but i am going to run some more next summer.

 

PVD04 can you post up dyno chart from regular 93?

 

The first one I posted was a comparison between 93 octane and my first run on E85. Once I get my tune worked out a little better I will post more results. I will also be posting gas mileage results after a few more tanks of gas. I have been spending a lot of time "tuning" so my gas mileage will be atypical.

-Paul