[JStang]

Originally Posted by x-ception

You guys seems to know a lot about e85, I just filled up with 5 gallons of it and loving the power, is it possible to put the cobb on map 0 while still having e85 in the tank? Will the car run fine? also if I run out of e85 should I change the map back or can I drive moderately to the gas station with regular gas on E30 map?

Your car will run fine on map 0 with some E85 in the tank. You might get some fuel mixture codes though.

If you do not have E85 in the tank, do not run the E85 map. I don't think you will run into any issues as long as you baby it to the station but I would take the 30 seconds and flash to the proper map to be on the safe side.

[M BROK3]

Originally Posted by JStang

Your car will run fine on map 0 with some E85 in the tank. You might get some fuel mixture codes though.

If you do not have E85 in the tank, do not run the E85 map. I don't think you will run into any issues as long as you baby it to the station but I would take the 30 seconds and flash to the proper map to be on the safe side.

Thanks

Cobb needs to come out with on the fly map switching already.

[marv85]

Originally Posted by Manny_World

So, the question is (don't hate me for this one).... how do you not mix gas, drain the tank?

Just run your tank very low and fill up with race gas. That should be good enough

[raceyBMW]

For race gas, if you are running 91oct normally, get it down as low as you can (less than 2 gallons) and then put at least 6 gallons of 104oct in, that will get you to right around 100oct. Obviously more 104 will get you higher octane, but also adds weight.

No need to drain the tank, lol.

[JStang]

Time to bump this thread up. I am planning on running my car for the first time this weekend and have a few questions in regards to race gas vs. E30. Most discussion in this thread is about blending E85 with pump gas. There isn't a whole lot of feedback on the race gas map.

I have ran the E30 maps and the car feels good. Logs look fine with the exception of a few timing corrections and the LPFP failing to meet requested PSI. I am not even close to maxing out fuel trims so that is good.

I know very little about fueling so I have a few questions:

Would I have the same issues with the LPFP not hitting requested PSI running race gas? My initial guess is no due to the fact that E85 is composed differently from standard pump fuel. Theoretically speaking, wouldn't it be safer to stick with race fuel over E85 on the stock fuel system?

Will I need to blend the race fuel with 93 octane or is running 100% race fuel safe for the race fuel map?

Would I see more power out of the race fuel map vs. the E30 map or will they be about the same?

Throwing price and availability out the window, is there any reason to run E30 over race gas?

[COBB Tuning]

Originally Posted by JStang

Time to bump this thread up. I am planning on running my car for the first time this weekend and have a few questions in regards to race gas vs. E30. Most discussion in this thread is about blending E85 with pump gas. There isn't a whole lot of feedback on the race gas map.

I have ran the E30 maps and the car feels good. Logs look fine with the exception of a few timing corrections and the LPFP failing to meet requested PSI. I am not even close to maxing out fuel trims so that is good.

I know very little about fueling so I have a few questions:

Would I have the same issues with the LPFP not hitting requested PSI running race gas? My initial guess is no due to the fact that E85 is composed differently from standard pump fuel. Theoretically speaking, wouldn't it be safer to stick with race fuel over E85 on the stock fuel system?

Will I need to blend the race fuel with 93 octane or is running 100% race fuel safe for the race fuel map?

Would I see more power out of the race fuel map vs. the E30 map or will they be about the same?

Throwing price and availability out the window, is there any reason to run E30 over race gas?

The race map is designed for straight 100+ octane unleaded race fuel (not a blend of 93 or anything else).

We made the same power with the E30 blend and race fuel.

The race fuel will not tax the fuel system as much as an ethanol blend.

In the end, it's up to what's available in your area, what you're willing to pay for fuel, and what you feel comfortable running.

Whatever you do, make sure you log to verify the car is happy.

Have fun at the track!

-Josh

[JStang]

Originally Posted by COBB Tuning

The race map is designed for straight 100+ octane unleaded race fuel (not a blend of 93 or anything else).

We made the same power with the E30 blend and race fuel.

The race fuel will not tax the fuel system as much as an ethanol blend.

In the end, it's up to what's available in your area, what you're willing to pay for fuel, and what you feel comfortable running.

Whatever you do, make sure you log to verify the car is happy.

Have fun at the track!

-Josh

Thanks for the quick answers Josh!!

[VNeBLOB42]

Originally Posted by JStang

Time to bump this thread up. I am planning on running my car for the first time this weekend and have a few questions in regards to race gas vs. E30. Most discussion in this thread is about blending E85 with pump gas. There isn't a whole lot of feedback on the race gas map.

I have ran the E30 maps and the car feels good. Logs look fine with the exception of a few timing corrections and the LPFP failing to meet requested PSI. I am not even close to maxing out fuel trims so that is good.

I know very little about fueling so I have a few questions:

Would I have the same issues with the LPFP not hitting requested PSI running race gas? My initial guess is no due to the fact that E85 is composed differently from standard pump fuel. Theoretically speaking, wouldn't it be safer to stick with race fuel over E85 on the stock fuel system?

Will I need to blend the race fuel with 93 octane or is running 100% race fuel safe for the race fuel map?

Would I see more power out of the race fuel map vs. the E30 map or will they be about the same?

Throwing price and availability out the window, is there any reason to run E30 over race gas?

don't you remember the Turkeybaster115 thread?

a lot of exchanging between race fuel vs ethanol..

[raceyBMW]

Originally Posted by COBB Tuning

The race map is designed for straight 100+ octane unleaded race fuel (not a blend of 93 or anything else).

We made the same power with the E30 blend and race fuel.

The race fuel will not tax the fuel system as much as an ethanol blend.

In the end, it's up to what's available in your area, what you're willing to pay for fuel, and what you feel comfortable running.

Whatever you do, make sure you log to verify the car is happy.

Have fun at the track!

-Josh

With the race gas maps, running 100+ octane, do you still need to worry about fuel trims? Or is that really more of an E30 issue?

[JStang]

Originally Posted by VNeBLOB42

don't you remember the Turkeybaster115 thread?

a lot of exchanging between race fuel vs ethanol..

I will NEVER forget that!

[Carl Morris]

If cost is no object, I'd prefer race gas even though E85 is worth a few hp more. But cost and availability are usually an issue. I can get E85 in 3 places between my house and my work, and you can't argue with the performance.

Fuel trims are generally only an issue with alcohol.

[Spoolin Montego]

Originally Posted by COBB Tuning

The race map is designed for straight 100+ octane unleaded race fuel (not a blend of 93 or anything else).

We made the same power with the E30 blend and race fuel.

The race fuel will not tax the fuel system as much as an ethanol blend.

In the end, it's up to what's available in your area, what you're willing to pay for fuel, and what you feel comfortable running.

Whatever you do, make sure you log to verify the car is happy.

Have fun at the track!

-Josh

What mixture E85 and 91 would you guys recommend for the E30 map?

[Carl Morris]

I'd go heavy on the E85. The timing map on the E30 OTS race map was really aggressive. I ended up running it at 50/50 and still ended up pulling a bit of timing here and there.

[VNeBLOB42]

Originally Posted by Spoolin Montego

What mixture E85 and 91 would you guys recommend for the E30 map?

that a tough one.

I would start by doing the 30%, Log it and add another gallon of E85, log it and so on. Anything more I would guess the fuel trims would be off because its not designed for anything much more than E30.

ACN 91 just sucks, just saying.

[Evil///M]

Originally Posted by Spoolin Montego

What mixture E85 and 91 would you guys recommend for the E30 map?

I do a 2:1 ratio of 91/e85

[COBB Tuning]

Originally Posted by raceyBMW

With the race gas maps, running 100+ octane, do you still need to worry about fuel trims? Or is that really more of an E30 issue?

Never a bad idea to check your trims, but you should be running the same as any other tune with the race fuel. Ethanol can cause issues with fuel trims due to the extra volume required to achieve the same AFR.

-Josh

[COBB Tuning]

Originally Posted by Spoolin Montego

What mixture E85 and 91 would you guys recommend for the E30 map?

30% may be adequate, but it will depend on a lot of factors (altitude, condition of vehicle, etc.). I would start with the 30%, but be very diligent with your logging to verify there are no issues. If you see bad timing corrections, up your ethanol percentage and change the fuel scalar or pull some timing from your map and you're good to go.

Generally, more ethanol means more knock resistance, but also more volume required from the fuel system.

-Josh

[VNeBLOB42]

Originally Posted by Evil///M

I do a 2:1 ratio of 91/e85

Really? That's not too bad to run E30 MAPs. That is approx. E35 on 10 gallons of 91.

How are the logs? Did you have to adjust the fuel scalar?

[brusk]

Anybody know of any easy access in the fuel system to siphon off some fuel to measure the ethanol content?

[Evil///M]

Originally Posted by VNeBLOB42

Really? That's not too bad to run E30 MAPs. That is approx. E35 on 10 gallons of 91.

How are the logs? Did you have to adjust the fuel scalar?

Nope. Hasnt been runnining too good since after I had my turbo's replaced for some reason. I just switched back to AGR STG 2 FMIC with 91+e85 and its running great. I think it might just be a cobb issue. I'll flash it back probably next week.

And also for everyones information, there is a v4.03 e30 map available now.

[Killerfish2012]

Originally Posted by COBB Tuning

The race map is designed for straight 100+ octane unleaded race fuel. Have fun at the track!

-Josh

Josh, Thanks so much to the team at Cobb for working hard, and giving us the full release of the 100 octane race map! I just wanted to let you know that all your work is greatly appreciated. I will be using this map at the track, and an airstrip event next year, when I drop in my LSD.

Cheers.

[Evil///M]

Also for everyones info the v4.03 map is now available. I'm gonna test it out in a few days, depending on how my clutch holds up...