[kianf22]

Hey all! Wondering if it's safe to add 1-3 gallons of e85 to a tank of 91 and if it will successfully raise the octane on the B58. Looking to go with JB4 and 91 is the highest available grade in my area but I have an e85 station nearby.

[JD11937]

Originally Posted by kianf22

Hey all! Wondering if it's safe to add 1-3 gallons of e85 to a tank of 91 and if it will successfully raise the octane on the B58. Looking to go with JB4 and 91 is the highest available grade in my area but I have an e85 station nearby.

I know some people do this on various 91, 93 octane maps to help improve timing. I haven't tried it, I just run an e40 tune but I would suggest starting with a small amount and seeing how the car reacts. 1/2 gallon to a gallon depending on the quality of your E85.

[kianf22]

Originally Posted by JD11937

I know some people do this on various 91, 93 octane maps to help improve timing. I haven't tried it, I just run an e40 tune but I would suggest starting with a small amount and seeing how the car reacts. 1/2 gallon to a gallon depending on the quality of your E85.

Thanks I'll do that and log and see how it goes. Wonder if anyone else has experience doing this though. Also do you have any experience with octane boosters like torco and boostane? Adding a couple gallons of e85 would be cheaper than using one of those octane boosters but in the event the b58 doesn't like the e85 it might be my only option to increase octane. California 91 is garbage and 100 Octane at $10 a gallon is just too expensive.

[MR.///M]

hi which map should run with only a ctless dp. also is it safe to run a higher to go e30 or will i be needed supporting mods

[kianf22]

Originally Posted by MR.///M

hi which map should run with only a ctless dp. also is it safe to run a higher to go e30 or will i be needed supporting mods

I would try logging map 1 and 2 and deciding after that but map 2 should be fine. You'll get more help with the jb4 on the n54tech b58 jb4 forum. This is an old post.

[B58_Ken240i]

I have done 1-2 GAL fine but nothing more with stock HPFP. You will see fuel pressure drop in the log and car will go lean. But if its easily accessible you should add it with each fill up to help with keeping timing stable. Map 2 was best I could do.

I am pretty sure in the 2 series BMW manual given with the car it states 1-2 GAL of E85 with fill up is okay. I would double check, I feel like when I was doing it, before I upgraded HPFP, I read that and was like, oh cool.

Here is link for JB4 forums: https://www.n54tech.com/forums/

Just find B58 and you can post your logs in the "support l go review"

[mike@x-ph.com]

Originally Posted by kianf22

Hey all! Wondering if it's safe to add 1-3 gallons of e85 to a tank of 91 and if it will successfully raise the octane on the B58. Looking to go with JB4 and 91 is the highest available grade in my area but I have an e85 station nearby.

use this website to calculate mixture and octane
https://www.brewcity**********/about...ol-calculator/

you can successflly raise the octane from 91 to 93 using E85

[BEM-S4]

You can also add octane booster to help with the 91... when I ran my Stage 1 wagon NYC to LA certain states we had to use 91. We used Royal Purple octane booster, with that everything ran perfectly fine.

[MarcoZandrini]

I don't think the rubber in our cars' fuels systems is designed for E85. I know BMW and other car companies lobbied the fedgov to not make 15% ethanol as the fuel standard because the fuel systems aren't designed for it. Use an octane booster.

[MarcoZandrini]

Originally Posted by BEM-S4

You can also add octane booster to help with the 91... when I ran my Stage 1 wagon NYC to LA certain states we had to use 91. We used Royal Purple octane booster, with that everything ran perfectly fine.

Hmmm, Royal Purple sez that it's octane booster is not street legal! Check the bottom of the page!

https://www.royalpurple.com/product/...ctane-booster/

[BEM-S4]

Originally Posted by MarcoZandrini

Hmmm, Royal Purple sez that it's octane booster is not street legal! Check the bottom of the page!

https://www.royalpurple.com/product/...ctane-booster/

Ha, I had no idea but probably wouldn't have cared. Such concerns go out the window when one is on a Cannonball run. I just ordered it on Amazon and hoped for the best, it worked pretty well. Used most of the case on the trip with no complaints.

[kianf22]

Originally Posted by BEM-S4

You can also add octane booster to help with the 91... when I ran my Stage 1 wagon NYC to LA certain states we had to use 91. We used Royal Purple octane booster, with that everything ran perfectly fine.

I heard octane boosters coat everything in nasty orange stuff. Kinda turned me off using those.

[kianf22]

Originally Posted by MarcoZandrini

I don't think the rubber in our cars' fuels systems is designed for E85. I know BMW and other car companies lobbied the fedgov to not make 15% ethanol as the fuel standard because the fuel systems aren't designed for it. Use an octane booster.

Is an octane booster really all that better than e85? There are so many people running e85 without issues. It's cheap and close to my home. The orange stuff that coats the spark plugs when you use octane boosters can't be good for the car, can it?

[BEM-S4]

Originally Posted by kianf22

Is an octane booster really all that better than e85? There are so many people running e85 without issues. It's cheap and close to my home. The orange stuff that coats the spark plugs when you use octane boosters can't be good for the car, can it?

I live in PA where 93 is easy to get. My car made one cross country trip and as such will ingest 5 tanks of 91 with octane boost in its entire lifetime. For my purposes I was most concerned with lower octane screwing up my Stage 1 tune and negatively impacting my performance over the course of 1K miles. I don't have a great answer for you simply because it wasn't a huge concern for me, I'll blow it out with a few tanks full of 93 and not think about it ever again.

[dradernh]

Originally Posted by BEM-S4

I was most concerned with lower octane...over the course of 1K miles.

Other than CA, was it in the Intermountain West that 91 was the highest octane available?

[BEM-S4]

Originally Posted by dradernh

Other than CA, was it in the Intermountain West that 91 was the highest octane available?

I forget exactly but we were relatively good through IL, then hit 93 again in Texas. So if memory serves no 93 in MO, OK, NM, AZ, CA.

[MarcoZandrini]

At altitudes greater than 5000 feet you won't find much above 91 octane. Why? The air is thinner, less dense. Hence, your engine can't pull in as much air (oxygen) at higher altitudes. The last time I drove across country I drove from San Diego to metro DC. Took I8E to Phoenix and then north to I10E and then north to Flagstaff to pick up I40E. I filled up in Phoenix and noted when I got to Flagstaff that the available fuel octanes were a few points lower than those available in Phoenix.

[B58_Ken240i]

Originally Posted by BEM-S4

You can also add octane booster to help with the 91... when I ran my Stage 1 wagon NYC to LA certain states we had to use 91. We used Royal Purple octane booster, with that everything ran perfectly fine.

Ocane booster's like "Boostane" are great for improving timing.

I do not recommend filling up every tank with it... Only on track/drag days. You can google MMT and find alot of articles of its affects. Also, you will want a Catless DP.

[MassNerd]

Originally Posted by MarcoZandrini

At altitudes greater than 5000 feet you won't find much above 91 octane. Why? The air is thinner, less dense. Hence, your engine can't pull in as much air (oxygen) at higher altitudes.

Our cars are turbo charged and turbos can compensate for the less dense air. NA engines, yes, significant power loss.