91 octane is crap- filled with 91/100 blend

[anashayel]

Does anyone know what a perfect balance for 91/100 octane mix on a empty e92 m3 tank?

[Dodge2Dub]

Originally Posted by anashayel

Does anyone know what a perfect balance for 91/100 octane mix on a empty e92 m3 tank?

11/4 to get 93.

[dcstep]

Colorado is also a 91 octane state, but, given the altitudes and lower air density, 91-octane is closer to optimal than for those at sea-level. I've posted my dyno runs on PG's dyno thread. My car actually loses hp with 100% 100-octane. With experimentation, I found the optimal blend is roughly 70/30 blend of 91/100. My dyno is at around 5,400-feet above sea-level.

I limit my use of blend to autocross events. The gains are pretty small, but my baseline hp is 65-hp down from sea-level (due to low air density), so every little bit helps.

For those in CA and other sea-level locals, going to pure 105-octane may or may not add more power than pure 100-octane. As I found out with multiple dyno runs, there's a limit where the engine will stop making more power and actually start to lose power. If it really matters to you, then invest a little time and money in comparitive dyno runs. The ole butt-dyno isn't really reliable.

Dave

[phrogbubbaE92]

Originally Posted by ApathyCSL

i really like this thread, i feel like its very helpful for the California guys..

+1

there is also a VP at 3804 Ingraham St, that sells unleaded 100 octane (for the Socal guys in SD)

[Boosted-M]

Originally Posted by dcstep

Colorado is also a 91 octane state, but, given the altitudes and lower air density, 91-octane is closer to optimal than for those at sea-level. I've posted my dyno runs on PG's dyno thread. My car actually loses hp with 100% 100-octane. With experimentation, I found the optimal blend is roughly 70/30 blend of 91/100. My dyno is at around 5,400-feet above sea-level.

I limit my use of blend to autocross events. The gains are pretty small, but my baseline hp is 65-hp down from sea-level (due to low air density), so every little bit helps.

Dave

I know a couple of tuners in Colorado that love E85 and make great power on it due to the oxygen content to help with high altitudes..

[phrogbubbaE92]

Originally Posted by anashayel

Does anyone know what a perfect balance for 91/100 octane mix on a empty e92 m3 tank?

i just did a 60/40 mix in mine and did extremely spirited runs up and down palomar mountain in San Diego. Along with the 30 mile ingress and egress to the mountain I got around 14-14.5 mpg; and i was hauling AS%.. On just plain 91 i will get around 14.8-15.7 mpg with highway/city driving. I was EXTREMELY impressed with VP's 100 octane being that i was at 5-8k rpms for the majority of the time up and down the mountain. I didnt think i was going to make it to and from on one tank of gas.. the only down side is that the price per gallon was $8.99... If and when I go autoxing, i will most definitely use the same mix.

Performance was also noticeable in the low, mid, and high rpm range. As stated previously, there is almost no jerkiness initially from a dead stop. The power throughout the band is exponentially smoother than the feel with just 91 as well. Fwiw, this was just from my experience today and i am in no way an expert. Hope this helps..

[Dodge2Dub]

Originally Posted by TrackRat

^^^ I'd suggest that you contact VP Racing Fuels for clarification.

So I went there last night, along with a couple other members based upon the posts above. It truly is a VP Racing fuel station. I asked who owns them, and they said VP. 100 octane and above are VP fuels. 91/87 octane are supposedly top tier refined gas (ie. Shell and Chevron).

[dcstep]

Originally Posted by Boosted-M

I know a couple of tuners in Colorado that love E85 and make great power on it due to the oxygen content to help with high altitudes..

My tuner says that also, but he's putting that crap in WRXs to get huge HP.

My BMW tech, who's a friend also, says that he's replaced injection systems in BMW 3-series that used E85 and would highly recommend against it in an M3 with a stock injection system.

Dave

[Boosted-M]

Originally Posted by dcstep

My tuner says that also, but he's putting that crap in WRXs to get huge HP.

My BMW tech, who's a friend also, says that he's replaced injection systems in BMW 3-series that used E85 and would highly recommend against it in an M3 with a stock injection system.

Dave

LOL.. Maybe we are talking about the same guy (Adam from Revolutions)..?

Did the BMW Tech need to replace the stock injection system because people are trying to put E85 in a non-flex fuel vehicle or a car that was not modified for it (Larger injectors & Tune for the fuel)..?

What I'm trying to find out is if you guys are getting great results with a 91oct/race gas blend then why don't we get a few tuners to Tune for E85.. You will see additional benefits from the E85 and it will be in the $4 range compared to the $8-$10 91oct/race blend..

[mdosu]

wow, I may be moving to California in a year. I am not looking forward to this. My car has been filled with 93 Shell consistantly for it's life...

[Dave07997S]

Originally Posted by Dodge2Dub

11/4 to get 93.

That would actually get you 93.4. I blend in 12.7gallons of 91 and 4 gallons of 100. This gets you right at 93.15.

Dave

[Dave07997S]

Originally Posted by mdosu

wow, I may be moving to California in a year. I am not looking forward to this. My car has been filled with 93 Shell consistantly for it's life...

Where are you moving to in Cali?

A lot of shops carry racing unleaded.

Dave

[Dodge2Dub]

Originally Posted by Dave07997S

That would actually get you 93.4. I blend in 12.7gallons of 91 and 4 gallons of 100. This gets you right at 93.15.

Dave

Ha ha, that would require a calculator everytime you filled up, based upon how much fuel was left in the tank at the time. Whole numbers are easier.

Personally, I rarely fill up more than 14-15 gallons....don't like running the car on absolute empty.

[dcstep]

Originally Posted by Boosted-M

LOL.. Maybe we are talking about the same guy (Adam from Revolutions)..?

Did the BMW Tech need to replace the stock injection system because people are trying to put E85 in a non-flex fuel vehicle or a car that was not modified for it (Larger injectors & Tune for the fuel)..?

What I'm trying to find out is if you guys are getting great results with a 91oct/race gas blend then why don't we get a few tuners to Tune for E85.. You will see additional benefits from the E85 and it will be in the $4 range compared to the $8-$10 91oct/race blend..

No, Sheldon. The problem was putting E85 in a non-modified car, but I don't know particulars. It wasn't even M3, just BMW 3-series.

[Dave07997S]

Originally Posted by Dodge2Dub

Ha ha, that would require a calculator everytime you filled up, based upon how much fuel was left in the tank at the time. Whole numbers are easier.

Personally, I rarely fill up more than 14-15 gallons....don't like running the car on absolute empty.

LOL, don't laugh..I always keep a running number what I think I am at. If I need half a tank or about 8 gallons I need 16 octane points to get me at 93 octane for the new gas I am putting in, I put in 2 gallons which is 18 points..its a sickness.

Dave

[ttt]

Originally Posted by Dave07997S

I always keep a running number what I think I am at. If I need half a tank or about 8 gallons I need 16 octane points to get me at 93 octane for the new gas I am putting in, I put in 2 gallons which is 18 points..its a sickness.

Wow that's true dedication man. Major props!

[808E90]

There's only one station that sells 100oct here in Hawaii ... I've always wanted to try it but also wondered how long that gas has been sitting. I know not many people use 100oct so I have a feeling that its been sitting for some time.

[jtn83]

Originally Posted by Dodge2Dub

Interesting. Our local 100 octane fuel station has VP Racing insignias over all of the pumps and on their marque. Google states that it is a Chevron, but Chevron doesn't list them as being apart of their network.

Check out the streetview below and tell me what you think?

Clicky!

Dodge2Dub,

When I had my GT500 I had an intake/pulley/and tune for 100 octane and that is where I used to fill up when I ran the 100 octane tune. If you want 100 octane, that is the place to buy it in SD.

After reading this thread, I'm still hesitant to believe it's that big of a difference. My GT500 had custom tunes for 91/93/100 octane. It definitely made a difference, but that's because it was tuned for it. I find it really hard to believe that a stock car would make that big of a difference. I agree that the over oxygenated and ethanol injected fuels hinder performance, but enough for the "butt dyno" to register on a stock tune is hard to believe.

Has anyone dyno'd their stock M's on 91 and >94 octane to register a real difference?

I'm not trying to detract, but as an economist, I like to see real ceteris paribus proven results before signing off on $100/tank.

Cheers,
Jason

[Boosted-M]

[Leonardo629]

It's already been proven by pencil-geek's dynos...

Originally Posted by jtn83

Dodge2Dub,

When I had my GT500 I had an intake/pulley/and tune for 100 octane and that is where I used to fill up when I ran the 100 octane tune. If you want 100 octane, that is the place to buy it in SD.

After reading this thread, I'm still hesitant to believe it's that big of a difference. My GT500 had custom tunes for 91/93/100 octane. It definitely made a difference, but that's because it was tuned for it. I find it really hard to believe that a stock car would make that big of a difference. I agree that the over oxygenated and ethanol injected fuels hinder performance, but enough for the "butt dyno" to register on a stock tune is hard to believe.

Has anyone dyno'd their stock M's on 91 and >94 octane to register a real difference?

I'm not trying to detract, but as an economist, I like to see real ceteris paribus proven results before signing off on $100/tank.

Cheers,
Jason

[Singletrack]

Originally Posted by Boosted-M

That Ethanol should really be around $3-3.25 if gas is priced at 4.35 for the fuel economy to be in the same ballpark per gallon. Also, if the unleaded gas has Ethanol in it, then the price has been artificially inflated.

[Singletrack]

Originally Posted by m3heaven

You don't need to have a high horsepower car to see the benefits of ethanol. If you saw the gains of running E85 in any turbocharged car or even NA cars you'd see why. E85 is like running 110octane.

I came from driving an Evo X and E85 alone gave me +50~whp +70~wtq over running 91 octane. It also burns cleaner and the engine itself is also cleaner. Have you seen an engine that's been running E85 compared to normal gasoline? The 20-30% increase in consumption was offset by the lower price.

I fully support anyone's desire to use E85 inside their engine, but I have yet to hear a compelling reason why this is a good idea for * typical consumers*. Your average person is not going to tune anything for E85, they will buy a flexfuel vehicle and call it a day.

The alcohol they put in that car will be overpriced and get worse fuel economy than gasoline. Even setting the price of Ethanol appropriately to make up for the loss in fuel economy is not adequate because of the hidden costs associated with providing the fuel in *this country* - subsidies for the corn industry; embargos on Brasil and any other lower cost producers. Although I have yet to see Ethanol offered at 25-30% less than gas - the picture above certainly doesn't show it.