BMW M5 Forum and M6 Forums banner
1 - 19 of 19 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter · #1 ·
I'm seriously thinking about giving 5 gallons of Sunoco's GT100 unleaded "race-gas" a try in my M5 next week. Ever since I bought the car in March I've been suspicious about the available 91 pump-gas/wood-grain here in Sacramento CA, and wanted to determine if better gas actually would make the car run noticeably better.
After a little searching and researching I found a guy that sells the "California-legal" Sunoco 100 octane unleaded gas in drums and pails @ 5.15 a gallon. I plan to drain the tank as much as possible before putting it in to avoid diluting it too much.

Has anyone here on the board tried GT100 or a similar product in an M5? Anyone have any concerns (it is real gas from Sunoco and not an additive) about using it?

I'll report back my findings unless I get disouraged about the test.

- Jan.
 

·
Moderator Emeritus
Joined
·
5,150 Posts
I don't think you will find that much difference after putting just 5 gallons in your car. It takes the ECU a while to readjust to the better gas. Do a search, there are plenty of threads from before regarding putting race gas in the M5. A lot of people do it for track days, 1/4 mile drag races, etc...
 

·
Registered
Joined
·
3,006 Posts
The car will adapt but its not gonna be hugley dramatic. Ive put race gas in my car but mixed it to the point where i get about 97 octane, the car pulls a bit harder, it's nothing major and woun't go hard core on it or anything, if you want to do it it is safe to do once and awhile. Just wait till the tank isready to be filled up like normal then put the race gas in give it some time and see what you think.
 

·
Registered
Joined
·
992 Posts
A few times a year I run only 100 octane from Sunoco - no issues.


On the track, it pulls faster, seems quicker through the revs and just makes it enjoyable.

On the streets, 100 octane is worthless and you it will only seem "peppier" - only on the track for a weekend will you notice any difference.

Knock yourself out - at $5.15/gallon - it's worth it for the fun of it.

No issues with the engine - it handles it just fine.
 

·
Registered
Joined
·
12,393 Posts
There's a 76 station on Watt just across from the old PacBell buliding that has 100 in the pump.... Why futz with a 5 gallon pail.

There are a few stations around CA that pump it- do a search and you find links- may need to call a few to confirm.
 

·
Registered
Joined
·
1,980 Posts
On the stock engine the 100% GT100 is wasted, you can mix 50/50 with super and not tell a difference, I have 55gal barrels that I pump from (its cheaper).
I also haven't found any difference between the Unocal or Sunoco. The GT100 has ethanol mixed into it which I like better. Sunoco has a 98 without ethanol that I will try out soon, but its hard to find in my area. cherrsagai
 

·
Banned
Joined
·
136 Posts
I have used Sunoco GT100 at the track before (Infineon Raceway sells it at the pump) and it didn't make a real difference power wise, but the car did run noticibly smoother in the upper RPMs not to mention it was quieter as well. I waited until my tank was almost empty, then pumped about 7-8 gallons into the tank.
 

·
Registered
Joined
·
9 Posts
Discussion Starter · #8 ·
First of all, thanks all for your feedback, and ard, that 76 will be researched by me next time I go to Tower records on Watt (best record store in Sac for my taste at least). Thanks for the info!

As for the results: I did put in 5 gallons of the GT100 in an as-drained-as-I-dared tank on Monday, played a few days and filled back up with good ol' CA 91 today and yes, there is a slight difference. Not huge, but some of the hesitation when accelerating hard, especially on lower gears was gone. I won't go through the hassle and spend 5:15 every time I fill up from now on, but I may eventually get some now and then.

Not too exciting obviously, but worth the effort.

- Jan.
 

·
Registered
Joined
·
1,610 Posts
A more economical way to use 100 octane gas is to mix one gallon of it with five gallons of 91 octane. This way you'll get an over-94 octane fuel that surely is higher octane than the factory engine management can take advantage of.
 

·
Registered
Joined
·
12,393 Posts
BKH said:
A more economical way to use 100 octane gas is to mix one gallon of it with five gallons of 91 octane. This way you'll get an over-94 octane fuel that surely is higher octane than the factory engine management can take advantage of.
Agreed. My review of this subject in the past (various posts)led me to the conclusion that 94-96 is the limit with stock DME software.
 

·
Banned
Joined
·
136 Posts
Or try adding 1-2 gallons of Toulene in with a full tank of gas. Very effective way to boost octane.
 

·
Registered
Joined
·
2,004 Posts
Here in Canada, we have 94 octane at the pump, it's all I use in my older car. I'm new to the 5 group, and wondering that if this gas has 10% ethanol, is that a bad thing? I was told by the dealer, that the ethanol mix is frowned upon by BMW, through internal memos.
 

·
Registered
Joined
·
1,610 Posts
Hope this formats OK, here's an octane blending chart:

Octane chart for blending racing gas with 92 Unleaded gasoline
100 OCTANE RACING GAS --UNLEADED

GALLONS
1 2 3 4 5 6 7 8 9 10 11
9 1 96.O 97.3 98.0 98.4 98.7 98.9 99.0 99.1 99.2 99.3 99.3
2
2 94.7 96.0 96.8 97.3 97.7 98.0 98.2 98.4 98.5 98.7 98.8
O
C 3 94.0 95.2 96.0 96.6 97.0 97.3 97.6 97.8 98.0 98.2 98.3
T
A G 4 93.6 94.7 95.4 96.0 96.4 96.8 97.1 97.3 97.5 97.7 97.9
N A
E L 5 93.3 94.3 95.0 95.6 96.0 96.4 96.7 96.9 97.1 97.3 97.5
L
U O 6 93.1 94.0 94.7 95.2 95.6 96.0 96.3 96.6 96.8 97.0 97.2
N N
L S 7 93.0 93.8 94.4 94.9 95.3 95.7 96.0 96.3 96.5 96.7 96.9
E
D 8 92.9 93.6 94.2 94.7 95.1 95.4 95.7 96.0 96.2 96.4 96.6
E
D 9 92.8 93.5 94.0 94.5 94.9 95.2 95.5 95.8 96.0 96.2 96.4

10 92.7 93.3 93.8 94.3 94.7 95.0 95.3 95.6 95.8 96.0 96.2

11 92.7 93.2 93.7 94.1 94.5 94.8 95.1 95.4 95.6 95.8 96.0
 

·
Registered
Joined
·
12,393 Posts
use periods not tabs or spaces... silly software

.............100 OCTANE RACING GAS --UNLEADED

GALLONS
...........1.....2.....3.....4.....5

etc


or do it in excel, save it as a jpg...

Here is the formula:

(Gallons of 100 octane x 100) + (gallons of low test x low test octane)
(total gallons of 100 + gallons of low test]


for example, 9 gallons of 100 plus 9 gallons of 91:

9x100 + 9x91 = 900+819 = 1719

divide that by 9+9 gallons: 1719/18 = 95.5 octane
 

·
Registered
Joined
·
487 Posts
ard said:
There's a 76 station on Watt just across from the old PacBell buliding that has 100 in the pump.... Why futz with a 5 gallon pail.

There are a few stations around CA that pump it- do a search and you find links- may need to call a few to confirm.

Yep, filled up at this station plenty of times. Its at the corner of Watt and Marconi I believe.
 

·
Registered
Joined
·
1,069 Posts
Silly me, I just drive over to the local Esso Tanks teller and put Super Plus (97 octane) in whenever I feel like being flamboyant.

True is however, the German 91 vintage does just as well for less.

I suspect however, that the quality of gasoline in Europe is better overall to the US market so we don’t have to look for the ultimate in motion lotion to get our kicks.

Ken
 

·
Registered
Joined
·
175 Posts
I have seen a number of threads concerning 100 octane (USA) fuel, but until now had never seen it at a public gas station. Compared to the West Coast, 93 octane is standard for the "Super" or "hi-test" grade, so do not know how many East Coasters are looking for 100 Octane gas. Every so often Amoco (now BP) or Sunoco will have 95 octane.

Today I was at a Sunoco station in Melbourne FL (Central Fl, East Coast) at the intesection of I-95 and 192. They had separate pumps of racing fuel with a rating of 110. Price was $5.999 per gallon. Super at 93 was $2.56 per gallon. Over double the price. Not cheap in my book. Do not know how much they sell, but for anyone who is looking for it - there it is.
 

·
Super Moderator
Joined
·
10,462 Posts
kwalls said:
Silly me, I just drive over to the local Esso Tanks teller and put Super Plus (97 octane) in whenever I feel like being flamboyant.

True is however, the German 91 vintage does just as well for less.

I suspect however, that the quality of gasoline in Europe is better overall to the US market so we don’t have to look for the ultimate in motion lotion to get our kicks.

Ken
Fortunately, for us in the US, our octane rating (anti knock index, as they call it; AKI) is calculated using Research and Motor octane ratings. The formula R+M/2 give our US octane rating. 97 RON in europe is around 93 or so US. For us californians, with 91 the best generally available, i think you will see a little improvement if you mix in som 100 to get around 94.
At least it feels that way when i've done it at a track day.
German 91 would be like our "regular" here.
Mike
 
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top