93 octane?

Roadrnr06 · Postby **Roadrnr06** » Sat Aug 29, 2009 9:14

chickenwafer wrote:Running more octane than you're tuned for isn't going to help your performance, in fact it can hurt it. You always run the lowest octane you can get away with, so if your new map is for 93 octane then try and get 93.

I wish they sold 93 up here, looks like every State soon is going to 91...sheesh. When I lived in Pennsylvania premo was 94, and some places had 96.

Do you mean that in the long run as far as injectors and such? I put down a 13.1 at Bandimere, this is definitely a record for this car at this altitude. With 91 octane in it my car runs a 13.56. 4/10's is a lot in regards to bracket racing so I am leaning towards sticking to what I am doing. Unfortunately, bracket racing season is over, so hopefully by next year I will be running E-85 and none of this will matter!

Operator · Postby **Operator** » Sat Aug 29, 2009 9:14

TheNewBlack:

Try "Pilot" travel gas stations. Similiar to you, I have 91, 93, and 100 octane programs. And up here in Cheyenne I go to the same Pilot station for my fill ups, so I can get the 93 to run the 93 program.

Cesaros wrote:you can get 103 at a special place here in cheyenne...

I know the airport sells race fuel for half off on Sundays....

Operator · Postby **Operator** » Sat Aug 29, 2009 9:14

http://www.pilottravelcenters.com/Locations/Location.aspx?location_id=316

Phone (303) 292-6303
4640 Steele Street
Denver, CO US 80216

Give'em a call.

chickenwafer · Postby **chickenwafer** » Sat Aug 29, 2009 9:14

Roadrnr06 wrote:Do you mean that in the long run as far as injectors and such? I put down a 13.1 at Bandimere, this is definitely a record for this car at this altitude. With 91 octane in it my car runs a 13.56. 4/10's is a lot in regards to bracket racing so I am leaning towards sticking to what I am doing. Unfortunately, bracket racing season is over, so hopefully by next year I will be running E-85 and none of this will matter!

Are you talking about the downsides to running higher octane than you're tuned for?

The problem is mainly incomplete combustion since you are running a gasoline that has a higher resistance to combustion so with your tune you won't be able to ignite all of the fuel.

In turn this puts extra wear on your ignition coils, plugs and plug wires, and can lead to MASSIVE carbon build up and gum up intake/exhaust valves. On a rotary carbon build up a big no no haha.

AIM WO4 · Postby **AIM WO4** » Sat Aug 29, 2009 9:14

I'm pretty sure my car isn't tuned for anything more than 87. Studies do show that going too high is a waste of money, and not good on the engine.

ULBSORY · Postby **ULBSORY** » Thu Jan 21, 2010 9:14

At the truck stop in greeley i coudnt tell you exactly the roads but if you look up western sizzlin in greely off the highways its right across the high way from it. Its a big gas station/truck stop they sell all kinds of gas even race gas

LaginWagon · Postby **LaginWagon** » Sat Jan 23, 2010 9:14

chickenwafer wrote:Running more octane than you're tuned for isn't going to help your performance, in fact it can hurt it. You always run the lowest octane you can get away with, so if your new map is for 93 octane then try and get 93.

I wish they sold 93 up here, looks like every State soon is going to 91...sheesh. When I lived in Pennsylvania premo was 94, and some places had 96.

You can get 93 at the intersection of 287 and 56 in Berthoud. I go there all the time for our vehicles & bikes.

VRx8 · Postby **VRx8** » Sat Jan 23, 2010 9:14

http://www.cosportbikeclub.org/local/highoctane.html

323Bf · Postby **323Bf** » Sat Jan 23, 2010 9:14

hmm... We have 91, 95, 98 and 100 octane gasoline. and no car in europe goes under 91 octane... But the most gasoline stations don´t have the 91, but one tank more 95...

Stealth01 · Postby **Stealth01** » Sat Jan 23, 2010 9:14

I believe the European system grades fuel differently than the EPA here in the US...

erod550 · Postby **erod550** » Sat Jan 23, 2010 9:14

I am planning on getting my car tuned for high altitude at MAC Autosport in Parker. I will be running 91 because I don't want to have to drive halfway across town every 2 days to fill up. I'm willing to give up a little power for the convenience of stopping at a gas station on the way home.

Operator · Postby **Operator** » Mon Sep 13, 2010 9:14

I know it's an old thread and the OP was looking for 93octane. But I just wanted to confirm that they sell Race gas (100 octance) at 3201 Wadsworth Blvd in Wheat Ridge. Though it cost me $5.99 about a week ago.

Justin · Postby **Justin** » Mon Sep 13, 2010 9:14

As long as we're resurrecting old threads, here is a thought. I'm not convinced that the lower octane requirement at altitude holds true on turbocharged cars. My understanding is that the thinner air and lower ambient air pressure as compared to sea level results in less air being stuffed into the compression chamber on an NA car during the suck cycle. This effectively lowers the compression ratio of the engine, thus the lower octane requirement. Turbos make up for a decent chunk of the altitude loss, so I'm not sure that those running off the shelf maps wouldn't have possible detonation issues with anything less than 93 octane. Probably not, but something to think about. That said, if you're going with a custom map, this is a moot point. I know that lots of people run OTS maps just fine, but lots don't as well. I wonder if this is a contributing factor in cars operated at higher altitudes.

chromal · Postby **chromal** » Mon Sep 13, 2010 9:14

Justin wrote: I'm not convinced that the lower octane requirement at altitude holds true on turbocharged cars. My understanding is that the thinner air and lower ambient air pressure as compared to sea level results in less air being stuffed into the compression chamber on an NA car during the suck cycle.

This effectively lowers the compression ratio of the engine, thus the lower octane requirement. Turbos make up for a decent chunk of the altitude loss, so I'm not sure that those running off the shelf maps wouldn't have possible detonation issues with anything less than 93 octane.

My understanding is that 2-3 PSI of boost is all that's necessary to make up the high elevation penalty experienced by naturally-aspirated cars operating between 6000-14000ft elevation. High elevation doesn't so much change the compression ratio, rather, it reduce the starting airmass to be compressed, or stated differently, at the end of the intake portion of the piston stroke, the density of air/fuel mixture in the cylinder is lower at high elevation. However you think of it, that reduces the power.

Forced induction makes up this airmass/density loss at elevation with boost, and so there's no high-elevation octane reduction because there's no high-elevation airmass reduction when operating under boost of 2 to 3+ PSI (or more). The cylinder/piston has more material to compress, and pre-ignition is correspondingly more likely under the higher temperatures and pressures made possible by relatively more material being compressed to a given fixed small volume just before ignition.

At least, that's how I understand it.. some more about this all was written about here.

TheNewBlack · Postby **TheNewBlack** » Tue Sep 14, 2010 9:14

.....here we go again.....

93 octane?

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