BM3 stage 2 93octane map.

[Pauloh7979]

Can I use stage 2 93octane map with shell v power 91octane?

[chewbakam4]

Why not juse the 91 map?

[Djdnav]

Do you even know what octane ratings mean? It’s basically resistance to knock. When you use a lower octane, you generally have to pull timing or lower boost to avoid knocking. If you use a map with less knock protection for the fuel, you negate the whole point of having that tune, and run the risk of engine damage.

If you drive like a grandma, your car won’t explode, but I wouldn’t be boosting it at all.

[GP87]

Originally Posted by Pauloh7979

Can I use stage 2 93octane map with shell v power 91octane?

Depends on which country you are based. In the U.K. (and I think, most of Western Europe), we get the good stuff which is rated 99 RON.

[Kuervers]

Originally Posted by Pauloh7979

Can I use stage 2 93octane map with shell v power 91octane?

Why not just use husky 94 or if esso/petro can 94?

[overlook637]

Originally Posted by Pauloh7979

Can I use stage 2 93octane map with shell v power 91octane?

You can. Ideally you want to use the tune / octane thats matching. I wouldn't use lower octane on a hot day or driving the car hard.

As noted above. The ECU will detect knock and pull back timing. Knocking is terrible for a engine. Without the ECU correcting the timing it would result in excessive heat and pressure in the head/piston.

[Pauloh7979]

Shell is near by home and chevron is the only one that carries 94 in town and it's 10min drive.
If there is performance difference between stage 2 91octane and 93octane, I'm willing to drive 10min for the chevron 94. So basically what I wanna know is that if there is noticeable performance difference between stage 2 91 and 93.

[overlook637]

Yes there is a noticeable difference between 91 and 93 tunes. However, a street driver may not ever notice this difference. Figure a 20hp 20ft-lbs difference in the tunes.

[Djdnav]

Originally Posted by Pauloh7979

Shell is near by home and chevron is the only one that carries 94 in town and it's 10min drive.
If there is performance difference between stage 2 91octane and 93octane, I'm willing to drive 10min for the chevron 94. So basically what I wanna know is that if there is noticeable performance difference between stage 2 91 and 93.

Octane doesn’t create power.

Octane allows the engine/tune to create the power it’s supposed to without detonating or pulling timing, which negates the point of running a higher octane tune. If you use 91, get the appropriate map.

[FSociety]

Petro 94 is good for 93oct maps

[mike@x-ph.com]

Originally Posted by Pauloh7979

Can I use stage 2 93octane map with shell v power 91octane?

You could but it should not

[Pauloh7979]

I heard chev 94 has ethanol in it :\
Looks like I have to stick with shell 91 and also stage 2 91 tune..

[Lee808]

Originally Posted by Pauloh7979

I heard chev 94 has ethanol in it :\
Looks like I have to stick with shell 91 and also stage 2 91 tune..

Most pump gas is at least E10 unless it says otherwise.

[TR930]

Can you run a 93 tune on 91 gas at altitude? Denver area?

[Lee808]

Originally Posted by TR930

Can you run a 93 tune on 91 gas at altitude? Denver area?

Lived close by in New Mexico a few years. High altitude sucks the performance right out of your car. Beautiful part of the US though.

[Djdnav]

Originally Posted by TR930

Can you run a 93 tune on 91 gas at altitude? Denver area?

REALLY? You shouldn’t do it at sea level, a higher density altitude makes it worse.

[TR930]

Umm, Denver has a LOWER air density, not higher.

[Djdnav]

Originally Posted by Djdnav

REALLY? You shouldn’t do it at sea level, a higher density altitude makes it worse.

Originally Posted by TR930

Umm, Denver has a LOWER air density, not higher.

I'm very aware. Look up the definition of density altitude.

[TR930]

Originally Posted by Djdnav

I'm very aware. Look up the definition of density altitude.

Maybe I'm dumb, but the air up here is less dense not more dense. We run 91 octane up here which at sea level is close to 93 octane hence my question.

[Djdnav]

Originally Posted by TR930

Maybe I'm dumb, but the air up here is less dense not more dense. We run 91 octane up here which at sea level is close to 93 octane hence my question.

Lower air pressure (which happens from higher altitudes), humidity, high temperature, contaminants, etc lower the oxygen density in a given volume of air. Less air density= higher density altitude.

Fuel octane rating doesn’t change with altitude, the dme just compensates for lower air density and pulls timing and fuel. It’s the same deal with small airplanes. When you climb, you lean the mixture to keep the ratio optimal.

[MPOOR]

Originally Posted by chewbakam4

Why not juse the 91 map?

Well said ~ specific maps are tuned for specific types of fuel.
If you run 91 fuel, run 91 map. If you run 93 fuel, run 93 map.