87 or 93 octane?

[eddiemcnally]

I take my '06' H2 to a chevy dealer. My mechanic is a former Hummer shop foreman. In Vegas the Hummer dealer shut down so that's why he works for chevy. He said to only put 87 octane and not to put 93 in and he seemed pretty sturn about it. That's awesome for the pocket. My question is if I put the power programmer in for 93 octane for the better gains, will I be hurting anything?

Thanx for your time, Eddie

[guruerror]

I run 93 in my 05 religiously...mostly out of habit...and partly because I figured with my 'Performance' tune (Superchips Cortex), 93 would be 'better.'

Did he mention why he was so adamant about 87?

[eddiemcnally]

Just cause it was not tuned for it I guess! What sort of gains did you get with your super chips including gas mileage? Do you like the results? I'm thinking about putting a hypetech in, have you heard anything about them?

Thanx, Eddie

[guruerror]

After the Performance tune the truck definitely 'felt' like it was snappier and had a bit more umph in the acceleration. I say 'felt' because I've never had the truck dyno'ed to document.

The stiffer shift pressure definitely feels much nicer than the stock setting.

MPG changes that are specific to the tune would be hard to say...I made several mods all at once (larger tires, lower gears, exhaust, and headers; then the tune two weeks later)...what I can say: after all that I still get 11.5 (which is exactly what I was getting before).

[HUMTECH]

If you are gonna run a 93 octane tune it will advance your spark timing. It calls for higher octane fuel due to its resistance to burn. If you advance the spark timing you want to slow the burn, thats what higher octane will do. You can run 87 but if you hear "ping" or detonation you should bump up to a higher octane reading

[MARKCORE]

Originally Posted by HUMTECH

If you are gonna run a 93 octane tune it will advance your spark timing. It calls for higher octane fuel due to its resistance to burn. If you advance the spark timing you want to slow the burn, thats what higher octane will do. You can run 87 but if you hear "ping" or detonation you should bump up to a higher octane reading

Beat me to it.