BowtieFever

I know my owners manual says that 87 octane (regular) is recommended for the LO3. However, I have a Hypertech Street Runner Chip which recommends 92 octane or better(premium). The chip is just there mild performance one, and was pretty much a waste of $$$. But, I also advanced my timing to 4*, over the factory setting of 0*. I have always run 93 octane just to be precautious. But, do I really need to spend the extra money for the octane?

Anyone with similar results?

91Bird305

If ur timing is advanced to 4-8* then deffiently run 92-93 octane. If not then it doesn't matter.

wasp

i run sunoco 94 only ..............it also burns cleaner which cant hurt

fast_broker

iTrader: (1)

The lowest octane that shows NO knock counts is all you need.

91BlkRS

well i've been running 93 in mine and it's the stock lo3 because it runs cleaner, but what octane level will give me the best performance?? i heard 87...

fast_broker

iTrader: (1)

In general, the lowest octane that gives you the highest cylinder pressure, which usually is the lowest octane that shows no knock counts.

most persons are advancing their spark a bit. This makes one encounter knock without knowing it as the ECU retards the spark for you, by up to 8 degrees or more!!! By adding high octane fuel, you have then corrected the problem and can feel faster because you actually are.

There is a 2-4 degree range that shows will produce max power in most engines under high-load high-rpm conditions. Most modern day ECUs have no where near this much advance for emmissions reasons. Advancing the distributor fixes some of the areas but makes other areas too far advanced.

I hope this makes sense.

v8powr

so if im running a stock LO3 with TBI using 89 octane with outlaw octane booster what should i advance my timing to? The 90 model LO3 is set at 0 BTDC i believe so i would like to take advantage of a little timing adjustment if possible?? what are the gains if any??

wasp

just curious, sunoco has 94 and mobil has 93 octane........why you run 89 with octane boost

v8powr

i always run midgrade gas but the oulaw stuffs supposed to help keep the fuel componets clean and if it boost my octane up a little, so be it. I just like it cause of the good things ofive heard from folks. I just wanna jump my timing a little for beter full throttle performance if possible.

t-top89

iTrader: (3)

I might be wrong but, i think octane booster only accounts for .2 or .3 of a point. Just throwing this out there!!

FRMULA

Lot's of other things come into play, camshaft, timing curve, etc. but here are the basics...

The low static compression ratio of the LO3 does not merit more that 87 octane. Anything else is a waste of money and will not increase performance enough to matter.

Having a Power Adder (N20, Turbo, Blower) increases cylinder pressure under load conditions when the power adder is in use.(dynamic cylinder pressure) Therefore higher octane is needed when a power adder is being used. The more boost = more cylinder pressure = more octane. An L03 makes a great power adder motor because of it's low static compression ratio. This also does not compromise streetablilty because pump gas can be bought anywhere.

A high compression engine makes power with high static compression. (12, 13, 14 ,15:1 and higher) instead of using a power adder to increase cylinder pressure it uses it's pistons. A high compression motor NEEDS high octane fuel to run at top performance without detonation.
You cannot pull into ANY OLD gas station and buy 104, 114 etc. Not to mention race fuel is $$. This makes daily driveability ludicrous.

A good balance is moderation 10, 10.5, 11:1 ratios are pretty steetable with 93 octane. Too much static compression makes it prohibitve to use a power adder without going to race fuel.

t-top89

iTrader: (3)

WELL SAID FRMULA!!!

91Bird305

Don't let the octane booster stuff fool you. When they say 3 points they mean .3 So if u use 89 and put that stuff in your only boosting it to 89.3 No joke. So don't even bother buying the stuff.

A lot of u probably didn't know that did ya?

t-top89

iTrader: (3)

Thats what I thought!

v8powr

well, not trying to prove anyone wrng or anything but used to if i was going 55 in 5th gear and gave it 3/4 or full throttle...ifd get a knocking sound like lugging. now all it does is go no noise. i thik i could use a little advance on the timing though, but i dont know how far i can go

fast_broker

iTrader: (1)

You can advance until you see knock counts on the scan tool. Then back off a degree or two...

kevm14

Is 10 counts of knock during a 1/4 mile run too much? I guess you'd say any counts are too much...I run 89 and I'm pretty sure my top-end is clean. Besides a possible lean-running problem, my exhaust is LOUD (gutted cat, no muffler). Could this be causing false knock counts?