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Running 100 octane

4.6K views 13 replies 11 participants last post by  ZO6/Les  
#1 ·
I was wondering if running 100 octane in the Z will have any long term effects on the engine?

I have been told that you can pick up some pretty HP buy running 100 octane.

I have tried the NOS additive(black can w/3 octane boost ) and you can feel the difference, especially on hot days and when you are running the a/c.

Thanks for the help.
 
#3 ·
It shouldn't BE leaded......
If it is...DO NOT USE IT PERIOD..............
You will ruin the emissions equipment....and it will be warram=nty voided.
That said, 100 octane should be avaialble without lead......
I think it is an expensive answer, to a non issue.............93/94 is good enough.
 
#4 ·
Bigdaddy2x3 said:
I was wondering if running 100 octane in the Z will have any long term effects on the engine?

I have been told that you can pick up some pretty HP buy running 100 octane.

I have tried the NOS additive(black can w/3 octane boost ) and you can feel the difference, especially on hot days and when you are running the a/c.

Thanks for the help.
You will not be able to extract any more energy from the 100 octane with your engine. Your compression ratio is fixed so only if you would increase hte compression ratio would you need a higher octane rating.
/panzer slips into educational mode

...The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the car. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more. ..

extracted from "How Stuff Works" website

What does octane mean?
 
#6 ·
Bigdaddy2x3 said:
I was wondering if running 100 octane in the Z will have any long term effects on the engine?

I have been told that you can pick up some pretty HP buy running 100 octane.

I have tried the NOS additive(black can w/3 octane boost ) and you can feel the difference, especially on hot days and when you are running the a/c.
As long as it's 100-octane unleaded, no harm no foul (except to your wallet).

If you're experiencing any knock retard (WOT in 4th on hot days, you almost certainly are), the 100 octane should help. If not, it won't.
 
#7 ·
Unless the hot air is causing knock retard (you would need to scan the car to know) increasing octane is a waste of money. If you are getting some knock a higher octane (especially when racing) could be good insurance.

Just my .02.

Les


Bigdaddy2x3 said:
I was wondering if running 100 octane in the Z will have any long term effects on the engine?

I have been told that you can pick up some pretty HP buy running 100 octane.

I have tried the NOS additive(black can w/3 octane boost ) and you can feel the difference, especially on hot days and when you are running the a/c.

Thanks for the help.
 
#8 ·
If we were comparing just octane ratings and all else was equal, then the 100octane wouldn't have much of an effect over 94 octane (you really do need 94 octane min for hot days).

However, street gas is often blended with ethanol (damn EPA regs), where race gas isn't. No, ethanol has less energy per gallon than gasoline - something like 1/2 as much (if I remember right). Around here, the best I can get at the pump is ethanol-blended 91octane - which just plain sucks.

Or I can spend $4.25/gal and get 101 octane that isn't blended with ethanol.

Now, I'd love it if our cars were setup to run alcohol, but we'd need bigger gas tanks (36gal instead of 18 for the same range), and bigger injectors. The benefits are Alcohol is a renewable source of energy AND we could run a shitload more compression with it.
 
#11 ·
As far as long term effects go...

I ran 1/2 tank of 100 Unleaded (76) about every two weeks in an LS1 engine for 26,000 miles. 02 sensors were fine, plugs were fine.

My testing on a 10.1:1 engine indicated no gain with it though. I'd put 50% in for "insurance" at track events. Superstition mostly. I do the same with the Z06. Keep in mind we run 91 at the pump.
 
#12 ·
I'm Running 104

I run 104 gt plus(Sunoco). I feel an improvement, but my timing is at 28Deg. at 17-18 I think the 93 is fine. It is not so much the octane as what timing it allows. I picked up almost 2 mph last outing since timing redo. Thats with a higher temps and humidity and losing 1/8 mile drastically do to lowering my car(spinning 1st and second).



Randy
 
#13 ·
We were fortunate to have the head Z06 engine manager at one of our local club meetings. This question was brought up to him on the 100 octane vs 93=94 octane. He said unless you modify something (intake, exhaust, cam, etc.) from stock form you will not make any more HP...... The LTFT's take over and timing will not be advanced to make any difference. When they were developing the fuel tables they had to calibrate from 91 octane California crap gas to 94 octane Sunoco. He also said most cosmetic changes to the engine would result in no change to losing HP (02's). The only plus would be to change to a K&N type air filter.

This was verified by several people who added a Donaldson type air filter to an 02 and had less HP. The LTFT table allowed less advance and the end result was the car running rich and making less HP. This is for the 2002 Z06, on the 01, a Donaldson would make more HP. Hope this helps.
 
#14 ·
I agree with his comments about octane, but totally disagree about his comments on an intake, whick make no sense. If more air is of no value what is good about a K&N vs. anything else? Has anybody ever found more HP from a K&N and the stock box - I doubt it. Also colder air reduces IAT which makes more power, reduces risk of knock retard and will cause the ECM to not pull timing on the high end.

Many of us have proven gains from a cold air intake system. In my case I picked up 15 RWHP with no changes except a T1 from Halltech. After a few hundred miles and the ECM fully recalibrating I was still over 10 RWHP up from stock.

No flame, just a difference of opinion based on actual tested results :)

Les



Gordy M said:
We were fortunate to have the head Z06 engine manager at one of our local club meetings. This question was brought up to him on the 100 octane vs 93=94 octane. He said unless you modify something (intake, exhaust, cam, etc.) from stock form you will not make any more HP...... The LTFT's take over and timing will not be advanced to make any difference. When they were developing the fuel tables they had to calibrate from 91 octane California crap gas to 94 octane Sunoco. He also said most cosmetic changes to the engine would result in no change to losing HP (02's). The only plus would be to change to a K&N type air filter.

This was verified by several people who added a Donaldson type air filter to an 02 and had less HP. The LTFT table allowed less advance and the end result was the car running rich and making less HP. This is for the 2002 Z06, on the 01, a Donaldson would make more HP. Hope this helps.