91 and 92 octane??

[New C5er]

Just wondering if any damage would be done to a c5 by using 92 octane for 400 to 500 miles. Just came back from the Washington State coast and the highest octane allowed there is 92. In Oregon and california only 91 is availabe. What do you B.C. vette owners do if they go south , or do you leave your vettes at home then? Saw lots of vettes down there, wonder how they and others run their vettes on such low octane. Everyone use Toluene??

 

[FordPrefect]

Could be wrong but I thought stock C5s were rated at 91 or better? If that's the case you are fine with 92.

Got my own question, is there any real benefit to exceeding the octane rating?

 

[Keith Tedford]

I think the owner's manual for the 2005 says that premium is recommended but not required.

 

[CCO]

Could be wrong but I thought stock C5s were rated at 91 or better? If that's the case you are fine with 92.

Got my own question, is there any real benefit to exceeding the octane rating?

good question Wayne. I've come to the conclusion after reading thoughts on this on and off for years that exceeding the manufacturer's octane rating is a misconception and total waste of $$ and that no benefit or increase in performance is realized.
Further: the combustion process and burn rate of higher octane fuels is much slower (yes slower) than lower octane fuels and can have an adverse effect on starting.

Conversely, if lower octane is used to save money, the result is poor performance due to timing cut-back by the knock sensor and computer, or engine damage due to severe donation and excess pinging in older engines.

The only exception would be to stop pinging in the combustion process due to carbon buildup and subsequent increase in compression ratio, bad timing, or another problem causing the pinging. (as a temp. fix)

I would suggest a Google search of fuels and their characteristics to verify.

C.

 

[CCO]

Just wondering if any damage would be done to a c5 by using 92 octane for 400 to 500 miles. Just came back from the Washington State coast and the highest octane allowed there is 92. In Oregon and california only 91 is availabe. What do you B.C. vette owners do if they go south , or do you leave your vettes at home then? Saw lots of vettes down there, wonder how they and others run their vettes on such low octane. Everyone use Toluene??

Wow, what are you normally using then if 91 - 92 is "so low"? Do you have high compression and been modded out needing a 'race gas' of much higher octane?
If not, you should be fine with 91-92. IMHO.

Having said all that I have heard of pump stations using lower octane (cheaper) gas in the higher octane pumps to raise profits -- In the rare case that happens then of course the engine will ping and run rough.

That's a different scenario than what you're asking of tho.....but I have heard of it happening in the US.
Perhaps a good reason to stick with the branded stations rather than taking more of a chance on the 'cheapies'. Just a thought -- one never knows one's luck these days with pricing and usage as high as it is.

Good subject with many views and much reading out there.

C.

 

[New C5er]

A 91 octane thread from California

We now have the solution to make the pinging and knocking from the 91 octane of California gas a problem of the past.

We have started stocking cases of Turbo 108 Racing Fuel Concentrate. It comes in 16 oz. bottles.

THIS IS NOT A FUEL ADDITIVE!!!!! 108 octane racing fuel in a bottle.

This concentrate is rated at 108 and you use 32 oz. every time you fill up to give you 95 octane. Use 48 oz. per tank full and it will bump up your rating to 98 octane. It is more cost effective over 100 octane gas and will bump up your octane rating higher when mixed.

All you do is pour in the 108 concentrate in your tank and then fill up.

You will feel the difference. No more pinging or detonation.

We have tested it and you can feel how much better your WOT is as well as how smooth your car will run. Acceleration is now a pleasure again.

Pour it in and you will be addicted!!

Barrie Bennett gained 6 hp on his 2001 Z06 on the dyno using this stuff!!!!!! I am sure he will chime in and give his opinion of this great booster!!

Product info can be seen here:
Yahoo! Small Business: Web Hosting, Domain Registration, E-commerce & Email

Unless I'm mistaken the C5 I brought back from Alberta said 93 or better octane recommended. Will check manual later........

 

[New C5er]

Chevron 94 in all my engines.......

My c5 gets Chevron 94 and runs real great on it. Usually don't speed much, but the occasional time I have been fed up being behind some doddler I am usually in fourth or fifth and then I will give it a bit of extra gas and that thing really surprises me with 350 lbs of instant torque and horsepower. Am of the old fashioned school, baby it and you'll have a lot less work to do on it.Usually I set the cruise at 106 km/hr and get good gas miege that way too.I live in a town (village) of 2,500 and I think I'm the only vette owner here.

 

[New C5er]

Manny's answer to this................??

Wonder what Manny's thoughts are on that California thread on racing fuel additive.

 

[Bishs]

good question Wayne. I've come to the conclusion after reading thoughts on this on and off for years that exceeding the manufacturer's octane rating is a misconception and total waste of $$ and that no benefit or increase in performance is realized.
C.

I agree from what the GM people told us at the National Corvette Museum a few years ago. The Premium IS needed for ZO6's and higher.
I have run 89 in our C5s and never had a problem.
Now in my `06 C6 quite often I will run 89 on long highway trips.

 

[CCO]

Wonder what Manny's thoughts are on that California thread on racing fuel additive.

Yes I wonder -- he would know -- My guess is that it's a blessing for older engines which may not be as compatible with newer gasolines and engines that aren't 'puter controlled, knock sensored, or have metals (valve seats) that are compatible with today's fuels.
On more recent motors I believe one has to be careful with what one puts in the tank for fear of 02 sensor and catalytic failures.
I've used additives too and believe in them, but I try to be aware of what possible adverse affects they're having.

Some hands on experience would be very helpful here for sure.

BTW Al, you asked about Toluene: I've tried the program and found it to help but is not be very cost effective. I couldn't determine what effect it was having on the 02's and catalysts so I stopped using it. The gains in mileage were in the 3% range after doing some careful checking.
Not a lot of places carry it and the ones I found who did were quite expensive.

You have probably read some on it and seen the websites on the subject but in case you haven't just google for info. It's interesting reading.

C.

 

[DrJer]

Note: I'm not an expert but:

As far as I understand, unless you are running the ragged edge on your calibration AND are into the throttle enough to cause detonation because of worse octane gas than it was tuned with you will have zero damage/are fine to run whichever fuel.

Race fuel is leaded and is not recommended. It can foul oxygen sensors.

The higher the octane number, the slower it burns - this allows increased timing to be run by aftermarket tuning (read: more power), expands slower pushing the piston down smoother/longer (read: more power -but you'd be hard pressed to feel the difference) and reduces the chances of detonation (ie. the heat and compression of the air/fuel mix ignites to a dangerous pressure before the programmed ignition timing.) <--- which your knock sensors would notice

Driving on the highway with 91/92 octane is not an issue.

(Again, not an expert but I am trying to inform myself as much as possible)

 

[Manny@Dasilva]

Note: I'm not an expert but:

As far as I understand, unless you are running the ragged edge on your calibration AND are into the throttle enough to cause detonation because of worse octane gas than it was tuned with you will have zero damage/are fine to run whichever fuel.

Race fuel is leaded and is not recommended. It can foul oxygen sensors.

The higher the octane number, the slower it burns - this allows increased timing to be run by aftermarket tuning (read: more power), expands slower pushing the piston down smoother/longer (read: more power -but you'd be hard pressed to feel the difference) and reduces the chances of detonation (ie. the heat and compression of the air/fuel mix ignites to a dangerous pressure before the programmed ignition timing.) <--- which your knock sensors would notice

Driving on the highway with 91/92 octane is not an issue.

(Again, not an expert but I am trying to inform myself as much as possible)

I love it when people can answer for me :agree:

 

[New C5er]

Toluene...

The toluene was only something I would use to raise the octane level if the gasoline octane would be too low in whatever state or province I were in. Did a lot of reading about toluene, by chemists and ex Fi employees and according to all there are no damaging qualities in it. Will not rob the motor of cleansing agents etc. in gasoline etc. etc. It would be a matter of spending more for toluene and then spending nothing for a repair because the lower octane would somehow cause knocking etc. Would rather rather err on the side of caution. Old school thoughts. For instance the manual on my truck recommends changing the platinum plugs every 150,000 MILES, I change them at 50,000 kms.

 

[New C5er]

Racing fuel..

There is such a thing as 100 octane racing fuel that is unleaded.

 

[New C5er]

Raacing fuel..

Sorry, forgot to add that the 100 octane unleaded fuel is called Rokket fuel, formerly Union Oil from down in the States.

 

[Riley P]

Rock on! We have toluene at work for cleaning electrical connections. Maybe my car is thirsty. I'll have to ask the boss what a 5 gallon pail costs.

I was always under the impression that it didn't matter what fuel you used, they all had the same burn rate and the only benefit of higher octane fuels was it's resistance to detonation meaning you can run a higher compression ratio and that is part of what makes more power. I did not realize it burnt slower.

Some people claim that high octane fuel has more power. This is only somewhat true. Gasoline has the same amount of energy in it no matter what octane you run, however, lower grade fuel usually have ethanol (5% mid grade, 10% regular). Ethanol only has about 70-80% the energy of gasoline so in effect, high octane fuels do have more energy so to speak.

Now, the cool thing though is E85 has an octane rating of..well, some say 105 but I just found out it's more like 94-96...not as sweet as I thought as you could run a crap ton of boost in an engine using E85 if it were actually 105 octane.

Toluene has an octane of 103

 

[CCO]

The toluene was only something I would use to raise the octane level if the gasoline octane would be too low in whatever state or province I were in. Did a lot of reading about toluene, by chemists and ex Fi employees and according to all there are no damaging qualities in it. Will not rob the motor of cleansing agents etc. in gasoline etc. etc. It would be a matter of spending more for toluene and then spending nothing for a repair because the lower octane would somehow cause knocking etc. Would rather rather err on the side of caution. Old school thoughts. For instance the manual on my truck recommends changing the platinum plugs every 150,000 MILES, I change them at 50,000 kms.

Just realized that I used Toluene to raise octane and Acetone in another program some time ago to help mpg's. My bad.....C5'er

The link to the site on Toluene I've misplaced, tho. It was quite neutral and very descriptive and had charts. I'll have to look again when I get a chance.

I wish I could find Toluene in larger quantities thereby a little cheaper by volume.
Only supply I could find local was a paint store who sold a liter for about $15! Pricy.
I need some for my SHO which now has a tune requiring slightly higher octane that is commonly available here.
A pint or 2 of toluene/tank would bump that just nicely. seems to me that would bump the octane by about a point .
Anyone got the numbers and/or a weblink?

The octane booster I've seen in stores has MMT in it which has been attributed to rotten egg smell when burned in the catalytics of modern cars. Had that once years ago in a Ford and it was awful.

C5'er what ratio of Toluene to gas did you use and for what octane increase?

thanks

C.

 

[New C5er]

An apology is in order from me.......

Sorry that I started this thread, cause I was misinformed about the whole thing, Have only had the c5 since June now, and remember that it was not in the manual that the required 93 octane issue came up. It might have been the fellow that I bought the car from but it was probably from me myself that made me think that. All my Honda products cars etc. all state 92 or better in the manual. Therefore something as a vette made me think it should run on at least more than a Honda etc. Have always used Chevron 94 in all my vehicles. One of the last Hondas had 450,000 kms on it before it was totalled. It had never had the motor touched outside of reg. maintenance. Sorry for stirring things up.
Al......( now in penance mode)

 

[Riley P]

Hey Al! Stir it up! This has become a really interesting thread. I for one am glad you started it.

450,000km is quite decent. All our family vehicles and friends vehicles were GM's (mid 80's) and seemed to crap out around the 330,000 km mark...however, the engines and tranny's are cheap to rebuild and you get another 300,000 out of them.

I wonder how well the new stuff lasts, I don't know anyone anymore that keeps their stuff long enough to get over 300,000 km. I have heard great things about our LS engines though.

It turns out I can get my hands on Toluene in a 5 gallon pail for about $65 through work! That's a little more reasonable!

 

[CCO]

Hey Al! Stir it up! This has become a really interesting thread. I for one am glad you started it.

450,000km is quite decent. All our family vehicles and friends vehicles were GM's (mid 80's) and seemed to crap out around the 330,000 km mark...however, the engines and tranny's are cheap to rebuild and you get another 300,000 out of them.

I wonder how well the new stuff lasts, I don't know anyone anymore that keeps their stuff long enough to get over 300,000 km. I have heard great things about our LS engines though.

It turns out I can get my hands on Toluene in a 5 gallon pail for about $65 through work! That's a little more reasonable!

That is a good price, Riley. I'll check around more and find someone who can get some local. It must be out there.

Al , nobody is getting stirred, no worries -- As Riley says it's interesting to hear what everyone has learned and all the angles.

C.