austinseanchris

Hey guys...I'm in a dilemma here and not sure whats right and whats not? Right now I'm running at a 10:5:1 compression rate(FYI). I recently had a set of AFR Eliminator aluminum heads put on my 78 Vette which replaced the factory cast heads. While we're talking about the motor, I'll add that I have a Crane Cams 270 duration/470 lift cam, Comp Cams 1.6 roller rockers, and edelbrock performer intake and a Holley spreadbore to top it off along with an MSD ignition system and March underdrive pulleys. Also, all emissions equipment(smog pump, cat convertor, o2 sensors, egr valve, etc) has been removed and the exhaust now consists of Hooker Super Competition headers, true dual exhaust and exhaust cut-outs at the header collectors. Now, I was told after doing the heads that it'd probably help to run a mixture or 100 octane(unleaded) along with the 93 that I normally run. So I thought I'd just start filling her up with 100 unleaded at $6.99/gal(yea, I know its expensive!) from now on. So far, she's running great. But I was trying to shop around and see if I could get the fuel cheaper and came across a friend of a friend that can get VP-110 LEADED race fuel for $6.91/gal and its 10 octane points higher. So I thought, well why not, right?

So, I did some checking on VP Race fuel's website and it says the VP-110 is good on engines with high compressions and with cast iron heads. It doesn't mention anything about cars with aluminum heads? Will it hurt them? I've been online for a few hours now reading how leaded fuels gum up cats and o2 sensors, but considering I dont have either on there, I don't think they'll get gummed up! But the highest fuel I saw on VP's site that mentioned anything about aluminum heads was an UNleaded 99 octane race fuel. I've also read other places that running leaded race fuels burns up pistons and rings faster? The car the way it sits dyno'd at 321 HP at the flywheel which I don't think is too bad for a car that had 185 HP from the factory. But, I have a lot in this car and only put the best oils, parts, etc on it even though I know a lot of times your just paying for the name...But it makes some of us feel better and all warm and cozzy, right?

Ok, so basically I just need to know am I or will I be hurting the car in any way whatsoever by running a 110 leaded fuel? Secondly, if no danger is involved, do I need to remove all unleaded fuel from the tank before mixing it with leaded? I know these ?'s may sound stupid but if you search google, you'd be surprised at the mixed reviews from everyone on this topic and it seems to be a big gray area that no one seems to know. Maybe I'll get a lot of the same replies or maybe someone has ran into this issue before??? Any help would be greatly appreciated...thanks!

Oh, btw, if your gonna just reply to tell me I'm not gonna see any HP gains or tell a difference in the fuels and not to waste my money, that's not helping me, lol. Whether I see it or not, if its safe to run, then I wanna feel that warm and cozzy feeling after getting ripped off by paying $6.91 for a gallon of fuel if that makes any sense?

70Donnybrooke

I don't know about aluminum heads, but there is no problem in mixing unleaded and leaded fuels. I do it all the time. In fact the local seller of racing fuels gave me a formula for figuring out the exact octane. I can't find it right now, but it is more involved then just splitting the two.

gkull

If your motor does not ping why add high octane?

You need to read up on static and dynamic compression ratios.

Your choice of cam and intake manifold hurt your HP. of those nice heads.

I've had some 350's with 100 more hp that ran just fine on unleaded super. Why waste money on race gas. No it will not hurt anything in a catless system

73StreetRace

I think it won't hurt, but it won't help your engine either. I mean your engine won't make more HP with this race fuel.
It's probably a waste of money. Choose the lowest octane fuel that won't make your engine ping in the hardest conditions.

baxsom

i have read that running higher octane than needed will actually hurt performance because as octane goes up BTUs go down meaning that there is less actual energy in a gallon of 116 octane as in a gallon of 87.
It makes sense. After all octane is just simply resistance to detonation from compression. The more volatile the fuel is the easier it will explode when compressed.

gerry72

That's really an academic argument. If the engine isn't on detonation threshold and timing can be optimized for maximum power on the lower octane and gains nothing more with higher octane then, yes an 89 octane will produce more power than a higher octane fuel but the difference is statistically insignificant as you need scientific precision to measure that difference. It would never show up in the seat of your pants. But you really shouldn't make this comparison with the more exotic racing fuels (like 116) since they use blends that have to be accounted for when the engine is built and in the tune up. Much the same as an engine is designed to run on lower octane.

jackson

Surely you meant 321 at rear wheels.

be advised: regardless if leaded or unleaded; many race gasolines contain toluene and/or similar organic solvents.

110 / 116 leaded race gas etc will not hurt your motor.

However, race gas might damage an OE in-tank bladder or OE fuel strainer aka sock. I do Not Know it will damage YOURS. I believe sunoco race 110 may've dissolved an OE sock in a bladderless '71; I do Not Know it did but I believe it did.

Rmorgan&11

You will also may need to change carb jetting !

DRIVESHAFT

Have you tried running it on 93 octane super unleaded?
If not, I would try it. If it works you will save a ton on gas, and with aluminum heads it might be OK.
If it doesnt work, you could still run super unleaded but with a little of the VP race gas mixed in to boost the octane.
Yeah, I know I really didnt answer your question, but it seems like the guys above me already covered that pretty good.

Jims66

To answer your question........, No, 110 Leaded gas will not hurt your engine (which includes your aluminum heads).

RobRace10

Race gas will also will make it harder to start in cold weather. I would try 93 octane and if needed add a little race gas. It's a waste of $ running all race gas with your setup.

GeorgeS

I have a 327 in my 68. 10.5 CR and a similar Crane cam. Z274 I run 93 octane with no problems. As mentioned above, 110 octane will work fine but I am not sure you need it. I would save the money...

Ghunt

What about Avgas. In my area it is averageing 3.75 to 4.50 and is 100
octaine leaded. Its been running it in my airplane for 32 years and hasn't damaged the aluminum heads yet.

GHunt

Mike Ward

What problems are you guys trying to avoid or fix with these expensive fuels?

96z51

what is your total ignition advance? is it pinging on premium pump gas? 10.5:1 and an aluminum head with that big of a cam should be fine with pump gas.

enkeivette

You don't need race gas. I make probably 300hp more than you do and I run off 91.

Rmorgan&11

Used to get AV Gas at around $3 a gallon to run in my Blown Boat Motor , but every airport I haved tried refuses to sell it anymore out the door so to speak ....no plane no Fuel !!! & NO Drums !!

austinseanchris

Wow at all the replies. Well I guess to try an address all the points and replies I've seen, I've always ran the car on 93 Octane and its done fine. No pinging, knocking ,etc. But the guys at AFR told me it'd probably be a good idea to run at least a mixture and that it would help out in the performance. Nothing that I'm going to feel behind the wheel but maybe 5-10 hp on the dyno. Like I said in my initial post, I could care less about the cost of race fuel vs. pump gas(geez that sounds big headed and no, I'm no millionaire, lol). But if it makes the car run cleaner, better, and if the lead adds a little lubrication to the heads, then I'm all for running it. I'm not running it expecting to p/u 50 HP or anything like that nor am I running it b/c I'm having issues with spark knocking, I'd just feel better deep down knowing that I'm running a higher quality gas. Am I the only one that feels like this towards their car? lol, or maybe I'm slightly crazy, who knows?

Also, on another side note, I am aware of the carb jetting and timing issues. Right now I'm set right at 10 degrees. After talking with several people, they have indicated that fine tuning and testing a car on a particular fuel can work wonders. They said a car fine tuned on 87 pump gas can simply out run the same car if you run race gas through it. However, fine tune everything to where your running 110 leaded fuel and its set up for that and you'll out run a car thats not fined tuned to run on 87. Basically if you set the car up to run on a particular fuel, run that fuel. If you deter from that, you take the chance at losing performance(or so I was told...). But thanks for all the support and help...I found the technical information useful...However, the "don't run it, your wasting money if it runs on pump gas" replies didn't help a bit...

Mike Ward

Your first three points I've quoted indicate that you've been completely mislead as to the chemistry, technology and basic mechanics behind gasoline and piston engines. 'Racing gas' is not higher quality, better for your engine or cleaner running. You must be quite young if you don't remember the crap that lead adds to a combustion chamber

Point 4 might just have hit the nail on the head.

Point 5 sounds like you're not appreciating what the knowledgeable people here are trying to tell you. I'll cross AFR off my list of credible vendors if they've actually said what you claim.

austinseanchris

Mike, its not that I'm not listening to people, but its funny how its completely mixed reviews on the the whole fact. And a lot of replies simply state "Dont waste the money..." As far as lead, sure, there are bad things in that fuel, but at the same time, theres bad things in unleaded fuel as well. Theres bad things in everything...even food you eat! There has to be truth behind both ends of the spectrum. Its like this...Some people stand behind Castrol while others say its crap. Some stand behind Mobil 1 and say its the best and both have their reasons...So, with that said, thats your opinion, but when a head manufacturer, a race fuel distributor and several corvette enthusiasts say it'll be no problem running it...makes you wonder??? Not sure why that makes you cross AFR off the list, but whatever...I guess I'm not getting anywhere with you???