Race Gas, Do I need it?

[buzzard]

I mentioned in another post that I wanted to hit 100 in the 1/4 on pump gas and without slicks. It came up that I don't need race gas unless the engine is pinging. It's not.

Wouldn't race gas burn better, and make more power, than pump gas? I was thinking about 100 or 105 Octane, not the crazy expensive stuff.

[Flexicoker]

I don't know about making more power, I think it just allows you to make more power by utilizing higher compression ratios or forced induction. I'm under the impression that you want to use the lowest octane you can get away with without pinging or knocking, not only because its cheaper but also because it burns easier and quicker (hence the problems with detonation in higher compression ration engines)*

*disclaimer - I'm no expert, this is just what I've heard from others, I'm interested to hear what other people have to say.

[squirrel]

I agree...race gas lets you run more compression by burning slower.

If you want to go quicker, and are willing to run race gas all the time, then put in some 13:1 pistons. Personally I'd rather lose the performance and keep the driveability of lower compression.

[buzzard]

Yeah, I'm somewhere around 9.3:1 compression. I want to continue running pump gas on the street. I just didn't know if race gas would help on the occassional trip to the track.

[Bugman]

Race fuel will allow you to run a few more degrees of timing advance before it starts pinging at the track.

-Jeff

[Evilfordcoupe™]

That wouldnt be "PUMP" gas then so to speak......

A different cam?????

-Jason

[buzzard]

I'm not changing the cam or anything in the motor. Except for new lifters.

Will I go faster with race gas?

[plan9]

[ QUOTE ]
Will I go faster with race gas?

[/ QUOTE ]

maybe look for some alternatives other than the motor... perhaps lighten the car up a bit... you are very close to 100mph.

only problem is, i know youve got a coupe but know nothing about its interior or what can or cannot be yanked off

[Evilfordcoupe™]

You will go faster with race gas!!!

-Jason

[Hanible_H20]

I could tell the differece when I forgot to purchase my normal 114 octane turbo blue and bought 110 octane Sunoco at the track. I've got enough compression, that I can't run pump gas though. I was missing the extra grunt off of the corner. I didn't think that I would be able to notice the difference when I switched. The specific gravity, and other characteristics of the fuel make a bigger difference than it's octane rating though.

My lawnmower doesn't bogg on the tall stuff as much as it does on pump gas either!!

[WZ JUNK]

I bought the $4 a gallon 101 octane last Saturday and I could not tell any difference over pump gas. Your engine my require it but I do not think I will spend the money again. I am in the same fix as you but with a different number. I want to break into the 12's and I am just .2 away.

[buzzard]

I work at a big Chevy store. The guys have been ribbin' me about all the time I spend on my car and I still can't outrun a new Vette. So my new goal is 12.6. That's what the '05 Corvette does. I'm a ways off, but I don't expect to attain a goal in a week. It's something to work towards.

I actually have two seats butted together, so the passenger seat comes out next time. And I'll pay more attention to how much weight I have in gasoline. Heck, the first run I had my tool box in the trunk!

[2tall2beahotrodder]

I work at a drag strip. I have raced on pump gas and race gas and i dont see much difference. Its not worth 4 bucks more.

Try racing with 1/4 tank full. and go on a diet if you cant loose car weight. Hell go nude! You dont need to wear those heavy 3 pound jeans!

[Mutt]

Only if you want your exhaust to smell good. I saw no increase in performance over pump gas with lower compression. Compression is one of the things that builds horsepower. Higher compression needs higher octane gas to avoid detonation - and the fuel burns slower. If your car runs fine on 92 octane, a slower burning fuel will not give you any more horsepower.

http://auto.howstuffworks.com/gasoline3.htm


Mutt

[Deyomatic]

I don't think 9.3:1 is high enough to warrant race gas unless you are really advancing the spark or unless you have forced induction.

[38Chevy454]

I am glad that several people have backed up my original statement. Race gas will only cost you money if your engine does not require it.

Save the money you would spend on race gas and get a new cam and bigger carb, then see what you pick up in the quarter. If not enough, look into better heads. With cast iron heads you don;t want much more than 9.5 compression to still allow pump gas.

Those new vettes are fasst, but your coupe looks better....

[Deyomatic]

What is your rear end ratio? If you don't want to touch the motor, maybe slightly lower gears are in order.

[50dodge4x4]

Don't those new Vets run $45,000 or more? Have you spent that much on your coupe yet? Didn't think so, maybe those guy's would be willing to put up a few grand to help in your effort?

I don't thing race gas would make you go faster unless your on the verge of pinging and can't tell. Guess it wouldn't be that big of a deal to try it once, then you would know what it does in your car. Sure would kinda suck to find out that would be all it took to get you over your edge, but never tried it.... I say shell out a few bucks and give it a try, then you will know.
gene

[buzzard]

Gears are 3.55's. I have another chunk that I was going to set up as a 4.11 spool, for the track. But I've been thinking and looking at some numbers.

With 3.55's and my tires(28.3), I should be able to hit 105 at just under 6500 in 3rd gear. That saves me one of my shifts. So there almost second saved right there!

[Mutt]

Here's some more info for you....


http://theserviceadvisor.com/octane.htm

http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

Mutt

[Unkl Ian]

Get the engine and trans out of a new Vette.That will get you close real quick. http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif



What size is your motor ? And don't tell me you want to go that fast with a 283. http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Hot Rod To Hell]

Well, whether you need it or not, the fumes do not burn your eyes like pump gas does! http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

My cam has quite a bit of overlap, and when sitting in traffic for a few it starts to choke you out a little... your eyes get all watery and stuff.... that doesn't happen with the good stuff! http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif

[38Chevy454]

Damn, HRTH, so that's my problem in my 38's 454. The cam is too fuckin big and that makes it smell bad when it idles http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

Guess i will just have to suffer http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif

edit: I know my cam is big, I was trying to be joking

[Deyomatic]

Did you play around with this one? I'm not sure what you are running for HP in the motor or how much your ride weighs but it supposedly tells you your ideal ratio for 1/4 mile. I think that with the added "get up and go" you should be able to at least compensate for that other shift to fourth if you go lower.

http://www.richmondgear.com/112901.html

[Crease]

Good question buzzard, the replies were not what I had expected. Im learnin all kinds of stuff today!

[buffaloracer]

I've found that the rear gear ratio has very little to do with top quarter mile speed and a lot to do with et. Good fuel will allow you to advance the timing and that sometimes but not always helps the et and mph. We used to advance it in low gear and retard it some in high when we were racing with a dual point.

[67Imp.Wagon]

[ QUOTE ]
I work at a big Chevy store. The guys have been ribbin' me about all the time I spend on my car and I still can't outrun a new Vette. So my new goal is 12.6.

[/ QUOTE ]

Tell them to take the tires you have on your coup and see if a Vette will still run 12.6.

Your car is way cooler than a Vette and sounds better. Screw em. There just jealouse still cause you got to see that Golf match that weekend on TV and they worked.

[Crease]

[ QUOTE ]
Tell them to take the tires you have on your coup and see if a Vette will still run 12.6.


[/ QUOTE ]

Damn straight! Try moving your tranny to the back of the car, that may help a bit too.

[buzzard]

[ QUOTE ]
Did you play around with this one? I'm not sure what you are running for HP in the motor or how much your ride weighs but it supposedly tells you your ideal ratio for 1/4 mile. I think that with the added "get up and go" you should be able to at least compensate for that other shift to fourth if you go lower.

http://www.richmondgear.com/112901.html

[/ QUOTE ]

I don't think I trust these calculators. I just plugged in the numbers for the Vette. Running 12.6, at 3100lbs, it says the horsepower is 265. http://www.jalopyjournal.com/ubbthreads/images/graemlins/confused.gif

[Hot Rod To Hell]

[ QUOTE ]
[ QUOTE ]
Did you play around with this one? I'm not sure what you are running for HP in the motor or how much your ride weighs but it supposedly tells you your ideal ratio for 1/4 mile. I think that with the added "get up and go" you should be able to at least compensate for that other shift to fourth if you go lower.

http://www.richmondgear.com/112901.html

[/ QUOTE ]

I don't think I trust these calculators. I just plugged in the numbers for the Vette. Running 12.6, at 3100lbs, it says the horsepower is 265. http://www.jalopyjournal.com/ubbthreads/images/graemlins/confused.gif

[/ QUOTE ]

At the rear wheels, I'll bet you'd find you're not too far off! http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

My chevy II made 400 HP at the wheels the first year I had it out... 1 week later I took it to the track and it ran a traction limited 11.15 @ 124.

The calcualtor says it should've gone 11.06 @ 118, so it's not that far off... http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

[buzzard]

Mutt, thanks for the links. Very interesting stuff. I figured 38Chevy454 was right in the other post, but I wanted to bring it up for discussion so others got to see it. It's just real suprising to me.

[krupanut]

Yeah, it says I should be running 11.99 at 108! http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

[flynj1]

Back to the gas, raceing fuel has a lower flash point so you can run more comp., You need to run atleast 10. 1 to make it work, at 9.3 you will go slower because the fuel wont burn fast enough to be efishent because of lack of comp.

[OldCarPilot]

To answer your question... No. Not with your setup. http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif
There is a LOT going into the new Vette. The coputer helps the car run at optimum air/fuel ratio through out its RPM range. Its weight is almost 50/50 front and rear. Traction controls... etc. Stuff that the older cars just don't have.

[Deyomatic]

Buzzard, I'm not saying I'd bet my life on the accuracy of the results of that calculator, but that particular one is supposed to find the "optimum" gearing for the 1/4 mile straight line. I definately don't think enough people consider gearing.

My friend has a 90s Eagle Talon with the AWD and turbo. He ran a 13.7 with minimal bolt on mods. In stock form, that 2.0L motor was pushing 195 HP. His was probably around 300. Believe it or not, this is about a 3000 lb car.
I put a 350 hp small block in my 80s Caprice, which is also about a 3000 lb car, and the best time I could run with that was 16.2. Traction was not an issue, because as you will see, the gearing wasn't such to allow the tires to lose alot of traction. I'd bet that if you figured the HP that gets to the wheels, it would be VERY similar to my buddy's Talon, which had a 5 speed manual tranny. Mine was an auto.

So, to draw this out even more...we have similar HP and similar weights, but we have about a 2.5 second difference. The Talon runs a 4.15 gear ratio and my Caprice had a 2.73.

Sorry for the boring, long winded, late model explanation, but I really think you need lower gears!

[buzzard]

I agree that I probably need some lower gears. And I'm working on a solution! Thanks for the input.

[3blapcam]

What engine are you running? Carb? Gear and Tire size? I'm sure your coupe will go 12's with a half ass built 350 w/ good carb and good tires. How much does it weigh? If you're trying to run 12's/100mph w/ a vacuum secondary 600 Holley... good luck. If you had a 383, dart heads, and demon carb, I could see your concern on why it won't do it.

[buzzard]

327, Dual Edelbrock 500CFM carbs, 2.02/1.60 camel humps, roller rockers, Comp Cams XE274H cam, stock bottom w/ flattop pistons, Muncie, 3.55's (open right now), with 235/75 28.3 tall tires (radials?! http://www.jalopyjournal.com/ubbthreads/images/graemlins/shocked.gif)

I have no idea how much it weighs. Thats a good question. How much does a fenderless A with a SBC weith?
Anyhow, that's my rundown.

[3blapcam]

Sounds like a pretty stout setup. I'm not a Chevy guy, so I don't know what cam that is off the top of my head. I don't think you can get a whole lot more out of that motor without hogging out the heads (assuming they aren't) or increasing compression/lightening the pistons. I saw it run at the DOTD, but I don't remember how far off your goal you are. Put cheater slicks on it and it'll probably do what you want. I don't know what that weighs, maybe 2000lbs w/ driver?!

"I need Naws, I need Naws now!" -- best line ever.

[plan9]

[ QUOTE ]
327, Dual Edelbrock 500CFM carbs, 2.02/1.60 camel humps, roller rockers, Comp Cams XE274H cam, stock bottom w/ flattop pistons, Muncie, 3.55's (open right now), with 235/75 28.3 tall tires (radials?! http://www.jalopyjournal.com/ubbthreads/images/graemlins/shocked.gif)

I have no idea how much it weighs. Thats a good question. How much does a fenderless A with a SBC weith?
Anyhow, that's my rundown.

[/ QUOTE ]

you can go to a weigh station and see if theyll weigh the car http://www.jalopyjournal.com/ubbthreads/images/graemlins/smile.gif

eventhough the race gas question has been answered, i find it funny when people with econo cars insist on putting 91 octane into their tanks. Urban Legend - running higher octane will give better performance and keep the engine in good running order. heh...

[Hellbilly_Buzzard]

All you will do is polute more and lighten the wallet with a higher octane fuel if it is not necessary especially with a lower compression engine.

[Hanible_H20]

In classes that don't allow aftermarket heads, a lot of guys are running 305 heads. They don't flow as good as aftermarket, but what they lack in flow, they make up for in increased compression.

[tomslik]

might try backing off the timing a couple of degrees and see.
yep, i'm serious.