alcohol vs race gas

with a small block hi rpm combo-- if you took the same engine[ obvious jet change ] and ran back to back dyno test with each type fuel, what would you think the difference would be in hp figures? basicly I am curious about the gain or loss that would come from only the fuel change. I know air temp and such will play a big role... just in general what would you expect to see ?

I can't help you on straight methanol alcohol compared to race gas but I have done back to back testing on 112 octane race gas versus E85 on one of my current race motors, it made 786 HP and around 650 Ft. Lbs. on race gas with jetting, it made 776 HP with 786 Ft. Lbs. on E85
This car is deadly consistent on E85 from early mornings till late afternoons, no guessing on the dials

This is from a very smart man (Sid Waterman told me this and it verified what I was seeing...I mention this because I've never seen some of the huge gains from alcohol as many claim but it's possible I just suck at engine building and tuning) and matched pretty close to what I already was finding.


Best carb gas to best carb alcohol: 3-4% for alcohol.
Best injected gas to best injected alcohol: 3-4% for alcohol. So that means...
Best carb gas to best injected alcohol: 6-8% for alcohol. So...if you are making 600 HP on carb'd gas and you switch to injected alcohol and both the carb and the injection is [censored] on tuned up you'd make 648 HP BEST CASE.

In practice, since I was building and tuning high RPM small block stuff, it was a [censored] to get the fuel curve correct without a minimum of three by passes and I could have used one more. I did play with slowing the pump down a bit, but the car got sluggish in the gear change. I was shifting at 8500-8800 at that time. There is also getting the by passes to not only open at the correct time, but they have to close at the bottom of the gear change (4 speed) at the same time and then open again. Much easier said than done.

In the end, I would go back to carb'd gas on a tunnel ram and not screw with it.

I had a feeling that if you tweaked the gas you could get it pretty close !! I am very aware of the consistence on alky....to me , that's the biggest pro for using it . but , I was thinking to much as usual! so I can run the gas and chase the afr a bit...not going to lose big time ? lower rpm torque improvements seems common though.

what compression ratio is on that one ?

Not to hijack, but Monte always claimed you could make more power on gas than alky, but never explained why. How? Anyone I know who switched to meth picked up power.

I'm not sure where he said that but I'd love to read it. I suspect that he was talking about using alcohol with nitrous. In fact, I looked into it being the glutton for punishment that I am. And I was constantly told to run the engine on gas the nitrous on alcohol, bit not alcohol on both. I don't remember now exactly why that was, but I suspect the shear volume of fuel would be so great that you couldn't get big enough ports to handle the fuel, and with the latent of heat vaporization of alcohol, you'd never get enough temp in the intake tract to vaporize all the alcohol, which, as I understand it would only add to the massive fuel stratification issues present with high volumes of fuel.

NM loves meth. Oh wait.

Not sure what you consider High RPM, but A fellow racer I race with, runs a chevy. He started with a race gas and carb (950 I think) that was custom build to his engine specs. Switch over to an alcohol carb (another 950, pretty sure, custom built to his specs). He picked up a few small numbers in 60' and maybe 3-4 hundredths in the 1/8. He switched to ron's toilet over the winter and picked up another 3-4 hundredths in the 1/8, but said throttle response is unreal with the toilet. That was all on track data. This past winter he freshened up his combo and dyno'd it with the gas carb, alcohol carb and toilet all on the same day. I forget the actual numbers but the gas and alcohol carb where within 10-15hp of each other and the toilet made just a little more, but he said the torque curve was better with the toilet. Each combo will like things differently but if the carb either gas or alcohol are tune properly they will preform just about the same IMO. I think he turns that combo to like 6500-6800ish its a 434.

we have a small block mule engine I teach the students how to tune stuff on the dyno. We have a decent carb and single plane intake on gas, a flying toilet on E-85, and a port electronic fuel set injection set up. The engine makes 15 HP more on the E-85 set up on gas, and 5 HP more on the EFI set up on gas, compared to a Holley and single plane manifold. That's benn tuning on it for several years. Back in the day I did not like alcohol carbs and injectors for bracket racing because of sliming the oil, cylinder wear, and having to drain the system to prevent moisture contamination. Today the newer alcohol carbs and injectors are much better and the cylinder wear is improved, and they do not slime the oil nearly as bad. Most hard core bracket guys I talk to love the consistency of alcohol as a fuel. But since I race NSS, I have to stick to gas as a fuel.

Real world experience is sometimes Alky carbs can't move enough fuel so loss of power but with injection Alky wins hands down!

Why are people with no restrictions running M5, because it makes more power than any gas, Q-16 ect...

Your 11.0:1 bracket engine will not see a huge difference but an all out effort will.

I love running alcohol in my bracket car because I’m lazy and it’s more consistent. I put a trap door in my fiberglass trunk lid and the only thing I do on a race day is add alcohol every round. Head guru Darrin Morgan told our class that hands down race fuel is faster and more efficient. I would never build a weekly bracket car that needs Q16 or some other high dollar fuel. To me that doesn’t make sense.

Certainly I'd consider alcohol for a bracket car and most things blown.

Can you elaborate on why Darin thought was faster? I know it's more efficient.

This was only a two day (16 hour) theory class on head porting full of formulas and tips so no he really didn't go into the subject. I know he had a deep dislike for it and he didn't try hiding it. Lol. I would sure like to have him baby sit me while I ported one intake runner. Out of that 16 hours we spent 15-20 minutes on the exhaust side discussion and everything he taught me has paid dividends.

I've read some of his exhaust side theory on speed talk so I have a general idea of what he thinks!!! And it's not what many people think.

I thought about doing one of those seminars but I never had the time. Haven't been to a PRI show since 2002 or so. I don't think Morgan is even doing those seminars anymore is he?

Think about double the amount of fuel suspended in the intake charge. The weight and density as compared to gasoline. Also think about the energy in any given fuel.

Gasoline is more power, just an issue of efficiency. Bracket motors, and forced induction work better on alky for reasons unrelated to efficiency.

Think about a basic bracket motor going from gas to alky. Double the fuel volume in the chamber and you've increased compression. Lower the temperature as well, and presto.

Thinking about E85. I was looking a 5 gallon junks. Either Jaz or VP. It stated race gas not pump gas. Guess its the alcohol. Need to get new plastic jugs and move to metal pails?

Thank you!

I recently sold a complete W 9 top end to a well-known . Truck puller under his rules he could make more power with oxygenated gasoline then alcohol most of the guys in the class were converting back to gas I do not know what the Pacific rules were

I made 863 hp on pump E85 and would turn the motor to 8800 in the car.. small block of course. seem to be hard on bearings in my opinion..

Bearing wear being different on e85 would only be from 2 things. Detonation/tune, or oil dilution from tune as well.

On my 12:1, solid cam 408 I made 50hp and about the same more in tourque with Alky over 110 fuel.

Gains depends on the Induction and combustion efficiency of the engine, and how well the converter and gear are matched to go with it. I just had a customer switch from a 650 on gas to a 650 on methanol and pick up 1/2 a second in the 1/8 mile. My SB2 head engine in my dragster would slow down with anything other than gas (no nitro in this conversation...;-) ) So it's really subjective to the combination.

I suppose the best way to illustrate the situation with alcohol is an example.


Take any NA engine in the world, injected, or carbureted. Give unlimited resources to modify for maximum performance, and in no case will alcohol, out perform gasoline.

The reduced energy in alcohol, as compared to gas will always prevent it from reaching the efficiency of gasoline.

There is an example of gas exchange in the lungs that is appropriate for this as well.

Think of the available space in the induction tract as seats on a bus. When the bus pulls up to the stop, and people get on, in this case fuel atoms, only so many can climb aboard. The bus is going to a job site, where the strength of the people filling the seats is critical to the amount of work that can be done. People twice as powerful do twice the work, when you can only haul so many at a time to the job site.

I help a friend w/ his Camaro. 436" sbc, 14.5:1 compression, AFR heads, glide, 9", ladder bars, etc. Makes somewhere around 700 hp.
Ran on alcohol (4150 Demon 825 cfm carb) and ran a best of 5.78 in the 1/8 mile w/ a 1.24 sixty foot at 2900 lbs. Ran this configuration for years.

Switched it to race gas a few years ago (112) and went to a 1050 Dominator...same manifold (Edelbrock Victor 4150) w/ the tall 4500 adapter. Now it's 100 lbs heavier at 3000 lbs and it went a best of 5.93 w/ a 1.27 sixty foot. It lost a noticeable amount of lowend torque and obviously some HP, but never dyno'd either setup.
Knew it would slow down some, but was hoping the Dominator would help not to slow down too much. It has more in it (still needs more tuning), been a long time since the car was run, but it won't run what it did on the alcohol.

My personnel opinion on straight methanol, not race methanol like M1 or M5, is it will as fast or faster by a tiny bit on straight methanol compare to non oxygeneated race gas
I switch to pump E 85 several years back and love it, deadly consistent and half as much cost per gallon as the local race gas and the motor runs cooler No issues with oil dilution either

cab, don't you burn about twice as much alky as you would gas ? wouldn't that make alky about the same cost as gas ?

E85 is suppose to burn 30% more, I think straight industrial methanol may be close to 80 to 90% more than race gas but it is a bunch cheaper per gallon and runs a lot cooler, it also burns a lot slower in the cylinders so it pushes down on the pistons quite a bit longer also
The one bad side of straight methanol that I'm aware of is the oil dilution due to methanol sucking moisture out of the air and having it condense inside the cylinders also as well as in the oil

There are some inaccuracies posted so far.
Methanol burns slightly faster than gas. I run 34 degrees timing on alky, a lot of 440-1 motors on gas run more.
Methanol has more energy than gas based on a stoiciometric mixture, because it runs at least 2.2 times the volume of fuel per cfm of air than gas.
The fact that some claim gas makes more power may well be that only very high rpms allow this? The statement flys in the face of thousands of racers seeing reduced ETs going to methanol.
Methanol lowers charge temp considerably, increasing the amount of air (measured as mass) inhaled

The reasons some motors make more power on alky are mostly based in the inefficiencies inherent in the type of motor. No one is arguing that almost all bracket type engines will behave better on alky for bracket racing.

The decrease in timing requirement in a few motors isn't related to the fuel being better, but the increase in chamber efficiency brought about by twice the volume of liquid in the chamber, and how that effects compression. Also the reduction in temperature.

The effort required to deliver twice the volume of fuel, and the space that it consumes in doing so will always handicap the process in high efficiency engines. A normal 1.8hp per inch bracket motor would almost always be helped by alcohol. A 3hp per inch gas motor would be crippled by alky.

It really just comes down to the energy density of fuel.


Fuel Density
kg/m3kg/m^{3}kg/m​3​​ Specific Energy
MJ/kgMJ/kgMJ/kg Energy Density
MJ/m3MJ/m^{3}MJ/m​3​​
Gasoline 716 -47.3 -33,867
Kerosene 830 -46.2 -38,346
Diesel Fuel 830 -44.8 -37,184
Ethanol 784 -29.7 -23,278
Coal (Anthracite) 1350 -27 -36,450
Methanol 787 -22.7 -17,855
Wood 600 -15 -9,000
Coal (Lignite) 801 -15 -12,015

We made 18 hp more with q16 over pump e85..back to back .the e85 carb was a little bigger

How much was the Q16 a gallon?

. $20 a gallon.. vs E85 at $3.. personally I loved E85 just couldn't make it happy where we were at even experimented with race blend E85 at $20 a gallon
. I will tell you my valve spring bill offset the cost in the fuel for sure.. we like to leave the starting line absolutely as cold as possible on cue and used to like to leave the starting line at 180 degrees on the E . Which was definitely hard on the valve springs and valve job

$20 a gallon.. vs E85 at $3.. personally I loved E85 just couldn't make it happy where we were at even experimented with race blend E85 at $20 a gallon

were there a HP difference with the race blend e-85?

were there a HP difference with the race blend e-85? [/quote] . Unfortunately only tested in the car never on the dyno and personally didn't see much to gain with our application

. Unfortunately only tested in the car never on the dyno and personally didn't see much to gain with our application [/quote]

That "goofy" e-85 you had made Q16 smell good. It should have come with a Hazmat suit

. Unfortunately only tested in the car never on the dyno and personally didn't see much to gain with our application [/quote]

Thaxs……. I kind of wonder if there were an real world advantage of using the race blend verse mixing your own.

VP C85 makes more power than pump by a couple percent. Due mostly to MTBE, and some other unsavory chemicals. One of which I think is one of the propane family.

Smells terrible, but works better on higher compression ratios. Stays consistent, and has the best corrosion inhibitor I've ever used in an alcohol fuel.