Methanol Carburetor torque increase

[1972ho]

Does running a methanol carb. mostly increase low to mid range torque over a race gas carb. and if it does will it change the torque convertor flash stall and if it does change the flash stall will increase it or decrease the stall.I have just heard that the Alky carb.'s make more power but not top end power is this true.

[ProPower engines]

Tuned correctly its a win win in both areas.
Fuel systems especially carbs don't always have enough fuel volume delivery to make power all through the power band and unless the system is designed correctly issue are the result.

Any carb system I have used always needed a large return system to be sure the carb had all the fuel the engine would need.
Mostly for circle track engines of all sizes but its easy to get over fueled at lower engine speeds and run lean on top if the correct bypass system is not used. I have seen some guys just use a big pump and no return and would blow through tons of fuel and never get it right.
Some guys swear by electric pumps and others by mechanical or belt drive but they look at cost of the system over all and will tend to cheap out some where like a pump.
I would suggest that at a minimum of #10 or #12 line from tank to pump be used and a minimum of #8 or #10 to feed the carb/s with a pressure sensitive high speed bypass used along with a main bypass such as what if found on a fuel injection system
This way the fuel supply is increased as the demand is increased

[bigjoe1]

Dont hold your breath about any big increases with an alcohol carb.. I have never seen any big increase in HP, and very little increase in torque. I probably depends on what race gas you were running before, but race gas is very good nowadays.


JOE SHERMAN RACING

[1972ho]

Anyone that has changed from gas carb. to a Alky carb noticed if there stall rpm changed.

[user-z68766209]

Maybe 5% increase going to alk...

[woody b]

It depends on the converter, but you probably won't see a drastic enough increase to make a significant change in stall. However, it could lower the stall required by the engine. FWIW I've never ran gas.

[1972ho]

That is what I have seen just transbrake hitting it at home it is lower by about 400 rpm it was lower than that until I raised the timing about 4 degrees.And this is a carb that I have already ran with gas just converted to Alky.

[lada ok]

If you want max benefit from alky, .... you must build an engine specifically for it
Same as swapping petrol to LPG

[woody b]

Are you saying the stall is 400 rpm lower with alky? If so something is wrong with your alky set up.

[grant6395]

if your intake tract is sized properly for a gas setup,it will more than likely make less of both with a carb on methanol.theres so much liquid in the intake tract,airflow is reduced.injection is a different story....

[jmarkaudio]

It all depends on the combo, I've seen a car pick up over 2 tenths with E85 over gas, methanol can give the same results in some cases. How efficient the engine is at burning gas will determine gains, the more efficient the less alcohols will help. And torque is usually where you see improvement, if the engine has gear and converter stall to take advantage of best average HP the gains will be less.

What carb are you running, and what is the combo, engine, car, trans, converter, gear...

[900HP]

if your intake tract is sized properly for a gas setup,it will more than likely make less of both with a carb on methanol.theres so much liquid in the intake tract,airflow is reduced.injection is a different story....

Not necessarily true.

Not one person has mentioned the intercooling that alcohol can provide. I have seen intakes and throttle bodies ice up because they get so cold. A colder mixture is a denser mixture so even though there is more liquid in the intake tract, the air/fuel mixture is in a more dense form meaning it needs less area to move the same amount of mixture.

No one has mentioned how much easier it is to keep a methanol motor cool so you can down-size your cooling system. Cooling systems weigh a lot. Weight does not usually help performance. (of course you have to carry more fuel so in a long duration race the weight change % in the rear can burn you)

No one has mentioned how much more consistent methanol can be because the AFR is roughly 1/2 that of gasoline. If the D/A changes by 1000ft it affects the methanol motor 1/2 as much as the gas motor.

None of this comes without a price though. Methanol is a pain in the ass as far as maintenance and upkeep goes. I've never had C12 dry out all of the seals in a fuel system.

[grant6395]

if your intake tract is sized properly for a gas setup,it will more than likely make less of both with a carb on methanol.theres so much liquid in the intake tract,airflow is reduced.injection is a different story....

Not necessarily true.

Not one person has mentioned the intercooling that alcohol can provide. I have seen intakes and throttle bodies ice up because they get so cold. A colder mixture is a denser mixture so even though there is more liquid in the intake tract, the air/fuel mixture is in a more dense form meaning it needs less area to move the same amount of mixture.

No one has mentioned how much easier it is to keep a methanol motor cool so you can down-size your cooling system. Cooling systems weigh a lot. Weight does not usually help performance. (of course you have to carry more fuel so in a long duration race the weight change % in the rear can burn you)

No one has mentioned how much more consistent methanol can be because the AFR is roughly 1/2 that of gasoline. If the D/A changes by 1000ft it affects the methanol motor 1/2 as much as the gas motor.

None of this comes without a price though. Methanol is a pain in the ass as far as maintenance and upkeep goes. I've never had C12 dry out all of the seals in a fuel system.

well,great info for the people that know nothing about the fuel or its properties.my personal experience with it was in both cases,one a twin carbed 600bbc(methanol) and an 850ish hp sbf(methanol,both lost hp and torque with methanol carburetors.they were good ones that were properly tuned and sized.again,,different story if they were injected..just my experience...but maybe I don't know what im doing either.

[ProPower engines]

The biggest issue with carbs is they tend to be rich at lower RPMs and go fat or lean on the top end of the RPM scale because of the way they are set up with no extra bypass's in the system.
I have run alky carbs for more then 25 years and never seen an engine loose power or torque.
from what I have seem most people will use a system and be cheap about the total package and its installation.
1st timers to alky try to run a new system to them on the car and not a dyno to find out how the engine will react before trying to race it.
Now those that have run alky before have an advantage to doing so where a 1st timer does not.
The important part is the base line set up which means diddly squat from the carb seller because unless it was built around your total package there will be a steeper learning curve then an " off the shelf system" and any of the custom systems I have used still were not spot on out of the box and were over fueling the engine.

and the most over looked item in the carb if the float adjustment. Anyone that has run gas for ever then made the switch has to relearn about the correlation between the float level and fuel pressure being run. and stay away from brass floats.
I seen alot of carbs with brass floats give more trouble then any other part of the system and they do not like high fuel pressure as they will deform in the bowl and hang up causing a low speed rich and high speed lean and an over all loss in power.


while every carb builder has there own ideas on what will work even for a custom purpose built carb can give some problems but without the experience it is a long road to get them right.

Long story short the engine should rum smooth and crisp at all times just like a well tuned gas carb.
If its blubbery at low speed and rich on the top end and absolutely hard to get the engine warmed up you did something wrong and its too fat for the most part and will go through fuel like no tomorrow.

Had a customer a few years back that switched to alky for a circle track car. Got the complete system custom made for his engine but refused to run it on a dyno to start with in a more controlled setting and during the 1st practice he used 22 gallons of fuel in 30 laps on a 4/10 mile paved track and they followed directions of the builder of the fuel system and used a barrel of fuel before qualifying.

The issue was using a gas carb setting for the float.I reset it to the fuel pressure he was going to run and problem solved.

[pamotorman]

back in the day murray jensen built 3 circuit alky holley carbs which ran very clean on circle track engines