If going to Methanol, do I need to raise the CFM as well?
Moderator: Team
-
- Member
- Posts: 58
- Joined: Fri Jul 02, 2021 11:03 am
- Location: West Mansfield, OH
If going to Methanol, do I need to raise the CFM as well?
Hello Gang, I have another dumb question for y'all...
Building the 433 BBC, all info says I should use a carb in the 800-850 cfm range. If I decide to go
to Methanol or E85, and the fuel now needs to be doubled (or there about), do I then also need
to raise the CFM rating of the carb?
Thanks,
Patrick
Building the 433 BBC, all info says I should use a carb in the 800-850 cfm range. If I decide to go
to Methanol or E85, and the fuel now needs to be doubled (or there about), do I then also need
to raise the CFM rating of the carb?
Thanks,
Patrick
-
- Guru
- Posts: 4607
- Joined: Sun Sep 18, 2011 11:31 am
- Location: Heading for a bang up with Andromeda as we all are.
Re: If going to Methanol, do I need to raise the CFM as well?
No.
You could use bigger intake ports because since your now going to have twice as much fuel vapor taking up room that was air when running gas.
You could well use more lift also.
You could use bigger intake ports because since your now going to have twice as much fuel vapor taking up room that was air when running gas.
You could well use more lift also.
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
Re: If going to Methanol, do I need to raise the CFM as well?
In theory, i would think you could get away with a smaller carb on alcohol fuels.
Re: If going to Methanol, do I need to raise the CFM as well?
No need to go bigger on carb, or ports.
When you switch to Methanol, it will lower the temp of the intake charge thru the carb, manifold and ports. The cooler charge will increase the air density, which more then makes up for the area lost to the added fuel.
When you switch to Methanol, it will lower the temp of the intake charge thru the carb, manifold and ports. The cooler charge will increase the air density, which more then makes up for the area lost to the added fuel.
Mike Jones
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
Jones Cam Designs
Denver, NC
jonescams@bellsouth.net
http://www.jonescams.com
Jones Cam Designs' HotPass Vendors Forum: viewforum.php?f=44
(704)489-2449
-
- Member
- Posts: 58
- Joined: Fri Jul 02, 2021 11:03 am
- Location: West Mansfield, OH
Re: If going to Methanol, do I need to raise the CFM as well?
OK, thanks for the reply's, I appreciate it!
Patrick
Patrick
-
- Guru
- Posts: 6389
- Joined: Tue Jul 24, 2012 11:15 am
- Location: Roseville, Michigan (just north of Detroit)
- Contact:
Re: If going to Methanol, do I need to raise the CFM as well?
NO ... but, if you already are using a very large carb with gasoline, you may need to go to a smaller air flow rated carb because that large carb may not be able to flow enough fuel for its airflow rating, when using alcohol; even after being modified for alcohol.patrickonb wrote: ↑Wed Aug 10, 2022 1:58 pm Hello Gang, I have another dumb question for y'all...
Building the 433 BBC, all info says I should use a carb in the 800-850 cfm range. If I decide to go
to Methanol or E85, and the fuel now needs to be doubled (or there about), do I then also need
to raise the CFM rating of the carb?
Thanks,
Patrick
http://www.rmcompetition.com
Specialty engine building at its finest.
Specialty engine building at its finest.
-
- Member
- Posts: 58
- Joined: Fri Jul 02, 2021 11:03 am
- Location: West Mansfield, OH
Re: If going to Methanol, do I need to raise the CFM as well?
Ahh yes, this does make sense!! Thank you.Walter R. Malik wrote: ↑Wed Aug 10, 2022 9:29 pm NO ... but, if you already are using a very large carb with gasoline, you may need to go to a smaller air flow rated carb because that large carb may not be able to flow enough fuel for its airflow rating, when using alcohol; even after being modified for alcohol.
Re: If going to Methanol, do I need to raise the CFM as well?
433ci. 850cfm @ 20.4 inH20 would be a small carby if it's got good heads and a cam wouldn't it ?Walter R. Malik wrote: ↑Wed Aug 10, 2022 9:29 pmNO ... but, if you already are using a very large carb with gasoline, you may need to go to a smaller air flow rated carb because that large carb may not be able to flow enough fuel for its airflow rating, when using alcohol; even after being modified for alcohol.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
-
- Guru
- Posts: 6389
- Joined: Tue Jul 24, 2012 11:15 am
- Location: Roseville, Michigan (just north of Detroit)
- Contact:
Re: If going to Methanol, do I need to raise the CFM as well?
It is all about IF that carburetor is able to supply enough fuel for the amount of air it can flow.
http://www.rmcompetition.com
Specialty engine building at its finest.
Specialty engine building at its finest.
Re: If going to Methanol, do I need to raise the CFM as well?
What will the airflow be at launch, and also top end? You need a carb that will work at both ends. I would think an 850 to 950 cfm for a 750 hp build,,,,,,,
1965 dodge Dart, 549 cu in wedge, 8.60 at 156 mph best. 2905 lbs, soon, 8.40s!
-
- Expert
- Posts: 994
- Joined: Sun Mar 21, 2010 9:48 pm
- Location: Somewhere, Alaska
- Contact:
Re: If going to Methanol, do I need to raise the CFM as well?
Not mentioned but noteworthy:
alky is nearly 50% by volume, oxygen. That's why you need to run roughly twice as much as gasoline. Methanol carbs tend to be smaller than gas on the same application so they have a bit stronger signal to the boosters, which helps pull the fuel. Carbs and methanol work, work well, but in my somewhat limited opinion, the best setup to run methanol is mfi. Simple, easy to tune, and much less headache than a carb......
alky is nearly 50% by volume, oxygen. That's why you need to run roughly twice as much as gasoline. Methanol carbs tend to be smaller than gas on the same application so they have a bit stronger signal to the boosters, which helps pull the fuel. Carbs and methanol work, work well, but in my somewhat limited opinion, the best setup to run methanol is mfi. Simple, easy to tune, and much less headache than a carb......
Mark Goulette
Owner/Driver of the Livin' The Dream rear engine dragster
Speed kills but it's better than going slow!
http://www.livinthedreamracing.com
Authorized Amsoil Retailer
Owner/Driver of the Livin' The Dream rear engine dragster
Speed kills but it's better than going slow!
http://www.livinthedreamracing.com
Authorized Amsoil Retailer
-
- Guru
- Posts: 1608
- Joined: Sat Dec 24, 2011 10:02 am
- Location: melfort saskatchewan Canada
Re: If going to Methanol, do I need to raise the CFM as well?
What kind of MFI do you like ?Coloradoracer wrote: ↑Sat Aug 13, 2022 10:31 am Not mentioned but noteworthy:
alky is nearly 50% by volume, oxygen. That's why you need to run roughly twice as much as gasoline. Methanol carbs tend to be smaller than gas on the same application so they have a bit stronger signal to the boosters, which helps pull the fuel. Carbs and methanol work, work well, but in my somewhat limited opinion, the best setup to run methanol is mfi. Simple, easy to tune, and much less headache than a carb......
The Word of God is quick and powerfull
www.therocketshop.blogspot.com
www.therocketshop.blogspot.com
-
- Expert
- Posts: 994
- Joined: Sun Mar 21, 2010 9:48 pm
- Location: Somewhere, Alaska
- Contact:
Re: If going to Methanol, do I need to raise the CFM as well?
I run a Killerron's setup, and it's the best thing I ever did for my program. Enderle is also another huge one, and in wide use everywhere. Both work equally well.
Mark Goulette
Owner/Driver of the Livin' The Dream rear engine dragster
Speed kills but it's better than going slow!
http://www.livinthedreamracing.com
Authorized Amsoil Retailer
Owner/Driver of the Livin' The Dream rear engine dragster
Speed kills but it's better than going slow!
http://www.livinthedreamracing.com
Authorized Amsoil Retailer