DragRaceResults.Com    Bracket Talk    Bracket Talk Forum  Hop To Forum Categories  Tech Talk - by Abruzzi    Gas vs Alky Jets
Go
New
Find
Notify
Tools
Reply
  
Gas vs Alky Jets
 Login/Join
 
DRR Pro
Picture of Wallace Cleaver
posted
Is there a formula or something that can tell you what jets will be in the ballpark if you switch from a gas carb to an alcohol carb of the same design and cfm? Say I ran 85 square, what would a starting point be for alcohol?


Multi-time First round runner up extraordinaire
 
Posts: 38 | Location: UT | Registered: January 01, 2015Reply With QuoteReport This Post
DRR Pro
Picture of chasracer
posted Hide Post
I remember reading some early conversion work on Holleys where the general practice was to drill a hole just above the jet in the regular gas metering block to .100-.125, then use gas jets to tune it in.

That would indicate that a starting point could be .185 for your application and of course it's going to be dependent on the size of the engine, compression, cam, etc, etc. On our small blocks (421-434s) we are in the area of 174-176, a BBC (555) is running 184-188s. All of them are in the range of 14:1 or higher.
 
Posts: 1135 | Location: The problem is not the problem. The problem is your attitude about the problem. Savvy?” ~~ Captain Jack Sparrow ~~ | Registered: August 21, 2000Reply With QuoteReport This Post
DRR Pro
Picture of jmarkaudio
posted Hide Post
85 square might be like a 950 Holley, 1.375 venturi and 1.75 throttle blade. 85 Holley jet has about a .095" hole. For methanol you may be in the .150 range with that carb. However there is more to it. All passages past the jet have to be sized larger as well. Mainwell, angle channel, and booster leg all add to the jets restriction until they are at least double the diameter.




Mark Whitener
RFD Heads
FTI Converter
Fab Shop Headers
Home built 2 circuit Dominator :-)
www.racingfuelsystems.com
____________

Good work isn't cheap and cheap work can't be good.
 
Posts: 1047 | Location: Florida | Registered: November 16, 2007Reply With QuoteReport This Post
DRR Top Comp
posted Hide Post
Wallace,

If you want to save yourself some headaches just box the carburetor up and send it to Mark. Problem solved.


Clowns to the left of me, Jokers to the right. Here I am.......
 
Posts: 5322 | Location: stuck in the middle with you! | Registered: March 11, 2002Reply With QuoteReport This Post
DRR Pro
Picture of Wallace Cleaver
posted Hide Post
I should have been more specific.

The car I just bought has a 377" with a 250 blower making 12 lbs. It has a carb shop 1050 dominator on gas.

I have purchased a Quick Fuel 1050 alcohol dominator.

I was just curious where to start jet wise on the alky one vs the gas one so I don't hurt the motor being lean. Boost + Lean = my retirement from racing


Multi-time First round runner up extraordinaire
 
Posts: 38 | Location: UT | Registered: January 01, 2015Reply With QuoteReport This Post
DRR Pro
Picture of Alaskaracer
posted Hide Post
quote:
Originally posted by Wallace Cleaver:
I should have been more specific.

The car I just bought has a 377" with a 250 blower making 12 lbs. It has a carb shop 1050 dominator on gas.

I have purchased a Quick Fuel 1050 alcohol dominator.

I was just curious where to start jet wise on the alky one vs the gas one so I don't hurt the motor being lean. Boost + Lean = my retirement from racing


Vern said it best, send it to Mark and let him set it up for you....You'll be either dead on or very close and will save a bunch of headaches tuning it...


Mark Goulette
Owner/Driver of the Livin' The Dream Racing dragster
www.livinthedreamracing.com
"Speed kills but it's better than going slow!"
Authorized Amsoil Retailer
 
Posts: 1504 | Location: Back home in Alaska! | Registered: February 13, 2011Reply With QuoteReport This Post
DRR Sportsman
Picture of FootbrakeJim
posted Hide Post
Speaking of Mark Whitener, (Jmarkaudio on here), anybody got a phone # or email address for him?
I have tried sending him a PM a few days ago, but I know that isn't always the most effective way to reach somebody...
Mark (or anyone who can provide me with contact info for him), a PM will be appreciated, or please email me at danm400@gmail.com

Thanks.


Dan "Jim" Moore
Much too young to feel this damn old!!
 
Posts: 1050 | Location: Farmersville, TX  | Registered: December 05, 2002Reply With QuoteReport This Post



DRR Trophy
posted Hide Post
I HAVE RAN A METH 1050 ON TOP OF 250 BLOWER 461BBC IT LIKED 190 JETS ID SAY START AT 180 GO FROM THERE ,YOU BETTER HAVE A GOOD PUMP I WENT WITH A BELT DRIVE BLP PUMP
 
Posts: 65 | Location: central indiana | Registered: May 16, 2016Reply With QuoteReport This Post
DRR Pro
Picture of Alaskaracer
posted Hide Post
quote:
Originally posted by FootbrakeJim:
Speaking of Mark Whitener, (Jmarkaudio on here), anybody got a phone # or email address for him?
I have tried sending him a PM a few days ago, but I know that isn't always the most effective way to reach somebody...
Mark (or anyone who can provide me with contact info for him), a PM will be appreciated, or please email me at danm400@gmail.com

Thanks.


Shoot me a pm. I'll give you his phone number. Just have to make sure he says it's ok. I know he's been busy lately.


Mark Goulette
Owner/Driver of the Livin' The Dream Racing dragster
www.livinthedreamracing.com
"Speed kills but it's better than going slow!"
Authorized Amsoil Retailer
 
Posts: 1504 | Location: Back home in Alaska! | Registered: February 13, 2011Reply With QuoteReport This Post
DRR Trophy
posted Hide Post
it would be safe to double the jet then start leaning it out for best performance, I believe its 1.88pct of gas
 
Posts: 26 | Location: washington iowa | Registered: May 16, 2011Reply With QuoteReport This Post
DRR Sportsman
Picture of sr4440
posted Hide Post
you could always do the math to figure it out.

1st find the area of the jet. https://www.wikihow.com/Calcul...the-Area-of-a-Circle

then muliply that number by 2.2.

now you know the area for your methanol jet, all you need is the diameter.
https://www.wikihow.com/Find-t...ircle-Using-Its-Area

now you have your answer.

Joe


Without data, you’re just another guy with an opinion.
 
Posts: 1301 | Location: TEXAS | Registered: February 07, 2003Reply With QuoteReport This Post
  Powered by Social Strata  
 

DragRaceResults.Com    Bracket Talk    Bracket Talk Forum  Hop To Forum Categories  Tech Talk - by Abruzzi    Gas vs Alky Jets

© DragRaceResults.com 2024