|
Re: 1250 dominator too much for my motor?
[Re: sshemi]
#1930103
10/11/15 12:27 PM
10/11/15 12:27 PM
|
Joined: Dec 2014
Posts: 304 Florida
Mark Whitener
enthusiast
|
enthusiast
Joined: Dec 2014
Posts: 304
Florida
|
It's not about HP, it's about induction velocity in the RPM range it runs in. Some heads and intakes are better than others, they maintain a relatively even velocity throughout the port. The 358 would work with a GOOD 1250, one with boosters that atomize the fuel well. Using fuel that vaporizes well will also help, like Q16 or C25. Being in Sweden I would lean toward a 1050, cooler temps there will make it harder to vaporize fuels.
Mark Whitener [url=www.racingfuelsystems.com[/url]
|
|
|
Re: 1250 dominator too much for my motor?
[Re: 70RT Charger]
#1930153
10/11/15 01:44 PM
10/11/15 01:44 PM
|
Joined: Jan 2003
Posts: 31,078 Oregon
AndyF
I Win
|
I Win
Joined: Jan 2003
Posts: 31,078
Oregon
|
Quick rule of thumb is HP x 1.4 = CFM. So you need to be making about 900 hp before you need 1250 cfm. Just how true is this? If it is I see ALOT of guys running way to big of a carb. 530 HP builds with 950 carbs. By that math figure it should be running a 750. If you used a 750 instead would you still have 530 HP? The formula is just simple math. An engine burns fuel to make power and the fuel needs air to burn. It takes 1/2 lb of gas per hour to make 1 hp and it takes 12.5 lbs of air for each lb of gas. So with a little bit of math you can figure out how many cubic feet of air is required to produce one horsepower. The size of the carb is a slightly different question than how much air the engine needs. How much air is a math question. The carb size depends on a bunch of other things such as throttle response and ability to vaporize the fuel.
|
|
|
Re: 1250 dominator too much for my motor?
[Re: sshemi]
#1930272
10/11/15 05:02 PM
10/11/15 05:02 PM
|
Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
|
master
Joined: Sep 2014
Posts: 4,457
Washington
|
Yup .5 BSFC and I'd call it a pig with a capital P-I-G.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
|
|
|
Re: 1250 dominator too much for my motor?
[Re: sshemi]
#1931634
10/13/15 08:53 PM
10/13/15 08:53 PM
|
Joined: Jan 2003
Posts: 19,384 Las Vegas
Al_Alguire
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 19,384
Las Vegas
|
As I said before those 1250 Holley's just have to much throttle blade for MOST ON HERE.
We run a splayed valve SB Chebbie with a 2.35 throttle blade. So engine size means nothing to be brutally honest.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
|
|
|
Re: 1250 dominator too much for my motor?
[Re: madscientist]
#1932060
10/14/15 03:41 PM
10/14/15 03:41 PM
|
Joined: Nov 2004
Posts: 6,890 North Alabama
Monte_Smith
master
|
master
Joined: Nov 2004
Posts: 6,890
North Alabama
|
Yup .5 BSFC and I'd call it a pig with a capital P-I-G. While that IS true in most cases.........for most basic calculations a .5 brake is still a decent number to use. It gets you in the ball park
|
|
|
Re: 1250 dominator too much for my motor?
[Re: Monte_Smith]
#1932141
10/14/15 05:50 PM
10/14/15 05:50 PM
|
Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
|
master
Joined: Sep 2014
Posts: 4,457
Washington
|
Yup .5 BSFC and I'd call it a pig with a capital P-I-G. While that IS true in most cases.........for most basic calculations a .5 brake is still a decent number to use. It gets you in the ball park Your right Monte...if I was calculating fuel system requirements I would use .5 BSFC just to do the quick math. I was suggesting that on the dyno .5 BSFC would be junk and I still stand by that. I have had my stuff go under .42 most of the time and highly prepped stuff go under .40 and I am by no means cutting edge. I'm trying to find a dyno closer to me, but I will dyno my junk here in the next month or so and I will post it up. If the BSFC is near .5 I will stop and fix it. I can't for the life of me figure .5 being the "rule" for even bracket crap after about 1995 or so (maybe earlier).
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
|
|
|
|
|
|