carb size calculator?

[H20MOFO]

I don't know 427 bbc 5300 r's what size would you do? BTW single tr. My 800 DP seems to run pretty good. Am I leavin some top end on the table? I'm runnin at altitude if that matters. Thanks Kreg

[YeLLowBoaT]

(cid * Rpm)/ 2(1728) * Ve= CFM needed...
if you were to have 100% VE you would need 654.83 cfm... so a 650 would be a great choice... 700 would also be a great choice.

[H20MOFO]

What if I want more than 5300:D So I'm over carbed for a 500 hp motor?

[Sleeper CP]

(cid * Rpm)/ 2(1728) * Ve= CFM needed...
if you were to have 100% VE you would need 654.83 cfm... so a 650 would be a great choice... 700 would also be a great choice.
Remember, those #'s represent the minimum required to produce a max`potential power. A 427 BBlk at 5,500 range will probably make more power with a 750 or 800 vs a 650.
I've tested a 351 Cleveland that the calc. said needed 715 CFM we ran a 750 and a 850, it made more with the 850 at 6,500.
Edit: 427x6000/3456=741cfm 741x1.1(ve@ 110%) = 815 I'm not sure how your altitude effects the calc's, what is it?
Just my .02
Sleeper CP

[YeLLowBoaT]

its just a guide line on how much air the motor needs in a static state and any givin RPM... just becuase it says the carb flows X RPM, does not mean thats what it will flow on top of your manfold. if you have the exact air/fuel ratio between 2 carbs, one able to deliver exactly what the motor needs and one that can deliver more thier will be no power change.

[SmokinLowriderSS]

I don't know 427 bbc 5300 r's what size would you do? BTW single tr. My 800 DP seems to run pretty good. Am I leavin some top end on the table? I'm runnin at altitude if that matters. Thanks Kreg
IF you are giving up anything, I highly doubt it is more than 10 or 15 HP. How much is 10 or 15 HP worth to you? Another $600 carb?
What do you LOOSE from the middle and driveablility by going even bigger?
I'm spinning 5,400 under Nitrous on a 454 under a 700CFM holley, and below WFO, it ALSO runs faultlessly.

[Oldsquirt]

Smokin, have you EVER tried a different size carb?

[cfm]

An 800cfm carb (airflow wise) should be fine on your motor.
I like to use 110%-130% on single planes and around 130-150% on dual planes. The larger % for engines with great heads/ good compression / modern cams / good modern intake.
Tunnel ram with 1 carb ? I know some people run it but why not two ?

[SmokinLowriderSS]

Smokin, have you EVER tried a different size carb?
No, for the following reasons.
The boat has run absolutely perfectly, 29 years. Perfect idle to on-the-carpet throttle response. Decent starting when cold, 1-bump-no-throttle starting when warm. Idle of 800 RPM.
Max engine RPM has never been over 4,900RPM alone, stock motor and no loader.
The max RPM has never been over 5,200RPM on Nitrous, untill this past summer.
Max RPM last summer was 5,000RPM alone.
This past summer, 5,400 was the max on Nitrous.
My RPM has slowly climbed as my HP has gone from maybe arround 290 dry to 500 on Nitrous. As it has, I have been thoughtful of carb needs.
IMO, the carb has never been really fully pulled on, untill this past summer, with the nitrous fogging in under it.
This coming summer, things have changed, rather dramatically.
The factory '049 heads are being ported right now, manifold matched, larger valves, re-guide to 11/32". The shop doing it has done so many of these heads that they believe 100HP is a fair figure. Primary concentration is in making the torque curve as strong, wide, and long as absolutely possible. They have a lot of history in marine and jet boat head work as well as racing hardware.
That MAY put me up close to 6-grand on the Nitrous at the top, I now NEED more carb IMO, planning on a Holley List 9381.
IMO, I don't need to go over 850 CFM, unless I just want to burn more fuel, and gain next to nothing.

[IMPATIENT 1]

http://***boat.com/forums/attachment.php?attachmentid=42374&stc=1&d=1194097136
get ya 1 of these and be done, i bought 1:D very nice work for alot less than most other carb shops;) my flow sheet showed 1182cfm wetflow:D

[Sleeper CP]

I'm runnin at altitude if that matters. Thanks Kreg
As they say " how high is up" ? What is it?
Sleeper CP
Big Inch Ford Lover

[H20MOFO]

Hey cp . I boat /live at 4500 ft. The mt. lakes around me are obviously higher. I'm thinkin of ditchin my TR how would that change #'s if any?( thinkin a brodix with a turtle?)

[Liberator TJ1984]

http://***boat.com/forums/attachment.php?attachmentid=42374&stc=1&d=1194097136
get ya 1 of these and be done, i bought 1:D very nice work for alot less than most other carb shops;) my flow sheet showed 1182cfm wetflow:D
I'm running 2 :D stock bore 454 :eek: :D

[IMPATIENT 1]

I'm running 2 :D stock bore 454 :eek: :D
damn it man!!:eek: you must be pulling big rpms, i'm just shooting to run 7k:D

[Liberator TJ1984]

Nope , running them on top of a 8/71....old school drag racer friend of mine told me You Cannot overcarb a blower motor , just have to tune correctly ! you want the biggest carbs you can get your hands on . He explained you want as little restriction as possible coming into the blower ,
so it works easier and stays cooler . just think about a FI Hat , they can flow over 3000cfm easily . it's metering the fuel is where its at .

[1968Droptop]

FWIW Kreg, a buddy is a running a 521 Ford w/ 2 Dominator's flowing 1120cfm each, and the engine LOVES it. Jet's seem to like to be overcarbed.

[H20MOFO]

Is a 4500 series carb overkill for what I have? If i'm going to buy a new intake I'd like to get it right the first time. How much is that allstate carb you guys are runnin? I'd like something(carb wise) that if in a year or two if I go blower I wont have to replace again. :confused:

[Sleeper CP]

Is a 4500 series carb overkill for what I have? If i'm going to buy a new intake I'd like to get it right the first time. How much is that allstate carb you guys are runnin? I'd like something(carb wise) that if in a year or two if I go blower I wont have to replace again. :confused:
IMO yes, but you can get away with too large of a carb by going with annular dischage boosters like a Holley 1050 part # 9375.
Just my .02
Sleeper CP
Big Inch Ford Lover

[IMPATIENT 1]

Is a 4500 series carb overkill for what I have? If i'm going to buy a new intake I'd like to get it right the first time. How much is that allstate carb you guys are runnin? I'd like something(carb wise) that if in a year or two if I go blower I wont have to replace again. :confused:
i agree with cp, get the 1 he suggested if you buy 1.
think i paid around 800 for shipping and everything for the 1 i posted the pic of. its a 1050 they build in house and build/flowbench to match your cam profile/motor set-up. i'm sure its not dialed in perfect, but they get em close enough. my specs call for a 1000cfm carb on my na motor, i wanted alittle bigger,

[H20MOFO]

Thanks guys.

[Liberator TJ1984]

Is a 4500 series carb overkill for what I have? If i'm going to buy a new intake I'd like to get it right the first time. How much is that allstate carb you guys are runnin? I'd like something(carb wise) that if in a year or two if I go blower I wont have to replace again. :confused:
If you are to go to a blower ? personally I would not go less than a 8/71 , that being said is they all cost pretty much the same from a 177 to the 8/71 , just have to shop around a little . anything 6/71 and up you are going to need >2Carbs< so if you just get 1 now make sure you can get another matching carb when you do go Blown

[cfm]

I maybe retarded but am I understanding that we are telling him to get a Dominator when all we know is that he has a 427cid that only turns 5300rpm ?
Did I miss a build up and other info somewhere else ?

[IMPATIENT 1]

I maybe retarded but am I understanding that we are telling him to get a Dominator when all we know is that he has a 427cid that only turns 5300rpm ?
Did I miss a build up and other info somewhere else ?
lol, yeah i was messin with him at 1st then everyone else joined in so i stuck it out :D :D :D :D
850 would do all that's needed plus it'd be easier to find another when it came time for the blower

[H20MOFO]

You guys are welcome to mess with me all you want, just please leave my wallet out of it:eek:

[Sleeper CP]

I maybe retarded but am I understanding that we are telling him to get a Dominator when all we know is that he has a 427cid that only turns 5300rpm ?
Did I miss a build up and other info somewhere else ?
In short,:) Yes, please see highlights below.
Is a 4500 series carb overkill for what I have? If i'm going to buy a new intake I'd like to get it right the first time. How much is that allstate carb you guys are runnin? I'd like something(carb wise) that if in a year or two if I go blower I wont have to replace again. :confused:
IMO yes, but you can get away with too large of a carb by going with annular dischage boosters like a Holley 1050 part # 9375.
Just my .02
Sleeper CP
Big Inch Ford Lover
It wouldn't be my first choice, but he can get away with a 9375 annular booster carb. And he could buy a matching carb in a couple of years and not have to start from scratch. As someone else said "blower engine's like big carb's".
And some people just like the way Dominators look. At his altiitude of 4,500' + how will that effect what he needs:confused:
Just trying to help:(
Sleeper CP
Big Inch Ford Lover

[cfm]

My vote is if he's itching to do something, grab a vic jr or RPM air gap and keep the present carb. Save $$$ for blower and required carbs. If it is this same engine that blower will go on, chances are that it won't be happy with two dom's anyway.
Then again, I don't know what this 427 is made of. Just know it is only being rev'd to 5300rpm.
So.........why am I making recommendations on something i don't know anything about other than cids and present rpm ? I answered it before. I'm retarded. LOL.

[H20MOFO]

Thanks again to most:D After lookin at cp's tunnell vs thread it made me want to kick my single tr to the curb, besides the fact "on mine" I have to jet 5 cyl to rich to get the other ones close. I guess if I switch manifolds b-4 I go blower i'll get a 4150 style intake.

[Sleeper CP]

Thanks again to most:D After lookin at cp's tunnell vs thread it made me want to kick my single tr to the curb, besides the fact "on mine" I have to jet 5 cyl to rich to get the other ones close. I guess if I switch manifolds b-4 I go blower i'll get a 4150 style intake.
That's why I posted it. Just to shed a little light on the subject for those that had very little idea. Hopefully it will give some people more info than they had before.
As I stated the dominator wouldn't be my first choice but if you went that way you would just be one more over carb'd jet boat. ;)
Sleeper CP
Big Inch Ford Lover

[Liberator TJ1984]

You guys are welcome to mess with me all you want, just please leave my wallet out of it:eek:
Sorry my Friend , this is not possible no matter how hard we try :D