Carb opinions 540's 700 hp...
 

I am doing 540's afr 325 cc heads bob m cams nearly every person said to see 700 hp I need Dominators and that is my plan but what might be easier option if height is issue? I cannot go higher then my 4150's are now...

Just wanted to see combos and if using Dominators what kinda jetting to start with ...

650hp+ is Dominator territory.

Should've went with oval ports and quadra jets for the torque you need.... Just figured I'd get that outta the way lol last build I did like that was 80p 84s with p/v's front and rear. 548 with 1050 dominator 640hp. Honestly a 1050 out of the box is prob going to be real close

Call Dale at CFM tim. He's less than 1/2 hour from your house.
4500 carb is going to be taller than the 4150.

4150 Hp 1000 pro systems carb.

Kubic?

Yes, but with a "C"

Thought so....

For 700hp a 4150 is plenty.

define plenty, almost every person has told me more power with dominators.... I look at it this way too, if I must BUY new ones, would it not be smart to buy carbs that will also support future?

I only have HP500 800's now, that wont be nearly enough..

This Holley Dominator is almost unbelievely out of the box. It is also available with less CFM. We have been screwing around with our old school Dominators for 15+ years including having them reworked by no less than 3 difference carb shops.....still sucked. Our boat would never consistently idle in gear and the spread in RPM in and out of gear caused you to constantly jack with the sticks....the dock manners sucked. Even with two people running the boat, it stalled and was difficult to restart when hot. Whenever we could, we just started the boat in gear. The Ultra Dominators will idle at 450-550 RPM in gear vs 800 RPM in gear with the old style Dominators. This has been the best change to the dock manners of our boat in 10+ years. You can run the Ultra Dominators as delivered with no change in jets or PV's and the AFR is spot on in the midrange and WOT.
How does it know? :D


https://www.holley.com/products/fuel...arts/0-80905RD

how can this be possible with so many differant equations n combos out there .. im interested cause my motors deffinately are a handfull around the docks .. i was just going to lock out my timing and be done with it .. im at 750 but certainly dont want to burn something down just slapping on a base line ajusted carb .. just asking cause you seem very impressed with theese carbs .. i have biggs performance carbs on there now that perform quite well .. that were far north of theese priced carbs ..

I've been amazed to see some numbers even those have pulled on 540's.

also i have a nice brand new pair of donminators that came on my pfaffs id sell for decent price if anyone is looking . i upgrated to my biggs stage seven carbs a month after i got my engines in .. jesse said he had the best cabs in the buisness .. so wtf i bought some .. theese been sitting drained on my shelf since ..

Exactly...maybe Holley just wanted to take the carb gurus out of the business.

4150 1000 prosystem

There's two carbs I would go with. Quick fuel dominators or holleys new ultras. I have zero interest in the aftermarket "custom " carbs that are supposed to be "spot on" for the application. May work in drag racing OK, but from my experience it doesn't work as well for boats. Having a wideband hooked up gives you a much better idea of what's really going on, and tuning them in the boat live is great.

Modern carbs have come along way.

Hey rob. You might want to consider a Daytona sensors type of ignition that allows a custom timing map for more timing at idle, rather than locking it out.

these here?

http://www.google.com/aclk?sa=l&ai=C...Fseid%3Dsrese1

4150 upto 850hp no problem. If it's under 800hp I wouldn't even bother with a Dominator run a 4150. I sold an OSO friend my old Baker Outlaw Carb (4150) for his 540. Dyno'd @ 750hp 6300rpm. sister engine with a Dominator made the same power. some of the World of Outlaw guys are making 900 on a finely tuned 4150.

I would call Steve @Baker Outlaw Fuel Systems. and tell him what you have as far as carbs now. He has a CNC and does work to the main bodies.

Thats an E-85 carb. But, they do make a 4150 gas 1050 carb thats very nice.

I've worked on some "custom" carbs built for the customers applications. What I've found with those kind of carbs, is while they ran 'ok' , once the wideband was hooked up, it was easy to see how far out in left field they actually were. Air fuel ratios dipping into the 10's at 75% throttle, cruise speeds so lean the pistons are starting to glow, etc. So, now its time to tune them right in the boat. Oh, wait, look here, they drilled the PCVRs out to .097, so when the power valve opens, its like a flood of fuel being shot into the engine. So you tune your primary jet for a nice efficient cruise. Then, at PV opening, the AFR shoots pig rich. Ok, well, without drilling and tapping the orifices to install a smaller pcvr jet, its easier to shrink down secondary jet, to get an acceptable WOT AFR. Looks great on the wideband, but problem now is, you have a chit ton of fuel coming from the primary circuit, and not much from the secondary circuit. Oh, now the rear cylinders are lean, and fronts are pig rich.

Tune the idle circuit time? Sweet, its got screw in air bleeds right? Oh wait, look here, they drilled out the idle feed restrictors. PFFT. Now, your getting a ton of fuel at idle. No biggie, just turn the mixture screws in to lean it out a bit right? DOH, now you do that, and the engine falls on its face when you shift it into gear because its starving for air too, since you cut that off by turning the mixture screws in. Ok, well, let me open the throttle plates up more. Oh, now it idles at 1200RPM in nuetral so it doesnt stall out.

With a billet metering block like a QFT, all that stuff is easily changeable, and you can easily tailor the carb to the engine, not just at wide open throttle, but from idle to wot.

Just because a "custom" carb builder fouled up a carb doesn't mean there is no virtue in having an application specific carb done properly.

Also, while the base offerings have come along way, that doesn't mean you can just toss on a "shelf" carb and everything is going to fall right in line.

Tuning whatever carb you end up with to your application is a reality you won't circumvent.
Id rather have a relationship with a local carburetor expert than be calling a summit racing tech line or asking online when you need help.

I wouldn't paint all boutique carburetor builders with the same brush either. Some guys build more than just WOT bracket racing stuff.

I've tuned many carbs in boats both NA and blown with and without widebands. Dean nickerson was supposed to be the guy for custom marine carbs. On the water with a wideband. Waaay off....on several occasions.

There are entirely too many variables for a guy to set a carb up to have an efi like fuel curve , on a bench. Every single boat is different. Nothing worse then spending a bunch of money for "custom" carbs, and having to go retune them anyway. Most of these guys would have been better with an off the shelf carb that allows fine tuning

I don't know dale at cfm. Have you tuned any of his carbs on the water using a wideband ?

Not yet.
He set it up with a base setup from the info I provided.
It will be furthur tuned on the dyno and then final tuned in the water with a wide band. (Having O2 bungs welded in the exhaust for a permanent A/F gauge)
This is the second carb I've had done there. the first was little 600 for my small block 306 I had in a little puddle jumper and I didn't have a wide band on the boat nor did I dyno the engine. That said, it was pretty close and only required some fine tuning once in the boat.

I'm not expecting to put the carb on and not have to fine tune it on the water, but I wouldn't expect to be able to just bolt on any carb and be done.

All I was really trying to say is that for a guy like me that knows enough to be dangerous, it's nice to have a relationship with a well respected, local to me, guy that I can dial up and speak to whenever I have a question. Let's face it, and to your point of seeing so many fouled up carbs by "experts", most of us know enough to be dangerous. Any carb in the wrong hands can be goofed up no matter if it starts as a shelf carb or a custom setup.

My advice would be to learn every thing you can about how to tune a Holley and do it your self. Trust me I have traveled down this road ! I have a custom carb from a well known carb guy the last time I sent it back to get FIXED it came back with a new set of $400.00 gaskets!

Joe, you make an excellent EFI salesman!

I know Dale is a go to guy for cars not sure about boats, none of my past engines needed crazy tuning or a big carb, my 600's ran sweet with hp500 carbs with doing wot runs **** off then pull plugs... But in this case I wanna make sure I don't starve engines for air or fuel, I can run my 800's to get by if needed I built engines around using dominator or equivalent ... I don't wanna spend lots of money and be close to max, rather have room for later ...

Guys say 900 is enough, others say 1050+ very respected people told me Dominators.... It's not really the carb being issue I wanna know if I am keeping my intakes or not...

Also, there really is no "jetting " baseline for a dominator that is unknown and not purchased yet.

Let's say you buy a pair of stock Holley's used. I'd look up the list numbers in the master catalog and put the carb to stock, and go from there. If its a modified holley, that's been drilled like a cheerleader on prom night, good luck with that trying to get a baseline for it!

If you have the room run a dominator. You also can get a 1050 in a 4150.

How about dynoing with your 800, and again with a dominator. Takes 5 minutes to swap carbs. See if its worth it to you or not. I'm sure someone has a carb u can borrow for the dyno

I look at it this way. You built new 540s to replace the old 548's that made 600hp. You spent a lot on new cylinder heads, paid extra for the CNC chamber porting, a custom cam for the engine , all in an effort to improve airflow. Why stop at the carb? If the heads (just throwing numbers out there ) are worth 25hp over the old heads, and the custom cams worth 25 HP over the old cams, what if your carbs are gonna cost you to lose 25hp? When you add it all up the carb upgrade would have been the cheapest power upgrade out of the package. Now if its 10hp then maybe not worth it.

On a 6000rpm 540 with AFR heads and a custom cam, making say around 700hp, you just may see a nice jump in power by bolting on a dominator. 600hp 540, prob not. Have guys made great power with 4150s, of course. Only way to know is to test. If your on the dyno and get your carb tuned at say 12.5 Afr at 6000, and swap it out for a dominator, you'll have to tune the dominator for a 12.5 Afr at 6000 as well for a direct comparison. I've seen where guys did this test, had the 4150 tuned perfect, then slapped a dusty old dominator on with a pig rich setup, see no gains or even losses, and say the dominator sucked. Not a fair comparison.

The phone call is free tim. Ask him about boat carbs. He's a super easy to talk with guy.
You'll learn more about carburetors in 1/2 hours than you can imagine.

I would say you can only recommend him based on reputation at this point without any empirical evidence.

The Quick fuels are really nice units, still confused how they had perfect AFR`s on the dyno for a 1200hp motor and a 1000hp motor out of the box with no changes.
Tim, I`d say you`d be perfectly fine with a QF 1050
Thy`re real preeeeety too

http://33outlaw.zenfolio.com/img/s7/...85452969-3.jpg

So to me the Dominators are better choice overall for ease of approaching my goal...

thats what I would do.my bet,the dom will win.

at the RPM you are going to run max and that power 4150 will be fine..contact patrick @ prosystems

No I agree Joe I was just getting more opinions, I will be going dominator because every person said it's gonna be better overall cost and tuning, my biggest concern was height but I think you said only like 1/2" taller? I can make that work I think ....I do not plan on running my 800's unless I run out of
Money and wanna get boat going because I can swap I takes and carbs mid summer easily... I know the 800's are way to small...

I just wanted to see more opinions that's all with proven combos if possible

What manifold are you looking at?

Rehr Morrison makes a 4500 to 4150 flange adapter so don't worry too much about that.