Best option is forced induction in a larger hull ;-) But we have already chatted about that!

Your builds going to be perfect for this summer. I would recommend giving Norm a call at least, maybe fill out his online form first. If you like chatting with him next step is decide how much power increase would make you buy a set? 20+hp a side is well worth the cost IMO. You can easily sell your carbs for good money, plus your reliability stays the same.

It definitely be worth the test to try each carb, especially if Norm is willing to do that free of charge. I'd be trying both carbs, see what happens, then make a decision. Its a no lose situation.

Which model dominator did you get Rob? Not all dominators are the same. Just booster design can have a huge impact in the carb's performance. An Annular high gain style booster, can make much better torque down low, and sometimes better top end HP, then a down leg.

Exactly, a no lose proposition, 1 of 3 results, modern dom beats it, they are same, 4150 beats it but by how much? Like i said though, my 548 ISNT the first motor in the 600 to 850 hp range that one of his 4150's has walked away from a dominator, we can theorize, guess, tell our opinions, talk about our favorite carb but in the end having a high end carb builder bring his carb to dyno then personally tune it, goes from a discussion to real world. I would love to see this happen!!

Looks like the valvetrain was starting to fuss around 5500 on the dyno. I'd have to see the airflow #'s to pretty much confirm this.

Does he have the Daytona Sensor's ignition box also ? I forget.

Yes. We played around with the idle timing quite a bit, and got it pretty much where it seems happiest.

For sure. That be an awesome test. As was yours . The more testing we do, the more we learn. For years and years, I kept hearing about how roots blowers make intake air temps of 200 plus degrees, and intercoolers on them make it soo much cooler , but nobody ever had any actual intake air temp readings to back it up when you asked them. Not even some of the blower companies or intercooler companies. Then we go and start putting intake air temp gauges in our intake manifolds, and find out that a 10-71 setup with no intercooler, isn't even barely at 140 degrees in the intake at 6000rpm in the boat. And that with a intercooler, the iat temps on the roots were as low or comparable to a intercooled centrifugal setup in some other boats.

Most of the stuff I've dealt with tinkering, has mainly been supercharged marine stuff. I have a question regarding the N/A stuff, and carb/intake relationship.

I see alot of guys here stick to 4150 intake setups. Its typical they add 2" of carb spacer to the manifold, and pick up power. How come nobody runs an intake like a Profiler, that pretty much has a built in spacer in it? Seems like most respond favorably to more plenum volume. Seems like when you get into the 540, 572, 598 ci , 6000rpm big blocks, especially ones with higher static compression, proper cam, good heads, good exhaust, all netting a good volumetric efficiency , the CFM requirement is up there, in the 1000-1100 range.

It be cool to see how a 572 like Rob's, does with a 1050 dominator, 1170cfm custom 4150 from Norm, then bolt on say, an out of the box 850 carb. Seems like in the racing world , when the big cube big block chevy's start getting into the 700+hp range, most builders go for the 4500 series carb, unless they are class limited to a 4150. Most of the guys over on speedtalk claim they have seen the dominator almost always beat out the 4150 carbs at that level when dyno testing . But, they also aren't running a 4150 that flows 1170cfm from a guy like Norm.

If we took norms carb out of the equation , it seems like Tims 4150 quick fuel thats rated at 1050cfm, was comparable in power to the 1050 dominator it was tested against. On a 650ish hp engine combo with those carbs. It be interesting to see what would happen, if those carbs were bolted on a setup making say, in the 750hp range. Im sure if we bolted them on a combo thats making in the 500hp range, it be a no brainer the 4150 would likely be the winner.

I posted this a while back in another thread. Figured it might be relevent to this discussion

I would love to see tims QF1050 on a 750, 850, 950 hp motor against a 1050 dom, if they both made 654/655 hp on my 548, they both flow 1050 cfm at same flow standard is there any reason the equal flowing dominator other than looking cool should out perform it anywhere?

And this would help the carburetor tuning for sure.

The more dialed in you can get the ign, the more dialed in you can get the carb.

I got the Holley 4500 1050 sportsman 2 circuit carbs. I couldn't find any down side to them as they are built off of the same body as the hp gen 3 and they are polished...for $800.00 smacks. However I am certainly no carb genius!!

Norm loves aerosol carbs, he even sends a personal note in the return shipping as to his enjoyment he had working on them...........

Yes. Many times over and over, a dominator carb has proven itself over a equally rated cfm of its 4150 sibling. Look at the comparison of a Ultra HP 4150 950cfm, and the 950 Ultra Dominator. Both rated at 950cfm.

Like you said earlier, its not just the cfm rating. How the fuel is atomized, distributed, etc. If the 4150 style carbs were all thats needed for a 750hp deal, holley, quick fuel, demon, prosystems, and many others wouldnt have sold many dominators. Bck here made more power with a dominator on his 540 after swapping the 4150 carbs and what not .

Heres a good read from prosystems about this topic

https://prosystems.websitetoolbox.co...in-cfm-6223685

For sure. However, we have ran them before the daytona setups with custom timing settings at idle. It certainly helped for sure. But even prior to that, they idled very well. Heck, we have used quite a few sets of 1050-B2 carbs on roots and mike tkachs 1200hp whippled engines. Whether they were on a 900hp 540, or a 1200hp 8.3 L whipple, the jetting was very close, and the air fuel ratio curve was very flat. For some out of the box carbs, thats pretty impressive. 300hp difference in output, but almost identical jets, tells me the carbs are doing a good job at metering the fuel.

With that being said, do i think they are hands down the best carb for every application, no. And once in the boat, they need some adjusting for sure. As have most carbs ive seen, after they come off the dyno

Anyone have $1800 to burn ? Would love to see real world tests on one of these. ;)

http://www.silverbackcarbs.com/index.php

http://www.silverbackcarbs.com/images/fly1.jpg

What the??? That looks pretty cool. Looks like something from the future. Wish I had 1,800 right now let alone to burn. Lol

Very interesting design

Any of you guys follow the annual carb shootout amongst the various big names in carbs ?

Not the last one...you have a link ?

I dont know if they are still doing it anymore? Was pretty cool.

If i recall, in the 2012 one, quick fuel took first place in the out of the box class, and big block chevy class. Maybe it was aed. Ill try and find it later when im home

Don't worry about it, I assumed you meant there was one recently. I followed the 1st one when it went down.

Mild Thunder - thanks for the links for the single carb intake induction and prosystems post, very interesting.

Rob - Cool build! Looking forward to seeing how this one turns out - especially if you compare a 4150 carb to a dominator on the dyno.

I'm going to try 2200 CFM throttle bodies with an HVH style 4500->4150 modified spacer on my Brodix HVH 4150 intakes vs. my current 1000 Holley TB's. Similar to Smitty's testing, but I don't have the dominator intake... which may help my flow velocity. I'm not pulling engines, but I do plan to do as close to back to back water tests as possible. I only question whether 2200 is WAY too much throttle plate, but according to Prosystems - maybe not.

Well, again, AFTER tayloring timing curve and tweaking afrs I was able to gain 10-12 solid hp at wot over the best carb I dynoed with BUT I also found that last 10 hp by pulling 1 to 2 degrees of timing out on top past my highest amount so carb might have done that if it had a timing table like a efi does, I was able to beat my best corrected and observed tq by about 4-5 ft lbs but I still havent found the 20+ ft lbs I lost down low from 3000-4600. I did some steady state testing at 4400 wondering IF giving tb less than wot would bring back tq, it did not. Testing with a single blade TB thats supposed to flow slightly less tomorrow, would really like to test with a 1600 cfm TB to see if that torque would come back or if carb simply worked better at those rpms, going to be intersteing to hear what YOU find, Smitty
EZ striper also said they had idle issues with the 2200 when they ran one, I havent worried abput idle yet on dyno

Thanks for the testing information, Smitty. I'm watching your thread closely and really appreciate what you're doing. It would be very interesting to put a 1500-1600 TB on it to see if it is a carb/fuel temperature or atomization issue.

How much are the injectors tipped (if any) on your dominator intake? I've been told that getting them to fire as much as possible at the back of the intake valve is a must to avoid spraying the runner wall like some of the aftermarket package deal offerings are.

Here is what I ended up doing with Brodix 4150 intake (basically did it to figure how I needed to machine my intakes and fuel rails):
https://lh3.googleusercontent.com/-i...2Bassembly.jpg

https://lh3.googleusercontent.com/-1...keassembly.JPG

Based on this, I found I could get 14 degrees of tilt on mine and still be able to install the rails:
https://lh3.googleusercontent.com/-B...ont%2Bview.jpg

I'm trying to get out in front of the idle issues with the 2200... KVOGT on here got his blower motors with dual 2100's to work with Holley EFI nicely. I'm going to try the same alpha-N idle/speed density cruise to top end combo strategy he's using out of the gate... Even if it does auto-tune properly, it gives me a lot of table resolution to really focus on the tip-in event on those big throttle blades.

Rob, when do you plan on completing and dynoing? I need to finish the cad on the adapters.

I love that tip in on your injectors, great engineering. I really didnt give it that much thought but am now that im seeing these low tq numbers not quite where they were carbed. Im going to try a few fuel changes on dyno tomm and pull from 2800 to 4600 and see if theres anything more to be found, norms theory almost completely agrees with your tipped injector angle, he feels my injectors may be spraying fuel acrossed the air path in the port, causing a curtaining effect and that maybe at higher rpms/velocitys it has enough airflow to negate it, we'll see, nice work though on that angle, i may do same thing on my final intake i run, Smitty

My goal would be to have these motors wrapped up and on the dyno by early May

Smitty, have you tried firing the injectors at different degrees before and after TDC to see where they are most efficient for your motor ?

No as i am batch firing them, i will say this though, the last motor i dynoed, a 550hp 502 mpi, it made zero difference in hp /tq ANYWHERE when i switched batches opposite of what they are supposed to be, found same result running one batch down even side of motor and one batch down odd side, fwiw, Smitty

It be interesting to see what happens to the bsfc , with changing injector timing. I assume the camshaft events can dictate a need for a change in injector timing? Id think that if the injector timing was based on say a stock cam, and you go to a bigger cam, that opens the exhaust valve sooner, and had more overlap, maybe firing the injector later, so that you arent blowing fuel out the exhaust?

Maybe not much power to be gained here, but maybe some fuel efficiency? Just thinking out my azz on this

This efi stuff is cool chit, i cannot see how you can do all that it can do, by not getting a setup on an engine dyno. How can you do all this stuff by tuning on the water on a custom build? So much that can be tuned. Timing maps, fuel maps, injector timing, knock sensor setup, and so on.

It wouldn't do anything for the antique batch fire, but in sequential you can time it so you don't have puddles of fuel sitting on the valves being sucked out into the exhaust stream by the overlap of the cam. It does affect the efficiency of the motor and the Bsfc. It can also affect the EGTs burning the extra fuel outside of the motor down the exhaust pipe. Mixing the fuel and air at the proper time would enhance the atomization process in my opinion.

It takes a while, it's not as easy as some of the salesmen on here claim. Some of the systems are less complicated than others, the parameters have to be set for the marine application. They can be amazing once dialed in, some may throw it in the lake before getting there. Try putting dual wideband 02s on your carb motors, they may not be working as well as you thought.

I've been wondering if injection timing could be used to help push more air in the cylinder. Use something kind of like a miller cycle cam with late ivc and inject when the piston is at or near bdc and the airflow has pretty much stopped. You would need large capacity injectors which could handle most of your fueling needs in a short window of time.

Ive been running widebands on my carb engines for years

I'm guessing General Motors had some reason for putting the injectors in the cylinder head of the LS motors.

Do you run 1 or 2 sensors

Currently, I have a single ngk powererdex wideband. I did have dual FAST unit prior to the NGK. On the dynos, I have used the NGK, and Daytona sensors widebands.

My engines bank to bank wise, have never varied more than a couple tenths. I believe that is thanks to the dual carb setups, and straight two lobe rotors. My buddy's with twisted lobes, shows a little bit more difference from bank to bank, but nothing crazy.

You're referring to direct injection, which injects directly into the cylinder. Reduces the risk of preignition and detonation due to the fuel not being present during the compression stroke.

It can theoretically greatly improve economy by having localized stoich mixture only around the spark plug. But I think emissions prevent fully utilizing that strategy.

I would expect a couple tenths between banks and think that was fine. My brother just ran into an issue with a new QF 950 seeing as much as 2 points difference between banks, that could melt something. Just my opinion.