Carb to EFI
 

Hey , I’m fed up with the dominator always rich at idling want to go EFI.
individual throttle body’s or plenum with single body ?
and was going with fueltech as efi

need to hear you comments

If you mean 8x ITBs like a hilborn (which is what I have), then no, don’t do that. It’s lovely, but a fair bit of setup to get just right and give no vacuum signal which makes the efi system a bit harder to sort.

But for example, a 4 barrel TB to replace your carb - I have one of them too. It’s a nice piece of kit (with injectors into the manifold, not on the TB) and is straightforward. I have no experiences of the 4 barrel TB setup with injectors on the TB.

But if I was building my engine again, I would go with a full plenum and single throttle
body setup. You can get nice long runners on them to support good torque, simple throttle setup and good vacuum signal for the ECU.

Read up on some of the Daytona Sensors discussion on here lately. A lot of carb guys love those.

And if you go with a smaller 4150 base/flange size carb, then you will most likely not have the problems you are experiencing with a Dominator size carb. I once had Dominator size carbs on my 468cid engines that were on those engines when I originally bought the boat---after having a local guy try to tune them a little he kind of gave up and said they still just want to run too rich and gave me a black transom and throwing raw gas out the tailpipes. It got old very quickly---not so much that they could not work, but getting them to work properly was a hassle and just not user friendly in my opinion.

So when I built my 540cid engines I went with a Holley 4150 size carb---830cfm initially, then to a 950HP. Both worked great. I may get some push-back from you guys about properly tuning the Dominators, but anything can be fairly easy when/if you know what you're doing and those were Doms from about 30+ years ago and carb tech has come a long way since then.

I love the simplicity (for the most part) of a carburetor, etc.---I am more of a carb guy.---but I will try to find a way to make those 4150 size carbs work before I try to use a 4500 size Dominator ...and I will admit, when it comes to FI those Hilbonre FI with those velocity stacks are awesome looking.

For what it's worth it's Just my experience and .02 guys---doesn't mean I am right.

What is your timing at idle ?

https://cimg7.ibsrv.net/gimg/www.off...af1ee1a5f.jpeg
I am thinking something like this with fueltech What you think ?

Might be helpful if you told us your engine, boat, application, and goals…
I’ve put a LS in my boat, using the TBSS with upgrades 92mm throttle body.
Holley, fueltech, etc were all back ordered during covid. I went with a ligenfelter trg-002 to convert my gen4 58x/4x into a 24x/1x with a basic brain so I could get dbc vs dbw on throttle body. It works great on the cheap. Just charge the battery before starting. It gets picky on low battery starts. No issues when running, so far.

Lots of guys swear by fueltech. I prefer Holley but to each his own. My next upgrade would be Holley efi that’s fully potted for the tuning capability.

that intake looks solid to me. I’d go with a fast lsxrt if I needed a different intake.but power goals may dictate a high ram intake for you.
i Don’t know your application but here’s the biggest pain on this whole project… fuel pressure.
I have dual 55 gallon tanks then into the fuel/water separators into control valves through the pump, regulator/filter/return, and up to fuel rail.- this is a formula for fuel pump death when offshore. Will it work, sure. Will I have a pump fail? Probably faster than I should per tech support.

ive opted to add a fuel surge tank so I can have a low pressure pump pull it from the tanks through the fuel water separators and into the surge tank. From there a high pressure pump will take over and my return will be plumbed into the surge tank. I’ll still carry a spare pump just in case….

I love efi… so many advantages but the fuel delivery piece has been a pain for me.

https://cimg5.ibsrv.net/gimg/www.off...6cb17cc1a.jpeg
This is my motor . 572 Dart big m block merlin heads stainless marine gen 3 exhaust running full dry . Ignition system still stock with MSD coil only . Cam specs attached

Have you considered this

https://www.holley.com/products/mari...er_efi_marine/

Who makes that intake, your biggest issue with this particular style intake and I DO love them is thermostat housing clearance/flame arrestor clearance on a single engine. You CANNOT put a 90 degree elbow on one front of one of these NA and not kill off serious hp. Id like to see a intake like you pictured with about 2' longer runners (about 8"). I have made some OUTSTANDING hp numbers with modded Edelbrock proflow intakes/ throttle bodys that are very similar to what you pictured, did lots of flow development / dyno testing on various things bolted to the front of the throttle body with almost shocking results. Ive made HP numbers (680+) with a Edelbrock proflow ) on 509/515 engines with 89 octane BUT was hard (almost impossible) to implement in that config in a single engine boat, Smitty