Edelbrock Pro-Flo XT EFI system BBC in a marine application
 

https://www.summitracing.com/parts/edl-35883

Has anyone tried this as a marine application? Rebuilding the 502 in my 96 Baja 252 and it has a standard 502 Mag MPI setup with a MEFI 1 ecu. I am looking at my induction options and I came across someone running this on a 502. I tried calling Edelbrock but after being on hold with tech support for over an hour I gave up.

I know it requires a WB which I know don't typically last in a marine application but I will replace the O2 each season if the system will work.

Do you want to buy a product where the tech line keeps you on hold for an hour?

Honestly this day and age I'm not sure of one out there that does not. I prefer Holley honestly but I wanted to know if anyone has experience with this system.

No experience but I think you’ll be better with something from Holley. If you wanted a better way of controlling everything, a Holley ecm can be made to work with the mpi sensors. Adding the O2 sensor is not hard and can be made to last. Having a knock sensor is good too. All can be done with the Holley.

Holley ECM is approved for marine use and there are many sources of information online to help troubleshoot issues,
and as said above you can use just the ECM and harness on your existing system.

I have had great service from Holley's tech line.

Steve

I don't know why this mantra keeps coming up. Yes SOME people have issues with wide band lasting, but I think placement is key. I run mine full time for the last 12 years. Replaced it once.

Agree with above...holley makes a very similar if not the same setup and I would hands down go that route. Then swap to their either hyperspark or CNP(coil near plug) ignition and have a damn near bulletproof setup that's easy to work with and tune...just my thoughts.

And to add....I'm no expert on induction types however I believe a different type of intake may work better in the marine world...like a "standard" 4 bbl type intake that's port injected with a 4 bbl throttle body on top...holley makes one of those as well...just a thought.

https://www.jegs.com/i/Holley/510/55...AaAsWtEALw_wcB

Holley offers this but with a single plane, not sure for a boat a single plane is ideal for low end tq. I agree Holley is superior over edelbrock and almost twice the price too.

Could go with a sniper kit and get your own dual plane or whatever intake you choose is an option as well....that's a HP kit I believe you linked and they are pricey....however coming form someone that is in the process of replacing the entire EFI system because I went the cheaper route initially...spend the money up front and do it once!! You won't be sorry trust me hahaha

Hilborn 300-800 Hilborn Big Block Chevy Intake Manifold Kit (holley.com)

I vote this because it would be super b!tchin!! hahahaha

You may want to download the software from several manufacturers to see which one works for your application. Single plane intake doesn't matter with EFI. Tunability for marine application is key.

You could use an aftermarket ECU with your stock set up and have more tunability.

The ProFlo XT Intake makes great horsepower AND torque. Better than a single plane carb manifold.

The Edelbrock EFI stuff is very limited for advance tuning and is garbage.

Smitty (Articfriends) in here has done a bunch of dyno tests with this manifold on marine motors and has messed with their EFI system, I would talk to him.

I would use the Pro-Flo XT intake with a different EFI system.

That always cracks me up.

I'd buy the intake separately and then build a Holley HP system for it.
Smitty says that intake flat out just performs.
Check out my Holley EFI thread for build and pricing when all finished.

I'm one of those guys that can't make O2 sensors last! Now only use them for tuning if needed, and run open loop full time (with O2 removed). System has been 100% reliable for approx 500 hours in my 42' Sport Fish running 509 BBC/Arneson power.

Steve

The proflow front mounted tb intake with some tb work is a great piece itself, it will make outstanding hp and slightly better tq than any open plenum intake on a typical 502 build with marine cam. The software sucks, I would buy just the intake and use holley.
a couple things to note though: , no one has had these intakes in stock for sale for well over a year so that's a consideration, that delivery date of may 2023 has been moving since 2021.
Flame arrestor /entry of throttle body: to get most out of that intake, a very good cone filter with a entry taper device is very crucial. The last engine I dynoed and tuned with one, I tested countless cone filters, volutes, etc. a brief synopsis is this: 515 (4.530 bore 502) was making around 650 hp with the proflow, that hat hp dropped to the 620 range with most clamp on cone filters. It went to the 680 hp range with a volute clamped on TB and barely had a hp drop with a 10" cone clamped to that volute. Its very difficult to get a thermostat housing under it, it can be done by clearencing the bottom of TB itself. Forward clearance in your boat is a consideration too, IF you have to put a 90 on the tb, you'll kill the power and it will never make its full potential so you'd really need 11 or 12 " in front of tb to use a non restrictive filter, Smitty

I always love reading your responses. Your so damn smart it make me feel like i bumped my head.

WOW thank you for this well thought out information and I cant believe the back order. As for a cone filter on there yeah your not getting a long one without a 90 degree elbow. Granted if I achieve 550hp out of this rebuild I would be more than happy.

How would I adapt the throttle linkage to the new Edelbrock TB and now you have me worried about the clearance with the TB and the stat housing. If I were to go this route if available I would do as mentioned use the intake and use Holley HP as the management system.
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thought about running the stock MPI but I was told it falls on its face CFM wise after high 400hp range or I would just adapt Holley HP to it and be done.

It's not a huge difference but from what I've been reading you could get a 500 efi intake and run holley injection? You can get 550 out of that intake from what I've read....just a thought?

As a old school guy I love these, but how do they perform against something like the XT system? Has anyone did a back to back dyno test of this type of intake compared to a single plane, or XT?

I was going to run a 525 intake but I was told it has special injectors so I bailed plus the guy I was buying it from was jerking me around. I just want SIMPLE, im not looking to stop the world with this thing just want some fun reliable power. I know (fun, reliable & boat) do not belong in the same sentence!! Im thinking the XT with Holley HP would be a kick ass setup but now the TB clearance issue on the stat housing and the manufacture lead-time nonsense can be an issue.

Speedway motors says it ships by 11/29/22 but I am going to call and see how realistic that is or if it is total BS to get the hook set then drag you through the water of WAITING for months on end. Winter is long but not that long!!
I curious how I will adapt the throttle linkage to the Edelbrock cable style TB linkage??

I think you have the 525 efi injectors mistaken for the 500efi injectors.

Don't get hung up on the injectors, you will need to buy some and tune it anyway.

As an fyi: Edelbrock got bought out not too long ao. Same company that bought out CompCams. There's some useless facts for the day. :)
Actually maybe not that useless, as I don't think Edelbrock does all, or much, of their own castings in house now because of this.

So before going through all the trouble of swapping intakes, how bad is the stock MPI? Are they really as restrictive has I have been told, is it really worth swapping it out? Again im not looking to make a 75mph boat here I just want a fun lake boat that works well and decently performs. Best I ever saw out of this thing was 62mph once, it would normally run around 58-60 at WOT and cruise around 38mph at 3,500rpm. I knew something wasn't right as it began dropping off MPH was decently and when I opened it I found the below:

Parts suck to get now so I don't want to make this more complicated than it needs to be, I want my boat back in the water by Memorial day, engine was dropped off to the machine shop Friday. It was running on a MEFI-1 which is believe is garbage so swapping to holley is a MUST. I was thinking of going dry exhaust and a HOT cam but thats all out the window, I just want it to sound good, fire every time and enjoy being on the water!
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Looks like someone replaced one head gasket when they shoulda done both.

Don't give up on the MPI intake, it can actually support more HP than the 500/525 style. MPI will make more torque than anything on the market but won't go much past 5600 rpm for peak power. Articfriends(Smitty) is now enlarging these stock throttle bodies and that does make a pretty good bolt-on difference. Also let him school you on the flame arrestors, that plastic one you have is absolutely terrible and kills HP. He has made over 700 hp with a low CR 548 with a modified MPI intake.

Also, you probably have MEFI3? I'd just stick with that and save a couple grand versus going with Holley. It can be re-tuned and is more than capable for your plans.

One big thing if you like to run at high RPM for extended periods of time, the factory oil system sucks and kills oil PSI. Change block adapter, filter head, cooler, and go to -10 lines at a minimum and you will see another 20 psi oil pressure with no other changes. Couldn't believe the difference on mine, I was about to rebuild them for being tired as hot oil psi was getting close to 32 psi max, now it doesn't go below 50 psi.

Probably does have MEFI-1 judging by V-belts rather than Serpentine...

Edit: I can see the ECM in one pic, it's a MEFI-1

I want to go with a better remote oil filter/cooler setup I kinda figured the stock one is not the greatest. I am on a small lake so it is never at high RPM for more than a min or two at best but still I want to do whatever will make the engine happier. What did you go with for a cooler?

It is 100% a MEF-1 ECU so it has to go, trust me I would love to save a few K but I think alot of my issues are this ECU.
As for the intake I would love to just upgrade the injectors, keep the stock intake and toss Holley at it.

MEFI 1 can even do what you want. It just can't deal with boost all that well. Injectors are a PITA for alternatives with that intake because they are Honda-Kehin style injectors - not impossible, just not an easy bosch/delco crossover. Get them from a good source and flow matched, lots of Chinese copy junk that will burn down your motor out there. You can have your stock ones cleaned and flowed, go with adjustable regulator, crank fuel psi up to 60 psi, and support your power goals still.

I went with a 3"x18" (Teague) cooler mounted above the bellhousing, -10 AN lines, Improved Racing thermostatic oil filter head, and new billet block adapter (rest from Summit).

Where are you located?

Putnam County within NY state. Boat lives on lake Mahopac.

When I pulled he rail the injectors have these black caps look like an adapter as the opening in the manifold is way to big for the injector so they added these adapters. To me this is juat another source of a fuel leak??

I will look into the parts you listed for the oil cooler, as for making -AN lines I have made way more in my time that I ever wanted too LOL I am a fan of Russell line and fittings.

A vacuum leak maybe, not a fuel leak from those black rubber grommets. Fuel is not in contact with them. I agree that it seems like a kludge of engineering but it's what we got.

Whoa whoa whoa.....don't just abandon the MEFI 1 just yet.... For the HP you are looking to get the MEFI 1 will work fine. The stock intake manifold with the previous version flame arrestor will likely get you the HP you are looking for. For your situation there are some serious advantages to sticking with the MEFI 1.

1) You have an ECM that works
2) Wiring harness works
3) Ignition system etc already tied in
4) MEFI 1, in spite of being the oldest version, is the easiest to tune (other than lacking fidelity in the fuel table)
5) You don't have to spend thousands on a new intake, ECM, wiring harness etc.

IF you are going with any boosted application, then yes, ditch MEFI 1, but that does not sound like the case.

As far as injectors verify the ones you have and their flow rate. They may be able to handle the HP you are targeting without blowing through the duty cycle. If you need higher flowing Keihin I have had luck with RC Injection in Torrance, CA. Not affiliated but they got me what I needed.

PM if you want to chat as I have done something similar to what you are doing with a MEFI 1 and would take pages to type out.

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Can you plug into a mefi1 with a laptop like Holley and make changes?
To me seemed like you needed an engineering degree to figure out mefi1 but I have no experience with it .

Yes, just need software like MEFIburn. I haven't tried it but the solutions are available.

I don't mind spending the extra cash on Holley if it makes life much easier, just need to do a few extra side jobs lol. I just dont want to be stuck fiddling around with an antiquated system fumbling around to find out I need to upgrade anyway. Plus if I ever did decide I want to toss the kitchen sink at it and feed it all the BOOST I know the EFI is already there.

Yes. It is easy but does have a steep learning curve. Is it as eloquent as the newer systems? No. The biggest problem I see is people start messing with things that don't need to be messed with within the MEFI 1 bin file. Fuel table and spark table are virtually the only two items you need to tinker with. There may be a few other cats and dogs parameters you may want to play with later but they are not game changers for initial tuning.

Use MEFI Burn to download the existing factory .bin file

Save this file in multiple copies.

Use TunerPro and open up a copy of your factory tune to dive into the fuel and spark tables.

Save this as a NEW file (don't overwrite the original).

Use MEFI Burn to upload the new tune to the MEFI 1. Takes about 3-5 seconds. Must be done with KOEO. No live updates while the motor is running. One of the downsides of MEFI 1 but not insurmountable.

The VAST majority of the scalars, constants, and flags shown in TunerPro for a MEFI 1 .bin file are actually not implemented nor used, so they do add some confusion for those looking at it for the first time.

Yes wideband is a must.

Heres some info:
A 525 uses the same EXACT injectors as a mefi1 454/502. I have found a 55lb import injector that I sell as match flowed sets, its slightly shorter so I machine bottom spacers to ensure it is in rail enough BUT your stock honda/keihan factory ev-1 connector injectors IF they flow fine will be just fine, I wouldn't change them unless when cleaned and flow tested they are terrible. I flow and clean alot of early 454/502 injectors and 525 injectors at my shop and for most part they clean up and flow fine.
Injector SIZE : your stock injectors are 48 lb, 48 x 8 is 384 lbs per hr at 3 bar (43.5 psi). 384 x 2 =768 , if your bsfc was .500 that means they would support 768 hp, assuming your bsfc is closer to .58 which is typical of mpi engines I tune and dyno you can deduct 16% from the 768 which would still get you to 645 hp maxed out. Even at 80% of that, it will get you over 500.
Stock fuel pump: stock fuel pump is 190 lph, its done at about 560 to 580 ft lbs tq/hp before injectors are.
Upgrade fuel pump/efi regulator /fuel cooler lines: IF your going to aim for more hp than stock fuel pump can supply and you upgrade it, you can got from 3 bar/43.5 psi to 4 bar/58 psi.
58 psi will increase the flow of your injectors by 15%, that 15% will take your max hp easily to 600 hp at 80% duty ccyle/.58 bsfc. I have pushed stock injectors close to 100% duty cycle over 675 hp with no issues.
Wideband/02 sensors somewhere in your current exhaust: If you do ANY mods, regardless of intake, etc, a wide band 02 sensor somewhere in your exhaust that you make tuning decisions from will keep you from running pig rich somewhere OR making pretty little piston ashtray gifts for your smoking friends!
Mpi Intake: I have made well over 600 hp/600 ft lbs of tq with mercruiser black intake by cutting down runners even with plenum floor/boring out TB and making 67 mm blades vs stock 60.
Flame arrestor: The flat plate gen 6 FA is a restrictive hp killer on modded engines
the Gen 5 mefi 1 factory fa is BEST flowing factory piece, those aluminum necked down adapters with clamp on KN fa's from various suppliers flow WORSE than stock and kill massive hp on modded engines
In recent testing I found the Gaffrig oval FA is by far the very best
Throttle linkage on edelbrock proflow (assuming you could actually get one), You put a throttle post thru side of their curved lever and make a bracket to bolt on side of intake, Ill post up a pic if I can find one.
Your boat in picture: Since its a single and doesnt appear to have sufficient room to put a large enough FA on the proflow, I wouldn't even consider it. A 90 KILLS a bunch of the hp gain that its known for. A proflow will embarrass a vic jr with a modded tb and good air flow but most that gain will evaporate if you clamp any 90 onto it. A merc mpi long runner intake will beat both a vic jr and proflow in early tq due to runner length at expense of top end hp but singles unless they are really a fast, stepped hull need square tq/hp. Guys get caught up on peak hp numbers that come from big cams, short runner intakes that sacrifice torque. Then boat sucks to drive, wont pull no prop. wont get on plane loaded down etc. If I think of anything else to ad I will, Smitty