PDA

View Full Version : 502MAG MPI to 500EFI



Dr. David Fleming
01-08-2010, 09:24 PM
Have a chance to pick up a 500EFI fuel injection system and valvecovers along with the factory camshaft. Anyone framiliar with installation of this on a 502MAG MPI? California Speed and Marine has a primary wiring harness for the conversion and a bracket to mount the MEFI 3. Seems no place to mount the Mercathode and I don't know about any fuel line problems? I already have the CMI e-top headers and Crane roller rockerarms, springs and lifters. Heads are ported and polished with racing valves.

Opinions on how practical this swap is would be appreciated - Donzi 22ZX has Merc K planes and Latham external steering on the Bravo 1 drive.

Seems California Speed and Marine offers a relieved, extrusion ported and shortened runner manifold for the 502MAG MPI fuel injection system. Wonder about this as an alternative to the blue engine injection system. Any opinions out there?

MOP
01-08-2010, 09:45 PM
IMO it is easierto get a carb setup to run then fooling with injection, be as you seem to have all the base breathing apparatus I would just research a good cam for your application the 731 comes to mind which should be Ok with your exhaust. Finer minds may dispute and no arguments on this end!

Phil

The Hedgehog
01-09-2010, 09:04 AM
You will need to do the heads and exhaust too or else you won't really get much out of all of that work.

Actually you can do the heads, cam and exhaust without the manifold and be fine.

I though that the 731 would revert water in a stock exhaust. I know that the 741 will BIG TIME. I have a friend that put a 741 on the 502 EFI combo with lightning headers. He sucked water and was out looking for some CMI's within a day.

MOP
01-09-2010, 09:19 AM
Bill all he needs is the cam he has head work, roller rockers and exhaust, it will be more cost effective to stay with the carb with little noticeable usable HP difference.

Phil

CJmike
01-09-2010, 09:44 AM
Did the same thing last year but I started with a 454 but used the 500efi set up and 525efi cam. I like that cam better. But if you went with the 500efi camshaft you should be able to get buy with a stock 500efi computer. Most of the swap is pretty straight foward. The tuning is the tricky part. That cost me way more than I wanna admit. But it can be done and I like the end result.

The Hedgehog
01-09-2010, 10:06 AM
Did the same thing last year but I started with a 454 but used the 500efi set up and 525efi cam. I like that cam better. But if you went with the 500efi camshaft you should be able to get buy with a stock 500efi computer. Most of the swap is pretty straight foward. The tuning is the tricky part. That cost me way more than I wanna admit. But it can be done and I like the end result.

Post up a couple of pics of that bad boy under the hatch!

The Hedgehog
01-09-2010, 10:09 AM
Bill all he needs is the cam he has head work, roller rockers and exhaust, it will be more cost effective to stay with the carb with little noticeable usable HP difference.

Phil


I agree and think that he would actually make more power with a carb.

I do see the allure with the EFI system though. I am a big fan of mine.

handfulz28
01-09-2010, 11:22 AM
Did I miss something? Dr D has an MPI, says nothing about a carb?

The fuel system/plumbing/routing is going to be different. So unless you get the whole 500EFI fuel system you'll need to make changes. Also depends on which year your MPI setup is as to whether it would be suitable for the upgrade.

The only power improvement you'll experience is a result of the camshaft. IMHO you're better off putting the money into head work and a camshaft, plus ECU programming. It's not that difficult to get the 502MPI to make ~500hp. And I don't think you need the modified plenum for that either.

CJmike
01-09-2010, 11:31 AM
This is about the only one I have that looks decent.
http://i304.photobucket.com/albums/nn200/CJMikeK/boat%20exhaust/IMGP1647.jpg

The Hedgehog
01-09-2010, 02:59 PM
This is about the only one I have that looks decent.
http://i304.photobucket.com/albums/nn200/CJMikeK/boat%20exhaust/IMGP1647.jpg

Pretty.

Needs a full dress centerfold shot!

MOP
01-09-2010, 03:10 PM
Love the Dana's!

The Hedgehog
01-09-2010, 03:18 PM
Did I miss something? Dr D has an MPI, says nothing about a carb?

The fuel system/plumbing/routing is going to be different. So unless you get the whole 500EFI fuel system you'll need to make changes. Also depends on which year your MPI setup is as to whether it would be suitable for the upgrade.

The only power improvement you'll experience is a result of the camshaft. IMHO you're better off putting the money into head work and a camshaft, plus ECU programming. It's not that difficult to get the 502MPI to make ~500hp. And I don't think you need the modified plenum for that either.

I think that Phil meant that can be easier, cheaper and make more power if he went a carb route. That is true. No bottlenecks there.

You are correct, he is opening a can of worms. The plumbing will not be a huge difference but it will the whole system would be much better. Lots of things like injectors to think about. Just ask CJ here.

ALL of the MPI/EFI systems are upgradeable and reprogrammable (except for the systems that have a PCM555). From MEFI 1 - MEFI 4 series are all reprogrammable. I have done that with both 1's and 4's. Tex and others have done 3's. 3 and up are better. This is especially if you want to use boost since they have boost tables in those series.

Eddie Young can speck out a package for a 500hp combo. This will include heads, cam, exhaust and reprogramming. So can Mark Boos, Tyler Crockett and others. And no, you will not need a new pleneum. Somebody did the back to back comparison. The difference is somewhere around 10 hp on the extrude hone. To do it right, you will drop around $5k and that is if you don't have to go into the block.

I think that the regular 502 MPI is a great package for modification. I have done about everything imaginable with mine. Cam, Heads, stroked to 540, exhaust, injectors etc. Good for over 900 hp with boost. I still have the ole pleneum and 502 block. Polished on the outside but a few other things on the inside. I could go back to N/A and pull around 575+ hp by taking off the blower and having it reprogrammed.

Dr. David Fleming
01-09-2010, 04:34 PM
Well, I appreciate your response to the 502MAG MPI/500EFI upgrade. The 10 hp on the extrusion hone is a surprise. The hp increase from the cam is logical as that is one of the most important design item in an engine. Crane made the 500EFI cam I wonder how that would work in a 502 MAG MPI without going to the blue fuel injection setup?

John at Arizona Speed And Marine said he offers the extrusion hone because the way Mercruiser made the plenum top too close to the ram tubes. He also said that the whole fuel injection in the 502 MAG MPI was really made for the 454 MAG MPI and it is too small for the 502. Ten hp for $675 not counting installation costs and shipping seems like a lot of money for the increase yet every hp counts.

Another item with the blue manifold, is that the 22ZX sold for say $58,000 with the small block chevy - Big block chevy, 502MAG MPI was I think around $88,000 and the22ZX with the 500EFI sold for $130,000. I heard it was a $38,000 option on that hull. Correct me if I am wrong. So the pop the hatch impact of the 500EFI stands for braging rights if not outright sheer outrageous horsepower. The 500EFI along with 525 are professional race engines used in competition.

Another issue is that a 500EFi modified 502MAG MPI is that this change becomes a bastard hot rod setup. A lot of marine mechanics will walk away from this and repair/troubleshooting gets expensive. Tyler Crockett will fly anywhere in the USA to fix your boat etc.

Doing this swap or not doing this swap is a hard temptation to resist and is why I am kicking it around here. Thanks again.

CJmike
01-09-2010, 05:23 PM
Love the Dana's!

I like the way they look. But dana's customer service is horrible. They made a mistake but it is was my "fault". I got the tailpipes fixed on my dime to make them right. With what I spent on the custom Dana's and fixing them I could have just bought CMI's. But they look nice and functional well now.

The Hedgehog
01-09-2010, 05:35 PM
Well, I appreciate your response to the 502MAG MPI/500EFI upgrade. The 10 hp on the extrusion hone is a surprise. The hp increase from the cam is logical as that is one of the most important design item in an engine. Crane made the 500EFI cam I wonder how that would work in a 502 MAG MPI without going to the blue fuel injection setup?

John at Arizona Speed And Marine said he offers the extrusion hone because the way Mercruiser made the plenum top too close to the ram tubes. He also said that the whole fuel injection in the 502 MAG MPI was really made for the 454 MAG MPI and it is too small for the 502. Ten hp for $675 not counting installation costs and shipping seems like a lot of money for the increase yet every hp counts.

Another item with the blue manifold, is that the 22ZX sold for say $58,000 with the small block chevy - Big block chevy, 502MAG MPI was I think around $88,000 and the22ZX with the 500EFI sold for $130,000. I heard it was a $38,000 option on that hull. Correct me if I am wrong. So the pop the hatch impact of the 500EFI stands for braging rights if not outright sheer outrageous horsepower. The 500EFI along with 525 are professional race engines used in competition.

Another issue is that a 500EFi modified 502MAG MPI is that this change becomes a bastard hot rod setup. A lot of marine mechanics will walk away from this and repair/troubleshooting gets expensive. Tyler Crockett will fly anywhere in the USA to fix your boat etc.

Doing this swap or not doing this swap is a hard temptation to resist and is why I am kicking it around here. Thanks again.

You can use the big cam from the blue motor in a 502 EFI. It has been done many times. You will need to be careful with fuel pressure and programming since the smaller injectors have a smaller margin of error. This goes up as you raise the hp. I have a friend or two that have had to run for more injector as they upped the ante. I would go the route of CKMike and do the bigger injectors. That being said, I have extracted over 550hp out of a 502Mag MPI with the stock injectors and a MEFI 1.

The runners do come close to the top of the intake. You don't need to extrude hone for that. You can have them milled down flush. That is what I did. I would not fool with ASM. Too many bad stories. There was a guy building a sister motor to mine when I went with big power. He sent his to ASM against Eddie's advice. When it came back MONTHS later, they comped him the price. He was not happy when I talked to him. Eddie did the boring and honing on mine himself. I made a good bit more power.

If you want to get into any big power including blue motors, you need a good mechanic or need to know what you are doing. Blue motors are cute. I have spanked quite a few of them with my non blue Mag motor. Bragging rights come with that big number on the GPS. The one you see when you drop the hammer. Popping the hatch should be done afterwards.

500 EFI's and 525's are nice packages. They are well built and reliable. Outrageous? I guess that it is all relative. A bunch of guys here have duplicated them with equal parts on a bunch less $$$. There are situations that I would own some blue. I would pay a premium but not the amount merc wants. I love my custom engine. I will stack it up to Merc's stuff for both fit/finish as well as the dyno numbers any day.

mrfixxall
01-09-2010, 06:15 PM
Have a chance to pick up a 500EFI fuel injection system and valvecovers along with the factory camshaft. Anyone framiliar with installation of this on a 502MAG MPI? California Speed and Marine has a primary wiring harness for the conversion and a bracket to mount the MEFI 3. Seems no place to mount the Mercathode and I don't know about any fuel line problems? I already have the CMI e-top headers and Crane roller rockerarms, springs and lifters. Heads are ported and polished with racing valves.

Opinions on how practical this swap is would be appreciated - Donzi 22ZX has Merc K planes and Latham external steering on the Bravo 1 drive.

Seems California Speed and Marine offers a relieved, extrusion ported and shortened runner manifold for the 502MAG MPI fuel injection system. Wonder about this as an alternative to the blue engine injection system. Any opinions out there?


Ummm! I think you mean arizona speed and marine, pistons are differant compression ratio so you wont get the full effect as to a 500 efi..
As for a cam i wouldn't use a crane 731 or a 741, call Bob mandare at marine kinetics 585-654-8583 ,tell him what your doing and have him grind you a camshaft...Trust me you won't be dissapointed.

If you really want a kick azz controller look into painles wireing mefi4,they supply the software for your laptop for tuning,the engineer ever gave me his personal cell # so if i wanter to go deeped into the software he said he would give me the code to brake into other folders for finner tuning..

Dr. David Fleming
01-09-2010, 06:32 PM
Yah, I love your enthusiasm, man it is contagious! Want to get in my big power donzi and go kick some ass!

I just got an e-mail from J. Shofnar (sp) who designed the blue manifold for Merc Racing. He said Mercruiser wanted one to develop the New 502 engine they are developing for next year, and then Merc decided to make the new manifold themselves using his design. I think he is not really happy about that.

J. Shofnar also says that ASM makes a wiring harness to adapt the 500EFI manifold to the 502MAG MPI Mercruiser setup think it is about $600 but saves chopping up the old harness - no cut and paste bull xxxx to do the computor. They also have a bracket to mount the MEFI 3 on the intake upper plenum $70 I think. I just had CMI add the small bolt bosses to my E-top header to put the MEFI on the headers like it attaches to the Mercruiser exhaust manifold. CMI makes a plate to attach it. I wonder if Merc Racing takes it off the exhaust in case the engine looses water pressure and they don't want it cooked on the header?

I told J. Shofnar from ASM he should give us the story on how he developed the blue engine manifold as it is one of the great fuelie setups of marine racing. Wonder if he will reply?

Was surprised to hear that folks have had trouble dealing with ASM as they seem a pretty professional bunch from what I can see.

The Hedgehog
01-09-2010, 07:13 PM
Yah, I love your enthusiasm, man it is contagious! Want to get in my big power donzi and go kick some ass!

I just got an e-mail from J. Shofnar (sp) who designed the blue manifold for Merc Racing. He said Mercruiser wanted one to develop the New 502 engine they are developing for next year, and then Merc decided to make the new manifold themselves using his design. I think he is not really happy about that.

J. Shofnar also says that ASM makes a wiring harness to adapt the 500EFI manifold to the 502MAG MPI Mercruiser setup think it is about $600 but saves chopping up the old harness - no cut and paste bull xxxx to do the computor. They also have a bracket to mount the MEFI 3 on the intake upper plenum $70 I think. I just had CMI add the small bolt bosses to my E-top header to put the MEFI on the headers like it attaches to the Mercruiser exhaust manifold. CMI makes a plate to attach it. I wonder if Merc Racing takes it off the exhaust in case the engine looses water pressure and they don't want it cooked on the header?

I told J. Shofnar from ASM he should give us the story on how he developed the blue engine manifold as it is one of the great fuelie setups of marine racing. Wonder if he will reply?

Was surprised to hear that folks have had trouble dealing with ASM as they seem a pretty professional bunch from what I can see.

I have not heard one good thing about them in quite some time. They did do the manifold though.

I heard that they had a few decent products but service is horrible.

Eddie has a guy that makes the harnesses. They are plug and play.

I think that a 500hp sleeper motor would be very cool in a 22ZX. A great combo.

MOP
01-09-2010, 08:14 PM
I like the way they look. But dana's customer service is horrible. They made a mistake but it is was my "fault". I got the tailpipes fixed on my dime to make them right. With what I spent on the custom Dana's and fixing them I could have just bought CMI's. But they look nice and functional well now.

I know the Dana's are wider, they should offer a kit with offset tubes.

mrfixxall
01-09-2010, 09:11 PM
Yah, I love your enthusiasm, man it is contagious! Want to get in my big power donzi and go kick some ass!

I just got an e-mail from J. Shofnar (sp) who designed the blue manifold for Merc Racing. He said Mercruiser wanted one to develop the New 502 engine they are developing for next year, and then Merc decided to make the new manifold themselves using his design. I think he is not really happy about that.

J. Shofnar also says that ASM makes a wiring harness to adapt the 500EFI manifold to the 502MAG MPI Mercruiser setup think it is about $600 but saves chopping up the old harness - no cut and paste bull xxxx to do the computor. They also have a bracket to mount the MEFI 3 on the intake upper plenum $70 I think. I just had CMI add the small bolt bosses to my E-top header to put the MEFI on the headers like it attaches to the Mercruiser exhaust manifold. CMI makes a plate to attach it. I wonder if Merc Racing takes it off the exhaust in case the engine looses water pressure and they don't want it cooked on the header?

I told J. Shofnar from ASM he should give us the story on how he developed the blue engine manifold as it is one of the great fuelie setups of marine racing. Wonder if he will reply?

Was surprised to hear that folks have had trouble dealing with ASM as they seem a pretty professional bunch from what I can see.

Im not to fond of the merc intake manifolds,their limited to hp unless your forcing air through them..If i remember correctly max hp sucking air is around 615 hp but would be good for what your doing with your boat.

I prefer throttle body's with direct port injection,you can do more N/a hp with them and their not a pain in the azz to work on..everything is accessible with out taking the upper plenum off..

Listen to hedge! ASM suck when it comes to customer service and i heard their prograhming is not that good..talk to eddie like hedge said if you want your chit to rock!!!!!!!!:)

The Hedgehog
01-09-2010, 11:01 PM
Im not to fond of the merc intake manifolds,their limited to hp unless your forcing air through them..If i remember correctly max hp sucking air is around 615 hp but would be good for what your doing with your boat.

I prefer throttle body's with direct port injection,you can do more N/a hp with them and their not a pain in the azz to work on..everything is accessible with out taking the upper plenum off..

Listen to hedge! ASM suck when it comes to customer service and i heard their prograhming is not that good..talk to eddie like hedge said if you want your chit to rock!!!!!!!!:)

Good point on the 615hp. That is on the money. I heard that 615-620 it it. On special instances I have heard as much as 640hp but not on a regular basis.

Eddie was dynoing one and had it huffing and puffing at 620. He then put on his Holley system with a single plane manifold and pulled 675 with clean AFR's.

The point is that you are probably passing up some free hp in the 475-500hp range with the stock system. If you want to do a sleeper then go with your manifold and get that kind of power. At the same time, if you want to look trick with the blue manifold....well why not be paid in free hp and do something totally big. It won't cost more, will make more power and run great.