Intake Manifold Help
 

Hello guys,


A little help; I need to change my intake manfiolds and would like to install an aftermarket manifold with a little more umph. The engine is a generation v 502 EFI.

What manifold would be compaitable with then engine?

All suggestions welcome

Changing the intake manifold will do nothing. It flows enough for a stock engine already.
For an upgrade, most people will just port and rework the stock intake.

I agree. Waste of time unless your getting serious about modding the engine.

fixx
 

i beg to differ..cool day they will run the same,,on a hotter day a air gap style intake will shine keeping the intake air charge cooler..

the only intake that will make a differance is a edlbrock air gap..that would be my only choice for a stock set up..

Thanks for the feedback.

Well, mine have cracked anyways so i would prefer to change them rather than weld them. Stock manifold is a bit expensive.. Can anybody point me in the direction or at least provide me a part number for an intake manifold that will fit my Gen v 502 efi's?

Thanks

Talking EFI.

I don't think your going to find a manifold that will work with the rest of the Merc FI system. Is this what you have?
http://www.perfprotech.com/mercruise.../180?model=507
You could try posting in the parts wanted section on boating forums or search the net for used ones. Or you could always chang to carbs. 2K for just the manifold section is rediculous.

fixx
 

my bad,,did not see the efi..

your screwed...look in the swapshop of you need to buy from merc...only other option would be is to find 2 set's of merc 500 efi manifolds..that will work with your ecm and dist..525 wont work..

What is cracked? upper or lower. do you need 1 or 2 manifolds. Randy

I know of 4 502 magnum MPI intake set ups, two are stock and two are ported.
The ported ones pushed a Cafe Racer into the low 70's, I would guess that would take 475-500 HP.
Also have the cams and computers from the ported ones. The first thing you need on any of the BBC motors is a good exhaust.

There's a guy in the swap shop, dirty dan, that has a couple post. Looks like he has a pair sitting on a table in his pics.

Yeah, Thats the correct manifold.. I know 2k is rediculous. It is the lower part of the manifold that cracked and flooded my engine. I don't want to get to deep into tunning i'd rather just have something that I can plug and play without fondling with the ECU. Where I live there really isn't anyone that can tune these motors.

Thanks

Will the MPI manifolds fit an EFI motor? Where can I find these? Will i need to start playing around with the ECU to get it functioning correctly?

Carb isn't really an option.. Our weather gets to 120+ and I don't want to be facing all the forward-reverse-forward headaches associated with carb's

I have a lower intake from a 2000 502 mag I can make a good deal on. Randy

I'm not positive of all the exact changes, But just so your aware, All the merc 454/502 intake part numbers (805233A6) for the EFI/MPI are the same starting in 1993 through about 1998.
502 MAG MPI BRAVO (GEN VI) GM 502 V-8 1998
Click on Serial number
0L017000 THRU 0L085432
http://www.mercruiserparts.com/Show_...+INTAKE+PLENUM

But sometime after 1998 or more importantly the engine serial number 0L085433 THRU 0M024999 had a change in intake manifold part numbers (861300A2) along with a change in fuel injector size & part numbers & fuel regulator PSI.
502 MAG. MPI BRAVO (GEN VI) GM 502 V-8
Click on Serial number
0L085433 THRU 0M024999
http://www.mercruiserparts.com/Show_...+Intake+Plenum

Here's the list of engines for you if needed,
http://www.mercruiserparts.com/selec....asp?type_id=8

Good luck.:)

There are a couple on Ebay right now -look under Mercruiser.fuel injection. Good Luck, should not be to hard to locate some new manifold sections.

MPI Intake
 

I have a complete upper and lower with fuel rail 500 + freight PM your email addres and I will send you pictures.

Here's the link

Will these fit an EFI?

The manifolds everyone is replying about are EFI. Electronic Fuel Injection, The MPI means Multiport Fuel Injection. There are two styles, the older system used a lift pump that mounted on the seapump. The other style are the ones that have been pictured & uses a cool fuel electric pump mounted behind the seapump. The 500efi & 525efi are completely different. Which one do you have? Can you post some pics? I have both styles that I can sell. Randy

Hey there.. I have a 502 gen v EFI. Please forgive me as I am far from being a merc guru. I know bits and pieces here and there but that's about it. I am basically looking for something i can bolt on, close the hatch, turn a key, and go!

MPI intakes
 

What year is your engine package? I am guessing you have the VST style injection with MEFI 1 ECU and utilizing the Keihin injectors. The other style Manifold typical in 99 on up Cool Fuel systems utilize the Weber style injector.

I have both styles with the appropriate fuel rails.

Engines are 1995's

Year
 

Your engine is VST using the Keihin injectors

Pics
 

Some pics of my manifold

manifold
 

your manifold is for the weber style injector

I take it the other style manifold has the vst pump that mounts behind the plenum. If that is the case I have the entire setup still mounted in a boat but needing a new home. Randy

Fyi
 

For future reference the difference is in the injector port the Keihin style is counter bored, and the boss on the lower for the 8 inch bolt

Thanks for the heads up tunertech, I will have to pull the other setup off of the engine. Randy