Vortec L31 MARINE MANIFOLD project! Q&A

Performance modifications, tips & tricks

Moderators: flyingpolarbear, Dev, James B.

Hog
Posts: 5025
Joined: Tue Dec 11, 2001 4:00 pm
Location: 1997 Chev ECSB L31 350 1997 GMC Sierra SLE RCSB, Ontario

Post by Hog »

alsolek96 wrote:"Entire fuel rail is stainless steel and brazed together as a single unit with no possibility of leaking. Fuel pressure regulator has a lower pressure than stock at about 50-55psi instead of 60-63."

Does this mean run the automotive regulator?
Not necessarily, you just need to adjust the Injector Flow Rate (IFR) to account for the change. This must be done anyways if you are using different sized injectors anyways.

peace
Hog

alsolek96
Posts: 4
Joined: Sun Mar 25, 2012 6:33 pm
Location: Connecticut

Post by alsolek96 »

Hog wrote:
alsolek96 wrote:"Entire fuel rail is stainless steel and brazed together as a single unit with no possibility of leaking. Fuel pressure regulator has a lower pressure than stock at about 50-55psi instead of 60-63."

Does this mean run the automotive regulator?
Not necessarily, you just need to adjust the Injector Flow Rate (IFR) to account for the change. This must be done anyways if you are using different sized injectors anyways.

peace
Hog
Can you give some details on injector flow rate? I am running different injectors, Lucas Injectors. 42lb @ 43.5 psi , 48lb @ 58psi

Hog
Posts: 5025
Joined: Tue Dec 11, 2001 4:00 pm
Location: 1997 Chev ECSB L31 350 1997 GMC Sierra SLE RCSB, Ontario

Post by Hog »

alsolek96 wrote:
Hog wrote:
alsolek96 wrote:"Entire fuel rail is stainless steel and brazed together as a single unit with no possibility of leaking. Fuel pressure regulator has a lower pressure than stock at about 50-55psi instead of 60-63."

Does this mean run the automotive regulator?
Not necessarily, you just need to adjust the Injector Flow Rate (IFR) to account for the change. This must be done anyways if you are using different sized injectors anyways.

peace
Hog
Can you give some details on injector flow rate? I am running different injectors, Lucas Injectors. 42lb @ 43.5 psi , 48lb @ 58psi
Sorry if you have posted this already, but what fuel pressure are you running at KOEO? In other words what rail pressure are you reading with the fuel pump running, engine not running, or engine running with the vacuum reference disconnected?

Since your injector flows 42 lb/hr@43.5psi(3BAR) and 48lb/hr@58psi(4BAR). If your fuel rail preessure is 60 psi that injector will now flow 49.4 lb/hr.
If it is running 55 psi it will flow 47.23lb/hr.
You would then take the newer IFR(injector flow rate) convert it into whatever engineering units the tuning siftware uses and enter that value into the calibration.
The blackbox PCM uses grams per second (g/sec.)

49.4 lb/hr=6.22 grams per second
47.23lb/hr=5.94 g/sec.

The IFR must be accurate as these values are used by the PCM to calculate how much fuel the engine will get via adjusting the injector pulsewidths or how much fuel is "squirted" into the engine.

peace
Hog

alsolek96
Posts: 4
Joined: Sun Mar 25, 2012 6:33 pm
Location: Connecticut

Post by alsolek96 »

stroker97k1500 wrote:The only difference bw the Volvo MPI and the Mercruiser MPI marine intake manifold is the paint color..... That's it
Just to clear this up for anyone looking to buy a marine intake. The Volvo is very different then the mercruiser. Save yourself the headache and buy mercruiser.

willis82
Posts: 33
Joined: Sun Nov 15, 2009 5:33 pm
Location: Grand Rapids, MI

Another marine intake on the road

Post by willis82 »

Just thought I'd give everyone here who contributed to this thread a big thanks. Put my marine intake on this weekend, was a huge success with the help of all the information here. Now there's another marine intake on the roadways. This intake is definately what GM should have done from the get go.

James B.
Moderator
Posts: 2821
Joined: Thu Apr 03, 1997 4:00 pm
Location: '98GMT400, '98GMT410, '99GMT420, '00GMT420

Re: Another marine intake on the road

Post by James B. »

willis82 wrote:Just thought I'd give everyone here who contributed to this thread a big thanks. Put my marine intake on this weekend, was a huge success with the help of all the information here. Now there's another marine intake on the roadways. This intake is definately what GM should have done from the get go.
Good to hear. Thanks for posting your results!

ghansen
Posts: 5
Joined: Thu May 17, 2012 9:39 am
Location: Victoria, B.C., Canada

Post by ghansen »

Hi, I've just been reading about the marine intake conversion. I wish I knew about this about 10 years ago but better late than never. Does anyone out there have a marine intake for sale. I'd like to install the intake and a cam in my 97 L31. I have the cold air intake, edlebrock headers and full exhaust. Currently I have a power programmer flashed my ECU but I would like a little more power without completely changing out the engine. Any help would be apreciated.
Thanks

ghansen
Posts: 5
Joined: Thu May 17, 2012 9:39 am
Location: Victoria, B.C., Canada

Looking for a replacement intake manifold for L31

Post by ghansen »

I just found that Edlebrock makes a replacement for the L31 intake manifold that looks fantestic and possibly a lot cheaper thatn the Marine version of the L31. Anyone had any experience with this unit and the details of how to make it work in regards to the electronics, etc..

Whipped383
Posts: 2104
Joined: Mon Mar 01, 2010 9:12 pm
Location: Salt Lake, 97K1500,ECSB, 383,Whipple,0411,Marine, 03K2500,CCSB,8.1&Allison, Whipple in progress

Post by Whipped383 »

Do you have a link? Are you talking about the scorpion?

Chevy 97
Posts: 1077
Joined: Tue Jan 24, 2012 1:19 pm
Location: 97 ECSB K1500 6.3L 4L80E 14 bolt SF Hydro Boost, Headman Ellite Headers, 140 amp alt.

Post by Chevy 97 »

Whipped383 wrote:Do you have a link? Are you talking about the scorpion?
http://www.boats.net/parts/search/Merc/ ... parts.html

Is this the manifold you were refering too?

Image

I wouldn't mind this manifold.

ghansen
Posts: 5
Joined: Thu May 17, 2012 9:39 am
Location: Victoria, B.C., Canada

Post by ghansen »

The Edelbrock Manifold is a Victor EFI manifold http://www.summitracing.com/parts/EDL-29135/. It needs a rail kit, injectors and wires as well as a throttle body but otherwise a complete replacement. $315.00
As stated in the blurb from Summit Racing; These Edelbrock Super Victor EFI intake manifolds make it simple to convert competition engines to electronic fuel injection. They have injector bosses precisely positioned and machined for excellent fuel spray patterns and maximum power. These manifolds require a universal 4-barrel throttle body, fuel rail set, fuel injectors, fuel pump, and regulator, which are each sold separately.
Also they are stated to be used for drag racing.

JR96CK
Posts: 1515
Joined: Fri Apr 03, 1998 8:12 pm
Location: Texas

Post by JR96CK »

I don't know if this has been mentioned already, but since I'm selling my marine manifold, I needed to weigh it to make up a shipping quote. I knew they were heavy, but I did not think it would weigh 62 pounds! That's the bare upper Aluminum plenum and the (still painted) cast iron lower section bolted together, no injetcors, no fuel rail, no throttle body, no sensors attached, etc.

At least I don't feel like such a weakling now, having previously thought I was straining to pick up a 30 pound intake. :/

ghansen
Posts: 5
Joined: Thu May 17, 2012 9:39 am
Location: Victoria, B.C., Canada

To: JR96CK

Post by ghansen »

You say your selling your marine intake. Is it available? If so I'm interested.

JR96CK
Posts: 1515
Joined: Fri Apr 03, 1998 8:12 pm
Location: Texas

Post by JR96CK »

Yeah, I put up a thread a few days ago over in the classifieds. Someone beat you to it though, as I just sold it earlier tonight. Thank you for the interest though, and if I come across any more, I'll pass the info on to you.

silver97
Posts: 8
Joined: Sun Jul 22, 2012 4:39 pm
Location: Virginia

Post by silver97 »

alsolek96 wrote:
stroker97k1500 wrote:The only difference bw the Volvo MPI and the Mercruiser MPI marine intake manifold is the paint color..... That's it
Just to clear this up for anyone looking to buy a marine intake. The Volvo is very different then the mercruiser. Save yourself the headache and buy mercruiser.
If you are talking about the 4 bolt T.B. pattern and the 3 bolt which we need, Volvo and mercruiser have them both. I just bought a red Volvo intake with the 3 bolt(correct) T.B. next to it was a black mercruiser with a 4 bolt T.B.

Whipped383
Posts: 2104
Joined: Mon Mar 01, 2010 9:12 pm
Location: Salt Lake, 97K1500,ECSB, 383,Whipple,0411,Marine, 03K2500,CCSB,8.1&Allison, Whipple in progress

Post by Whipped383 »

Theres that but the fuel rail is also different on one of the mounting ears.

lwrs10
Posts: 37
Joined: Fri Nov 23, 2012 3:00 pm
Location: Pensacola, Fl

Post by lwrs10 »

Time to turn this thread upside down!

I found this Mercruiser intake today. The boat it came off of was a 1999 425hp Vortec 350.

This is a MUCH better option performance wise i think!



Ran out of injector on my truck, so I started hunting for a marine intake so I can run normal injectors and fuel rails. Me and a buddy are both doing it at the same time.


He found his intake the other day for $200 local:

Image

Your standard cast iron marine intake.


So I continued on my hunt for mine. THIS is what I found!!!!


Look at those huge billet aluminum fuel rails with cross tubes.

Image


Its a dual plane high rise aluminum intake

Image


36lb injectors, Bosch style.

Image



Image

Image



It uses the exact same MAP sensor as our motors.

Image



It says Mercruiser on it, but i would bet alot of money its a Edelbrock Performer RPM re-branded for Mercruiser.

Image



It uses a standard water neck configuration. This will take some planning to figure out how to get our radiator hose on here...

Image



I will get the intake cleaned up, paint removed, and start gathering parts to swap it on my 1996 350 in my S10. So far, it looks like our throttle body will bolt right up, even though the one on this intake i bigger.

More to come!

CrazyHoe
Posts: 6228
Joined: Tue Feb 19, 2008 8:30 am
Location: Mtl; '98 2dr4x4 Tahoe, L31,Hookers Long T, 0411,EFIlive, 4L80-E,dual 3",marine int+inj

Post by CrazyHoe »

Sweet! Dual plane Vortec = torque.
Someone correct me, I think a pre-Vortec, TBI rad hose should do.

lwrs10
Posts: 37
Joined: Fri Nov 23, 2012 3:00 pm
Location: Pensacola, Fl

Post by lwrs10 »

found it!

its only $379 brand new.....

http://www.perfprotech.com/mercruiser-p ... ?model=947

JR96CK
Posts: 1515
Joined: Fri Apr 03, 1998 8:12 pm
Location: Texas

Post by JR96CK »

NICE. 8)

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