GM MPFI to AMC V8...pipedream or nightmare?

[Tinkerjeep]

Okay, so here is another pondering I have:

The GM MPFI system on the later 1990s and up Chevy trucks with the iron 5.7L/350 V8...swap it onto a AMC 360???

Versus the Howell GMTBI which is basically a dirt-simple, "dumb" TBI system...for $1600 + an aftermarket controller to allow the driver to tune his TBI after doing performance mods like adding headers and duals, or removing a Cat, or swapping cams.

Versus a Edelbrock MPFI system which is the "Premium" aftermarket MPFI system engineered and built specifically for the AMC 360-401 up to 450HP...for ?$3000+. Its a smart system and supposedly self tunes...but that buy-in is rough. Most of our Jeeps aren't even worth that!

So any thoughts/experience swapping these onto a modded AMC360 or 401? These things are almost literally in every junkyard in America! You can find them on 'Burbans and all kinds of Chevy trucks! I don't know when they upgraded to, or if its basically the same system they use on current V8 GM cars/trucks.

[JeepsAndGuns]

Are you talking about the CPI injection? Or newer than that? After after 95 they dropped tbi and went CPI, but also was when it went OBD2, which is big money to tune.

I am running a modded 16197427 and running MPFI. Run really nice. I bought the bare intake and fuel rails from the edelbrock kit and added my own injectors, throttle body, and retuned my TBI ecm. Theres pics and whatnot on here somewhere. Just search under my screen name.

I would stick OBD1 just for ease and afordability of tuning.

[Tinkerjeep]

I'm not sure what they used, I was under the impression it did not use a Throttle Body Injection, but used individual injectors over each port, just like the Edelbrock MPFI...so Them's the initials I called it by.

I am not a GM bookworm, so I have no idea what Initials GM chooses to apply to their FI systems. All I know is what I have picked up from guys taking about FI systems here or in JP magazine. Like I said, I'm not even an FI "Noob" 'cause I don't have any engines with FI on them.

So forgive my ign'ance.

[blazer3664]

I have these two threads JeepsAndGuns posted some time back marked.
http://www.ifsja.org/forums/vb/showthread.php?t=148346
and
http://www.ifsja.org/forums/vb/showthread.php?t=154287

I may go that direction at some later point.

First I need to get my heap going, but other things keep getting in the way.

Jim

Edit - Just noticed my triple 7 post #, might have to go buy a lotto ticket, that would get my heap funded..........maybe.

[Tinkerjeep]

Read all that...seems like its the idea I have, and the parts I wpuld likely source, except maybe a different intake for longer runners, Dual planes seem to work better for that as BillUSN-1 mentions.

The disappointment I have is that not one of the guys building these systems at the average cost of likely at least $1,000 EVER posted MPG before and after.

[JeepsAndGuns]

Well I never drive my cherokee for mileage. Its my fun weekend toy and I have a mild 401, not to mention every time I drive it, I drive it with a lead foot. Also when I tuned the system, I tuned it for max power, not mileage. AE, PE, timing, ect... all tuned for power with no reguard for mileage. But if your curious, here it is:
https://www.fuelly.com/car/jeep/cher...AndGuns/159400

As far as the intake. I doubt you would come out cheaper using a different intake, unless you already had, or could buy it for dirt cheap, and do the machine work yourself. If you bought a brand new intake and then paid a shop to do the machine work, you would be spending more.

[Billygoat]

Originally Posted by Tinkerjeep

Read all that...seems like its the idea I have, and the parts I wpuld likely source, except maybe a different intake for longer runners, Dual planes seem to work better for that as BillUSN-1 mentions.

The disappointment I have is that not one of the guys building these systems at the average cost of likely at least $1,000 EVER posted MPG before and after.

With the areodynamics of these rigs, I doubt anything other than a boneyard DYI TBI will ever pay for itself, even the DYI for dirt cheap will take a while.

You get major cool factor for the upgrades, just don't expect payback other than

[Tinkerjeep]

Originally Posted by Billygoat

With the areodynamics of these rigs, I doubt anything other than a boneyard DYI TBI will ever pay for itself, even the DYI for dirt cheap will take a while.

You get major cool factor for the upgrades, just don't expect payback other than

I get already, so its not an issue.

Did get gas today...and wonder of wonders: 9.1mpg ALL city driving...that's more than a 10% increase...must be the extra few degrees I advanced the initial last week. Of course the ambint temp is finally where it should be -above 60*. So maybe lack of having to sit for thirty seconds to warm up is a bit of a factor.

[chrism]

I have installed GM TBI's on two different FSJ's. You are not going to get much better mileage. A little but not a lot. What it does add is much better drivability. On both 360's (stock) there was a night and day difference in drivability.

If you are looking for milage I think you need to combine EFI with an OD tranny. I have a LT1/700R4 combo in my wag. I have tuned it specifically for milage since I drive it every day to and from work. I am able to get 17MPG consistently on my commute which is about 50/50 stop and go and highway (max 70mph). On straight highway @ 70MPH my best MPG ever was 21, but I average about 19. It took a lot of driving and tuning to get it there and I have to have a light right foot. All of this is also on stock tires and 3.31 gears.
I also have switchable tunes so I can go to my full power 91 octane or E85 tune if I want to mess around. 50/50 E10/E85 + the vette lt1 tune (with a few tweaks) really makes that thing scream.
In a daily driver FSJ I would pick the engine swap over the expensive EFI system. My next iteration is going to be a 5.3/700R4 when the LT1 dies.

[Tinkerjeep]

Wow. Interesting...A whole engine plus the tranny to get that mileage. But swapping in all that will also cost quite a bit. Without the GM motor in front of it (retaining a AMC V8) there is no easy way to get an OD tranny in a Jeep, unless its a manual.

[JeepsAndGuns]

Originally Posted by Tinkerjeep

Without the GM motor in front of it (retaining a AMC V8) there is no easy way to get an OD tranny in a Jeep, unless its a manual.

Manual trans or this if you want a chevy auto:
http://www.advanceadapters.com/produ...ngine-adapter/

Novak makes several adapters for AMC V8's- 304/360/401, plus the 6's

700R4, 4L60, "early" 4L60E

Been thinking of this if I keep the gas 360 in the Wag

[mud89]

Originally Posted by Tinkerjeep

a Edelbrock MPFI system which is the "Premium" aftermarket MPFI system engineered and built specifically for the AMC 360-401 up to 450HP...for ?$3000+. Its a smart system and supposedly self tunes...but that buy-in is rough. Most of our Jeeps aren't even worth that!

That's cheap, the mass air sequential port EFI system from PRO M racing costs $5000 . According to Daniel it's an awesome system, but as you say this is not for a $3000 rig, so just for info :
http://www.promracing.com/amc-v8-com...fi-system.html