D100 Turbo Pet Project

[K-Note72]

So I have this pet project in mind that I'm entertaining for later on down the road. It's inspired by a late 70s D100 my Gramps had back in the day, that I had some nostalgic memories of (namely remember the grill). This is more of a passion project that I'd imagine goes against "what everybody else does", so here's what I got in mind:

-Mid-to-late 70s D100, either stepside or shortbed panel w/ small lift (they both look good so it's hard to pick)

-225 Slant 6
-Aftermarket EFI
-Turbo setup with mild boost (mild enough to keep stock engine internals)
-Either 518/46RH or a500 trans (see below)
-833 geared somewhere between 3.55 or 4.10

Since I have a half hour commute going anywhere, a small engine and a decent cruising trans are vital to making it cost-effective in the long run (the turbo makes it peppy and worthwhile). I'd like the capability to tow a car on occasion, so that's where I figure on beefier springs, bigger (power) brakes and a trans oil cooler. The turbo adds to fuel economy when I'm cruising (excess of teens mpg would be nice), and beef up power when I'm towing or just laying on the gas. I know that the "bigger engine" crowd will chime in at some point, but tbh if a naturally aspirated slant came stock in a D100 then a slant with a turbo and overdrive trans will do just fine (Ford's doing the same thing with the ecoboost in their F150). Sure I could probably save on the work and just get a newer pickup that could do all these things, but the passion just wouldn't be there (plus I'm seeing long-term reliability with cars and trucks go down as they become more and more reliant on electronics, the basic EFI is the most I feel comfortable relying on them).

There are PLENTY of turbo slant projects out there, so I have options to pick from as far as turbo setups go. I just have a few questions I was wondering if anybody could answer:

• 518 vs 46RH, which trans is which? I have a 91 Dakota with the V8 4x4 and auto trans w/ selectable OD, marketed as the tow haul pkg so I figured that was a good starting point. However, I just can't find out which one that trans is, and I've gotten conflicting claims as to which is which. UPDATE: I think in fact my Dakota actually has the A500 unit, the 518 seems to be for the Ram and the 500 fits my Dakota model year. Remember, my trans has the pushbotton selectable under/overdrive
  
• Anyone who has dealt with a boost setup, any idea what's a good mild boost pressure? Again, just want a turbo setup I can run with EFI and electric fuel delivery and can run without having to upgrade engine internals. If needed, I could consider an oil cooler
• What is the usual idle rpm for the slant? Not a major question upfront, just curious what stall the torque converter will need to be.

I know that the slant came as an option in the D100, and I'm told they can handle very well on boost (not that I'd plan to put much through it), I just haven't heard of too many people doing the same thing so I wanna brainstorm on this.

 

[LocuMob]

Only thing I'd worry about is towing a car with the slant, turbo or not. (I'm one of those big block guys here to preach! No, not really) Other than that I think it's a cool idea.

 

[dodgefred]

cool i like the idea of an EFI TURBO setup.

 

[K-Note72]

Only thing I'd worry about is towing a car with the slant, turbo or not. (I'm one of those big block guys here to preach! No, not really) Other than that I think it's a cool idea.

If a Ford ecoboost can haul, so can a Slant! Besides the extra bells and whistles, the ford has direct injection, a turbo and a 6spd trans. Besides basic TBI injection, I'd be giving the slant the turbo and splitting the gap with the overdrive trans. Should I need the extra torque, I'll just hit the button and drop outta overdrive. That's also why I wouldn't be going too highway with the axle gears. The only trouble would be finding out which model trans is in my Dakota so I can use it as a baseline.

cool i like the idea of an EFI TURBO setup.

Yeah I hear there are fewer turbo troubles with efi than with a carb. Plus people are pushing out crazy boost through the slant, so mild boost shouldn't be any trouble at all. Supposedly the slant was originally designed to be cast from aluminum so they gave it thick cylinder walls, but due to production costs they scrapped the aluminum idea and stuck with iron yet kept the thicker walls. Guess that's more reassurance against seeing a rod hanging out the side of your block

 

[paul massaro]

hey my old beast would haul the mail with 3.91's in the butt with its /6 auto . but the 383 hp auto would run around the /6 , while its hauling the load .

 

[K-Note72]

hey my old beast would haul the mail with 3.91's in the butt with its /6 auto . but the 383 hp auto would run around the /6 , while its hauling the load .

I'm not saying the slant would be super powerful at it, but the slant w/ turbo should be just enough to get it done (since it'd only be towing a car or the like on occasion). Remember, the ones people remember from back in the day were naturally aspirated mills.

The goal is something I can get decent mileage with just cruising around, and then drop the OD in the trans whenever I need to haul something (get the best of both worlds). I still have my 91 Dakota, but it's seen better days and really the mileage isn't great (in best condition on a good day that 5.2L got 21mpg). That trans was cool cause I could drop outta OD at the push of a button, helped if I had a full truckbed going up the steep county line hill. Since the 5.2 it's mated to is still from the LA series, and the slants were often mated to the same transmissions as the LA engines, I figure it shouldn't be too big of a deal.

 

[paul massaro]

well /6 and 'a'poly and 'la'wedge motors were bolted to the same autos and stick bell housings . there is an adapter/spacer involved for the /6 . not sure about dowel pin placement although .

 

[K-Note72]

well /6 and 'a'poly and 'la'wedge motors were bolted to the same autos and stick bell housings . there is an adapter/spacer involved for the /6 . not sure about dowel pin placement although .

I've been looking at spacers, some people are scavengine ones from junkyard pickups using the slant, some are having them custom made, and one suggestion popped this up AdvanceAdapters.com | Engine & Transmission Conversion Adapters - Advance Adapters

P.S. After strenuous searching, I think the trans in my Dakota is the A500. This correct? there's so much jumping around on which is which, and dodge used quite a few transmissions models through the 90s so it gets hard to narrow down

 

[paul massaro]

could be a a518 as well . never used them yet , but the a500 is a od 904 and the a518 is an od 727 . theres a deep pan on some years a518's . more fluid makes cooler running . but if a fuel injected 5.2 gets 21 mpg then the choice is done . better torque better fuel mileage and you could turbo that as well .

 

[K-Note72]

could be a a518 as well . never used them yet , but the a500 is a od 904 and the a518 is an od 727 . theres a deep pan on some years a518's . more fluid makes cooler running . but if a fuel injected 5.2 gets 21 mpg then the choice is done . better torque better fuel mileage and you could turbo that as well .

That was when it was running better, right now it gets close to 17 (has a cracked piston ring on cylinder 8). I also had to scrap the cat converter and drop in a k&n air filter to get it up to that point. I know these are only verbal claims, but people across deparate forums claim easy 20-24mpg on a decent carb tune. EFI can improve on that, and with granny driving the turbo can push that a bit further.

As far as the trans goes, I think it might be the 500. I had to go to wikipedia for this (UGH) but the 500 is stated to have the overdrive unit bolted to the back of the trans. Plus my dakota has a button like this to the left of the steering wheel

 

[65 sporty]

Like Paul said the A500 is based on the 904 and the A518 is based on the 727. Both transmissions have bolt on O-D units. The pan on the A500 is the same shape as the 904 and the A518 pan is the same shape as the 727. I believe your Dakota will have the A500

 

[K-Note72]

Like Paul said the A500 is based on the 904 and the A518 is based on the 727. Both transmissions have bolt on O-D units. The pan on the A500 is the same shape as the 904 and the A518 pan is the same shape as the 727. I believe your Dakota will have the A500

Oh so the 518 is selectable OD too? It's not just a fixed 1/2/3/OD? If that's the case then I think I'll go with the 518 since it's supposed to be a heavier duty unit.

I got confused because through that decade-long period they went through a few different names and a couple variations, and it was hard getting a clear difference between the units.

 

[65 sporty]

The A500 is also known as the 42RH and the A518 is the 46RH. Your correct the A518 is the stronger unit

 

[7mopar]

The A518 has a larger and longer case. Will require transfer case relocation and drive shaft modifications. The trans mount is in the same location for eather. Also shift linkage and fluid lines will need to be changed.

 

[LocuMob]

Oh so the 518 is selectable OD too? It's not just a fixed 1/2/3/OD? If that's the case then I think I'll go with the 518 since it's supposed to be a heavier duty unit.

I got confused because through that decade-long period they went through a few different names and a couple variations, and it was hard getting a clear difference between the units.

I got confused about that myself years ago.

The A518 has a larger and longer case. Will require transfer case relocation and drive shaft modifications. The trans mount is in the same location for eather. Also shift linkage and fluid lines will need to be changed.

That's the important info right there! Let you know what you need to do, before it becomes a surprise, and ruins the day.

 

[K-Note72]

The A518 has a larger and longer case. Will require transfer case relocation and drive shaft modifications. The trans mount is in the same location for eather. Also shift linkage and fluid lines will need to be changed.

Do you happen to know what the dimensions each case has, the 518 & 500 vs 727 and 904? Or maybe an online resource that wll tell me those technical specs other than "4-spd automatic"?

 

[K-Note72]

Since this project involves a turbo and efi conversion, the both of which together haven't been done too much on a slant 6, I've been looking around at what resources I can that cover that. Given the runners on a slant 6 cause fuel distribution issues, and a basic tbi system doesn't fix that, I'm looking at any MPFI setup that could work. There's this one here DeBiase EFI that involves scavenging the mpi system from a GM 3.8L V6. While so far this is my best choice, I was wondering if anybody on here has tried something similar with a slant. I have a 92 Jeep with a MPFI 4L, just sitting, and was curious if that would work instead

 

[dodgefred]

Friend of mine has the same idea funny aint it? His plan is to use A 4L EFI and 904 from an AMC PACER. he is just scrounging in his barn for a suitable tranny with OD.

 

[K-Note72]

Friend of mine has the same idea funny aint it? His plan is to use A 4L EFI and 904 from an AMC PACER. he is just scrounging in his barn for a suitable tranny with OD.

Yeah if I recall the 904 is only a 3spd. Much nicer having OD, even nicer with an OD unit cause you can have the best of both worlds.

When exploring MPFI options for the slant, a lot of people ask about the jeep 4L's since they have that. I'm only asking about the Jeep option cause I actually have one sitting at home, wasting (host of electrical problems, but the EFI system should be unaffected)

 

[7mopar]

Ever thought about rails and injectors from the 3.9 v6?