Fj80 diesel swap? (1 Viewer)

[norwayacdc]

I’m looking at swapping a diesel and manual transmission into my 96 fj80. What are your guy’s recommendations? I’d like to get as high mpg as possible. Only way I’m going to be able to keep it is to turn it into a commuter.
Thanks,
Gunnar

 

[mudgudgeon]

If you're doing it to save money, you're barking up the wrong tree.

Unless you do a huge amount of miles every year, fuel savings will probably never pay for the conversion cost.

 

[Comet]

6bt.

 

[Comet]

You will save nothing but the ride isn’t free anyway.

 

[mjosoba]

If you’re doing it purely for the commuting ability, I’d say it will be cheaper to buy a decent little commuter.

If you’re set on a swap, I’d say 1HD-FT, or 6bt. Don’t discount the LS’s either. They seem to return decent mpgs.

 

[mehbohdi]

$10,000 - 30,000 (in conversion costs) buys a lot of gas.

 

[mudgudgeon]

$10,000 - 30,000 (in conversion costs) buys a lot of gas.

Not to mention diesel is more expensive at the pump.

 

[PIP]

$10,000 - 30,000 (in conversion costs) buys a lot of gas.

Some folks like an 80 series, but dislike the 1FZ and 4 speed auto. $30k is a small number compared to new vehicle costs.

 

[Tank5]

I got 20-22mpg with a 6BT/nv4500 in an 80 series with 4.11 gears, over drive gears in the tcase on 37s. It’s not cheap to get to that point but it is the best mileage I have ever gotten in in an 80.

 

[mjosoba]

I got 20-22mpg with a 6BT/nv4500 in an 80 series with 4.11 gears, over drive gears in the tcase on 37s. It’s not cheap to get to that point but it is the best mileage I have ever gotten in in an 80.

What’s the consensus now on lift for the 6bt? 4” pretty much mandatory? That might play in too, as far as 1HD vs 6bt. I want to do a 24 valve VE pumped one some day!

 

[PIP]

What’s the consensus now on lift for the 6bt? 4” pretty much mandatory? That might play in too, as far as 1HD 6bt. I want to do a 24 valve VE pumped one some day!

No lift needed, just higher capacity front springs.

Why a VE 24v? ISB head is rather terrible unless ported. 24v guides wear rapidly, you'll have oddball injectors. #6 injector line requires a hole cut through the firewall to remove in an 80 series.

 

[mjosoba]

No lift needed, just higher capacity front springs.

Why a VE 24v? ISB head is rather terrible unless ported. 24v guides wear rapidly, you'll have oddball injectors. #6 injector line requires a hole cut through the firewall to remove in an 80 series.

I drove a guys p pumped 24v once and loved it. He said it pulled much better than his 12v and was more efficient. I have no interest in that kind of power, and have driven the VE pumped 12’s vs p-pumped and they were much smoother, not nearly as loud, and more efficient. Just seems to be best of both worlds to me. And that dynamic timing is nice.

Edit: I’d prob go the common rail head route. I believe they’re smoother than the VP44?

 

[Tank5]

What’s the consensus now on lift for the 6bt? 4” pretty much mandatory? That might play in too, as far as 1HD vs 6bt. I want to do a 24 valve VE pumped one some day!

I had a 12 valve with the VE pump.

I was running a 4 inch lift to fit the 37” tires. I don’t know that a 4” lift is necessary to fit the 6BT.

 

[PIP]

I drove a guys p pumped 24v once and loved it. He said it pulled much better than his 12v and was more efficient. I have no interest in that kind of power, and have driven the VE pumped 12’s vs p-pumped and they were much smoother, not nearly as loud, and more efficient. Just seems to be best of both worlds to me. And that dynamic timing is nice.

Edit: I’d prob go the common rail head route. I believe they’re smoother than the VP44?

I have not experienced an efficiency advantage with a p-pump 24v over a 12 valve. Over a vp44, definitely. A loud engine would indicate he was running vp44 pop pressure- very wrong for p7100. That would get me questioning fuel economy claims....

 

[mjosoba]

I have not experienced an efficiency advantage with a p-pump 24v over a 12 valve. Over a vp44, definitely. A loud engine would indicate he was running vp44 pop pressure- very wrong for p7100. That would get me questioning fuel economy claims....

Definitely not vp44, I’d say. He said had to get adapters to run the mech injectors, maybe new lines but couldn’t say for sure. And it was much more quiet than the VP44. As to the efficiency claims… idk. He just said he liked it much more and it ran better on less fuel, and I sure enjoyed it. Wish I’d kept more info.

 

[Somebodyelse5]

I got 20-22mpg with a 6BT/nv4500 in an 80 series with 4.11 gears, over drive gears in the tcase on 37s. It’s not cheap to get to that point but it is the best mileage I have ever gotten in in an 80.

Curious what else you'd done to that motor, was the 20-22mpg from a box stock 6BT? Which one?

There's a lot you can do... 4" straight pipe, turbo, water / meth injection, propane, etc etc. Curious about the potential

 

[PIP]

Curious what else you'd done to that motor, was the 20-22mpg from a box stock 6BT? Which one?

There's a lot you can do... 4" straight pipe, turbo, water / meth injection, propane, etc etc. Curious about the potential

12 valve should average just under 20 mpg in an 80 with 35ish tires and mixed driving. P-pump engines typically deliver about an mpg less than ve engines. Freeway mpg can be wildly high- 25mpg or so if you drive slow 55-60mph. Expect 22-23 freeway around 70 with cruise on.

Stickshift usually gets better mpg than auto.

My 12 valve powered ZF6 CCLB Superduty weighs 8800 lbs empty with a Bradford work bed and some tools in the boxes. It is solidly 18.5 mpg daily driving and everytime I take it on long trips I'm towing a heavy trailer where it gets around 16-17 mpg.

You can get bad mpg with a 12 valve if you have something messed up like timing is off, poor quality injectors, sloppy converter with an auto or gearing that is higher or lower than optimal. Turbos are a big factor as well. Early free flowing turbos will get great highway mpg's, but will be slow to spool and smokey. On the opposite end a he351 with large compressor and tight exhaust will spool quick, but is a restriction on the highway.

Intercooling is another factor. I've seen some really restrictive, poorly executed intercoolers in 80 builds. It's better to leave it non-ic than force the air through a Rollercoaster of piping.

You also need to be sucking cool air. 80 underhood Temps are very high on hot days. Open element filters under the hood are poor performers on 80+ degree days.

 

[norwayacdc]

Thanks for all the reply’s, I’ve reached a crossroads where I have to start selling stuff. I’m selling one of my 60’s and was planning on using the profits from that on a new motor for my 80. It was my first car and I’d prefer to keep it. Might not make much sense but I much rather daily an 80 then get a cheap commuter car.