Mileage with H55F and 2F (1 Viewer)

[Mike S]

Gary Kardum is installing an H55F in my stock 1987 FJ60 and I should pick it up next week. I am doing this to make the truck more driveable at highway speeds, save the drivetrain, and get a little lower 1st gear.

With the 31" GoodYear MT/Rs and stock 3:73 gearing, I expect to improve my mileage a bit. Anyone have actual experience to share on mileage improvements with this set up?

Thanks

Mike S

 

[Cruiserdrew]

Mike-I can't answer your question, but I was at Mudraks today and saw your truck up on the lift-Its the red/orange with brand new MTR's right? That's a good looking 60. When you are there picking yours up, you can check out my blue '84 that's getting a bit of work there. With that set up your revs per mile should be pretty low and give you very pleasent freeway cruising. I hope your mileage improves, but I wouldn't count on that to pay for the swap. Did you get your T-case rebuilt at the same time? I am contemplating a 5 speed as well.

 

[Mike S]

Andrew - Right - a "tomato red" 60 with new MT/Rs. Got the engine, PS, and smog sorted out, new clutch assembly, 5 speed and Tcase rebuild, plus a few little things. Gary certainly knows Cruisers.

I am not figuring to get a big payback in mileage, but I am will take what I can get.

I will probably be there next Saturday afternoon to pick it up. I was conpemplating and OME suspesion set up but decided to drive it for a while to see what it's lake with the changes that Gary has made. I'll definitely check your truck when I am there...

Mike S

 

[CruisinGA]

Lets look at the numbers-
I believe the O/d on an H55 is 70% if so,
You will be doing 2000 RPM at 70MPH compared to the 2800 RPM you were doing before. Right in the max. torque range of the 2F (1800 RPM).
I really cannot comment on gas mileage, other than I would assume a noticable increase.
I would really like to know how much quieter highway driving is, and if it can hold 70/75 mph in o/d.

 

[dogboy]

for what it's worth: with the engine decently tuned, running 3" OME lift with 33 x 10.5 BFG AT/KO's, a heavy Kaymar rear bumper with tire carrier, and some steel drawer units (read: alot of added weight),
were averaging 12-14 mpg on a city cycle/ 15-17 mpg on the highway with our 2F/H55F setup. Cruises nicely on the highway....

-dogboy- '87 FJ60

 

[Mike S]

D'Boy - Any problems pulling the larger tires on a grade? Do you find youself dropping into 4th a lot?

 

[theferg]

Actually overdrive (5th gear) on an H55F is 0.845 or 84.5% (as per TLC FAQ). Comparatively it's not much of an overdrive, but you KNOW I would take it. Also, the gas mileage thing is debated. If you run your Cruiser at the same top RPMs as before, then your gas mileage with be just about the same. But, if you run your Cruiser at the same top SPEED as before, then you will see improved gas mileage. This is because the overdrive will allow you to be at a lower RPM at a high speed.

-Ferg-

 

[cruiseroutfit]

[quote author=Mike S link=board=1;threadid=7604;start=msg63838#msg63838 date=1069009663]
D'Boy - Any problems pulling the larger tires on a grade? Do you find youself dropping into 4th a lot?
[/quote]

I'm not D'Boy, but I do have a 2F/H55f combo in my FJ40...

I run 35's and 4.56 in the axles.. works great on the road.. I can cruiser at 85mph as long as I don't hit any hills, I have to drop it to fourth to stay around 65mph on hills. Well worth the swap in my opinion... We have done dozens of them in the last ten years and I don't know of a single complaint besides the $$$. And of all of them, the only one to have any problems was a used unit that came from Austrellia bolted to a 2H diesel, it has whining gears but hs worked fine behind a turbo'd 2H pushing a HEAVY FJ45 30,000+ miles.

 

[Mike S]

[quote author=theferg link=board=1;threadid=7604;start=msg63839#msg63839 date=1069010377]
Actually overdrive (5th gear) on an H55F is 0.845 or 84.5% (as per TLC FAQ). Comparatively it's not much of an overdrive, but you KNOW I would take it. Also, the gas mileage thing is debated. If you run your Cruiser at the same top RPMs as before, then your gas mileage with be just about the same. But, if you run your Cruiser at the same top SPEED as before, then you will see improved gas mileage. This is because the overdrive will allow you to be at a lower RPM at a high speed.

-Ferg-
[/quote]

Ferg, I believe that equates to about a 27% overdrive? It's a reciprocal calculation, as I understand it.

I drove my last cruiser (a 72 FJ40) into the ground in 150,000 miles with my lead foot and 4:11 gears. With the larger tires, overdrive, 3:73 gears, and a little more sense attained by growing older, I should make this one last longer.

 

[theferg]

Hmmm. I was going off what I read there.... And read and heard elsewhere. Didn't know it was a reciprocal calculation--don't even know how you would set it up in said reciprocal calculation. But regardless, I wasn't baggin' on it at all--I'd LOVE to have any tiny bit of an overdrive...I just remember it being said that compared to other 5 speeds, it's not much of an overdrive.

-Ferg-

 

[cruiseroutfit]

27% underdrive in 1st gear

16% overdrive in 5th gear

The NV4500 has a 27% overdrive

H55F 1st 4.843:1
H42 1st 3.55:1
H55F 5th .845:1
H42 4th 1:1

 

[rick_d]

I first put a H55 in my FJ60 in 1996. I was trying everything to improve the 12/13 mpg I was getting. Even before the tranny, I tried a Jacobs for a few months, a new OEM carb, trouble shot all of the emissions, OH the intake/exhaust etc.

I gained less than 1 mpg with the tranny.

BUT, it was the single best mod I ever did to the truck and do not regret it one bit.