VDJ79 H150 into HDJ80? (1 Viewer)

[Brendon85]

The TT kit is for H150 @mudgudgeon - my research indicates you'd need the guts of the H150 rather than the H151. Mainshaft, Layshaft etc. are different part numbers unless I've read incorrectly.

The TT kit including a gearbox rebuild kit with bearings etc. is 2k in round figures plus labour.

A new H152 is $3300, but needs an input shaft swap and the input bearing retainer machined down to work behind a 1FZ/1HD-# etc. This is about 4.5 hours labor all up.

The other thing is, I had 33s/35s on any manual 1FZ vehicle I've owned (one N/A, 1 turbo) and I don't think it'd have the legs at 2k rpm to pull anything other than a mild hill, gets old shifting gears all the time on the highway. Unless it's got stock tyres, I'm not sure if @Brendon85 will see much benefit. The shorter first of the H150/152 is also nice with the bigger tyres.

In context of fitting a H152 to a FZJ105

My understanding the bearings in the H152 are better than that in the H151?

Would using the gearbox bearing maintainer from H151 avoid having to machine the bearing maintainer from the H152?

Once the bellhousing has been swapped over from the H151 to the H152, will the gear stick require modification?

Will the transfer case from the H151 bolt up to the H152?

Apologies for all the questions. No idea what is required for this job. Just wanting to help the fuel economy on the highway.

 

[AussieHJCruza]

In context of fitting a H152 to a FZJ105

My understanding the bearings in the H152 are better than that in the H151?

Would using the gearbox bearing maintainer from H151 avoid having to machine the bearing maintainer from the H152?

Once the bellhousing has been swapped over from the H151 to the H152, will the gear stick require modification?

Will the transfer case from the H151 bolt up to the H152?

Apologies for all the questions. No idea what is required for this job. Just wanting to help the fuel economy on the highway.

The 'case' is the same H151-H152 (or very similar at least) so once the input shaft is swapped, it's a bolt-in affair.
What size tyres do you run? What's your current highway fuel consumption?

 

[Brendon85]

The 'case' is the same H151-H152 (or very similar at least) so once the input shaft is swapped, it's a bolt-in affair.
What size tyres do you run? What's your current highway fuel consumption?

Currently getting 24L/100km. Using 33" tyres.

 

[mudgudgeon]

Currently getting 24L/100km. Using 33" tyres.

You've got a bigger problem than needing a taller 5th gear!

I routinely got 14-15L/100 km.
I'm don't have a light right foot either.

The only time I saw over 20L/100 was off road. Driving in sand, or a lot of slow speed hilly stuff where you're in low range or low gears constantly.

I had 4.1:1 diff gears in my hzj105 (4.3:1 is stock) so similar final dice to what you'd get with a h152. At highway speeds, anything more than a slight hill would have me shifting back to 4th. Because of this, I don't think there's any real gain in economy.

Higher 5th gear will make it less noisy at highway speed. Beyond that, I'd question the value

 

[AussieHJCruza]

Agree with @mudgudgeon - best 1FZ fuel economy I've ever had was 15.6 L/100 with an FZJ80+A442, stock size tyres, fresh out of a tune up with new correctly gapped spark plugs, genuine new leads and distributor cap, air filter etc.
Average in Manual FZJ80 with 33s (either 285/75 or 255/85R16) was 17-18 highway, not driving it gently and the turbo FZ (95 FZJ80 with H151 and 315/75r16) used to get 17-20 depending on terrain.

1FZ-FE max torque is at 3600rpm for the Coil-Pack engine.

I can't find a BSFC graph for the 1FZ but I'm not sure there's a lot to be gained from dropping highway RPM.

One more thing, is your 24L/100 corrected for the 33" tyres?

 

[Brendon85]

You've got a bigger problem than needing a taller 5th gear!

I routinely got 14-15L/100 km.
I'm don't have a light right foot either.

The only time I saw over 20L/100 was off road. Driving in sand, or a lot of slow speed hilly stuff where you're in low range or low gears constantly.

I had 4.1:1 diff gears in my hzj105 (4.3:1 is stock) so similar final dice to what you'd get with a h152. At highway speeds, anything more than a slight hill would have me shifting back to 4th. Because of this, I don't think there's any real gain in economy.

Higher 5th gear will make it less noisy at highway speed. Beyond that, I'd question the value

When I got the car ~2019 it was getting 24L/100km.

Since then I have had the engine rebuilt and replaced a bunch of parts.

The last work I had done was a new aftermarket ECU and wideband O2 install.

The only mechanical work that has not been addressed is the

Gearbox
Transfer case
Differentials

The car was getting 24L/100km before and after accessories. It made no difference with the figures.

From reports I received, the 1FZ-FE is notoriously heavy on fuel.

I have heard numerous reports saying the figures I am getting are normal.

 

[mudgudgeon]

Along with 4.1:1 diff gears, I was running 33" tyres.

This gave me around 8% overdrive compared to stock gears and stock tyres (memory of GPS speed check. Would have to redo calcs to be sure)

 

[mudgudgeon]

When I got the car ~2019 it was getting 24L/100km.

Since then I have had the engine rebuilt and replaced a bunch of parts.

The last work I had done was a new aftermarket ECU and wideband O2 install.

The only mechanical work that has not been addressed is the

Gearbox
Transfer case
Differentials

The car was getting 24L/100km before and after accessories. It made no difference with the figures.

From reports I received, the 1FZ-FE is notoriously heavy on fuel.

I have heard numerous reports saying the figures I am getting are normal.

I missed you had a 1fzfe.

Still think you have a problem. My fzj80 sees 16-17 litres/100 on 33s.
A 105 is slightly heavier than an 80, but not 7 litres/100 heavier

 

[mudgudgeon]

24L/100km = about 9mpg.

I know a lot of USA 80 owners complain about 10mpg as being bad economy. But that's with auto trans. USA models had no manual transmission option.

Depending on how you drive, a manual should be able to do quite a bit better economy wise than the older 4 speed autos.