HZJ 105 going boost or T case gearing

[Bullitt]

Hi All,

Am curently running quite modified 105 series @ 33x12,5 M/T.

Car weights around 2600 kg netto.

It's great machine but it lacks power- especially on sand and mud condition.

Also would like to go 35x13,5 MT as 33 are not enough on rough terrain conditions.

Shall I go engine boosted or T case geared?

Toyota LandCruiser 105 Series [1998 - 2007] HZJ - Diesel 4.2L Low Range & Overdrive Gears

Any ideas?

 

[Bullitt]

Anybody?

 

[gungriffin]

Being a US forum there aren't many people with the HZ engine. I can say that from what I have read, with the UZ gas engine regearing is almost mandatory with 35s. I wonder if you might not make more progress asking on the 80 series forum. I have the 4.88 gears in my 100 and it certainly gives the vehicle good pickup on 34s.

 

[bigredmachine]

personally i would regear the axles instead of the t-case or go for more boost. if your thinking of adding a bigger turbo or going fo rmore boost you can get more info in the diesel/24v section as sadly we only get the gassers here in the us so there aren't many diesels

 

[Spike555]

Regear the diffs, that is the easier and cheaper option.
By changing tire size you have changed the final dive ratio and now it is to high to give you the low end power you want/need.

 

[Bullitt]

Being a US forum there aren't many people with the HZ engine. I can say that from what I have read, with the UZ gas engine regearing is almost mandatory with 35s. I wonder if you might not make more progress asking on the 80 series forum. I have the 4.88 gears in my 100 and it certainly gives the vehicle good pickup on 34s.

Thanks Mate!

Well 4,88 seems to be pretty rough, right? Are U running 4,5 petrol?

So probably, having only 135 hp on diesel N/A shall I go even more rough like lets say 5.29?

Other options are:

4.10, 4.56, 4.88

Actually no idea about stock ratio but heard its 4,3....

 

[Bullitt]

personally i would regear the axles instead of the t-case or go for more boost. if your thinking of adding a bigger turbo or going fo rmore boost you can get more info in the diesel/24v section as sadly we only get the gassers here in the us so there aren't many diesels

HZJ 105/80 is running on 4,2 diesle N/A- 135 horse power.

Am noit a fan of boosting stock N/A engoine as I know its gonna be much less reliable than factory one- what in 4x4 extreme conditions is the most essential.

 

[bigredmachine]

there have been plenty of guys that have done a mild turbo on the 1fz which is also n/a from the factory. if your only doing 7-10 psi I don't think that would be an issue for reliability.

you would probably be fine with 4.88 gears, good balance between being able to drive on the highway and having low end grunt.

 

[Bullitt]

there have been plenty of guys that have done a mild turbo on the 1fz which is also n/a from the factory. if your only doing 7-10 psi I don't think that would be an issue for reliability.

you would probably be fine with 4.88 gears, good balance between being able to drive on the highway and having low end grunt.

Well Am thinking of 4,88- but looks like theres plenty otions for 80 none for 105 as the rear crown & pinion is different in 80 and 105.
Any ideas where to get the correct setup?



Thanks!

 

[bigredmachine]

Well Am thinking of 4,88- but looks like theres plenty otions for 80 none for 105 as the rear crown & pinion is different in 80 and 105.
Any ideas where to get the correct setup?



Thanks!

not a clue, we don't get the 105 in the us so I would be surprised if you could get gears for it in the us, best guess would be Australia or Europe. maybe you could use 80 thirds in the 105 axles assuming that the spline count is correct

 

[gungriffin]

Thanks Mate!

Well 4,88 seems to be pretty rough, right? Are U running 4,5 petrol?

So probably, having only 135 hp on diesel N/A shall I go even more rough like lets say 5.29?

Other options are:

4.10, 4.56, 4.88

Actually no idea about stock ratio but heard its 4,3....

Only you can decide what you want out of this experience. There is no single correct answer. Do you want performance or to just maintain your present level of performance with larger tires? Do you want reliability or power? Do you want to spend a little or a lot? Do you want a dedicated off road vehicle (that you trailer to the trail) or do you want to be able to drive on the highway?

I would most likely speak with a company about regearing the axles. At a minimum with larger tires (34" and up) you should regear to maintain the stock drivetrain gearing. My parts came from Carl at Just Differentials. I would suggest talking with him. He will best be able to convey the pros and cons and most likely will have the parts (or recommend where to find them).

My 100 is the gas 4.7 with a supercharger, doug thorley headers and an exhaust. Ha ha lots of HP, but it takes premium fuel (98 RON) fuel and uses about 18 l/100km (13MPG)

 

[hoser]

It's great machine but it lacks power- especially on sand and mud condition.

Also would like to go 35x13,5 MT as 33 are not enough on rough terrain conditions.?

If your biggest complaint is lacking power on sand and mud, then I'd say you need to go turbo.

 

[DieselEd]

Regear T-Case (you can get some custom made gears in the russian market)
+ keeping everything else stock
+ reliable
- find someone who will do this conversion
- even higher rpms on highway speeds (if you you go really low)

Regear Axle
As far as I know there are no options for the 105. The markets supplied with an 105 are usually not the liquid enough to spend even more money on vehicle or 35's (except AUS). Again I am sure you can get custom gears made in russia. Since the economy is weak it's cheap for EU/US/AUS citizen to shop some parts.

Turbo
The head of the HZJ105 as well as the piston rings do not like boost. You can get some torque out of it with an safari turbo for example, but do not expect huge gains. The 1HZ is simply not designed for power, it's a reliable engine for the worst environments.

Engine Conversion
Get an 1HD-FTE/1HD-FT Engine, pretty easy conversion (you might consider go automatic?). My HDJ100 is fully loaded 3.5t. It gets 22mpg fully loaded on the highway. 490.000 on the clock and runs like new.
I'd give my vote for that.

 

[gungriffin]

Regear T-Case (you can get some custom made gears in the russian market)
+ keeping everything else stock
+ reliable
- find someone who will do this conversion
- even higher rpms on highway speeds (if you you go really low)

Regear Axle
As far as I know there are no options for the 105. The markets supplied with an 105 are usually not the liquid enough to spend even more money on vehicle or 35's (except AUS). Again I am sure you can get custom gears made in russia. Since the economy is weak it's cheap for EU/US/AUS citizen to shop some parts.

Turbo
The head of the HZJ105 as well as the piston rings do not like boost. You can get some torque out of it with an safari turbo for example, but do not expect huge gains. The 1HZ is simply not designed for power, it's a reliable engine for the worst environments.

Engine Conversion
Get an 1HD-FTE/1HD-FT Engine, pretty easy conversion (you might consider go automatic?). My HDJ100 is fully loaded 3.5t. It gets 22mpg fully loaded on the highway. 490.000 on the clock and runs like new.
I'd give my vote for that.

I have been surprised at just how small the gains are on many of these Toyota diesels that have been turbo'd. With many American and German diesels the gains can be quite large. The sacrifice is that the reliability is not as high, even when they are stock.

What does 3.5t mean when you reference your HDJ100?

 

[DieselEd]

@gungriffin 3.5ton = 7.800lbs weight of the truck.

The diesels of the HZJ is a fully mechanical 4.2 naturally aspirated engine with NO turbo. This engine can run on the worst fuel, because there is nothing what could cause dirty sensors(there is none). There is no computer in this engine.I know a guy running 1.3million miles on it. It has never been opened. There is nothing to tune.

The 1HD FTE is just a modified more efficient version with electronics, diffrent components, turbo and more grunt. Still the 1HD FTEs ECU is not able to "adjust" the engines behaviour. It's more like a book: If this happens, do this and that. You can override that with a chip like the unichip q4. I dont think there is any sense in "tuning" a perfect reliable engine with enough power. If want it quicker I buy a BMW or so....

A modern diesel is more performance, efficiency and aesthetic orientated. Reliability is often only given in a clean and civilized environment. They also have ECUs with flexible parameters and more complex stuff for controlling the DPFand SCR crap.Upside of this: get a computer, play some numbers: boom you have double horsepower.

I work for a construction machinery manufacturer, we build our own engines. Our engineers always remind me: we do RnD for 4 years or more and still some guys think they can tune them in 3 minutes. Every component is build to accept a certain ammount of power. Do not think your engine is ok with tuning. Its a long term process if it will do another good 200hours tuned or 20000 hours untuned. True or not? I dunno, but these guys do the rocket science so I trust em.

 

[gungriffin]

@gungriffin 3.5ton = 7.800lbs weight of the truck.

The diesels of the HZJ is a fully mechanical 4.2 naturally aspirated engine with NO turbo. This engine can run on the worst fuel, because there is nothing what could cause dirty sensors(there is none). There is no computer in this engine.I know a guy running 1.3million miles on it. It has never been opened. There is nothing to tune.

The 1HD FTE is just a modified more efficient version with electronics, diffrent components, turbo and more grunt. Still the 1HD FTEs ECU is not able to "adjust" the engines behaviour. It's more like a book: If this happens, do this and that. You can override that with a chip like the unichip q4. I dont think there is any sense in "tuning" a perfect reliable engine with enough power. If want it quicker I buy a BMW or so....

A modern diesel is more performance, efficiency and aesthetic orientated. Reliability is often only given in a clean and civilized environment. They also have ECUs with flexible parameters and more complex stuff for controlling the DPFand SCR crap.Upside of this: get a computer, play some numbers: boom you have double horsepower.

I work for a construction machinery manufacturer, we build our own engines. Our engineers always remind me: we do RnD for 4 years or more and still some guys think they can tune them in 3 minutes. Every component is build to accept a certain ammount of power. Do not think your engine is ok with tuning. Its a long term process if it will do another good 200hours tuned or 20000 hours untuned. True or not? I dunno, but these guys do the rocket science so I trust em.

That is an awesome explanation. I have wondered about the HZ/HD engines for a while and you just answered most of my questions in a few sentences. Thanks!

 

[Bullitt]

@gungriffin 3.5ton = 7.800lbs weight of the truck.

The diesels of the HZJ is a fully mechanical 4.2 naturally aspirated engine with NO turbo. This engine can run on the worst fuel, because there is nothing what could cause dirty sensors(there is none). There is no computer in this engine.I know a guy running 1.3million miles on it. It has never been opened. There is nothing to tune.

The 1HD FTE is just a modified more efficient version with electronics, diffrent components, turbo and more grunt. Still the 1HD FTEs ECU is not able to "adjust" the engines behaviour. It's more like a book: If this happens, do this and that. You can override that with a chip like the unichip q4. I dont think there is any sense in "tuning" a perfect reliable engine with enough power. If want it quicker I buy a BMW or so....

A modern diesel is more performance, efficiency and aesthetic orientated. Reliability is often only given in a clean and civilized environment. They also have ECUs with flexible parameters and more complex stuff for controlling the DPFand SCR crap.Upside of this: get a computer, play some numbers: boom you have double horsepower.

I work for a construction machinery manufacturer, we build our own engines. Our engineers always remind me: we do RnD for 4 years or more and still some guys think they can tune them in 3 minutes. Every component is build to accept a certain ammount of power. Do not think your engine is ok with tuning. Its a long term process if it will do another good 200hours tuned or 20000 hours untuned. True or not? I dunno, but these guys do the rocket science so I trust em.

Great Answer. Thanks mate!

I am not going to change an engine to any other engine managed by ECU.

No way- not that philosophy.

Am also not going to have the turbo installed as this is unreliable option.

Again no way.

And so- I guess am gonna start searchin for 1HD FT- which I guess is fully mechanical operated engine (no ECU- right?) and swap & save my 1 HZ. Always can do revers when make decision for sale.

And secondary gonna make T- case regearing, what will dramatically improve offroad performance. Its cheaper than diff regearing.

That's gonna be my way.

HOWGH.