Replace Prado AWD to 4x2 and save fuel.

[Daniel Stapelberg]

I have a 3.0 1KZTE motor in my 90 series, consumption is about 6km/litre. I am going to swop the transfer case and front differential to the same as the 4runner , this way I can eliminate the AWD and run 4x2, still allowing 4x4 when I need.
Has anyone tried this? The 4 runner runs around 10km/litre, I'm hoping to get the same on my prado.
Interested to hear anyones thoughts.

 

[wobbly]

17mpg is poor - are you doing lots of stop/start city driving?

What tyres are you running? I got about 23mpg on bfg mud terrains on 255/85r16.

 

[Beau]

I believe the one or two people I've heard do this only save 1-2mpg at best. They also comment on the front end steering become a little lighter and feeling less controlled. In my opinion, not worth it for the hassle you'll go through. Also much easier to fit free wheeling hubs then swapping the transfer case out I believe. Try to improve your current fuel economy.

 

[Shayne]

Your money/time would be far better spent on making the engine healthy again , trusting Moggy's calculations because mpg i understand 17mpg is poor indeed .

Block the egr , remove and clean the intake manifold and stick a washer under bolts that hold your turbo actuator in place (effectively shortening the arm a little) and i will bet you will feel the improvement as well as improve fuel efficiency .

 

[AndyCook]

I drove from the alps across France and across UK to Scotland, around 1200miles
With front prop shaft removed from my landcrusier,
So it was 2wd due to a CV joint issue
MPG was identical to trip down with 4wd

So don’t bother...

 

[Chris]

+1. Waste of time. Spend your money on fuel instead. My consumption went up when I tried this and it was frickin awful to drive. The 4x4 system on Cruisers is so well made that messing with it is like putting pickle on rice pudding. What? I dunno, I ran out of ways of saying leave it alone.

 

[GeekOKent]

I have a part time 4x4 on the 105, and get about 2mpg lower if I do a long run with the front engaged.
Typically will get 24'ish and but with 4x4 in, I get about 22'ish.

So, just supporting what's been said. Don't bother.

However, my top speed is impacted. I typically sit at 70mph at 2200rpm or so, with the front locked this is more like 65mph.

Note please that the 105 is a much heavier and bulkier than the Colorado's - and that is before you consider all the stuff I have added in.

 

[AdventureWagon]

Could you trial this by removing the front (or rear) driveshaft and driving with the centre diff locked? At least you'll be able to trial for a time and see if it's worth it plus all you have is the faff of driveshaft removal/replacement.

 

[Chris]

KB, does your 105 have a center diff or just a transfer box? The 105's I have looked at have a transfer box and then locking front hubs so if you engaged 4x4 without the hubs you'd be spinning chunks of metal for nothing. I'm not big on the drivetrain for the 105 tbh.

 

[GeekOKent]

It's got a centre diff

 

[Daniel Stapelberg]

Your money/time would be far better spent on making the engine healthy again , trusting Moggy's calculations because mpg i understand 17mpg is poor indeed .

Block the egr , remove and clean the intake manifold and stick a washer under bolts that hold your turbo actuator in place (effectively shortening the arm a little) and i will bet you will feel the improvement as well as improve fuel efficiency .

Hi Shayne
I have blocked the EGR and already cleaned out the gunk from the manifold, to boot I have also had the turbo re conditioned even though was fine. Power had improved but not significally to satisfy the need to do more.
I will try the spacer on the turbo actuator - I had also thought of putting in a boost control with a gauge to get a better idea of the existing boost and how much it can be set using the boos vacuum controller.
Ill post my findings for this when i get around to it

Cheers

 

[Daniel Stapelberg]

Could you trial this by removing the front (or rear) driveshaft and driving with the centre diff locked? At least you'll be able to trial for a time and see if it's worth it plus all you have is the faff of driveshaft removal/replacement.

I have weighed this option, the front differential is a fixed permanently engaged unit. The drive from the differential to the wheels is also fixed - no hub locks and to fit hub locks would require to change out the hubs.
As much for the transfer box - also permanent engaged - this car is AWD and removing the front prop-shaft would not reduce the friction of the front drive axle enough to get a promising result.

I will have to go the whole hog and pull the front differential and replace with the one im taking off a 4 runner, the 4 runner diff has an actuator which engages the front drive shafts when 4x4 is required.
Also the transfer box is dis engaged while driving 4x2, it engages to drive the front diff when the 4x4 is required and the shifter moved to the 4x4 position.

I saw a few posts suggesting this will be a waste of time and money, I will still do this and i am positive it will give me the results i am aiming for.

Ill keep you posted.

 

[Daniel Stapelberg]

I believe the one or two people I've heard do this only save 1-2mpg at best. They also comment on the front end steering become a little lighter and feeling less controlled. In my opinion, not worth it for the hassle you'll go through. Also much easier to fit free wheeling hubs then swapping the transfer case out I believe. Try to improve your current fuel economy.

Hi Beau
Replacing the front differential will not change any of the existing front suspension parts, the hubs, upper/lower control arms will remain in place. its only the center diff part that is changed and is exactly the same shape and size as the AWD unit, just this has the engage.disengage yoke.

Free wheeling hubs require more effort - I think we are not talking about the same type of car here.

 

[Beau]

Hi Beau
Replacing the front differential will not change any of the existing front suspension parts, the hubs, upper/lower control arms will remain in place. its only the center diff part that is changed and is exactly the same shape and size as the AWD unit, just this has the engage.disengage yoke.

Free wheeling hubs require more effort - I think we are not talking about the same type of car here.

I never mentioned anything regarding the front suspension. Maybe you misread. Anyways, it sounds like you're going through a lot of effort chasing a couple more MPG when the likelihood is that the engine may just need some servicing done. Best of luck.

 

[Matt Vee]

Your money/time would be far better spent on making the engine healthy again , trusting Moggy's calculations because mpg i understand 17mpg is poor indeed .

Block the egr , remove and clean the intake manifold and stick a washer under bolts that hold your turbo actuator in place (effectively shortening the arm a little) and i will bet you will feel the improvement as well as improve fuel efficiency .

What is this Majic voodoo of which you speak, please expand

 

[Shayne]

What is this Majic voodoo of which you speak, please expand

You will find most of my learning here Matt https://www.landcruiserclub.net/community/threads/elecronic-diesel-tuning-devices.137797/

 

[AdventureWagon]

I saw a few posts suggesting this will be a waste of time and money, I will still do this and i am positive it will give me the results i am aiming for.

Will certainly be interesting to see how you get on. It must make some difference, otherwise the likes of Mitsubishi would not put a 2WD option on the Pajero and Triton (their ute) transfer cases.

 

[Chris]

The reason they put 2WD drive options on their 4x4s is because their systems are inferior to the one toyota designed. There are transfer cases and then there are centre differentials.

 

[Daniel Stapelberg]

I have a 3.0 1KZTE motor in my 90 series, consumption is about 6km/litre. I am going to swop the transfer case and front differential to the same as the 4runner , this way I can eliminate the AWD and run 4x2, still allowing 4x4 when I need.
Has anyone tried this? The 4 runner runs around 10km/litre, I'm hoping to get the same on my prado.
Interested to hear anyones thoughts.

Just to update my experiment - for those who would be interested.
I have purchased one complete Toyota Hilux surf 1996 model with the 1KZTE motor, all same spec as my Prado 90 series.
Next I will begine to remove the front diff and the transfer box, the surf will be converted now to run as a normal rear wheel drive and I have a use for this vehicle.
When i do the removal and installation I will make sure to take some photots and explanations, I have a detailed fuel consumption record of my Prado going back about 5 years, as the new system is fitted I will be able to cross check if there is an improvement or not. Obviously there will be pros and cons which I will list for all to see.
I am still confident this conversion will be beneficial in terms of reduced fuel consumption and also increased power due to less resistance of unnecessary wheel drives.

 

[David]

just my opinion but this just seems a pointless exercise to me, my HZJ 78 with part time hubs does not make a bit of difference to performance and next to nothing in mpg if it is in 4wd or not