V8 or not???

[DawidT]

Probably not a good question to ask on the Patrol forum , but here goes!!!
During December I towed my caravan to Kosi Bay and got my fuel concumption to average on 3.8km/l. This was done with my GQ 4,2L petrol with speed around 100 -115 Km/h, sand and tar road. This past week end I used my 4,8L GU petrol to Satara (also with caravan)at similar speed as with the GQ, and gues what, similar fuel consumption!!!!! My plan is to do Botswana and Namibia in March / April and by improving my consumption with 1km/l I could save in the region of R4000 - R5000....

I need advise on this matter :
1) will I get them any better -slightly better on consumption and what do I need to do?
2) do I go for a V8 Lexus conversion (GQ only) and what would the pros and cons be?
3) do I go for a diesel conversion, turbo or what ever is good?
4) will 4 gass analizer solve my problem?
5) how about changing the old points and condensor to electronic?
6) do I shut up and sit back and enjoy the reliability and peace of mind?

I know if you do the calcs it will take me forever to get your money back, so my aim is more "hormone" driven I do go away quite often and love the Patrols and WILL not change it for any other 4X4 (on nr 3 and 4 patrol now )

The plan is to leave the GU as is and use the GQ for the next 3 - 4 years and then put it on retirement. I was well aware of the fuel consumtion!!!

Please guys, any advise and some consumption figures and costs of any convertions

[Alex Roux]

Hi Dawid

I have limited knowlegde and will only comment on the stufff that I know something about.
2) Yes, consum,ption on Lexus will be better, but not significantly.
On a bad day (with jeep tracks, sand, heavy loaded etc), I do about 5km / l.
On a good day I get 6km/l.
So the Lexus will get you better consumption but not that significantly.

However it will take a long time to make it worth your while financially.
The conversion will cost you between R35k and R60k, depending on where you get it done. There are many who do it and they vary in quality. I will not go for the lowest price. The risks are there, you need to be confident that the guy doign the job knows what he is doing. Only go with strong references of Trols owners that are happy with their converions.

If I had a 4.2 I would consider a converiosn only as a last resort. So will consider the other options, if they are believed to potentially improve the consumption.

Also, the thing with these older design straight six Petrol engines of Nissan (Toyota's 4.5 in the Cruiser is the same), They are heavy on fuel, irrespective of the weight they carry. When upgrading from 4.2 to 4.5 or to 4.8, you will get more power, but the consumption is more or less unchanged (except you can chip the more modern ECU driven engines).
However, with the Lexus the consumption can be light if the load is light, but then also gets heavy if the load is heavy - like all Petrol engines do.

[Peter Connan]

I geuss I am known (berug? ) for being very conservative in these matters.

Here is my take: The petrol Patrols are not thirsty because they have six cylinders rather than 4/8/10/pick a number, they are thirsty because they are in design terms understressed in a lot of aspects, and because they are big and heavy and not terribly earodynamic. The primary aspects in terms of fuel consumption is that they run low compression ratios and their intake/exhaust systems are primaily optimised for low-rev performance.

Unfortunately this is exactly what makes them such killer 4x4's, as it gives them magnificent bottom-end torque (even more than an unblown diesel of similar capacity) and good tolerance to bad fuel and high altitudes. An indication of this is that everybody I know who has converted a Patrol to Lexus-power, has seriously considered lower diff/tansfer case ratios.

They are also relatively simple mechanically, particularly the 4.2, and thus if not incredibly reliable, at least easily maintained and repaired in the bush.

By good application of old-fashioned tuning techniques, such as increasing the compression ratio and gas-flowing the head, re-grinding the cam etc. their efficiency can be considerably improved, as can their power, and if this extra power is left strictly alone, they will be more fuel efficient. However, this will compromise both the bottom end and the reliability. The change to electronic ignition you mentioned is unlikely to improve fuel consumption greatly unless your distributor is worn, in which case it might help. It is worth doing though as it improves driveability and significantly eases engine maintenance.

Therefore, perhaps a turbo-diesel conversion is a better option, in that it delivers the benefit of lower consumption without necessarily suffering from less bottom-end. But there are still risks, we are all very aware of the hand-grenade issue. I do not really have any first-hand experience of diesels, but I have formed a distinct impression that a turbo-diesel needs considerably more carefull maintenance than the 4.2 Petrol. MY main gripe with diesels (an I realize this may seem a bit anal) is the way they sound. Particularly around a lion kill. Because for some reason I have yet to fully understand, it seems to be taboo to switch the flippen things off.

Personally I do not like modifying the motive units of overland vehicles, particularly where such modifications affect the main wiring harness, because almost all the problems I have had have been in those areas, but if it were financially viable I would consider a change to a non-turbo diesel. Maybe. But probably not.

[dieselfan]

MY main gripe with diesels (an I realize this may seem a bit anal) is the way they sound. Particularly around a lion kill. Because for some reason I have yet to fully understand, it seems to be taboo to switch the flippen things off..

No to hijack but some relevance, with both my Pathfinder and old Terrano I used to idle in first no pedals up some really steep obstacles. Infact none of the dongas at Hennops used to stall the engines. With my dad's 4.2 this should also be the case but we found it stalling almost as easy as a petrol?! Is it cause the engine is too tight? 2400km?

[Peter Connan]

Roy, the engines in both the Terrano and Pathy are effectively electronically controlled ITO idle speed. Most modern engines are, and if you suddenly release the clutch while going up a steep slope, the revs will flare momentarily.

The 4.2 is a fully-mechanical system, without any of that, and needs a little more attention.

[Tinus lotz]

Ek dink los hom soos hy van van sy ma af kom.....so werk hy en hou aan met werk......maak hom beter asem haal sit kleiner wiele op maar moet hom nie verander nie dit sal net verkeerd wees. Jules kry dan 7'km per liter

[DawidT]

Yip, dankie vir die komentaar Sy (Sophy is haar naam ) bly soos sy is - reguit van haar ma af!!!