So how can you make these things go downhill !

Submitted: Tuesday, Nov 02, 2010 at 22:34
ThreadID: 82269 Views:6109 Replies:10 FollowUps:16
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Got the new 4800 Patrol recently - no choice but an automatic, but keep the manual just to hedge my bets.

I've always been on the manual side of the auto/manual arguement and
owning the same car in both an auto and a manual was bound to be interesting.

When these debates occur and you read them I sometimes get the feeling
that replies just come with the same nominal points on either side and you tick
another box in a sort of matter of fact way and on you go.
I mean half the time it doesn't really matter, so you have an auto and its battery is flat , well who cares if your driving with mates.

Well I guess I was bound to find out the true merits of each where it counts.

With the Patrol just a few days old we take it on a 1000km run to Newcastles Stockton beach.
On the easy cruise this thing turns in fuel consumption in the 13's which I have never had in the manual so she's off to good start, then we hit the dunes and she's a dream, I never realized I could cut it thru the sand so well, want more, bang its there, going down a dune is to easy - I'm starting to like this car, who cares that it used 30lt/100km playing in the sandpit.

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Its now two weeks later and we decide to take on some serious Victorian bush tracks and for competitionmy brother turns up in his manual constant 4wd 80 series diesel, lifted double locked with 33 inch muddies plus plus and the standard Patrol is feeling just a little intimidated with its chrome mirrors and stock little 31 inch 693's.

Still this car likes to be feed and that ain't going to happen unless it earns its keep so we point both cars at a nice little test hill we have called the Wall.

Up first goes the 80 series, but at the rock step it falters spins up a wheel and slips back down.
Ok , this time we try a front locker and up she walks, then backs down and using just a rear locker walks up again just to show that the front & rear lockers work about the same.


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Then we point the standard Patrol at the hill (no lockers - but does an LSD) and up she starts , this was going to be a telling run , it starts off smoothly and hits the step.
But you could hardly feel it , she just sailed quietly up displaying excellant manners.
Very impressed we were !

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So the Patrol is looking good so I jump in the passenger seat and plugin another new toy I got with it while I ask my brother to drive it down a moderate wet hill.

The other new toy is a BlaZt computer interface to the cars ECU and I while I am engrossed in reading air flow, pressures, fuel trim and all the other displayed data we head down the hill.

However by now the rain is constant, the tracks only 15 degrees but its rough, rutted with wet grass and loose rock and the car starts getting uncomfortable, then its sliding and slipping about.
Its lovely 5 speed autobox has a tiptronic manual mode and we bang it in first but the engine braking is pathetic and it looks like the torque converter is slipping all over the dial.

Now we know all about "Driving thru the brakes" - a sort of academic way of going down slippy hills but this sort of stuff really only works when it doesn't matter - its sort of an extra box to tick so you can get thru your 4wd driving certificate.

When steep tracks get like ice and rough and rutted at the same time the idea of holding one foot steady on a pedal is beyond human ability let alone two at once.

Ok this project is going pear shaped fast, but we sort of stall out and the car just holds as we contemplate the next move.

There's only 100m to go to the gully floor.

Ah Hah , theres one trick left we can impose on this recalcitrant beast.

So we stick the auto Patrol into reverse , release the brakes and point the nose over the edge.

For the first 5 meters things are looking good, going forward with the cars auto gearbox in reverse certainly retards the forward speed and gives more control but you need to be very careful about pressing the go pedal.
But just when it looks like we have this thing licked something strange happens.

The rear wheels are overdriving the engine via the big oil pump excuse for a gearbox and the car wakes up and decides this isn't right and attempts to correct itself.
The ECU fires rapid commands at the throttle stepper motor in a desperate attempt to match engine speed to gearbox speed, but the car is now rolling faster and back feeds oil into the torque converter.
The engine can't react fast enough , at approximately 1200rpm the engine gives up, stalls out, and there you go sliding down a hill with wheels locked and your not really enjoying the scenery at all.

Damm these clever electronics, they may well protect transmission or whatever but I'd rather not we heading sideways towards the trees.

Well we survive the descent and then under more controlled conditions try to explore just whats happening.

3 times we run the test until we are stalled out with the check engine light on and hoping we don't have to some tricky reset or whatever to get mobile again in this weekends miserable weather.

Oh for my manual Patrol ! Its still sitting on the front lawn probably laughing its head off.

It appears that over driving the auto from the rear wheels is just not on in these cars, which means that as it stands their performance downhill is not up to it and until a solution is found the new car might have to be restricted to playing in the sandpit.

A seemingly obvious solution is to make the torque coverter fully lockup , but this has issues with damaging it should you drive engine revs down to a stall and at a minimum you would have to disconnect this just before stalling.

Ideas folks !
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Reply By: Member - Fred B (NT) - Tuesday, Nov 02, 2010 at 22:58

Tuesday, Nov 02, 2010 at 22:58
Hi Robin,
as I've said before... you just like to get into strife just so that you can tell a good yarn.... lol....
Sounds like an interesting time.
regards
Fred B
VKS 737: Mobile/Selcall 1334

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AnswerID: 434925

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 07:37

Wednesday, Nov 03, 2010 at 07:37
Hi Ya Fred - and i wasn't even driving this time.
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Reply By: Member - Ed C (QLD) - Tuesday, Nov 02, 2010 at 23:13

Tuesday, Nov 02, 2010 at 23:13
Did you have it in low range?

It's been a while since I've had low range engaged in mine (used mainly for touring & towing), but if my memory serves me correctly, the converter locks up in 1st low...

(I'm sure someone will correct me if this is in fact not the case...;-))

:)





Confucius say.....
"He who lie underneath automobile with tool in hand,
....Not necessarily mechanic!!"

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AnswerID: 434928

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 06:58

Wednesday, Nov 03, 2010 at 06:58
Low range for sure ED - I think the torque conerter doesn't lock up - or if it does the braking is so weak that this doesn't help.

Also the ECU will change gears to what it thinks is correct if some parameters go outside its pre-programmed range.
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Reply By: awill4x4 - Wednesday, Nov 03, 2010 at 00:12

Wednesday, Nov 03, 2010 at 00:12
Robin, you could change the low range gearing in your transfer case. There are a few options 23%, 43% and 85% available from Marks adaptors. The 43% ones will give you similar engine braking to that of a Patrol with standard transfer case gears.
You may lose a little in top speed in 4wd low but the auto will get you pretty close to that of a standard Patroll.
Even with the torque convertor locked the higher 1st gearing won't get you close to what you had with your manual 4.8 without changing the gearing.
I've tried driving with the auto in reverse in my GQ and found it only really works in 4wd high range as the car will stall in low range.
After having the auto rebuilt quite some time ago I never went back to that technique as the trans temps would have had to be going through the stratosphere going by the information I was given by an auto trans specialist.
Regards Andrew.
AnswerID: 434931

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 07:43

Wednesday, Nov 03, 2010 at 07:43
Interesting that you found this to, that stall out was a surprise to me Andrew.

I guess I need to check out the torque converter lockup situation first - I know some of the Patrol guys have lockups but they usually only have them for highway touring because , as you say , of possible bad effects down low , but hitting a tree is a bad effect also I think.

Also have to determine the exact role of any ABS actions in my senario , but higher ratio transfer gears will happen if they can help , the car redlines at 110 in low range so there is plenty to play with.

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Follow Up By: MrBitchi (QLD) - Wednesday, Nov 03, 2010 at 08:50

Wednesday, Nov 03, 2010 at 08:50
As Andrew said your only real option is crawler gears. Some of the Pajero auto owners have gone this route with very good results. The torque converter locks up at a much lower speed and you effectively have the same locked gearing and control as low 1st in a manual, if not better.
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Follow Up By: Robin Miller - Monday, Nov 08, 2010 at 07:40

Monday, Nov 08, 2010 at 07:40
Planning on 43% ones this week Guys - its a start but I believe now that the torque converter still can't be held locked so won't be as good as the manual but a good step in the right direction for whatever else we do..
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Reply By: Member - Bucky - Wednesday, Nov 03, 2010 at 06:42

Wednesday, Nov 03, 2010 at 06:42
Robin
That's why I got a manual

95% of my driving, I should have an auto.
5% I want a manual.

Would a torque lock up device void ya warranty ?

And are they out there.
How much ???


hope this makes sence, only had 1 sleep (and not that much) off night shift
Cheers
Bucky
AnswerID: 434938

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 12:54

Wednesday, Nov 03, 2010 at 12:54
Hi Bucky

Makes sense Bucky , but an extra sleep is always worth it.

Yes its hard to have both at once but that is my aim - to get the best features of both in the one car, I don't care much about warranty anyway - its unlikely the car will ever go back for a service - but the size of the deficentcy has suprized me.
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FollowupID: 706063

Reply By: Member - Julie & John (VIC) - Wednesday, Nov 03, 2010 at 08:30

Wednesday, Nov 03, 2010 at 08:30
Gday...
OK ... I'm crouching down behind this large piece of corrugated iron sheet for protection ... got me armour on ... and just say simply -

"Ya shoulda got an auto TDV6 Discovery 3/4 with Hill Descent and Terrain Control"

Moving backwards now to avoid all the flying missiles!

Cheers
Julie & John
AnswerID: 434945

Follow Up By: Member - Julie & John (VIC) - Wednesday, Nov 03, 2010 at 08:31

Wednesday, Nov 03, 2010 at 08:31
Gday...

But I did love ya story tho .... a good read ... felt all the pain.

Cheers
Julie & John
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FollowupID: 706035

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 09:25

Wednesday, Nov 03, 2010 at 09:25
Hi Guys

No missles from here - friends of mine were with the TDV6 that got hauled off the Canning for I think $14,000 the previous year so I'm afraid that left quite an impression - but I did test drive one and felt they were pretty good in many areas - but I probably would have gone a Prado and put a 100kg in the keel to kept it stable before the Disco.

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FollowupID: 706038

Reply By: Member - simon w (QLD) - Wednesday, Nov 03, 2010 at 09:49

Wednesday, Nov 03, 2010 at 09:49
Robin,
Try a search on patrol4x4.com forum - I remember a month or two ago there was a good outline of a conversion it was mostly, if not all, just electronics that are able to be enhanced with extra relays and switches. I did not pay too much attention as mine is a manual .

Great to see your testing results!
AnswerID: 434951

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 10:06

Wednesday, Nov 03, 2010 at 10:06
I'm a bit spoilt in being able to test the same car in two versions side by side Simon and the results are a lot clearer then.

I am on Patrol 4X4 and there is some good stuff but most of this stuff is around locking up for better fuel consumption or towing and if fact they go as far as to make the lock up conversions only work above about 50kmh , but it is good background information though.

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FollowupID: 706040

Reply By: Member - Captain (WA) - Wednesday, Nov 03, 2010 at 12:02

Wednesday, Nov 03, 2010 at 12:02
Another nice read Robin. But also another reason for the cruiser in the ongoing cruiser vs patrol debate. While the cruiser is more $$$ - it comes with Downhill Descent Control and to my suprise it works really well :) The ability to brake individual wheels is something you cannot do with normal braking.

Also, I have found that the 2.6 : 1 low range of the cruiser was streets ahead of my GU with its ~2:1. Even though I have used Descent Control, the 1st low of the 200, combined with the V8 diesel engine braking, and it hasn't been used in anger. In fact I reckon the engine braking is better than the 3.0L GU manual. The only thing I have driven that had better downhill engine braking was my manual 1HZ 80 series.

Cheers

Captain
AnswerID: 434971

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 16:35

Wednesday, Nov 03, 2010 at 16:35
Hi Captain

Plenty of reasons to go with a 200 Cruiser, but not sure this is one of them as I expect this to be a fixable problem.
Some issues with the Cruiser seemed not fixable - unless you put it in a vice and squeezed it a 150mm

I would love to have been able to drive the Cruiser under the conditions last weekend and try to work out those subtle little things that really make or break a package as opposed to box ticking talk.

In a recent post you may have seen how un-impressed we were with a bogged traction controlled Prado we played with, but to be fair it didn't have the power to play with of the Cruiser.

I'm sure the downhill descent is a real plus but most guys wanting the lot still seem to go with lockers anyway, sort of bypassing that bit I guess.

Its my intention to build the best car for my requirements - this mission is probably made harder by having a constant reminder of the my very capable manual one just sitting there in the driveway every night.

The lower gearing you had is something Patrols should have always had and I think that whatever the solution for my car is I will go straight to a set of 2.88 transfer case gears anyway.
I don't think you can go wrong with those but I still expect to have to work out an effective low speed lockup converter.

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FollowupID: 706075

Follow Up By: Member - Captain (WA) - Sunday, Nov 07, 2010 at 12:48

Sunday, Nov 07, 2010 at 12:48
Yeah, I had a locker in my 80 and it was a great addition. However, the traction control on the 200 is very effective. Ultimately its not as good as f&r lockers, but I reckon its better than a single locker with no TRC. I would reckon the TRC is about 80% as good as lockers, so now it means spending >$1500 to get only a 20% benefit. I may end up with a locker one day, but SWMBO is already giving me a caning for how much I have spent !

Cheers

Captain
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FollowupID: 706414

Reply By: Member - peter f (VIC) - Wednesday, Nov 03, 2010 at 17:23

Wednesday, Nov 03, 2010 at 17:23
Iv,e had 2 GQ autos an 89 on LPG and a 97 EFI and its great .the small dissadvantage in the engine braking dept is no big deal .mine have been anywhere
you would take a manual and why would you want to change gears ,makes driving
so easy . vic high country ,CSR simpson desert
mechpete .
AnswerID: 434991

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 18:00

Wednesday, Nov 03, 2010 at 18:00
Hi Peter

I think thats the crux of the matter - when you say "the small dissadvantage in the engine braking dept is no big deal "

In my assement in the lead up to getting the new Patrol I had
ticked the box "Engine braking not quite as good " also.

That might be the case for your cars , but it just isn't the reality with these 4800 GU patrols and I simply got that point wrong.

I have the advantage of not having to assume anything , but to have the near identical cars in the same difficult conditions as well as a comparison 80 series and one car was seriously deficent.

If it was a small thing , like just locking up a converter or better driving technique it wouldn't matter much.

But the measured reality was that one car just simply couldn't go on a number of tracks that the others could.

I often drive alone and am not willing to accept any compromise and will dump the new car for this reason if it can't be fixed.

Ona positive note I have spilt a lot less cups of coffee in the auto 4800.

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FollowupID: 706088

Reply By: jdwynn (Adelaide) - Wednesday, Nov 03, 2010 at 19:16

Wednesday, Nov 03, 2010 at 19:16
Robin

No one's mentioned using the hand brake yet. Alright, not everyone's preference but it works well with auto's when you need some assistance. Surely preferably to putting the trans in reverse. Is the new one same as the 20034 3L I wonder - drum brake on the drive shaft.

Be interesting to compare the engine braking with the 3L diesel auto, which is all I'm used to. Nothing like a manual diesel but never been a concern to me.

Cheers

AnswerID: 435007

Follow Up By: Robin Miller - Wednesday, Nov 03, 2010 at 19:38

Wednesday, Nov 03, 2010 at 19:38
No thats the kicker Jdwynn - handbrake is a little affair inside the rear discs.

Its use causes the rear wheels to lock up to easily - don't let um tell you a 3lt Gu is all bad.
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FollowupID: 706099

Follow Up By: jdwynn (Adelaide) - Wednesday, Nov 03, 2010 at 20:11

Wednesday, Nov 03, 2010 at 20:11
Well I'll be.........gee Nissan have a habit these days of "fixing something that aint broke".

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FollowupID: 706107

Reply By: Axle - Sunday, Nov 07, 2010 at 12:10

Sunday, Nov 07, 2010 at 12:10
Fuel consumption in the 13s?!!, that makes the diesel- pedo debate more interesting,.....LOL.



Cheers Axle
AnswerID: 435258

Follow Up By: Robin Miller - Monday, Nov 08, 2010 at 07:35

Monday, Nov 08, 2010 at 07:35
Hi Axle
13.6 on the 1000km run, so it deserves some praise I guess , but not to much as I think V8 petrol 100 series can pull into 12s on a touring run.
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FollowupID: 706500

Follow Up By: Axle - Monday, Nov 08, 2010 at 17:57

Monday, Nov 08, 2010 at 17:57
Hi Robin. I would say its the later VVT Toyo V8 that might get 12s...lol.


I'm wrapped with my 100s when it does 16s, ..lol. But it has been rebored 10thou oversize, so might not help it to much i suppose.


Cheers Axle
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FollowupID: 706543

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