Improved performance - GU Patrol

Submitted: Thursday, Apr 03, 2008 at 08:19
ThreadID: 56225 Views:5346 Replies:4 FollowUps:9
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I have a GU petrol 4.5 L Patrol. It weighs 3.8 t fully loaded with loaded, water, fuel, supplies, spares & passengers - a beast!

I have been considering how to lift the performance and /or improve the economy. I have reasonable records of fuel economy in a range of conditions.

I have investigated Unichip, which appear to be the only engine management system available, and consulted the Patrol on-line forum - very little experiences/feedback/opinions are found.

So I went to the S.A. Unichip distributor, Morpowa, at Modbury.

On the dyno the standard power was 73 Kw at the rear wheels, with faultless air: fuel ratios. The boys suggested that in these circumstances an ECU style chip would not be expected to improve matters much if at all, and that a decent tune may be worthwhile.

For $ 198 they gave me another 10 Kw of power by advancing the timing 7 degrees. There are some other side issues such as pinging when such an adjustment is made, so after some testing, it was backed off to 6 degrees advance. The air: fuel ratios improved very marginally at that new setting.

Their other advice was to do with fuel. They recommended using 98 octane (I have only ever used 91 octane - regular unleaded). For an extra 10 cents a litre, or $ 19.00 per fill, this may be a much cheaper alternative to $ 1,600 plus for a Unichip. I do approx 20,000 km per annum in this vehicle, so this would cost $ 400 per annum. They suggest improved power and economy benefits. Early indications support this - the throttle is not open as far to drive at the same level.

When travelling in remote areas (half my driving done there, the other half getting there & back on the black top)) and 98 or 95 octane is not available, they have suggested adding an octane booster. The label on these octane boosters claims an increase of 6 or 7 octane levels, and a bottle to do a complete fill costs $ 11 - not so very different to filling up at the bowser with 98 octane. They have also suggested that if I wish to remain using 91 octane, but reckon on needing a bit more grunt - for example a heavy 4 x 4 session in deep sand - that I use some octane booster.

As it is almost impossible to replicate driving conditions, or to have a control in any comparisons of fuel economy and power, I am aware that any comparisons are going to be relatively subjective.

So as I have a 6,000 km trip on bitumen, station tracks and cross country coming up - in the Red Centre - I will be keen to observe the results of the tuning and different fuel supply.

Cheers for now.
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Reply By: traveller2 - Thursday, Apr 03, 2008 at 08:25

Thursday, Apr 03, 2008 at 08:25
I have acouple of vehicles that are 'supposed' to run ok on regular unleaded.
Both gain extra grunt and are smoother when using Premium, both also get an extra 100k out of a tankfull of fuel as well as stopping the throttle bodies gunking up like they do when using regular.
In my case it is CHEAPER to use premium and have been doing so since it became available. Neither vehicleis used for outback travel so always get premium.
AnswerID: 296301

Follow Up By: KSV. - Thursday, Apr 03, 2008 at 15:34

Thursday, Apr 03, 2008 at 15:34
Same here (for passenger car, not 4WD). My measurement suggest that money-wise I am doing same mileage with low-octane and high-octane petrol per dollar. But I can drive longer and harder from the same refill. This is beauty of electronic management – computer can easy adjust itself for better fuel.
FollowupID: 562432

Reply By: furph - Thursday, Apr 03, 2008 at 08:56

Thursday, Apr 03, 2008 at 08:56
I can understand you requiring some exra grunt, but how much over your (legal according to compliance plate) GVM is 3800kg.?
I am told RTA is now doing random checks on 4wd's.
AnswerID: 296304

Follow Up By: Truckster (Vic) - Thursday, Apr 03, 2008 at 09:27

Thursday, Apr 03, 2008 at 09:27
yea, hes only round 800kgs over the limit...
FollowupID: 562367

Follow Up By: Trevor R (QLD) - Thursday, Apr 03, 2008 at 09:45

Thursday, Apr 03, 2008 at 09:45
He is still about 400kgs under my gross weight when fully loaded hehehe but this is our little secret.....

I have heard similar about rta rumours purph but as yet not seen it happen and I do a few k's past plenty of rta stops for heavy vehicles. Add to my rig, the caravan at 3tonne and the little old 4.2 is working pretty hard.

Regards, Trevor.
FollowupID: 562370

Follow Up By: Wizard1 - Thursday, Apr 03, 2008 at 10:18

Thursday, Apr 03, 2008 at 10:18
Seeing as he comes from SA the RTA has no juristiction......
FollowupID: 562376

Follow Up By: Rick (S.A.) - Thursday, Apr 03, 2008 at 18:42

Thursday, Apr 03, 2008 at 18:42
The exact amount over the GVM is "friggin heaps".

Wizard 1 is correct, but watch the insurance company wriggle out from under me if this issue arises. They (CGU, through my broker) have actually been very good so far and I have ejust got cover at no charge for the vehicle while I do some sub-contracting.

In any event, here in South Oz we surely must have something similar to the RTA?

FollowupID: 562472

Reply By: Robin Miller - Thursday, Apr 03, 2008 at 09:01

Thursday, Apr 03, 2008 at 09:01
Really Rick - trade to a 4800 asap, while current high fuel price makes petrols seem less attractive to those not looking at the whole picture. They are a genuine about 10% more economical.

I think mine began with 117kw at rear wheels , and the Unichip was largely useless even though it could deliver up to 129 kw at rear wheels. Usually I leave it (unichip) unplugged becaue of side effects.

My cars weighs 2500 kg ready to roll with 180lt in it and no passengers or camping gear, and reliabily delivers 16-17 lt/100km over the long haul about 15 cruising and 20 in the bush.

Robin Miller

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AnswerID: 296307

Follow Up By: Rick (S.A.) - Thursday, Apr 03, 2008 at 18:30

Thursday, Apr 03, 2008 at 18:30
Happy to trade up to a 4800, Robin.

Just send the $ 25,000 changeover to me & I'll do it over the weekend.......hehee.

Same goes for trading to a diesel, so the old girl stays. I'm really quite happy with it, especially the way I've got it set up, just wanting to "optimise' as much as I can.

FollowupID: 562469

Follow Up By: Robin Miller - Thursday, Apr 03, 2008 at 18:56

Thursday, Apr 03, 2008 at 18:56
Hi Rick

Seen them for $25000 now that they are almost 7 years old.

But yep understand.

I had to do some "training" of the Uni-chip installers I used
as they didn't seem to understand that winding timing forward a few degrees actually stuffs up your torque off idle.

Conceptually the Uni-chip is not the right design for 4wding , but you can make do if you have an auto which covers up the lack of torque, I think that why they were coming out with a new design this year.

I only got one more or less to play with , because there is no car I felt I could buy which matches the Patrol, so the current one has to be improved not changed.

By and large its a waste of time going to high octane fuel unless you shave the head to 10 or 11 :1 and certainly not economic.

Robin Miller

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FollowupID: 562478

Reply By: Trevor R (QLD) - Thursday, Apr 03, 2008 at 09:51

Thursday, Apr 03, 2008 at 09:51
Pezza, where are you???

Pezza has a supercharged 4.2 Petrol GQ and after driving it, I would think this a great addition to the Patrol. If you got the moolah, then just do it and you will never sell the GU I gaurantee it. The grunt comes in from idle, probably more so than the big chevvy diesel powered patrols getting around. (when are you going to get that thing of yours dynoed Pezza??? so I have some cold hard facts LOL!!)

Hope it helps.
AnswerID: 296313

Follow Up By: Ti Trol - Thursday, Apr 03, 2008 at 14:56

Thursday, Apr 03, 2008 at 14:56
A supercharged 4.2 petrol GQ???? Tell me more!

Also, can anyone tell me why the 4.2 EFI is so fuel hungry?


FollowupID: 562424

Follow Up By: Trevor R (QLD) - Thursday, Apr 03, 2008 at 15:23

Thursday, Apr 03, 2008 at 15:23
What can I say Graeme? It goes hard but that may be due to the driver??? LOL!! he is mad as a cut snake in a 4b.....alright on anything that moves then hehehe.

I have sent him a link to this thread so maybe he will answer any questions you have directly???

Here is his profile. Have a gander at his pics if you want, the underbonnet shot is of his GQ shorty blown of course, that's that big shiny thing on top hehehe.

I have the worked 4.2 GU and I reckon Pezza's blown petrol goes every bit as hard if not harder than my very capable diesel. I want him to get it dynoed to show me cold hard facts as the weight factor between my fat GU and his rather skimpy GQ shorty would make a difference in the driveability so it is hard to compare side by side just from the drive. His shorty does drive real good though, hard to get someone who has spent plenty on their truck (me) to say his mates goes better hehehe.

Regards, Trevor.
FollowupID: 562430

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