4.5 GRX towing

[Eyetie]

I recently purchased a 1999 , 4,5 GRX patrol. i have had it serviced and fitted old Man emu shocks. i purchased this for my deep sea boat and will use it tow the Boat to Moz etc. I am finding that the patrol seems a little underpowered ? when towing my Invader Cat and i encounter a small incline the speed drops right down to approx 80 KM per hour ? is there anything you guys suggest i do to get more towing power out of the vehicle ? i am considering e dastek chip?

[Tinus lotz]

Welcome to the forum
What size tires are you rrunning?
Is it a auto or manual

[Marino4x4]

Hi Max

First try and change the petrol pump. The 4.5's have a problem with them. I changed mine about 3 weeks back and it made a huge improvement on the power. The car keep on accelerating now. Before the change it had a flat spot where it felt as if it was losing power. You can get a pump at Midas or a similar shop. Get an in-tank pump that can deliver 3-3.5 bar pressure.

Hope this helps

[Peter Connan]

Max, before you even consider modifying it, make sure it's working properly. Check out the fuel pump as Marino4x4 stated, and get it on a dyno to see what it's delivering.

If it's an auto and has oversize tires, you might be experiencing some problems, best is to tow in a lower gear. If it's a manual, tow in 4th gear anyway.

If it's all in spec and producing the right amount of power, and you're still not happy, sell it and buy a 4.8.

I am personally against modifying vehicles that are to be used to travel in isolated areas because any engine modification is likely to reduce either lifespan or reliability. If you don't go into isolated areas, you can modify all you want. I know of one guy who had a supercharger fitted to his 4.5 through Dennis McBeath (Alpine developments), so the sky's the limit (take note that about three weeks ago he blew his engine in Zambia and it cost him more than R35k to get his vehicle home, never mind what it's going to cost him to get it fixed), but I firmly believe that buying the car you want is cheaper and less of a hassle than turning something else into the car you want, unless you are an ace tuner who can do it all himself, in which case you wouldn't be asking these questions.

[Herrie]

If you tow heavy things with the 4.5 in 5th gear, the 5th gear might break! It is better to just tow it in 4th gear.

[Eyetie]

Hi guys thanks ... I will take it to a Dyno and see from there. Tyres are standard, it drives and pulls perfectly without the boat but man do I battle on any up hill !

I will ALS check out the fuel pump etc. thank u for the advice I will let u know how it goes .

I agree the 4,8 is awesome I used to have one biggest mistake ever selling it !

[Jorrie]

Hi Max

First try and change the petrol pump. The 4.5's have a problem with them. I changed mine about 3 weeks back and it made a huge improvement on the power. The car keep on accelerating now. Before the change it had a flat spot where it felt as if it was losing power. You can get a pump at Midas or a similar shop. Get an in-tank pump that can deliver 3-3.5 bar pressure.

Hope this helps

Marinus

Waar het jy die pomp gekry en wat is die spec? Ek het 'n soortgelyke probleem en moet my 4.5 Patrol se petrol pomp vervang.

[Tunja]

Hi guys thanks ... I will take it to a Dyno and see from there. Tyres are standard, it drives and pulls perfectly without the boat but man do I battle on any up hill !

I will ALS check out the fuel pump etc. thank u for the advice I will let u know how it goes .

I agree the 4,8 is awesome I used to have one biggest mistake ever selling it !

Eyetie, I reckon my 4.5 pulls well and when I towed a 2 ton trailer loaded with 1.5Ton bricks over Sir Lowries Pas last week I thought it would be a breeze...not so but once over the pass it would pull like a train with the added weight..... hmmm I have 285/75/16 mudz on so reckon that made a difference - check the fuel pump as suggested.

[Marino4x4]

Hi Jorrie

Ek het die pomp by n winkel hier in Bloem gekry. Was R450 vir die pomp.

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Ek kan een vir jou kry en pos as jy te veel sukkel of dalk wil seker maak jy kry een wat werk. Die pomp se dimensies is dieselfde as die oorspronklike, die hegtings pinte is netnie dieselfde vir die elektriese drade nie. Ek moes dit uitboor om n bietjie groter te maak. Dink die een pool is n 4mm gat en die ander is n 6 mm gat. Dit bout dan net vas aan die pomp. Die verskaffer het gesê die pomp is vir Nissan en Toyota, so ek reken dit is vir die 4.5 enjin bedoel.

Groete

[Mammoth]

Hi Eyetjie

I also have 285/75/16 tyres on my 99 GRX 4.5. I tow a block of flats (Wilk Topaz) and since changing to these tyres, have also experienced the loss in power, especcially on uphills. My vehicle is fitted with a stage 1 SAC conversion and it measures about 118 kw on the dyno with these tyres. Fuel pump was replaced with a BMW pump (maybe thats the problem)

I am seriously considering a stage-2 (redo head and valves). I do not want to go back to standard tyres as the smaller tyres just did not look right on the Troll.

I will be watching this post with huge interest to see what our friends with much more experience as I have , have to say. I have seen what the oil drilling nation can do with a Patrol with a turbo on - but that is totally insane...!