4.8L Performance upgrade options

[CarloG]

Having spent last month in Cape York in Australia I came across enough Patrols with enough modifications to make me poor for the rest of my life. There are some common things that i am considering to improve performance. As background I've got a 2005 4.8LGRX with 200'000km. I tow a conqueror companion thats about 1.8t all up and have been feeling a little under powered in the the low down revs area. 2"lift with 285/70/17 Mickey Thompson Muds on. Was really wanting 315/70/17 but would need to sort out the power first. And the lift.

Spoke to some folk in the tuning business in SA and they think the following will give me about 17% more torque and kw at the engine and wheel.

1. 76mm Free flow exhaust and remove the catalytic converter
2. Inistall a Unichip Uni-Q model
3. BMC / K&C air filter
4. As a further option is to put new branch manifolds.

Does anyone have an opinion on these 4 options and whether they would/could increase performance.

(as an aside the Supercharger option of said tuning company reckons for about the price of second hand 4.8L i could DOUBLE my kw and nm.) id rather just buy another Patrol...

[Peter Connan]

Lots of opinions, sorry if they sound negative...

Free-flow and de-cat: go for it, you have nothing to lose. But keep the factory manifold. It's pretty good, and changing to branches massively increases underbonnet temps, which really shortens the life of all the plastic clips and gubbins. Unless you are prepared to have the manifold ceramic coated inside and out (which does help power a little bit too). Make sure you pick an manufacturer who really understands how much a Patrol's suspension flexes. My free-flow exhaust has broken two diff breather fittings in the last six months...

Chip: You will probably lose as much as you gain. To my mind, this only delivers significant results in turbo engines, and then at possibly serious cost in terms of engine life, unless done very carefully and with improved engine monitoring.

K&N filter: If you drive dusty roads, this will ruin your engine in short order, unless you really wash and oil it frequently. In really dusty, convoy conditions, I am talking daily wash and oil. If you only drive on tar, go for it.

I really doubt all those will give you a true 17% improvement anyway. But they will prove 17% on the dyno, just by being careful with the testing. Just atmospheric conditions, tire pressures and engine temperature together can make up more than half that already.

My real opinion: either dump the cat and put it back on 31" tires and learn to live with it, or buy a Y62. 90% of the time, when a car breaks on a trail or overland trip, it's because of modifications.

[Tinus lotz]

Yes i argee with Piet mabe exhaust wil make it better the rest you going to throw money away....stil need to see the real better performance

[Wilkie]

Yes i argee with Piet mabe exhaust wil make it better the rest you going to throw money away....stil need to see the real better performance

TINUS TINUS TINUS ......sit n BLower op my ou....

[CarloG]

I really doubt all those will give you a true 17% improvement anyway. But they will prove 17% on the dyno, just by being careful with the testing. Just atmospheric conditions, tire pressures and engine temperature together can make up more than half that already.

Thanks Peter - good advice to measure all the" environmental" measure when doing a baseline dyno test.

Did read a massively long thread on filters last night on the aussie forum. My overall sense after reading lots of threads was that the oiled filters do have benefits. http://www.patrol4x4.com/forum/general- ... rs-171674/. i just spent a month in Australia in Cape York and can attest first hand that they have dust - lots of it. The Bull Dust they refer to appears similar to fesh fesh and the red dust is just awe-full. On gumtree they actually sell cars "with or without" red dust! Anyway - I digress.

A question - if under bonnet temps increase does this impact the temp of the air going into the engine and does this in turn hamper performance. I.e. is cooler er air better?

[David M]

Speak to Graham (Pathfinder). He recently bought a 4.8 with a stuffed head and decided to correct some of the mistakes that Nissan made with design while repairing the vehicle. That 4.8 hops.

[Kagiso II]

My School reckons:
Freeflow manifold by VIPER and NB NB NB NB!!! ceramic coat inner and outer [that will bring the under-hood temp to lower than current.
Also the freeflow decat exhozt 76 mm [ceramic first section]
Then let Graham freeflow the head - bigger valves AND THE CAM TIMING
no chip needed.. maybe, if you can get them, performance injector tips for the fuel injection ?
Then you have well into 200's KW in oomph.
Will it cost you? ja magtag, klomp geld

[Peter Connan]

I really doubt all those will give you a true 17% improvement anyway. But they will prove 17% on the dyno, just by being careful with the testing. Just atmospheric conditions, tire pressures and engine temperature together can make up more than half that already.

Thanks Peter - good advice to measure all the" environmental" measure when doing a baseline dyno test.

Did read a massively long thread on filters last night on the aussie forum. My overall sense after reading lots of threads was that the oiled filters do have benefits. http://www.patrol4x4.com/forum/general- ... rs-171674/. i just spent a month in Australia in Cape York and can attest first hand that they have dust - lots of it. The Bull Dust they refer to appears similar to fesh fesh and the red dust is just awe-full. On gumtree they actually sell cars "with or without" red dust! Anyway - I digress.

A question - if under bonnet temps increase does this impact the temp of the air going into the engine and does this in turn hamper performance. I.e. is cooler er air better?

Only if you have modified the inlet in such a way that it draws air from under the bonnet. The standard intake system gets it's air from inside the wheel arch.

Oiled filters do have benefits, but direct replacement units tend to have a smaller "paper area" than the standard filter they replace. As a result, to get higher flow they must have bigger holes.

So operating in dusty conditions means they either clog up faster, or let more dust through...

The best solution to reducing intake system drag is to fit a huge big Donaldson (or other cyclonic filter), but there is no room for this in the 4.8's engine bay. I have seen such filters fitted on the front of roof racks, but not here in SA.

[Wilkie]

My School reckons:
Freeflow manifold by VIPER and NB NB NB NB!!! ceramic coat inner and outer [that will bring the under-hood temp to lower than current.
Also the freeflow decat exhozt 76 mm [ceramic first section]
Then let Graham freeflow the head - bigger valves AND THE CAM TIMING
no chip needed.. maybe, if you can get them, performance injector tips for the fuel injection ?
Then you have well into 200's KW in oomph.
Will it cost you? ja magtag, klomp geld

I have a complete gas flowed head ready and available for anybody in need

[CarloG]

My School reckons:
Freeflow manifold by VIPER and NB NB NB NB!!! ceramic coat inner and outer [that will bring the under-hood temp to lower than current.
Also the freeflow decat exhozt 76 mm [ceramic first section]
Then let Graham freeflow the head - bigger valves AND THE CAM TIMING
no chip needed.. maybe, if you can get them, performance injector tips for the fuel injection ?
Then you have well into 200's KW in oomph.
Will it cost you? ja magtag, klomp geld

Thanks - have contacted Viper - is this the Graham from Gtech?