Outer Limits 4x4 Board

I have a disco 1 which i do alot of highway miles and off roading and i am finding the little engine dose not cut it on power or economy. not to mention i haven't even tried towing my comp truck with it yet
I am pondering weather to up grade to a lexus V8 which when you factor into the cost of adaptors, computers, gf box tailshafts ... the list goes on..... as do the dollars nthen mod plating

i was wondering if you can ... now this is a big ask, get better economy from porting the heads replacing the cam and possibly supercharging the origional 3.5???
the orig donk only has 165000Km so it is a nice little block in good condition for mods

any help or info would be greatly appriecieated on this subject.

Also would the standerd disco manual handle 200 KW? or would i be better off upgrading that as well

For a couple of hundred dollars you could put a 3.9 in it and see how it goes.Goes alot better then the 3.5. Its no powerhouse but has alot more then the 3.5

I have a 4.6 & thats short on power when towing !!
I need more too!!


Jeff

There's a 4.6 short motor advertised in the classifieds

The 1UZ fits but is a hassle.

I have one in my DAKAR and for the cost of making the UZ perform to my expectations I could have purchased a crate LS6 and it would have dropped straight into the hole rather than mucking around trying to make it fit.

Plus adaptors are available off the shelf.

The UZ is one fat engine.

jbell wrote:I have a 4.6 & thats short on power when towing !!
I need more too!!


Jeff

Ive been in a 2000 model P38 Rangie with gas injection on a 4.6.We towed a car from Broadford to Glen Waverely and you could barely tell it was even towing a car.It was a Disco been towed.I reckon you might have something wrong with yours.They have heaps of torque down low.

jbell wrote:I have a 4.6 & thats short on power when towing !!
I need more too!!


Jeff

I have a p38 4.6 with the bosch and when i got it it was a slug turned out to be the airflow meter there about $500 new best money i ever spenty no shit i got about a 30% power increase

Hi Guys,

I'm going through a similar exercise at the moment.
I have a 3.9V8 D1 fitted with a "unichip", and although it has much more power than standard, it is still "lacking"!

I have come to the conclusion that the overall gearing is wrong for towing.

I tow a 15' pop top caravan with ours, but will be soon upgrading to a 20' job with full ensuite, etc.
Weight will rise from 1,300kg to 2,000+ kg.

I have noticed in the past, that if I tow at 90kph, the D1 looses it on every small rise in sight, as the revs are only around 2,000.
However, if you tow at 110kph, the thing flies and has less trouble with the hills, and the rpm is up to something like 2,500.
The dyno showed this, from CNJ Automotive, who fitted the Unichip.


As you can see, 2,600 to 4,000 rpm is the best torque range.

I have done some research into the cheapest way to "re - gear" the vehicle, and it has come down to the transfer case.

The Disco LT230 runs 1.22:1 ratio and the Defender 1.41:1

If I fit the transfer case from a Defender into the Disco, instead of 100kph @ 2,200 rpm, it will raise the revs to 2,500 rpm, at the same speed!
That should be just enough to increase the pulling power and improve fuel consumption.

Cheers,
Ron

get better economy from porting the heads replacing the cam and possibly supercharging the origional 3.5???

Ha ha a comedian!
The only surefire way to get power for towing is torque, and torque = capacity.
You can get a 5litre conversion done for about 8K assuming you have a manual, as it will cost another 8 k to build an auto to take it.

I am happy with my 3.9RRC with aThor manifold and self modded heads and unichip and O2 sensors. Gives about 50% more power from 1500 to 2600RPM or so and great economy.
Regards Pilip A

Rover 5l? If so that is cheap!

Have a look at the Real Steel Site.
AFAIR the bits are about 3.5K.
Bruce Davis does a local turnkey for around 8K . One of my friends has one for towing a van.
Regards Philip A

8K is well in the ball park figure of a 5L motor if not too much.
I am just finalising the rebuild on my 3.9, and it has come up to a fair amount of $$$.

I could have had a complete 5L stepped liner (10.5:1 CR) block with the same rpi stage 1 heads, in my car and running for about $1500 ontop of this current rebuild cost. But thats not all, I would have been able to sell the 3.9, would have had less downtime, and much more power.
I learn by doing things and this was a learning curve I will never forget.

As Philip has already mentioned the Auto would be the next drama, but I have a supercharger to now go on the 3.9 so I might end up with that dilemma anyways

Philip A wrote:[
I am happy with my 3.9RRC with aThor manifold and self modded heads and unichip and O2 sensors. Gives about 50% more power from 1500 to 2600RPM or so and great economy.
Regards Pilip A

Phillip,

What did you do to the heads, and what difference does a Thor manifold make?

You can send a PM if you don't wish to put it here.

I'm after all the power I can squeeze

Cheers,
Ron

What did you do to the heads, and what difference does a Thor manifold make?

First I reread a couple of books on theory , then got out the Dremel and ground for about 30 hours. To summarise I blended the bowls of the inlets and exhausts, had the inlet guide cut flush with the inlet port roof, and opened up the inlets on the swirl side and broadened them next to the inlet guide stump.
I think most work is required on the exhaust ports as it looks like the core slipped over time there. I removed the "bench" below the seats and blended the bowl and broadened the port near the guide. I also raised the roof of the port by a couple of MM.
I also unshrouded the inlet valve to head area, and compensated by removing 20thou ( well 50 thou toatl to allow for a composite gasket).

This all gave me 7% across the board on Graeme Cooper's Dyno.

The Thor manifold is a complex casting by BMW used on D2 which increases the inlet length to throttle from about 14inches to over 30inches. It also has Hemholz resonance built in which "supercharges" the gas velocity at low revs. you lose 10% over 3Krpm and gain 50% at 2000RPM, with chipping.( compared to a base 3.9) It's not a bolt in and needs some fabbing particularly of the kickdown, IAC valve, TPS,
I have posted quite a few times on The AULRO forum so do a search there.
Regards Philip A

Regards Philip A

If I could post up a scan I have a dyno chart for my Lexus powered Range Rover that shows 235.2kw at the wheels.

Maybe that's why we fit Lexus engines?

If I could post up a scan I have a dyno chart for my Lexus powered Range Rover that shows 235.2kw at the wheels.

What transmission are you using and if a ZF, where did you get the adaptor?
Has it been engineered?
Who did the ECU integration?
Regards Philip A

Patrol 4.2 5 speed and full Patrol driveline.

I made the transmission adaptor myself and it has less than 2thou runnout.

Fully engineered and signed off by the RTA in NSW. The only "modified" item on the engineers report was the chassis everything else is listed as replaced.

The Autronic SM4 ECU was wired by Quickfit in Hornsby and has since been modified by me to make it work how I wanted.

Hijack over.

zuffen wrote:If I could post up a scan I have a dyno chart for my Lexus powered Range Rover that shows 235.2kw at the wheels.

Maybe that's why we fit Lexus engines?

Would love to see it. Presume you're now part time 4wd.

It's interesting the 3.9 plot above only has 90kw to the ground.

It's interesting the 3.9 plot above only has 90kw to the ground.

Mine has even less but its not the BHP its the torque and where it is that matters for towing.BHP=torqueXrevs.

Mine climbs really well and the major problem that I have is that my TC slips up to 20% at 1800RPM to 2200RPM from all the extra power.

I can climb Mt Ousley in 4th at 80-85 towing my 600Kg plus camper in top alternating in and out of converter lock. Not quite enough locked but plenty unlocked.
Regards Philip A
PS of course it could also be that one dyno makes more BHP than another.

[quote="zuffen"]Lexus powered Range Rover that shows 235.2kw at the wheels.[/quote]

235.2kw at the back wheels means something like 320kw at the engine. That ain't no standard Lexus/Toyota V8 - what mods have been made to the engine?

A bit of porting, some forged parts and a chunk of boost.

zuffen wrote:A bit of porting, some forged parts and a chunk of boost.

Is the story online? I'd like a read.

No, no write up online.

Plenty of information on http://www.lextreme.com" onclick="window.open(this.href);return false; under my username.

Philip A wrote:

It's interesting the 3.9 plot above only has 90kw to the ground.

Mine has even less but its not the BHP its the torque and where it is that matters for towing.BHP=torqueXrevs.

Mine climbs really well and the major problem that I have is that my TC slips up to 20% at 1800RPM to 2200RPM from all the extra power.

I can climb Mt Ousley in 4th at 80-85 towing my 600Kg plus camper in top alternating in and out of converter lock. Not quite enough locked but plenty unlocked.
Regards Philip A
PS of course it could also be that one dyno makes more BHP than another.

Thanks for the info, Philip.

Have you found a way to alter the speed that the torque lock kicks in?

Mine is a series 1 with the hydraulic lock.

Cheers,
Ron

Have you found a way to alter the speed that the torque lock kicks in?

Mine is a series 1 with the hydraulic lock.

Mine is also a ZF4HP22.

Well I do not think that I need a different speed lock, but I would like a tighter torque converter. There is a guy in Melbourne who can modify the trans to lock in 3. See if you can find the thread in AULRO. The unlock under load gives a handy extra gear for steep hills but is probably not great for the transmission temp, although mine has never overheated.

I think they raised the converter lock from 67Kmh in the 2HP22 in 3.5 flapper RRC to 85 Kmh in the 4HP22 to allow for the injector cut at 1500RPM on 3.9 14CUX which is about 80Kmh.

My guess is that they thought the unlock would be too noticable if at 67Kmh, but I would think you could have a shop adjust a 4HP22 back to 2HP22 specs for this. Cutoff is pretty noticable on overrun even with no converter lock.
I think this is controlled by the governor but I have never been able to find out 100%
Regards Philip A

The Torque convertor lock is a pain when pulling a caravan!
When it locks in, the revs drop to 1800 and you are in limbo with no power.

I believe the lock is controlled by a valve with a spring.
A Rover transmission guy, told me, altering the preasure on the spring, will changes the speed, but it is hit and miss.
You have to pull the sump off the tranny to alter it each time.

Sounds like a pain to me!

I'm hoping the change in gearing will help the problem.

Cheers,
Ron

Hi Ron,
Mine is a manual 3.9 v8 but I find it is also much better on the hills if I keep the revs at an indicated 2250 to 2500 which is an indicated 105 to 115km/h. Probably closer to an actual 100 to 110km/h. So it will be interesting to see what affect it has overall. No doubt your towing will improve but what effect it will have on your auto and fuel economy will be interesting to hear.
Also be interesting to see what effect it has on how it drives when not towing.
I just go a bit faster to keep my revs up but when I tow it is only a camper trailer :-)

I have read that some Defender owners prefer to utilise the Discovery gearing for lower highway revs but that is in a manual diesel so different characteristics.

Hi Justin,

Great to hear from you

I'll most certainly let you know how it goes on power and economy.

The speedos are 5 km out, compared to a GPS

The only Defender I know of with a 3.9 dico V8 auto, is the one MRAutomotive have.
I have spoken to them about it and there's runs very well with car trailer and LR on it.

Cheers,
Ron

Don't forget that a standard Defender has 32in tyres and Disco 29in so take that into account too when comparing to the MR Defender.