Thread: How well does your V8 Disco tow?

How fast you can climb a hill is controlled purely by how much excess power you have doing the same speed on the flat.
So i did a quick calculation and if your disco and camper trailer have an all up weight of 4.5tonne. To climb a 10% grade (which is a really steep hill on a main road) at 40kph you would be using 49kW of engine power purely lifting all that weight against gravity. I had a quick peek at the specs for the 3.9V8 and its peak torque is at about 3100 rpm at this rpm you would have about 100kW on tap whereas at 2100rpm you would have only 65kW to use (assuming a flat torque curve, which it definitely doesn't have, so you would in reality have less that 65kW). So with losses and amount it would take to move 4.5tonne along the flat at 40kmph, your hill climbing speed sounds about right. However if you had dropped it back to first at the same speed you would have had about 3200rpm and I reckon you would have been able to accelerate. Redline isn't till 4750rpm so you had a ways to go.

What i am saying is if you want to climb hills faster you basicly need to give is more revs. This is why a run up sometimes works.

This is also where diesels coming. Peak torque on a diesel is much lower say at about 1900rpm for an isuzu. This means a much larger amount of maximum power is available at the lower revs. (Power is what counts when climbing hills). So you don't have to revs as hard and you have a wider rpm band to play with. Have you been climbing a hill in a diesel and had a car in front slow you down. The engine falls below peak torque and you stuffed. Whereas petrol you have half a chance of accelerating again.

Hope i haven't confused you with numbers. I was hoping to explain why it behaves like it does.

Dan.

If you want to how i worked anything out just asked.

Originally Posted by wovenrovings

Hope i haven't confused you with numbers. I was hoping to explain why it behaves like it does.

.

Even easier way to explain it.........the piddly wover V8 just doesn;t have the capacity nor compression ratio to perform such a task well

He'll be needing to get used to it, or get rid of it

I've towed with heaps of rover 8's, 3.5, 3.9, 4.6, blown 3.9, they all suck towing heavy weights, no if's, no buts

what he said,,
V8 peak torque and power are up there ^^^

The D2 will quite happily tow the 1200kg camper at 115 to 120 up hill and down dale.
no ifs or buts.

but hates sitting on 100.

as woven says,, its just maths.

Pedro is right. Like most English engines it needs revs. 2,000 is simply not enough. You need at least 2200 to get anywere, and 3000 and up is where you want to be for hills. Torque drops off quickly with revs.

We tow a 2.6 tonne dirt road van with our 4.6 litre auto D2 and don't have a problem. The old 4.0 was quite marginal however.

On the freeway, as Pedro says, the 4.6 would pull all day at 115 kph in top if that were safe, but it will not pull below 100 kph in top.

The 4.6 runs happily on 95 octane, but 98 makes a significant difference.

Thanks everyone for the replies.
Found out the other day when I had check done on the LPG system that timing was out by 4 deg. First impression in normal driving is there is some improvement since but haven't had a chance to test it towing.

Does anyone know how easy it is to get a 4.6 and how much they are?

Thanks again
Roger

This is just my thoughts,,,

but if I was thinking of better towing performance out of my V8,,
it would be a 4.9 stroker with a decent cam,,

this would mean a longer term relationship with my D2.

To answer the specific question, Triumph Rover Spares (TRS) in Adelaide can provide a range of built up engines for the various models in various capacities. I got my 4.6 factory new via Land Rover, but if I were doing it again I would buy a TRS engine which has been "top hatted" to prevent liner slip.

From memory, a 4.6 for a D2 is around $5-6,000, and they freight anywhere very efficiently. They may not be the cheapest, but they are great to deal with and totally reliable.

TRS web site http://www.triumphroverspares.com.au...5&parent2id=15

They have a 4.6 on special on that page for $3995.

My old stage 1 Series tows quite well it has a high compression 3.5 and is undergeared it just seems to work