I am contemplating an extensive resto on my 1997 Disco XD. I am the original owner. It has always been slow and I wondered as to the most effective and least expensive way to increase power. Any thoughts on this ? Mike

 

Define slow? It's a small V8 hauling around a lor of 4x4 weight. My XD's and D1 with 235/85R16 or 245/75R16 can get up to 70-80MPH and maintain it unless I'm in the mountains then it's according to the elevation. Above 7800FT on 85 octane it'll drag down to 50-60MPH, but it still handles it.

 

I think he wants more power. Some folks change the cam. Others swap in a GM motor or larger Rover V-8.

 

I am just trying to make it easier to merge onto highways and pass if necessary. I was not wanting to put in a GM engine but wondered if a 4.6 rover engine would make much difference. It may not be wise to do this swap financially but not much about these cars does. Mike

 

Ive been down this rabbit hole so much its now more like a rabbit canyon...... looked at diesel too
no matter which way you slice it - a GM LS engine & tranny swap is the most economical and sustainable - RW performance engineering makes a adapter for the GM tranny to LR transfer case. LS swaps are so common now there is a huge knowledge base and product line.
I have 32" tires on mine with a 2" lift - its a pig, Im not sure what makes more sense - swap the diffs to 4:11's or LS swap.....

 

Not sure about an LS, but the 4.0 in my D1 is a pig compared to the 4.6 in the P38. Much better power in the 4.6.

I am surprised to read the LS is the most economical upgrade. Last time I investigated it would have been close to $15k when all is said and done. Maybe that has dropped.

 

Online, there is a company in England that re-programs the ECUs for more power. I didn't take the bait myself, but that is a relatively easy and cheap option, compared to swapping motors.

 

Well if you are willing to spend about 12 grand you can get the 4.0 up over 330 horsepower with new cams, head, and internals. If you know how to build an engine you can probably get it done for a fraction of that.

 

Like Walt says, my P38’s 4.6 is adequate for our mountain highways in southern British Columbia. The 4.0 in my D2 isn’t quite adequate. A 4.6 swap would for sure be the cheapest way to go.

 

One thing with a 4.6L the stock HP22 isn't really made to handle the extra HP or torque. You can't just floor it and off you go. The P38 HP24 has a different torque converter. If you do a 4.6L in a D1 (like I have in my 95 D1) and say you floor it from a light when it gets to 3rd right before it goes into 4/OD it'll slip guaranteed. I love the extra torque and HP, but you can't rocket off from a light like you can in a stock 4.0L setup. I haven't looked into a different torque converter, but it's something to keep in mind. I'm just careful and never let it get to the slip state lol.

A cam just tweaks the power band, and LR already tweaked it so you get low end grunt. You don't want a cam that gives you all sorts of power at higher rpm's as that's pointless in a LR V8 IMHO. You want power between 2.5k and 3.5k. On all the D1's I've owned 245/75R16 puts the speedo spot on with the factory gears. I just drove my second 97 XD back from Portland, OR, and it did fine in the mountains. I passed plenty of people and by the time I hit the end of the on ramp I was at speed. I live in SETX so it's flat, I rocket around pretty good vs say when I had an 05 Jeep Wrangler Rubicon that wouldn't get out of it's own way or go above 65MPH with a tailwind, it had the worse 4spd auto box I have ever dealt with!!!