Power vs Reliability vs Economy

[topcatcustom]

Assuming a RV8 was chosen over a diesel for a RR Classic long range tourer, and a very mild budget (NO racing required!!!), how much power could you get out of a pretty standard lump? Slightly torquey cam, polished exhaust ports? Can I assume a 3.9 would be most cost effective, and injection or carbs for reliability (more important than economy). Would a V8 be better than a diesel or is there no escaping the good old 200tdi's reliability and nice torque in the landy world?!

[kstrutt1]

I would reckon on around 200bhp would be a reasonable number, v8 has plenty of torque and will be smoother than 200tdi, for me the main reason would be the noise, the tdi is a noisy old 1st generation direct injection, the V8 is about the best engine noise there is.

The reasons most people change from v8 to diesel are fuel consumption and the better wading performance of the diesel, If you are not worried about these the V8 is the best option.

[kiwicar]

As Above,
a V8 will be a much better car to drive, for fuel economy EFI will be much better than a carb, especially if you did an aftermarket ECU conversion with mapable spark control. If you do all the above you could also lower the gear ratio so you rum at lower revs cruising (bigger tyres or a different transfer box ratio, or an over drive box).
Mike

[paul c]

One of the best cars I had was my 89 RR, 3.5 injected auto. good economy, very reliable, just enough power.

[topcatcustom]

I have a 200tdi in my 90 and whilst noisy and very vibratey it is a bloody fantastic engine- the only thing that has ever gone wrong has been a head gasket a while ago and was a straight fix, and after 200,000 miles without any rebuild and probably very mean servicing it still starts on the first stroke EVERY time. Very simple to work on and with my heavy right foot in my landy and 3t on a trailer quite often it still returns about 27mpg, to me that makes it a fantastic engine- and I think it is only so loud as land rovers have crap noise insulation and it is still mounted on solid rubber mounts instead of the nice soft ones that the 300tdi's etc have. - oh- and I dont run a fan and Never gets hot unless sitting in traffic jams in summer!

A V8 would be much nicer in a RR but in reality can you really choose an engine for 4000 mile round trips because it sounds better than another?!

Anyway I did start this thread as I would like to see a V8 make sense, but it does have a bit to contend with

If I went with a 3.9, standard injection and a mild torque cam I'm guessing it could give maybe 200bhp, what sort of mpg could it return? Probably be an auto too due to the amount of miles being consumed in short periods.

[stevieturbo]

Does anyone do conversions for some modern diesel V6 units ?

Could have the best of both worlds ! Bound to be some 150-200bhp super torquey modern diesels out there.

Although I'm sure it would be complicated.

V8 would be much easier if fuel consumption is a non-issue

[kiwicar]

As Stevie says a modern deisel V6 or V8, got to be a few rolled RR sports out there, a fair few must bave been bought by estate agents or doctors and as a result in a scrap yard by now should be a straight transplant with autobox, transfer box and loom (need custom propshafts).
My Vogue SE gave about 18 mpg on petrol, 21 on a long run if kept below 85 and it was a 100k plus unit, a new cam would probably added 1 to2 MPG to That, my first one was a 3,5 on boxer manifold an R87 cam about 9.7:1 comp and stage 1/2 heads and headers (probably about 190 bhp) with 4 speed with an overdrive and 33" rolling diamiter wheels, gave about 20 to 22 normal use and 24 on a run.
Personally if it were my money I would look out for chevy LS 5.3 with autobox and transfer box out of a chevy 4x4 ( or caddy pimp mobile) and put that in, unless I had found a low milage deisel rolled RR sport (going cheep ish) as I said above, (probably still go the LS route)
best regards
Mike

[topcatcustom]

Too big a project, its got to be simple and reliable- so I think I would stick with a RV8. Its a shame to ditch potential power but I also think a 3.5 over a 3.9 would be worth it as less chance of problems, maybe run a 75-80deg stat, with regard to carbs what would be better for torque and mpg- SU's or an Edelbrock 500cfm 4bbl on performer manifold?

[ramon alban]

Too big a project, its got to be simple and reliable- so I think I would stick with a RV8. Its a shame to ditch potential power but I also think a 3.5 over a 3.9 would be worth it as less chance of problems, maybe run a 75-80deg stat, with regard to carbs what would be better for torque and mpg- SU's or an Edelbrock 500cfm 4bbl on performer manifold?

TC, if perchance you decide to stick with bog standard 3,5 Efi, of what ever system of choice, you might consider minimising any possible power losses to ensure maximum output .

If so, read this treaty written to eliminate power losses but also doubles as a very passable health check.

http://www.vintagemodelairplane.com/pag ... wer01.html

And the cost? pretty much close to peanuts.

Yes, it was written for the SD1 but principally, not dis-similar to your system.

One further point, IMHO the Efi RV8 runs better with coolant temp in the region of 90 deg C, so fitting a low temp stat means your Efi will run rich, with darker plugs, poorer economy, and less overall efficiency. Even bores can be washed of oil.

Why? Because the coolant temperature sensor, seeing only 80 degrees C, disallows the ECU from providing an efficient combustible mixture.

Ah, I hear you say, Dont wanna risk overheating.

Well, if that's the case, do a full health check on your cooling system too, viscous fan, radiator and heater matrix flushing, block flushing (and reverse flushing too) eliminate air locks, the whole nine yards.

If some of that rings a bell, you may be interested to read:

http://www.vintagemodelairplane.com/pag ... ant01.html

[sweety]

My M8's 3.9 RR Classic never misses a beat & after a bit a bit of water proofing he often wades through 3-4ft of water with no probs but with the mods he gets about 17mpg on a run if thats of any help

[RoverP6B]

I run a 4.6 in my Rover P6B so I appreciate it is not as large and heavy as a RR, but with twin SU carburettors I see 25 to 29mpg typically on country runs., which is far better than when running the original 3.5 litre engine.

Ron.

[topcatcustom]

What can a good 4.6 be found for now? Still be a bit dubious about liners though on a 2000 mile long run, not sure if could be convinced that anything other than a top hatted or coscast lump would be as reliable as a 3.5, its just a pity about the power difference! Would like a gmc V8 diesel but I'm guessing they do about 5mpg!!!!!