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Petrol engine conversion


GBMUD

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I currently have a Td5 Defender and I think it is rather good.  Many voices in government however seem to think I am killing people with my choice(?) of a diesel engine.  Actually, when my car was built there was ONLY a diesel option as the powers that be made sure petrol was not a viable option and encouraged the uptake of diesels.  Now there is talk of scrappage schemes, tighter and more numerous LEZs end so on to persuade us back in to petrol (or electric, hydrogen, humus etc.) powered vehicles...

So, if I chose to replace the Td5 with a petrol engine, what might I choose and why?  A Rover V8 may seem the obvious choice, but what about something else? BMW 2.8(?) petrol engines were fitted in some South Africa models for a time. Where else might I find a petrol engine, never fitted as OE, that might be a suitable replacement? Merc 6 cylinder? Japanese?  It would be nice to find something with the flexibility for towing rather than just going for mega power. Extra marks will be added if there is an existing conversion for either the R380 or for a ZF4 auto.  

Chris

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I thing you may be over reacting a bit..

Diesel will be fine for th time being - sell it if you have doubt and buy something petrol ex factory. Modern vehicles are getting more and more difficult to convert and modify..

Good luck !

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I wouldn't do anything yet there are no actual problems yet.

Trucks are doing some interesting things with diesel derived engines on gas produced from methane bio digestors and there's a company putting filling points around the country. Meets the emissions regulations without adblue dpf egr etc etc. 

I don't know much about the technical side of it so I don't know if a conversion would ever be possible but I wouldn't jump in and stick a petrol engine in for the sake of it.

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Get a feeling this is more of a hypothetical question :-) 

 

Can't think of a single modern petrol engine with the capacity to move a 7 tonne train at motorway speeds and still be capable of returning near 30 MPG the rest of the time in something shaped like a box. Maybe the BMW 6 pots as you suggest. A VW/Audi 5 pot might work. The Lexus V8 is popular in the fast Ultra4 trucks. 

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The marine diesel world have been undertaking low NOx conversions for a number of years. We changed out camshafts injectors pistons and turbos to achieve the lower emissions. The same power was achieved with lower EGT, but I can't verify the fuel consumption as what is a few litres when you are burning 25,000 litres a day!

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I've driven the 2.8 Beemer 90. It's a hoot but has no bottom end. Also drinks fuel in scarey quantities.  The 3.0 would be fun but at 300bhp your drive train would disappear. It's also very thirsty

I think VAG V6's might be a route

Land Rover used to fit a V8

It's the towing thing really and the need for low down torque. The VAG 1.8 Turbo has oodles of low down torque, loads of mid range and will rev to hell and back. It's longitudinally mounted, has wasted spark tech and is available in lots of flavours as well as being Nails Hard.

Like most of the posters above, I'm for waiting until it's real news and not just media hype. Then I'll be running on veg oil al the time 

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Sorry if I gave the impression that I have a plan to actually do this, it is, as Mark suggests, largely hypothetical for now.  If at some future point the government decide that they are going to tax diesel vehicles off the road though, I want to know that I have an option to keep my Defender.  Rover V8s are all well and good, they are easy to convert but are rather old fashioned and well known drinkers.  I am keen to explore further afield in my theoretical search for a viable alternative - perhaps to find something that offers better potential fuel economy than the RV8.

I think that the cost, bulk and weight of batteries for an electric conversion are going to be my main objections. sorry Steve. :)

Lexus/Toyota V8s seem very attractive - I have been considering building a 'Tokyo TVR' but stuffing one into an MX5...

Do BMWs use ZF autos behind 6 pot petrols?  What about Mercedes?  That would make a very easy conversion and get two birds with one stone!

I do so little tough off-roading that 300HP is unlikely to be a major problem other than potential accelerated wear on the drive train. I wonder if one could 'de-cam' such an engine to have good torque off idle for towing? Being able to tow would be nice.  If such a conversion became popular it might be worth someone making a new cam/inlet to improve low down torque.

I like the idea of the VR6 engines.  Previous research for a different project suggested that they do not take well to conversion in longitudinal applications though - this may be over-comable...  The 1.8T would surely not provide enough torque for towing without lots of revving to get the turbo spinning?

One thing that might accelerate the need (or desire) for a petrol conversion is actually local regulations.  Here in the Horsham district there are concerns about air quality, as I suspect is the case elsewhere.  It seems ironic that the local authority worry about air quality in town, yet they seem to set traffic lights to frustrate the speedy and efficient passage of cars through town, instead making them wait at multiple sets of traffic lights and then accelerate and brake for the next set.  Anyway, whatever the reason, there is already an 'experimental LEZ' in place in Storrington, a large-ish village at the foot of the south downs.  You can bet your life that once this becomes permanent and mandatory it will spread to Horsham where I live.  This may have the effect of meaning that I can no longer drive my Defender into town - which I find to be a highly undesirable outcome.

Thanks for the contributions to my thought tombola,

Chris

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As you know, the milk float comment was a lame attempt at a joke, but on a more serious note, an electric conversion could be viable in a few years time. Given time for a number of those Tesla X buyers to pile their car into the car in front whilst messaging on the M25, there maybe some affordable conversion options, that have the low down torque required, range and the green credentials you need.

Also the latest crop of petrols from BMW, Mercedes etc. All now have twin turbos to give much better torque at low revs. Again in a few years, these could be viable options. The main headache being getting all of the electrics working. Not easy on today's cars.

 

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I think the VED will stay the same, adjusted for inflation.  Retrospective changes do occur, like the doubling the TD5 suffered, but they are uncommon.  But I share your pessimism that diesels will be taxed off the road in one way or another, mainly through fuel duty and LEZ charges.  There is nothing to stop any town or village council creating an LEZ once the short lived diesel cars have been replaced with petrol cars, leaving just the few long lived diesel vehicle owners to object.

I am considering obtaining a V8 or 2.5 pertrol (or both) to power my vehicles should this come to fruition - my 109 has a 200Tdi retrofit and my RRC is a factory built 300Tdi (which I had rebuilt by Turner Engineering just before emigrating, so could be a lot of money wasted).  ACR do some interesting tuning for 2.25 and 2.5 petrol engines, which would be an easy installation for most Defenders.  A V8 might be better, though, being of similar performance but smoother running in standard form than these bored and stroked 4-pots.  The ACR engines certainly aren't cheap, but then again, nor are most standard fully rebuilt engines, so their fuel burn compared to the V8 may be worth considering.

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13 minutes ago, SteveG said:

As you know, the milk float comment was a lame attempt at a joke, but on a more serious note, an electric conversion could be viable in a few years time. Given time for a number of those Tesla X buyers to pile their car into the car in front whilst messaging on the M25, there maybe some affordable conversion options, that have the low down torque required, range and the green credentials you need.

Also the latest crop of petrols from BMW, Mercedes etc. All now have twin turbos to give much better torque at low revs. Again in a few years, these could be viable options. The main headache being getting all of the electrics working. Not easy on today's cars.

 

I really fancy the idea of a 4wd Tesla's motors strapped to my axles - they can accelerate a Tesla to 60 mph in under 5s for the 4wd and 4s for the 4wd sport models (according to the sales staff), which means that a Defender or equivalent would achieve some staggering performance with near silence, extreme smoothness and no leaks!  With the engine, transmission, fuel tanks, exhaust, cooling and induction systems all gone, the space and weight capacity for batteries is huge.  The current problem is the cost and availability of the batteries and the lack of charging points.  A battery pack for a Tesla comes in at about £12k and would take a lot of adaptation to fit a Defender.  They can be charged from flat to full in about 8hrs from a portable charger, a few hours with a domestic mains charger (wired into the house supply, not a plug in charger) and under 30 mins on their super chargers, which will eventually be installed at motorway services and city centres, making the Tesla's 250 mile range (I suspect that is a summer figure with minimal light, wiper and heater use) viable.  But what about use outside of 1'st world nations?  250 miles (less for a Defender transplant) isn't going to be much use in Africa or the expanses of the US, Canada, Australia and alike.  Yes, you can fit more batteries, but that gets even costlier and heavier.  You'd be limited to European use, really, without extra battery power.  

Another element is steering - the energy used in a Tesla for steering is going to be tiny compared to running an electric pump for a LR's PAS.  You'd have to consider fitting a manual steering box from an older 90/110.  That'd spoil the drive more than just a little.  I think an electric vacuum pump for servo brakes and the existing hydraulic pump for ABS equipped vehicles probably wouldn't cause too much drain, though.

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Chris - some figures

There are two version of the 5 valve EA888 VAG four banger

Basic Passat lump starts in 1.8T form at 150bhp (4,300-6200rpm) and 180ft/lb. from 1,500 rpm (122ft/lb from 1,000 rpm

Top end 1.8T Passat lump (B5 longitudinally mounted) 170bhp and 240ft/lb from 1400 rpm

2.0T Audi A4/A6 B5 floor pan 168bhp and 207ft/lb at 1700rpm up to 306bhp and 280ft/lb at 1,800 rpm

The 2.0T R400 is still the most powerful production 4 banger for it's capacity ever put in a mass produced car - it was in excess of 400bhp

 

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1 hour ago, SteveG said:

As you know, the milk float comment was a lame attempt at a joke,

I did see that, and even the more serious idea lurking behind. :P

The problem for my application is very much as outlined by Snagger, that one needs to recharge too often for it to be viable for all my needs.  I want to be able to go to the Pyrenees, drive all day and then wild camp, or do the same in Morocco or the Alps, or other places where there is not the infrastructure to recharge every night - or three to four times in one day driving down there!

I should consider an electric car as well as the Defender.  ...or perhaps sell the Defender, the RR and MX5 and buy a RRS SVX - just for the sound! :)

Chris

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3 minutes ago, honitonhobbit said:

 

Top end 1.8T Passat lump (B5 longitudinally mounted) 170bhp and 240ft/lb from 1400 rpm

2.0T Audi A4/A6 B5 floor pan 168bhp and 207ft/lb at 1700rpm up to 306bhp and 280ft/lb at 1,800 rpm

Sounds like a useable range of torques...  I wonder what they do at 1000rpm?

Chris

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What about a Toyota V6 (5VZ-FE / 1GR-FE)? As used in the Land Cruiser J90/J120 (Prado). Don't know what low down torque is like, but those versions were designed for lugging vehicles of a similar mass and profile, and the peak power and torque is in the relatively sensible, not too likely to destroy the drivetrain, range. The older one at least didn't ought to be too bad on the electronics front.

Not sure fuel economy would be significantly better than an RV8 though - they're fairly thirsty in the Prado.

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1.8 does 122ft/lb at 1000rpm - 2.0 is very similar. Tick-over is about 700rpm and the turbo comes in at about 950

It's one of my favourite engines every - wasted spark, individual coils, relatively well sealed cam belt. My vapour build Auverland has one in it (in my head)

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On the subject of electronics, I was rather assuming that MS would work on a modern (Y2000 on) petrol engine.  Am I right in making this assumption, nothing too complicated?  Can MS do VVT, forced induction and so on?

Chris

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My 2p's worth:

1. Legislation is almost NEVER applied retrospectively so whatever you're driving now is likely to remain the same in terms of tax etc. (yes I know you're being hypothetical)

2. Swapping engines is unlikely to help as the legislation usually goes on the from-the-factory figures, so your hypothetical petrol-powered "TD5" disco would still be banned from the LEZ.

3. There are many engines which make more horsepowers than Land Rover but very few which make the torque, especially low-down as Mr Hobbit says. Even fewer which will live long happy lives with regular towing etc., the LR lumps tend to sacrifice a few MPG and pub-bragging HP numbers for longevity and flexibility.

4. Land Rover have fitted some petrol engines to the Disco 3 and full-fat RR etc, and a few known issues aside you've got to assume they are about as up to the job as you'll find.

5. All modern engine MPG figures are the work of fantasy (coughVOLKSWAGENcough). JLR tend to be more honest than most and suffer less under "normal" use.

By way of example: I drove a Volvo V50 2.0D, which claimed 79mpg. Sat at 70mph on the motorway with cruise control on it just about managed ~55mpg. The Jaaag X-Type I eventually bought for half the price claimed 45mpg (2.2D, a-la Puma/Transit) and, spending its life on the motorway at 70mph plus VAT it's currently managing 43mpg.

There's a shift in engine technology on the horizon as the whole VW emissions thing is leading to more realistic testing. Apparently the whole thing for smaller, turbo'd engines is dying off as they're only really good for passing the old testing regime. In the real world, larger less highly-strung lumps win the day.

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