discovery 3.9 v8 mods

[muddy4x4xfar]

hi all, is it possible to achieve somewhere in the region of 300hp if not more from a 3.9 v8 without a super charger. Also with this kind of power would the vehicle still be able to put it to its potential as regards gear box transfer box diffs etc? or are their mods namely a different gear box set up etc.

has anyone done it, if so what do you guys recommend. It will be a manual vehicle that i am building for rally purposes as well as road use. what im trying to do is build something rally car kind of spec but with my discovery 200 tdi soon to be v8.

Any advice much aprieciated

thanks

chris

[Bowie69]

300BHP from a Rover V8 is REALLY expensive (£5K?), much easier and cheaper to find a modern engine to do it.

My vote would be a Lexus 1UZ-FE, 250BHP out the box, megasquirt it, high flow exhaust and a decent airbox and you will see 280BHP, and be able to rev it to 9000rpm as well THEN you can supercharge then and you get an easy 400BHP without opening the block up, cheap as chips to, LS400's are sub £500 on ebay, so by the time you break the rest of it, it hasn't cost you anything.

[Gazzar]

Is there an adapter to the R380?

[Bowie69]

I would prefer to keep the autobox, but if you wanted a manual I am sure can adapt the two, as jad on here has to an LT77.

[vulcan bomber]

I would prefer to keep the autobox, but if you wanted a manual I am sure can adapt the two, as jad on here has to an LT77.

Stumpy R380..... I made the adapter.

[Bowie69]

Ah well there we go then

[Disco-Ron]

Before you consider anything you need to know what rules you'll be governed by, then you won't get a nasty surprise having spent a small fortune and possibly not be able to use it!!

[muddy4x4xfar]

Before you consider anything you need to know what rules you'll be governed by, then you won't get a nasty surprise having spent a small fortune and possibly not be able to use it!!

forgive me what rules? do you mean for rally driving, i won't be using it for that to be honest. I'm more after fast road use kind of vehicle but rally kind of spec. think bowler wildcat on a disco one, i know its never going to be the same but near enough

[Chicken Drumstick]

Stumpy R380..... I made the adapter.

Would you be interested in making more?

I have a 1-UZ for another project and being able to cheaply mate it to an LT-77/R380 would be tempting.

[Chicken Drumstick]

forgive me what rules? do you mean for rally driving, i won't be using it for that to be honest. I'm more after fast road use kind of vehicle but rally kind of spec. think bowler wildcat on a disco one, i know its never going to be the same but near enough

Have you posted this on here before? I recall at least one similar thread?

For road use that's fine, but if you are considering any form of competition, then you do need to know what rules you will be needing to meet. There will be many.

As for power.

Well first up, might I suggest an alternative option.

The 2.0MPI Disco's used the Rover 2.0 T-Series. Now I'm a huge fan of V8's (I own 4!!) and Rover V8's in particular (I own 2). But the T-Series is appealing in it's own right. Firstly Rover produced a very good Turbo version, which should be a direct replacement pretty much for the n/a 2.0 in the MPi.

Stock these make 197bhp. This is pretty much the limit for the internals. But if you are happy to beef them up a bit (pistons/rods), then they are as tunable as any other 2.0 T. So 300bhp should be easy.

And of course weight. A 4 pot will sit further back with less weight over the nose and while the RV8 is pretty light, I suspect the T-Series would still give a better weight advantage.

As for the V8.

Well depends how much you want to spend. You'll need to look at the basics, so good exhaust, long tube headers and a good intake system. A 3.9 should make 200hp+ like this.

Next up you could consider a cam. Lots of choice. But anything biggish will likely require flycut pistons, so will add cost. You really might want to budget for £1000 min to £2000 realistic. Although there are less wild cams that need less work, but will still require tuning.

And heads, you can spend a fortune on heads.

You might find you are also better of shopping around for a 4.6 to use as your base engine. The extra displacement will help and especially so 'under the curve', i.e. PEAK hp might not be higher, but it'll make more grunt/power in the mid and low rpm range.

Other options you could consider are power adders. There is some scope to make a twin rear mount turbo setup yourself with fairly small amounts of fabrication involved. But would certainly require some reading up first.

And options like Nitrous Oxide. It won't give you part throttle improvements, but if all you want it WOT power, then a 100shot of nitrous is hard to bet in the bang per buck sense.

As for gearboxes. Well the R380 is rated at 380nm of torque. A stock 4.6 RV8 exceeds this, which is why Land Rover only offer the 4.0 litre with the manual box. The LT-77 is similar. There are other gearbox options LT-85/LT-95, but you'll have to research what you want.

That said, it will depend on how you drive, a smooth driver can probably make use of the power and not break stuff that often, but it should be expected that gearboxes like this will fail at some point.

The same is true of the diffs and axles.

[FridgeFreezer]

Cheapest way to make that faster would be to drop in a 4.6 from a P38, not 100% plug-and-play but about as close as you'll get. Beyond that, as has been said, it's the law of diminishing returns - you're spending increasingly more and more money on tuning bits for very small gains.

If you really want 300+bhp you need to decide exactly what you want and how much you're willing to spend.

Whichever way you go, you may be better off selling the disco & buying a newer D3 or RR/RRS with a modern V8.

[vulcan bomber]

Would you be interested in making more?

I have a 1-UZ for another project and being able to cheaply mate it to an LT-77/R380 would be tempting.

Yes but it's not even close to being cheap, I don't currently have access to the machines I need to make it but hopefully I will in the near future and as far as I'm concerned,James owns the drawings for the adaptor so you will.need his permission to use them before I contemplate looking at them again.

[Henry Webster]

...think bowler wildcat on a disco one, i know its never going to be the same but near enough

That's pretty much what I have, 3.9 Discovery Rally Car. It is nowhere near 300 BHP, as others have said, that is pretty expensive for a Rover. Early 200 BHP is not, however and is plenty to have fun with. I have about 220, from a cam and a rebuild and with some hard driving puts us in amongst the Wildcats and in front of all but the fastest Tomcats!

Here's MuddyMoo doing her thing a couple of weeks ago, on the Allisport AWDC Hillrally.

https://youtu.be/CWJRIkg4wks