Designing a Range Rover Twin Turbo

RangieMatt · Post by **RangieMatt** » Wed Oct 03, 2007 9:57 am

Hi,

Title is explanatory enough

Me and my mate Russell both have 1991 Range Rover 3.9 Vogue's. His is an automatic, mine is Manual. To cut a long story short, we're wanting to do a twin turbo project on a shoestring, just for the hell of doing it. It's not for power, and we won't be doing any internal engine work, so I'm intending to run light boost. The object of the exercise is simply to see how cheaply we can do it, DIY style. I'll start with some vehicle specs.

Russells:

3.9 EFi, rebuilt less than 4000 miles ago, Fast Road Cam, 4 branch manifolds, 2.5" bore duplex exhaust system, no balance pipe. His is an automatic gearbox, which was rebuilt about 8000 miles ago with an uprated 4.6 clutch and should be good for up to 260bhp, and I can't see us pushing that.

Mine:

Dead standard, but fairly low mileage 3.9 EFi, standard, 5 speed manual box.

We're looking at various options for turbos, basically we want 2 pairs of fairly small turbos with integral wastegates, I'm open to suggestions if anyone has any?

Manifolds we can make ourselves, same with intercooler piping etc. The main question I've got is ECU related. Does anyone know how flexible the stock ECU is, I'm kinda guessing we'll have to switch it out as it won't handle the boost? Anyone know much about this?

Matt

Eliot · Post by **Eliot** » Wed Oct 03, 2007 10:50 am

Megasquirt is the easiest way to do it, assuming you dont want to rely on a third party (read mark adams) to map your existing ecu.
Also factor in the cost of a LC1 wideband lambda.

For turbos' a pair of turbos from a 2L engine should work ok - ford or scooby. Avoid diesel turbos, as the turbine (hot side) tends to be very small and would restrict top end.

kiwicar · Post by **kiwicar** » Wed Oct 03, 2007 10:57 am

Hi
first question, whar CR are you both running, from what I remember there are about as many compression ratios for this rangy as there were markets......
next, I think you can bodge the efi to work with some boost by putting a boost referenced fuel pressure regulator (and some fish tank plumbing) in the fuel feed and possably bigger injectors, horrid but cheep (until it runs your engine lean on full power and boost! I think you can also use a hack (bodgit box) into the water temp sensor feed to give a bit more enrichment with boost again not nice but you may get it to work.
personally I would go aftermarket ecu, vems, megasquirt or emerald and do that bit properly and sell the existing ecu's to recover the cash.
Mike

RangieMatt · Post by **RangieMatt** » Wed Oct 03, 2007 1:32 pm

Hi,

Thanks for the responses.

The CR of both engines is 9.13:1

I think an aftermarket ECU is going to be the way to go, just a bit of a pain, I reckon it'll be the single biggest expense

Nevermind, I may be trying to do it as cheap as possible, but I also want it to work, it hasnt got to be crap

What am I going to pay for a Megasquirt then, I can't find a price for basic kit, and assembled ones are up to £280.

kiwicar · Post by **kiwicar** » Wed Oct 03, 2007 2:32 pm

megasquirt.org for kits, but you need international money orders and the banks hit you for those (about £25)
or go to the extraefi.co.uk for a uk suplier, £280 for the kit ain't bad when you look at what you get!
Mike

Eliot · Post by **Eliot** » Wed Oct 03, 2007 6:53 pm

Phil Ringwood (extraefi) and Bill Shurvinton are both on this board and sell everything you need.

Post by **Coops** » Wed Oct 03, 2007 10:09 pm

Richard and dnb are also both on this board and are involved with vems ecu's

chodjinn · Post by **chodjinn** » Thu Oct 04, 2007 11:37 am

there's a janspeed tiwn turbo kit on ebay at the moment. Exactly the same as mine but no where near the same condition. It was already at 500 squids when i looked! Almost tempted to sell mine lol . . . not!

dnb · Post by **dnb** » Tue Oct 09, 2007 11:47 pm

I have this pair of plenums - would be ideal for twin turbo-ing:

Trouble is that it'll probably be a budget breaker! Metal fabrication isn't cheap.

For turbos on a 3.9 I'd suggest a couple of TD04s from a 1997 to 1999 UK spec Impreza turbo. They'll be about the right size for low boost and people are throwing them away in preference of the TD05 etc for their Scoobs.

I have a couple of TVR exhaust manifolds. They are a pair of short 4-into-1 systems, so they can be easily cut and welded for connecting to the turbos. I thought about twin turbos on the Griff once upon a time, but thought that the boss wouldn't approve...

As for ECUs: VEMS / MS etc - all will work nicely, and are quite easy to set up - there's plenty of help out there.

RangieMatt · Post by **RangieMatt** » Wed Oct 10, 2007 11:11 am

That is a NICE plenum.

I'm currently boffining up on Injection Systems and MegaSquirt etc. If I'm going to rip Lucas out, I figure it'll be helpful if I know what I'm doing.

Post by **katanaman** » Wed Oct 10, 2007 1:22 pm

dnb wrote:I have this pair of plenums - would be ideal for twin turbo-ing:

Trouble is that it'll probably be a budget breaker! Metal fabrication isn't cheap.

For turbos on a 3.9 I'd suggest a couple of TD04s from a 1997 to 1999 UK spec Impreza turbo. They'll be about the right size for low boost and people are throwing them away in preference of the TD05 etc for their Scoobs.

I have a couple of TVR exhaust manifolds. They are a pair of short 4-into-1 systems, so they can be easily cut and welded for connecting to the turbos. I thought about twin turbos on the Griff once upon a time, but thought that the boss wouldn't approve...

As for ECUs: VEMS / MS etc - all will work nicely, and are quite easy to set up - there's plenty of help out there.

Is that silicon hose I see? If it is what have you done to stop it completely collapsing under vac?

chodjinn · Post by **chodjinn** » Wed Oct 10, 2007 2:31 pm

That plenum top does look very nice, but quite a bit of work just for show though? Can't see there being much of a performance benefit, but bling it certainly is!

ian.stewart · Post by **ian.stewart** » Wed Oct 10, 2007 2:59 pm

I would have thought the cheapest exhaust manifolds would be a set of P6? or P5 rear exit cast manifolds, swop them side to side so they exit forwards and machine up some adaptors to suit the turbos

Paul B · Post by **Paul B** » Wed Oct 10, 2007 4:11 pm

RangieMatt wrote:That is a NICE plenum.

I'm currently boffining up on Injection Systems and MegaSquirt etc. If I'm going to rip Lucas out, I figure it'll be helpful if I know what I'm doing.

Any reason you can't use carbs, and do away with all the EFI black magic?

chodjinn · Post by **chodjinn** » Wed Oct 10, 2007 7:34 pm

Got a set of 2" SU carbs, turbo mounts, piping and ported SU manifold if ya want it, from a Janspeed set up. I'm not using them as fitting EFI now, sometimes wish i hadnt bothered!