Land Rover V8 Exhaust mod using Disco bits?

Simon B · Post by **Simon B** » Fri Jul 11, 2008 6:52 pm

A very long time ago a bloke from JE Eng told me about a fairly "economic" mod to my exhaust. It was to replace the cast manifolds (Land Rover v8) with ones from a Discovery and to change a couple of of the smaller intermediate pipes to the y piece.

Has anyone done this on the forum or know of a better mod that is still "economic"

ramon alban · Post by **ramon alban** » Fri Jul 11, 2008 10:00 pm

Simon, is this to generate mpg economy or less expensive exhaust installation costs?

stirlsilver · Post by **stirlsilver** » Sat Jul 12, 2008 2:57 pm

I've done it... Just a sec while I copy and paste the photos from another forum. All up ist was AUD $100 for the second hand manifolds and down pipes and $200 for new set of down pipes to be made up... Certainly makes a difference!

I bought the manifolds and the down pipes to suit. Thing is the down pipes do not suit my car so all I essentially needed from them was the flanges.

The first thing I noticed is that the down pipes are actually squashed and the squashed section of pipe is placed inside the flange and welded. Since I was going to be getting an exhaust place to do up a new set of down pipes that suits my configuration I had to decide how I was going to cut the pipes off. Whether to leave stubs of the original pipes or remove them completely. I checked to see how the gasket holes lined up with the ones on the flange and I found that the squashed pipes had a smaller inside diameter than the gasket (and manifolds).

I decided that I would remove the pipes completly including the squashed sections. So I took to them with cutting disk and a hack saw to remove all the weld and the squashed section of pipe.

I cut the squashed pipe with a hacksaw in 90 degree increments and I found that they were actually relatively easy to remove provided enough of the weld was removed. Sometimes they just fell out while cutting. Anyway I proceeded to remove all of the pipe.

A much better lineup

A little tiding up

And this section of the work is done!

I just realised that it is a lot of photos for something that is pretty simple and boring... but... you get that.

The next step will be to pull the guards off my car (again) fit the manifolds and somehow get my car to the exhaust place to have the new down pipes welded to the flanges and the rest of the exhaust system.

Well, i was back at it again today.

Finally got round to fitting those EFI manifolds that I bought. Thankfully they fit without any problems! Ok so the photos.

I pulled the guards off the car... AGAIN! Left hand side:

Right hand side:

It doesn't look like much when both guards are off:

Just a random photo I took of the guards:

Ok, well, I took to the exhaust with an angle grinder and made the necessary cuts and then removed the manifolds. They came off without too much hassle.

Then I got to putting the EFI manifolds on. Here is the right hand side done:

And then the left hand side... I came very close to stripping some threads here because for some reason the manifold I bought doesn't align perfectly on the top row of holes for some reason, but in the end I was able to carefully ease it in:

The doesn't seem to be a whole lot of room between the left hand manifold and the chassis rail:

The obsolete exhaust manifolds:

And that was my sunday!

I fired the engine up for kicks with just the manifolds and no exhaust... wow is it loud! I took some video which you can watch from the link below. It's only clear from outside the garage. Once you go inside it's nothing but distortion!!

http://www.youtube.com/watch?v=yhkjq3zGzj0

The next step is somehow getting this damn thing to an exhaust place... I'm thinking I might just drive it to work on tuesday and hope I don't get pulled over... It's 6km to the nearest exhaust shop.

The car should end up with a slightly different exhaust note when this is done. We shall see!

For the sake of completion, these are the downpipes the guy at ferndale exhausts did.

LH side:

RH side:

It's interesting, the engine behaves completely different with these manifolds. When I'm driving I find that i'm changing the gears at a much higher rpm (4000rpm or there about) because it just revs out so easily. And also when I stuck my head in the engine bay with the engine running. It's actually quietened down the engine too! It still needs a bit of a tuneup though.

landrovernuts · Post by **landrovernuts** » Sun Jul 13, 2008 5:49 pm

Depends what you are chassis you are putting this in. I have just done this on my v8 90 and it all fits loverly apart from the gearbox cross member.
I used 3.9 down pipes without cats, which I think are much better than 3.5 down pipes, but I had to use a gearbox crossmember from a 1990 Range Rover. The downpipes then connect straight to a td5 back end and the difference is very noticable. I had a full Janspeed system on it before, but this set up is more economical, much quieter and the engine revs much more freely, admittedly my EFI manifolds are are smoothed out and the ports matched to the heads and would recommend you do this to any v8 landy.

Simon B · Post by **Simon B** » Mon Jul 14, 2008 9:33 am

ramon alban wrote:Simon, is this to generate mpg economy or less expensive exhaust installation costs?

The chap said they disco set up was more economic on fuel and would allow the engine to rev a little more freely. My main reason for doing it would be economy if torque and bhp increased also I'd be happy.

stirlsiver, thank you for a very detailed reply, looks like smoothing and matching ports has a considerable effect on economy.

Simon B · Post by **Simon B** » Mon Jul 14, 2008 9:54 am

landrovernuts wrote:Depends what you are chassis you are putting this in. I have just done this on my v8 90 and it all fits loverly apart from the gearbox cross member.
I used 3.9 down pipes without cats, which I think are much better than 3.5 down pipes, but I had to use a gearbox crossmember from a 1990 Range Rover. The downpipes then connect straight to a td5 back end and the difference is very noticable. I had a full Janspeed system on it before, but this set up is more economical, much quieter and the engine revs much more freely, admittedly my EFI manifolds are are smoothed out and the ports matched to the heads and would recommend you do this to any v8 landy.

It's to go on my 110 CSW, not heard of fitting it to a Td5 before! My 4.6 on the 3.5 sounded very soft and muffled, fuel economy on lpg and petrol was poor. Is the Td5 exhaust a straight fit or will I need my welder!

landrovernuts · Post by **landrovernuts** » Mon Jul 14, 2008 1:01 pm

The disco 3.9 and the range rover 3.9 exhaust front pipes are the same, and I think disco 3.5 and range rover 3.5 are the same aswell. my personnel opinion and that of JE Engineering when I spoke to them last was that the 3.9 pipes are superior flowing, and that any efi manifolds and downpipes flow much better than standard landy manifolds and down pipes.

The only reason for connecting to a TD5 back end was, that I wanted as free flowing exhaust as possible without blowing my ear drums on the motorway. The standard landrover 90/110 exhaust will not connect to a set of 3.5 efi or3.9 efi downpipes and the standard exhaust will not fit on my 90 now as I have a long range tank where the 2nd silencer goes. It just so happened the TD5 exhaust is much freer flowing, does not interfear with the long range tank and connects straight to the v8 downpipes without any welding.

Simon B · Post by **Simon B** » Mon Jul 14, 2008 2:42 pm

landrovernuts,

Any idea if the Td5 pipe would fit my 110 as well as it does on the 90? This sounds like a good upgrade falling short of full on tubular headers and big money. Bet it sounds nice too!

landrovernuts · Post by **landrovernuts** » Mon Jul 14, 2008 7:51 pm

I am unsure if the 110 TD5 tailpipe will bolt on without looking at one, however I don't see any reason Landrover would make them different and would guess it would fit. Think you would need to check under aTD5 and just makesure that a 110 and 90 downpipe is the same and not different lengths

Definitley makes it go better, pulls an overdrive easilly now and sounds like a v8 should without blowing your ear drums when your on the motorway.

Simon B · Post by **Simon B** » Tue Jul 15, 2008 7:13 pm

Overdrive is on wishlist 2, need to engine rebuild and lpg system first, looking at a new dizzy cost and advance retard amp for the lpg it might pay me to go megajolt, didnt fancy the full on injection route just yet,

landrovernuts · Post by **landrovernuts** » Tue Jul 15, 2008 7:47 pm

The best thing I have ever done to the landrover is to fit the hot wire injection back on it. The engine was in my range rover before the tin worm took over, however when I fitted it into the 90 I fitted a Weber 500 and wish I had never bothered. On went the SU's and while it ran fine it had become gutless. Get your ignition sorted and convert it to efi and don't look back. More miles per gallon, more torque and power, no coughing and farting and no choke!

Simon B · Post by **Simon B** » Fri Jul 18, 2008 9:05 am

I tried to convince myself megasquirt on lpg wasnt the best direction for me and just stay close to original and simple. If ms can run run switchable maps then it'll be a goer I didnt know how it could do this in terms of the gas running out. Start up would be easy temperature related but when the lpg runs out or the user wishes to intervene?

A new dizzy and ignition amp will be the thick end of £350, cost to muck about with SUs? £100 so that's already $450 staying original.

I need help...!

sowen · Post by **sowen** » Wed Jul 23, 2008 6:48 pm

Stirsilver's exhaust looks similar to mine, except that I re-used the standard twin downpipes by cutting bending and welding them around my chassis. I then have twin 2" pipes which join to a single 2.25" pipe that runs through a 110 200tdi silencer then straight over the rear axle and through the pto hole. All in all, the range rover manifolds cost me £10, the donor downpipes and y-piece £2 and I bought four brand new 110 200tdi silencers for £60, and only ended up using one, so £15 for the silencer, and the rest used steel pipe from the original exhaust and new pipe from my local steel merchant. All in all, its messy in places but always gets good comments on how good it sounds

Simon

Simon B · Post by **Simon B** » Tue Aug 05, 2008 1:55 pm

I should really of checked this but...bought some Range Rover manifolds on eBay will they fir into my Land Rover 110CSW engine bay ok? I know the heads are the same so outlet ports will clearly match wasnt sure if they'd sit to far back and fouild the bulkhead.

If it's all tickety boo I need some down pipes.