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defender v8 stainless exhaust and manifolds


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Hi All, over xmas you all kindly helped out with my forever poor running (in the wet ) v8. I am glad to report all seems ok with some of the ideas so thanks. My next question is what would be seen as the best made/value stainless exhaust and manifolds ? , I want to treat the old girl and look for making more of the lovely v8 sound. Thanks again.

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A potential can of worms this one. Some say that the rimmers system is good. Others say its rubbish. Either way, one thing you can take to the bank is this... Make sure the manifolds are a 4-2-1 arrangement. The more common 4-1 arrangement is fine for sports cars but results in a loss of low-midrange torque, which on a heavy old 4x4 is where you want all the beans.... ;)

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I got the rimmer bros system on my 110 V8. The system fitted very easily together and is of very good quality. My 110 is a factory V8 so it might have helped with it fitting so easily.

I got the 4-1 manifolds and to be honist I've not noticed any loss of low to midrange power in fact I feel I've got more power it drives much nicer with the rimmer system on that it did before and considering that my 110 is heavier that a normal one I think any loss of power would be noticed.

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I got the 4-1 manifolds and to be honist I've not noticed any loss of low to midrange power in fact I feel I've got more power it drives much nicer with the rimmer system on that it did before and considering that my 110 is heavier that a normal one I think any loss of power would be noticed.

Im glad that your happy with your system. However the fact of the matter is that 4-1 manifolds are more geared towards top end power. Yes the 4-1 will probably be an improvement over old cast manifolds but you would find that if you now went to 4-2-1 it would feel even stronger...

http://www.sbdev.co.uk/Exhaust_Manifolds/Exhaust_Manifolds.htm

Yes this is a car tuning company, but the exhaust technology is the same. There is lots to be found on the topic.

If i had 4-1 manifolds and i was happy with them id keep them, but if i was buying them for 1st time id be buying the 4-2-1's.. :)

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V8's really want what the American's call "long tube headers". Sadly I don't think anyone makes such a thing for the Rover V8 in a LR. I have some on my TR7 V8, but they are a copy of what the works rally team used to use.

Tubular manifolds produce more performance via exhaust scavenging rather than flow. Ok bigger bore and larger collectors help flow and might give you a few ponies, but unless you are running high HP figures or boost, it just isn't the prime concern when it comes to exhaust manifolds. It's scavenging.

You want long primary pipes to achieve this is lower to mid rpms. "shorty" headers with short primaries will scavenge, but at much higher rpm. IRRC from something I read years ago, more like 6000-8000rpm. Which is why that design works well on things like high revving 4 pots (Honda VTECH etc) that may well rev to 9000rpm.

4-1 won't scavenge, you need the pulse from one cylinder to cause the scavenging on the inlet stroke of another cylinder on the same bank. Of course with the odd firing order of a typical V8 you can't get perfect scavenging without crossing over and linking a couple of primaries from each bank, but it's unneeded to see a healthy improvement.

For any tweaked V8 I'd like to see no smaller than 2.5" diameter collectors either. Don't know what the Rimmer system is like.

For torque and power you also want to have a H pipe connecting to the branches of the exhaust after the collectors. Doesn't matter how long across the vehicle this is, but it should be the same diameter as the surrounding pipe work. (assuming you want to run a dual setup). Y pipes work too, but you need to up side the outlet side.

Long tube headers (not Rover ones, just an example):

http://pacesetterexhaust.com/images/products/detail/70-2211.jpg[/img

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Im not sure. Never really looked into that. Until i can afford custom built 4-2-1 tubulars i was told that a good stop-gap was disco twin-port cast manifolds, disco non-cat downpipes and td5 system from there back.

Not only are the twin-port cast manifolds strong and dirt cheap, but they flow really well in comparison to most cast manifolds.

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@v8 Pete

I have RRC Classic 4-2 cast manifold (same as disco 1 I think) with the twin hole gasket,

then the 2-1 downpipes for the RRC/disco 1, NTC1863 & 1864

then the y piece for the same which ends in a big dia. Flange olive fitting, NTC4061

... Then the older V8 110 silencer, NTC4614

and the older tailpipe silencer NTC1800

All fitted together and works fine (except that am having problems with keeping the push in fitting to the Y pipe from leaking...)

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I did try the 4-2-1 disco manifolds before I got the system from rimmers bros, it was a pain in the backside it fitted poorly, leaked and just felt a mis-match of parts. A mate recommend the system from rimmers as he had no problems fitting his.

It's stainless from front to back, I fitted it in under an hour and is gas tight, sounds nice and not too loud.

It comes down to if you want ease of fitting then get the full rimmer bros one and have a slight loss in low down power if any. Or buy a mis-match of parts and have a nightmare in fitting some 4-2-1 disco manifolds as there's no stainless option for the mainfolds for 4-2-1.

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... as there's no stainless option for the mainfolds for 4-2-1.

Wonder if these could be adapted... I dont think they're stainless, but id rather have the "go" more than the "show" :) The only drawback being for that money you could prob have them made for you in stainless somewhere..

http://www.v8tuner.co.uk/product.php?id=856

Edit: Ive just seen that the full Rimmer system is £660 inclusive. Thats just nuts! For that kind of money you could find somewhere to make you a better system than that..including 4-2-1's

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What system have you got then??? Need for speed.

I did a lot of research into systems before buying and over all the rimmer system was in the middle of the group. I wanted something that was no hassle to fit or a mis-match of parts.

As for the "go" as I said I've gained drivability over what I had, if 4-2-1 are better then so be it but there's is no off the shelf full system including those manifolds.

I can't see the 4-2-1 being any better than what I've fitted, My 110 pulls like a train in 5th from 40-70mph and as I said earlier my 110 is just over a ton heavier than a standard 110 (unloaded).

I wasn't looking for race car performance all I wanted was a stainless steel system of a high quality that included manifolds.

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Right now i have twin-port disco manifolds with matching non-cat downpipes. From there back i will have standard td5 system minus 1 silencer box. This was on the advice of some pretty knowledgable v8 guys (2 of which were Nige and John from on here).

I made some local enquiries last year and a few different places quoted me between £600 - £900 for custom made system front to back in stainless including 4-2-1's.

Until i can afford this i will be happy with what i have. If you are happy with what you are running, then great. Im not saying what you have is no good. Its just that the OP asked what people recommended. Ask anyone who knows anything about exhausts and they will tell you that 4-2-1 is a superior configuration than 4-1 for low-midrange power/torque. So with that being said if i have £700 to spend on a system id spend it on a custom made system with 4-2-1 manifolds with optimum sized primary's rather than a one-size-fits-all Rimmer system.

You pays yer money, you takes yer choice :)

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Yeah it was my money. There were reasons why I bought that system.

As I said I looked in to whole exhaust thing before buying and made a choice that I was happy with. You might not be but so what.

I'd like a real life test to see what and how big a difference these 4-2-1 manifolds make and in my opinion it will be small.

Also the rimmer system isn't an one size fits all, they do two sizes and I got the one for a 3.5 and is not made by rimmer by the way.

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...You might not be but so what...

I get the feeling you think im having a personal dig :( Not my intention at all.

Im just trying to pass on info to the OP that was given to me by guys way more experienced with the RV8 than i am. Who am i to argue with them..

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Following Nige's epic exhaust thread, and my leaking manifold and overheating woes, I found an old Disco cast manifold 4-2-1, had it coated by Zircotec and got a custom made mandrel bent stainless exhaust by Powerspeed in Ashford.

Sounds great, and seemed to go a bit faster, maybe around 5mph on the top end.

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I have been following this thread with great interest. I have a V8 Defender 110 SW and live in La Paz, Bolivia, which is at a bit over 11,000 feet above sea level and have been thinking off and on about fitting a tubular exhaust manifold to get a bit more mid-range oomph. However when you add on another 120% to the UK purchase price to cover freight and customs it comes to a very expensive bit of extra oomph even not having to pay VAT! The RRC/Disco 1 option would be possible here as I am fairly sure that I can find some used manifolds quite easily. The other option I have is to have some 4-2-1 tubular headers fabricated, albeit in mid steel. Exhaust system corrosion not being a big issue here with the lack of oxygen in the air and the non use of salt on the roads. There is a garage locally that is capable of turning out virtually any type of exhaust system you care to mention, with the exception of inclucing a catalytic converter, as long as you can provide a pattern or a design. To this end I was wondering if anybody could provide me with the various diameters and header lengths for a 4-2-1 system.

Cheers,

Del

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