farmershort

farmershort

Well-Known Member
I'm shopping around for some suitable exhausts for my 110 defender with a JE 4.6 V8.

The engine started as a 3.9 from a disco, and I *think* the exhaust ports are the same as they were pre modifying the engine. I've found these fairly reasonable looking stainless tubular manifolds at rimmer:

http://www.rimmerbros.co.uk/Item--i-LR1109RH

I'm assuming at the moment that I should use the discovery versions, as the landy 110/90 versions will be for the 3.5V8... I have no idea if the fitment will be the same.

Thanks

Adam
 
They'll fit from 3.5 to 4.6, no difference in manifold fitment. Where they will differ is where they end up under the car for y piece fitment and what they may clash with.
Check the diameter of the primaries are same on the 2 versions and pick the ones that fit a 110 I suppose.
Je may be able to recommend a pair for you.
From the dyno figures you must have ported heads so you need ported gaskets.
Je will have these too I expect, v8 developments definitely sell them.
Then you need to port match the manifolds to the gaskets which is bloody hard work but essential to get the best flow
 
cooltide said:
They'll fit from 3.5 to 4.6, no difference in manifold fitment. Where they will differ is where they end up under the car for y piece fitment and what they may clash with.
Check the diameter of the primaries are same on the 2 versions and pick the ones that fit a 110 I suppose.
Je may be able to recommend a pair for you.
From the dyno figures you must have ported heads so you need ported gaskets.
Je will have these too I expect, v8 developments definitely sell them.
Then you need to port match the manifolds to the gaskets which is bloody hard work but essential to get the best flow
Click to expand...

exhaust manifold gaskets I assume? I have a feeling I'm missing a piece of info here.... I thought head porting refered to the other end tbh... the intake... which it all under plenum chamber on this version. if the exhaust manifold fitment is the same, how can the gasket be different?
 
From the dyno data you posted, you must have ported heads and I'm guessing larger than standard valves. The intake ports are opened up and matched to a valley gasket. The exhaust ports are also opened up and to a larger rectangle than the standard manifold gaskets, so you need a bigger gasket to match.

The exhaust manifolds will match up to standard gaskets so you need to place a large port gasket over each flange and draw a rectangle, then grind out to match. Nowhere near as easy as port matching aluminium.
It will also be well worth having your inlet ported and throttle bored out from 65mm to 72 if this isn't included in the deal.
 
images

Your inlet ports will be opened up to match this gasket, the limitation here is the close spacing on the 2 centre ports
exhaust.jpg

The exhaust ports will look a bit tidier than the above, but you get the idea
 
Makes perfect sense now. Thanks chap. If I'm honest, I do feel like I'm not JE's ideal customer or something along those lines... So it's great to have some advice like this without any hint of sarcasm.

I'm not saying JE is sarcastic at all, but he certainly is more about the engineering than the customer service.
 
farmershort said:
I'm not saying JE is sarcastic at all, but he certainly is more about the engineering than the customer service.
Click to expand...
Know doubt he has to deal with a lot of telephone enquiries that come to nothing and waste his time, but when it comes your order with him, the inlet and exhaust manifolds are part of the engine and getting them wrong will sacrifice performance.
So if you haven't already discussed and included inlet work in the deal, you should do.
He will either port your inlet or exchange it.
He will be able to advise on size of trumpets / trumpet base. I'm not sure whether he will recommend shortening / widening trumpets.
Having the throttle bored out will improve throttle response. It does reduce control slightly in off road light throttle situations, but having used one on similar setup to yours, it isn't a problem. The standard throttle is 65mm on a hotwire plenum chamber. It can be taken out to 71/72mm and a larger throttle butterfly (jag) fitted.
It might not sound like much of a difference in diameter, but it is when you Pye r sq to calculate area.
With all the above addressed, your heads will breath as they should
 
lANDYbrownlee said:
May be worthwhile looking at these...
Http://www.v8tuner.co.uk/product.php?id=856
theyre 4-2-1 rather than 4-1 which i think is for more torque and midrange and my understanding is they suit the v8 better. But im not an expert i think these are the ones i wanna go for though
Click to expand...

Thanks for the link, they certainly look the part! I notice they only seem to sell the manifolds, so I'll have to speak to them and see what flanged options they have for exhaust fitting.... I'm not a fan of clamps.
 
farmershort said:
Thanks for the link, they certainly look the part! I notice they only seem to sell the manifolds, so I'll have to speak to them and see what flanged options they have for exhaust fitting.... I'm not a fan of clamps.
Click to expand...
never noticed that cheers i dunno that theyre much different but ive been told 4-1 manifolds are best above 5k revs but then why would they be so popular on rv8's when thats not far from the limit
 
lANDYbrownlee said:
May be worthwhile looking at these...
Http://www.v8tuner.co.uk/product.php?id=856
theyre 4-2-1 rather than 4-1 which i think is for more torque and midrange and my understanding is they suit the v8 better. But im not an expert i think these are the ones i wanna go for though
Click to expand...

Well it seems they don't respond to voicemails or emails... Obviously they're too busy to need any more business...

The search goes on.
 
hmmmm, tvr wedge exhausts.... my mate used to have one of those.... it was like a garaged bonfire that he could throw his wallet onto every weekend :D

It'd be nice if it fit, I'll give them a bell and see if they know.

failing that, I've been reading an aussie forum that says that people consider the 3.9 disco 4-2 cast manifold to be pretty decent flowing, and then pair them with a decent 2-1 stainless exhaust system.

I'm not sure if the standard disco 4-2 manifold would be better or worst then the rimmer bros 4-1 tubulars though.... gas dynamics being what they are, the extra length of the tubulars would seem to offer the best flow options
 
I've had a browse on ebay at manifolds, I can't see a decent 4-2 3.9 manifold, but I notice that the P38 4.6 manifold looks pretty good in terms of length and 4-2 configuration.
 
Equal length primaries are beneficial, so the tubulars tick that box.
Janspeed probably do a full system.
I haven't mentioned them up to now because I'm not a fan of their manifolds not having bracing across the exhaust ports where they bolt to your heads. This leads to stress on the 4-1 weld with thermal expansion - unless they have altered their design. They only used to make the manifolds in mild steel then stainless y piece and backwards, for the range rover classic that is. RPI sell them
 
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