The V8 Owners Forum -

Currently converting my stag to a Range rover V8. The problem I have is that when i've tried to fit the Range rover exhaust (that came with the engine) I can fit the nearside with a bit of modification, but however the offside will absolutely not fit, the branches sweep foreward to clear all the ancillaries.
Ive been told that a Range Rover P38 nearside could be reversed and fitted to the offside. and used with my nearside manifold that I can modify. Can you mix manifolds like that? and how will that affect the breathing of the engine?
The original stag exhausts are two seperate entities with two tail pipes. And the Rover exhausts connect in a Y' piece together in a single pipe. I've been told if you separate the exhausts like the stag then the engine suffers in performance, is this true? On the back of this I would like to join the exausts together as the engine is an EFI I was going to use with the Lambda unit fitted to the 2" pipe I've got.
A new set from Monarch purpose made manifolds are nearly £600,
So is the messing about with different manifolds a good viable option or do I have to sell a kidney to buy the maonarch ones.
mick.

The manifolds will fit to either side and I doubt there will be any noticeable power loss, in fact there may possibly be a small gain, but I doubt you'd notice. I've alway considered that the Rover V8 needs a balance pipe at the very least, they never seem to run properly with 2 totally seperate systems.

mickjo wrote:Currently converting my stag to a Range rover V8. The problem I have is that when i've tried to fit the Range rover exhaust (that came with the engine) I can fit the nearside with a bit of modification, but however the offside will absolutely not fit, the branches sweep foreward to clear all the ancillaries.....

There's always a few Rover tubular manifolds of some description on Ebay. Just scour it on a daily basis until something turns up that will do the job, or can be modified to.

Anything tubular has got to be better than most stock cast manifolds, and 100lbs lighter to boot.

Just be aware that cast manifolds are much quieter than tubular.

Chris.

harvey wrote:The manifolds will fit to either side and I doubt there will be any noticeable power loss, in fact there may possibly be a small gain, but I doubt you'd notice.

Why would you get a power gain putting manifolds on the wrong sides?!

Dont forget that (unless they are 4 into 1 manifolds) manifolds are made (or should be- maybe not cheap nasty ones) to help draw gasses out from other cylinders and should be linked 1-5 3-7 on the r/h bank and 2-4 6-8 on the l/h bank. This is quite obvious when you look at cast manifolds and properly made tubular 4-2-1 sets. If you swapped sides you would put the pulse tuning out and would do it no favours.
Finally dont forget that the ports in the heads point down, so if you ended up cutting and shutting your manifolds and ended up putting the first bits upside down you would have a nasty little kink in the tunnel!

I think all that is right !

TC

topcatproduction wrote:Why would you get a power gain putting manifolds on the wrong sides?!

Because you would be avoiding having to have a longer system with a 180 degree bend in it................(Unless your tailpipes come out of the front of the car, of course....... )

I'm deliberately going to a Rover for the extra power and feel that the cast route (even though they are quieter Chris) will sufficate the engine as opposed to tubular will let the engine breathe much better, (I take your point about putting the pulse tuning etc out TC), I might have bodge a bit with the tubular manifolds they look the buisness when fitted. So I've just bought a nearside RR P38 manifold on ebay for £20 (Paul) which when swapped over to offside will give me the sweep foreward I need. I'm willing to try to see if I can get it somewhere near. For £20 what have I got to lose? Better than £600. I'm decided that I'm going to balance the engine joining into a single pipe then split at the back into the original stag exhaust boxes (harvey). Should sound interesting.
Any other thoughts are greatly appreciated.
mick

Mild steel will run cooler than stainless - and assist in reducing under bonnet temps

If temp still a problem ceramic coating does the business but is ££££

IAn

Ian Anderson wrote:Mild steel will run cooler than stainless - and assist in reducing under bonnet temps

If temp still a problem ceramic coating does the business but is ££££

IAn

Not so, Stainless is a better heat insulator than mild steel. This is why it warps badly when welding because the heat doesnt spread as quickly so you get much more localised expansion. In this instance though the difference is negligible. Figures are steel 31 Btu/(hr oF ft) stainless is 7-26 Btu/(hr oF ft) for comparison pure copper is 223 Btu/(hr oF ft) I guess thats why you dont see any stainless radiators lol.

Trust me on this

Stainless tubular headers radiate a LOT more heat than mild

IAn

Is that because mild steel ones go rusty and rust is a good insulator?

Chris.

Chris

I do not know the science behind it but Stainless radiate a lot more heat than the Mild steel ones.

Perhaps some stainless tubes are thinner wall, perhaps as you say rust insulates - I don't know but I didd not believe it - got the GT done in stainless and the heat is incredable

Mates whith steel pipes are cooler

Then the ceramic coated ones you can almost touch with the engine running

Ian

Ian Anderson wrote:Trust me on this

Stainless tubular headers radiate a LOT more heat than mild

IAn

I have a set of JP stainless manifolds (on the car when I bought it) and they create a tremendous amount of heat. All the rubbers seals under the boonet, rubber bonnet stays and engine mounts have melted.

I have had to wrap them in an attempt to control it.