Stainless steel manifold for P6

Barten

Barten

Active Member
I have seen a nice V8 stainless steel manifold supplied by RPI for the P6. Has anyone got any experience with this one, and have you got an opinion to whether ceramic coating is essential or not. I think I might coat it inside for sound and heat insulation, and then keep the outside polished.
Regards, Barten
 
Hi Barten

RPI developed this manifold for my two P6's. It is a very large bore and is intended to run with a 2 1/4" system (mine has one box only - sounds really lovely!). It is a very tight fit in the engine bay and really needs the pressing flanges grinding off where it passes the chassis legs / X member to give it just that little bit more room.

Personally I would always take some action to keep exhaust heat out of the engine bay, whatever the manifold. My usual solution is exhaust wrap - I haven't come across ceramic coating before. Bearing in mind the bore of the manifold, it ought to be quite feasible to coat it internally without wrecking the exhaust flow. Note that you will be committed to some sort of special system, even if it was only the Y piece to join to a standard system. Ideally you'd want a larger bore system, but no need to go as far as 2 1/4" or single box for a standard engine.

Note that these manifolds are 4 into 1. Ideally it would be nice to have 4 into 2 into 1. I'm told this is possible in the P6, but a) you need a smaller bore manifold, and b) you have to assemble it around the car, with different legs of the manifold going different sides of chassis legs etc! That was too much like hard work for me!

Regards

Chris
 
Hello Chris,
You must have developed a lot of upgraded parts for the P6, and even these manifolds! Good man. I saw your blue series 1 at Crick and was impressed. Is there any power gain through using these manifolds? And is the noise level ok to live with, even if the noise is glorious?
I also saw your louvred bonnet. It looked great on a series 1, do you think it also will be good looking on a series 2 bonnet. Do you have some kind of baffle plate underneath to awoid too much water getting in?
Thanks, Barten
 
Hi Barton

Theory says there should be a power gain with the manifolds. I prefer to think of it as eliminating a power loss! Gain will be highest at high gas flow - ie high revs, and it is entirely dependent on the rest of the system being equally free. Biggest power gains on any engine, though, are to be had from making sure it's running right!

Personally, I am very happy with the noise inside the car, but this is a very personal judgement.

The louvered bonnet is an attempt to address underbonnet temperatures. Step 1 is of course to limit the heat generated in the first place - hence the discussion about exhaust wraps etc. There are a couple of health warnings with the louvers though. First, there is some suggestion that they allow underbonnet fumes to access the heater intake. I have no practical experience as yet, but Rover used the same solution on the P7 prototypes and this comment from the owner of P7/4. This car has the louvers somewhat further into the centre though (P7/1 had them in exactly the same position as I have). Second, they wern't very easy to get put in! We first had a go with letting in a panel a little larger than the louvers, but that wasn't very satisfactory. Eventually the entire bonnet took a trip to Aston Martin Restorations at Derby, who were the only people we could find with a fly press big enough to get the whole bonnet in.

And yes, louvres look very good in an S2 bonnet as well! My Thai car has this set up with a single centre scoop. If you pm me your e mail address I can send you some photos.

Regards

Chris
 
According to RPI it is possible to ceramic coat them both out and inside, and with the size of these it should not restrict them too much. Hopefully it will reduce noise and heat significantly. What they charge for it I don't know yet. I saw the article from Nz about improving the P6. That was a series 2 and had louvres - looked very good.
I think I will keep my original bonnet as is, and then get hold of another to experiment with.
reagrds, Barten
 
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