Hi all my cars been away for the best part of a week having these branched manifolds fabricated, the company who has made them is quite prepared to jig up to produce more if there is an interest.




The setup will be pair of upgraded 4 into 1 manifolds, sport cats and down pipes as pictured they have been made the same for both sides so should have no clearance issues on LHD cars but obviously the first person with a LHD will receive a discount to be the trial car to prove this out.


So I guess the question is would anyone be interested in this setup?

 

Very nice , I'd love to see a before and after dyno run . Is that on your agenda ?
I'm also wondering if these will fit the STR , and if they can be supplied minus the cats and down pipe ? as mine are all near brand new magnaflow 200cell sorts cats and don't realy need upgrading , also I guess price is a factor , but if all the boxes were ticked I would be interested indeed,

 

I'm interested for sure, but the cost will probably be the deciding factor, $ per HP

EDIT

When you said branched I thought you meant 4-2-1 design but I just realised in the picture they are a 4-1 design.

That picture is of the actual manifolds that were made?

I'd be interested in a set of 4-2-1 manifolds with cylinders 6 & 8 separated (like the factory manifolds on the N/A engines) but not a 4-1.

 

Hi Cambo, yes that is an actual picture of the manifolds made for my car, they are a 4 into 1 there is not the space to do a 4 - 2 - 1 with long enough primaries. 4 into 1 should be better for enhancing low end torque while still providing some useful top end gain vs the 4 2 1. Obviously a 421 would be better for all out top end power.

Datsport, I am going to do a before and after dyno run so I guess we will see what this mod brings. As for fitting the str I don't see why not but will have to find a trial car to confirm. I will be able to get just the manifold part done but your downpipes would need to be remade to fit as the angle where the standard downpipe met the manifolds was no good.

 

Nice setup.
4 to 1 may be a good compromise for road use.
Full stainless I guess?

 

Yes full stainless

 

[QUOTE]Datsport, I am going to do a before and after dyno run so I guess we will see what this mod brings. As for fitting the str I don't see why not but will have to find a trial car to confirm. I will be able to get just the manifold part done but your downpipes would need to be remade to fit as the angle where the standard downpipe met the manifolds was no good.[ENDQUOTE]
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Remade/modifing downpipes does not worry me . it looks as if you have 3'' collectors and 3'' inlet 2.5''outlet cats ?
as cambo said $ per HP i think will be the sell point . shipping i think will also be killer pricy. but very keen to mull over your no# to see if its all worth it . we all know how hard it is to make a value or money performance gains on these jags .
and man those are some pretty parts ! kudos for the leap of faith test muleing your pride and joy like that for any and everyones gain ,nice !

 

I'm interested, looking forward to seeing details of power gain and cost. Well done for getting them made mate!

 

Do yourself a favor and have them ceramic coated before you fit them.
This will get rid of most of the heat soak issues at the same time

Cheers
34by151

 

Pretty pipes. Reminds me of good ole hooker headers.

 

Hot dog! Can't wait to see the results!

 

Any idea what the pricing is going to be like?

 

34 - I am intending on having them coated ( inside and out) but this process is expensive so I will offer to anyone that wants it done as an add on or obviously they can have it done themselves.

Klfong - price wise I am not sure, but be assured when proved out I will keep it as low as possible. What the exhaust company charge me plus a small mark up to help pay for the time and money invested so far but I will be open and honest about this when the time comes.

Datsports- Yes 3 inch collectors through the sport cat to 2.5 inch outlets, price maybe an issue (sending not so much) but one thing is for sure these are quality items so I guess it will be down to the rolling road numbers to see if we can get even more power out of it.

 

Hi Guys.


I'm new to the Forum and noticed this post. I designed these stainless 4-2-1 headers and have them fabricated specifically for XK8/R and XJR and they do fit in the engine bay. They require bespoke downpipes / CATS as the collector boxes and flanges are of course lower down. The CATS sit under / just aft of the bulkhead.


They are currently installed on both road and race cars in the UK, Australia / America and Germany.

Edited by Mod Team

 

I'm interested.

 

Hey Caldoofy, whatever happened with these headers & the exhaust system?

 

They are on the car now were fitted before Xmas running them to see if they fired any warning lights etc due to the air injection being deleted, but after two months of running I can report no issues. They are tight in there but I can report no contact issues with the body.

I have done a before Dyno run and am hoping to get a slot at the same Dyno this week for an after run (no other changes).

Let's see what they bring.

 

Awesome news, & thanks for the update. I wonder if any of the V8 Vantage heat shielding would come in handy for this sorta thing

 

Any news?

 

We'll finally got a slot on the same dyno as my before run today.

Graph is power and torque at the wheels, blue trace was before and red trace today's run.

If we ignore the initial torque blip on the blue trace there looks to be a consistent torque increase from 3.5k upwards (max gain 25 lbs ft at wheels).

In terms of power before run was 349.1 hp @ wheels and after 380.91 @ wheels.

Gain = 31hp at the wheels.

I think there is more to come following tuning as it is leaning out toward the top end so I will look to have live mapping done at some point.

Assuming 22% transmission loss as measured at the Dyno this means my car is at 488hp at the fly.

These are now available if anyone is interested inclusive of 200 cell sport cats at a cost of £1800 plus delivery (paramount sport cats on there own are £1200).

I can also now supply the twin 2.5 inch stainless exhaust systems with x pipe in place of the front silencer, two small silencers before the axle to eliminate drone and two large silencers at the rear at a cost of £1200 Inc delivery to the UK (or fitted if you can get the car up to Newcastle upon Tyne). These are top end systems obviously and mine has been on the car for 6 years now without issue.

Let me know if any interest.