XKR sport cats
Discussion
Yes I have but to be honest they will not give as much of a power hike as many people say.
They look good and give a nice V8 sound, but to get the power advantage you will have to change the old cast headers for a set of these.
If you want information of where to get then etc send me an eMail
They look good and give a nice V8 sound, but to get the power advantage you will have to change the old cast headers for a set of these.
If you want information of where to get then etc send me an eMail
Edited by NormanD on Wednesday 1st July 03:18
cardigankid said:
Ooooh, what are they exactly? 
Seeing what a BAD design the standard headers were I had designed a set of freeflow stainless steel headers made upThey will fit inplace of the cast headers so will fit on original Jaguar exhausts as well as all aftermarket.
The first picture is the first set fitted to my car but we are on the mark 2 sets now so an even better finnish
They will fit XK8/Rs as well as XJ8/Rs
Edited by NormanD on Wednesday 1st July 08:15
Hi Norm, are these the headers that Tom was having manufactured ? he did mention these at the Surrey dinner, though he was a little worse for wear. They look good. Let me know what power gains are over an ordinary manifold, but don`t forget the heat dissapation. Power will be lost if the underbonnet temperature is increased. Cast iron is a good dissapator of heat, hence their usage in general manufacture.
Yes they are the same, between Tom and myself we did the ground work and are now suppling to anyone else that wants them.
We have Paramount as an outlet for us as they have a large customer base.
Re power gains, we have not done a before and after on just them as yet.
I haven't had heat problems but we can get them ciramic coated, although that as expecive.
We have Paramount as an outlet for us as they have a large customer base.
Re power gains, we have not done a before and after on just them as yet.
I haven't had heat problems but we can get them ciramic coated, although that as expecive.
OK I could be showing my ignorance here but isn't the ideal to have the same length for all 4 pipes so you don't end up with an irregular gas flow through the later pipe work.
I've never studied the engine bay layout of an XKR, was there a lack of space to get balanced pipe lengths.
With the SC engine is the length of the headers less of an issue?
Does the variable valve timing also come into play here.
With fixed timing I thought the idea was to get the lengths setup on a harmonic of the valve open time at peak power delivery. I understood that if you got the lengths right then the pressure drop at the end of one pulse effectively sucked the start of the next.
I'm not trying to criticise I'm interested in the thoughts behind the design.
I've never studied the engine bay layout of an XKR, was there a lack of space to get balanced pipe lengths.
With the SC engine is the length of the headers less of an issue?
Does the variable valve timing also come into play here.
With fixed timing I thought the idea was to get the lengths setup on a harmonic of the valve open time at peak power delivery. I understood that if you got the lengths right then the pressure drop at the end of one pulse effectively sucked the start of the next.
I'm not trying to criticise I'm interested in the thoughts behind the design.
Some years back we built an exhaust on the old XK motor in a XK150 fhc coupling equal length outlet pipes on firing order. 153 into one primary, 624 into the other. It took our engineer some time to do it but the results were startling.
Ideally that is what you should aim for, though difficult on an 8 with no room.Lotus/ BRM did it back in the day, with the exhausts at high level.
Ideally that is what you should aim for, though difficult on an 8 with no room.Lotus/ BRM did it back in the day, with the exhausts at high level.
RW774 said:
Some years back we built an exhaust on the old XK motor in a XK150 fhc coupling equal length outlet pipes on firing order. 153 into one primary, 624 into the other. It took our engineer some time to do it but the results were startling.
Ideally that is what you should aim for, though difficult on an 8 with no room.Lotus/ BRM did it back in the day, with the exhausts at high level.
We'll have to talk about exhaust headers for 150FHCs when I come down in September:-)Ideally that is what you should aim for, though difficult on an 8 with no room.Lotus/ BRM did it back in the day, with the exhausts at high level.
Years ago I have a Dolly Sprint. One of the guys in the owners club built F1 engines for Hart. He'd made a balanced exhaust header for his Sprint. Only the Dolly's engine bay wasn't ever designed to take the Dolly's normal engine let alone a fancy header like this. The only way he could get the pipe work to go in was to bring one of the pipes up and over the top of the head. To change the front plug you needed to remove the exhaust manifold!
a8hex said:
OK I could be showing my ignorance here but isn't the ideal to have the same length for all 4 pipes so you don't end up with an irregular gas flow through the later pipe work.
I've never studied the engine bay layout of an XKR, was there a lack of space to get balanced pipe lengths.
With the SC engine is the length of the headers less of an issue?
Does the variable valve timing also come into play here.
With fixed timing I thought the idea was to get the lengths setup on a harmonic of the valve open time at peak power delivery. I understood that if you got the lengths right then the pressure drop at the end of one pulse effectively sucked the start of the next.
I'm not trying to criticise I'm interested in the thoughts behind the design.
In an ideal world, but there just isn't the roomI've never studied the engine bay layout of an XKR, was there a lack of space to get balanced pipe lengths.
With the SC engine is the length of the headers less of an issue?
Does the variable valve timing also come into play here.
With fixed timing I thought the idea was to get the lengths setup on a harmonic of the valve open time at peak power delivery. I understood that if you got the lengths right then the pressure drop at the end of one pulse effectively sucked the start of the next.
I'm not trying to criticise I'm interested in the thoughts behind the design.
So had to compromise and just get the best gass flow possible.
Also this header will fit everyones exhaust, if we went for longer lenghts then we would end up with the situation of finnishing with differances and that would create even more costs.
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