I need to do a poll or something to see how many people are game for a set of 4-1 fine tuned headers for the XK/XKR 2007-2009 packages. I believe the headers will be able to fit the earlier models as well with a different Cat setup but I will need an earlier model on hand to test fit once complete.

I'm wanting to finish my 4.2 Build first before moving over to the 5.0 F-type then V6 projects.

In order for me to justify building a properly engineered fixture and doing this right, I curious how many people are game for a set if I will price them cheap for the first 10-15 sets in order get things rolling. After the first initial sets I'm assuming a retail price of around 2200-2800$. For the first sets I'm willing to substantially drop the price depending on how many get on board.

As you guys have seen, I'm particular to quality and doing things properly. I would not build or design something that I would not put on my own vehicles. I would love to supply these if we can get enough people on board.

Certainly a power / torque adder option per the factory restrictive log style manifold.

 

I sure would. Mine is however 5.0 2015 xkr. 200 cell cats full exhaust swap pulley and tune.

 

My interest depends on the total cost and "bang for the buck". How difficult would the installation be? Looking for an estimate of the total cost, parts and labor including 200 cell cats and X-pipe, but keep the OEM active rear box. Would a custom tune be required to prevent a CEL? What do you expect the effects to be on HP and torque?

 

+1

 

Honestly, the primary reason for changing exhaust on a street car is sound.

That or because your existing system has leaks/problems.

 

Do i really have to answer yes to this question, ive been waiting months for this upgrade!

 

Also interested.

 

Well guys, I'm game to build it, I just need to justify the expense. I'm a busy guy as you can imagine but I'm dying to toss the money at this to finish them. The piping and 1000$ Collectors are just staring at me and begging for some tig welding.
I'm willing to finalize the collector design and weld up a set that has interchangeable designs to fine tune. Then to keep production cost down, use a formed transition. Due to supercharging, keeping a non-stepped pipe will help cost as well.

Either way these are not cheap to build. Just fab time is going to take me 80 hours minimum. I have to get a spare engine and head to mock these up on and then build a nice quality fixture to build these consistently and with quality.
You guys are seeing the quality of my efforts in the products I've been releasing and I'm willing to do more and more.

This project simply needs to be done. Without a doubt this is going to gain power and torque due to the restrictive factory design and unbalanced design at that. Anyone that is willing to buy a set will receive a discount on catalytics as well. Discount is simply going to be determined upon how many people join up.

This first header build is the 4.2, this will fit N/A and Supercharged. I need approx 15 people and I will supply full Data, Dyno, etc during build. I can have this complete by the end of January and ready for shipment.

Headers of this quality would typically cost 2800 retail. I encourage one to price a custom set of headers on a one-off project, this can typically run 5-8K.

I'm willing to bite the bullet now and say these will not be more than 2K for the first buyers.
Based upon similar engine data, such as a 2003-2004 Cobra DOHC engine, typical gains that can be seen are around 20-30 RWHP and up to 50 FT/Lb . I can not promise numbers as I have not seen data from anyone attempting this. Obviously, cars with tunes, pulleys etc are going to have the higher results. Tunes will not be required but you'll see the most benefit by optimizing this.
Plan is 1-7/8" stainless down to a 3" collector, to plan for the future for big power. Reduce after collector if needed to stock exhaust dia.

I'm not sure how to add a poll on here, but if I get enough people on board. I'm willing to do this for the 4.2 and the 5.0 XKR / F-Type as well.

I really would love to see this happen. Someone has to take the ball and run, I'm willing to do it I just need some backers.

 

Update on the 4.2 Build.

I'm ready to rock and roll with this. I know for certain the first headers will fit 4.2 XKR and XK for 2006-2010 4.2L. If someone can validate this... it may fit earlier year models. If the head port is same. I don't have one on hand.
I did some price figuring and if I can get 8-10 people on board for a set, I will price them at 1650$ to help cover investment of design build and fixturing cost. After initial orders pricing goes up.

I will disclose all details of the build and can have this complete in 2-3 weeks max. With before and after dyno, sound clips, etc. I simply don't want to toss money to the wind as I have a lot tied up in the carbon panel molds at the moment.


And yes, the plan is 5.0L headers and V6 Headers after and I will do the same process. I'm planning to purchase the F-Type shortly to join the garage of fun.


Any interest?

 

I'm in if they fit the older V8 cars and if the gains are reasonable (20hp or more). I believe the exhaust ports are the same; just a matter of routing and space. I have an XJR so I imagine there's at least the same amount of space, if not more.

 

Since I'm local, maybe you could PM me on headers, cats sized to the 3" headers, and maybe putting in an X pipe?

At $1650 I'm very interested, but with the 3" collector, it would make sense to get cats as well instead of the just the header.

 

Being rhd and these headers were designed to fit lhd how will we go with steering rack issues

 

Steve_M,
The head may fit the XJR fine when complete. It will require a different catalytic segment but header may be good.




Steve_K,
RHD and LHD can be solved by scanning and mirroring the part to verify fitment location. I can try to keep the parts symmetrical and that should solve it, if needed I can possibly make a second fixture for RHD.


The collector will most likely be 2.5" for this setup as not many people are ever going to need the 3". I'm running a 3" on my build as I'll be running a larger SC.
Tervuren,
I'll shoot you a PM with contact info to discuss possibilities. Cats will be needed or your stock piping modified to fit as the collector location for these headers will be at a different location. But I will discount the Cat systems for anyone that wants the headers.

 

Good to hear on changing to 2.5" from 3" for the collector, much better match for those that aren't supercharged, yet still a lot of flow for those that are.

I was some what reluctant before because of the 3" size.

 

Yes, the 3" is an option if anyone is planning something similar to myself. Goal is 650-750hp with this build and taking an F-Type to 800hp.
Most others with have plenty flow with 2.5".

 

Frickenjag have a 2015 xkr convertible with pulley tune high flow 200 cell cats and full racing exhaust. Have you produced headers for this 5.0? I am interested. Thanks.

 

Derek, I am interested in a set of 4.2 Headers for my 2005 XKR. I have looked all over and the only set I have found were in England @ http://www.badcatjagupgrades.co.uk...I would like a set of real nice professionally built Headers. Currently, I have installed a set of XJR Manifolds that exit on a 45 into a ball & socket and down through 2 1/2" Magnaflow 200 Cell Cats and then 45's into a set of 2 1/4" Quicksilvers. This is all I could come-up with as I'm still looking for that set of Headers. Are the 4.2 Headers you are building for 2005 XKR or the 2007 and if they are for the 2007, will they fit the 2005?

Billy Clyde in Houston
bcprice36@comcast.net

 

FrickenJag
Are you sure there are that much gain for 4.2 supercharged cars; 20-30WHP and up to 50 torque? That would be amazing if it is so. Mine is 08 xkr , are there evidence that headers are restrictive on our cars? I guess I have never heard of aftermarket headers on these cars.

 

Problem with the big cat headers is they don't merge cylinder 6 & 8

 

Personally I don't see why 20-30whp couldn't be achieved , just watched a stack of ls1 upgrades (tune and headers) that are yielding 40-60whp gains