Has anyone fabricated or seen a V8S or R with a proper set of equal length headers? I was browsing around and wasn't able to find anyone that has attempted this yet.

I'm working on fabricating a setup for the 4.2 and the 5.0 XKR and was curious to see if anyone had any results or feedback on the F-type.

I've seen some attempts with the XKR but nothing has popped up for the F-type.


Any feedback is appreciated.

Regards,
D. Fricke

 

Would there be any real performance benefits?

 

Without a doubt. I've been investigating the manifold design for the 4.2 and 5.0 engines. Due to the firing sequence the stock manifolds are restrictive, limiting exhaust efficiency while also functioning as a heat sink. The log style factory header design absorbs and retains a lot of heat.
The firing sequence has two instances that hurt performance. One at the 7-3 same bank sequence of firing, and next the 6-8 same bank sequence of firing. This results in a battle for the pressure / expansion of exhaust gases on each particular bank at these instances.
How Tony at Jaguar RSR controlled this, was to change the firing sequence of the engines. (The did some amazing work with these engines in the past)

That being said, a proper individual primary setup instead of the log style factory setup would certainly see gains. Limiting heat soak, easing exhaust flow and controlling the firing sequence flow. One large benefit would be cutting back on the heat generated and held in this area.
With the supercharged engine we would see strong gains from a 4-1 style header since one doesn't have to focus as much on vacuum scavenging.
One the non-supercharged, something like a Tri-Y header that is used in NASCAR would benefit. A non-supercharged will benefit more from the exhaust vacuum from each pulse in the firing. Thus drawing the exhaust gases out of the cylinder.

One engine that comes to mind for a comparison would be the 2003-2004 cobra. 4.6L and the same Eaton M112 supercharger. Typical gains on a supercharged engine of this nature is around 30rwhp at the same boost levels.

On the non-supercharged version engines, a Tri-Y header would see similar gains. The standard rule of thumbs from the engineers at Burns Stainless (Which are header/collector gurus) 5% Hp gain is a realistic expectation for a proper header. Some times we can see even better. Thus, I would assume 25-35 Hp on an engine such as the V8S. With a catalytic upgrade, could see even better.

I'm working on a 4-1 header design for the 4.2 and the 5.0 engine, which i'll tweak to fit the F-type setups. I plan to test the Tri-Y design on a non-supercharged to see the possibilities and compare to a standard 4-1. The Tri-Y's require a little more fabrication and have a few more merge pipes.

I've attached some images as reference to see the difference between a Tri-Y and 4-1 style collector.

So in short, The performance gains: Less heat, more power, more torque, engine operating with more ease.

I'll be posting some data on the 4.2L XKR setup I'm designing soon.

If anyone has any knowledge of someone that has attempted this , certainly post pics or info. Its greatly appreciated.


Regards,
Derek Fricke

 

I would be game for a set of headers for my V8S F-type. I have been relentlessly searching for any upgrades. Not much to choose from on these cars yet...

 

I'm willing to bet that you neuter the sound of the f type quite significantly if you make a major change to the headers.

 

On the contrary, I bet you a nickle it gets even louder... I've never had a car with headers that didn't increase in volume... (but I could be wrong...)

 

I didn't mean it would get quieter. I meant it would sound like crap afterwards.

 

Does anyone have any pictures of the existing headers?

 

As you can see, it's not a header system, but an exhaust manifold, which is always more restrictive than true headers.

 

They are log manifolds.

These are the 5.0L ones, same for both the supercharged and the (now discontinued) naturally aspirated engine;



The older 4.2L engines actually had two different design of exhaust manifold.

The naturally aspirated version had a "branched" manifold which isolated the cylinders from each other. Because of the firing order cylinders 6 & 8 interfere with each other reducing the volumetric efficiency of those two cylinders, the branched design helped relieve this problem. But the design was quite restrictive so the supercharged version got traditional logs.

The 5.0L has the same firing order, so you'd expect the same problem on those two cylinders.



It was confirmed by an ex-Jag engineer that the branched design would be better on the supercharged engine, if it were suitably enlarged, but because of space limitations they could not fit it in.

Some more info here https://www.jaguarforums.com/forum/g...-2l-s-c-80560/

 

It's all about the packaging because true individual tube headers cost no more to manufacture when it's done on an OEM level, I sold Ford vehicles for a number of years and all the Mustangs for as far back as I can remember had tubular headers.

Packaging them into this configuration might be a tad tight but I'm certain it can be done.

 

Forced Induction tends to make a nonsense of conventional N/A inlet and exhaust theory.

That said...

 

Well.. You could try a couple of those on your R, but they'll look pretty silly sticking straight out the side of your front fenders.

 

Ohhh..... Sidepipes on the F-Type! Sweet

 

I think we are on to something guys, this would be absolutely sweet. So much yes!

I think Jaguar decided on these types of manifolds for simplicity and cost of manufacturing. A cast style is certainly easier on production in comparison to a bending and welding operation. Also, eliminates their concern for quality concerns.

As mentioned above by Cameron the branched design is optimum. It just needs to be engineered properly and squeezed in. I think I can make a tri-y branch style fit. I'm going to get my hands on a scanner and try to digitize everything for modeling.

Depending on fire wall clearances, the set I build for the 5.0 XKR should fit the F-type. They are the same part numbers from what I'm gathering. The catalytics are slightly different I believe. Anyone have some photos of an F-type on a lift?

As soon as I wrap up the 4.2 design and prove the numbers out with proper data. I'm going to get onto the 5.0 XKR/F-type units. (Keep in mind if someone will be in the area with a F-type for prototyping, I'll be jumping into one later in the year).

As F-typical mentioned above, forced induction does play by different cards with exhaust theory. We are not as concerned with vacuum in these cases. Vacuum and Tri-y calculations have more of an impact on traditional N/A setups. The supercharged unit, we simply want to get the flow out as efficiently and fast as possible with minimal turbulence.

One thing I'm very interested to see is how the temps at the exhaust and in the engine bay will be effected by the headers.

...I'm still stuck on this side exhaust. Wowzers.

Regards,
D. Fricke

 

Any updates on your custom header designs?

 

Surely Gabriel.
To give an update, I finally go around to making the decision to build the 4-1 design for the Supercharged setups.
I conducted some part number research to see which engines the setup I'm building will fit along with the next designed setup.
The N/A engines I will test both a 4-2-1 (Tri-Y) and 4-1 to compare the data.

I needed to finishing ordering everything for my DAQ unit to collect proper data before and after the headers to see exactly what is effected for calculation verification.

Flanges are designed and being cut, mandrel bends arrived, narrowed down the exact collector calculations.

Now that everything on electrical side is in, I pulled the trigger on the collectors. Should have those next week.

I've talked things over with Kenny Thompson (Bundle of snakes builder for the Ford Gt) and Mike Colucci of Brumos Porsche to make sure my calculations made sense.

First setup I'll build will utilize a 3" collector since I am building this engine to run the 2.8H or 2.9 Whipple. For stock roots blowers, I'll most likely go with a 2.5" which is better for the 500hp range. I'm gunning for 600-700 to knock Hennessey's F-type numbers down. Thus, initial dyno numbers on my setup will be fair, but certainly not optimized for the engines current output. (I'll need a local subject to step up for some proper before and after numbers with a stock setup engine) With this in mind, For testing I'll need a 5.0 XKR and an F-Type R and S in the local area if anyone is interested.

My projection is I should have the 4.2 style 4-1 Setup complete in two weeks.

Regards,
D. Fricke

 

I'm glad you've continued to pursue this, i was going to start something like this myself but was struggling to get the finances together. Doing this properly is not a low-cost exercise, so i appreciate the effort.

I presume you've done your homework, but just to make it clear, there is a lot of information here on the forum which you need to know.

Buckhead Imports, they made some 4-1 headers and tested them on an X308 XJR.

https://www.jaguarforums.com/forum/x...stalled-80148/

https://www.jaguarforums.com/forum/x...%2A-%2A-80588/

Long stort short, the claimed 40hp gain was the difference between stock manifolds and old stock cats, vs. new headers and NO CATS.

Having been through a choked cats myself, I know how much power is lost in the cats, so the result is skewed because they did not do proper apples-to-apples testing.

When the time comes to make tests, be sure you do them in a credible way, i.e. same cats or no cats for both.

Also, Count Iblis has left lots of crumbs around the forum in various posts about the stock manifold design. e.g. "The earlier 4.0L manifolds actually flowed more than the later 4.2 ones." or words to that effect.

The most important statement (in my eyes anyhow) is regarding the firing order of the engine affecting the volumetric efficiency of cylinders 6 & 8, and that using a 4-1 header design actually makes that effect worse.

The regular log design exhaust manifold helped to improve the VE of cylinders 6 & 8, and the "branched" 4-2-1 design of the naturally-aspirated 4.2L was even more effective, but the overall design was too restrictive for the higher flow from the supercharged engine.

Count Iblis on the 4-1 design:

If anyone knows it's the man who helped develop this engine...

The tri-y is the way to go.

But after saying all that, I would not expect huge gains from headers alone, Buckhead "fluffed up" their results to make it look better, because there wasn't that much to be had in the first place.

Doesn't mean it's not worth pursuing, but the expectations have to be realistic...

Good luck with it, hope to see some results down the track.

 

Definitely Cameron. Certainly have some big plans for the Jaguar community. The forum research tool bar has certainly helped and Count has posted some good informative info as have many of you guys. I honestly think I have read every post on this forum now within the past few weeks regarding to custom work on these engines.
I certainly ran through Buckheads project and had some thoughts on it. Claims are one thing, data and dynos are another. Thus, I decided to move forward with a DAQ setup so that I can log RPM , EGT, A/F among everything else to have a true before and after. I have dyno'd the 4.2 XKR in stock form multiple times, as well as with the upgrading cats, and exhaust system multiple times. Once headers are on I will compare data.
Pertaining to Buckheads project, an area overlooked appears to be the collector design. This is typically one of the most important aspects of the header design. Its hard to tell what angle the merge is, but from my view it doesn't appear to be 12-15 deg. It looks like a short fast transition which would mean 25 deg. This is on the opposite end of the spectrum if you are wanting best performance. 12-15 deg is your ideal area. 25 deg only when you are limited on space. Additionally , if you noticed the exit. If we look at the exit port on the manifold in reference to their fabbed exit port, it appears they went with a transition straight to 3". In terms of exhaust velocity this would be a no-no at this power level. Under their assumption of hitting 700hp, maybe. The ideal scenario for this would be to converge at 15 deg, down to 2.5" or 2" at 300hp and then step back up at a divergent angle of 7 deg back up to 2.5"-3". I haven't seen the fully completed setup with exhaust mounted up, but I can only assume from photos this exiting flange that was welded directly onto the collector led out to 3". Even at 2.5" the transition for flow just isn't optimum.
In terms of 4-1 setups, the length of piping is critical here. Count and yourself are dead on with the ideal header being a Tri-Y. Especially for a N/A application where exhaust scavenging is very helpful. If the collectors are designed properly and everything is working together well, a 4-1 will make nice power, The transitions have to be setup correctly though. A Tri-Y could be dialed in on the Supercharged setup to have a little better gains, obviously this comes at a cost. Thus, why I want to analyze the two and design proper headers with both designs, no corners cut. With the hopes of supplying fellow Jag owners great products, I want to do it the most economically and best bang for the buck.
With thw setup I'm going to test first, I'm running a 1-3/4" primary, down to 2.5" merge, 7 deg out to 3" cat setup. I'm running this size due to the supercharger setup I'm working on. The finalized setup for cars around 500 hp will be a 2-2.25" merge , 7 deg out to 2.5".
I can't say what I expect the gains to be, I'm anxious to find out though. Sound alone should be phenomenal. One good comparison setup is the 03-04 roots cobras. Typical headers in the 500+ categories usually aid in around 20-30rwhp. The more boost, the more gains we can expect. I have seen some cars gain nearly 40rwhp with more boost. Keep in mind, these are mustangs and most vendors do not spend the time truly engineering the collectors. They are designs "shot from the hip". As I live right around the corner from a large vendor and discovered this myself. If optimally designed, I'm sure the upper data is more easily obtained.
*Note, keep in mind when you free up exhaust flow , we can expect to see a drop in the boost pressure. 0.5-1lb can be expected. Thus why I want to log this. This is why people may have fudged their numbers in the past.

My plans are to make and test a few different designs as funds allow me to. I'll at least get this setup finished and play around with primary diameter and the collector merge. I'll start posting some photos soon. Eye candy I'm sure is much more desirable than myself blabbing about it. Just trying to dot my I's and cross the T's so that everything is done properly.

Additionally, I have the fixtures for high-flow cats, and X-pipe midsection in the works. These are simply factory replacements that will certainly give more growl. I should have all of these completed in next few weeks as well. I've scanned the factory setup for CAD data and I'm working on the models for the fixtures this week.

Regards,
Derek Fricke

 

Not my cup of tea, but you might looking into crowdfunding (Kickstarter, etc.) if there's enough interest here. Just a thought.