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Pete,
these will mate up to the 4.2 N/A setup as well. Ideally the N/A will benefit the most from a Tri-Y design (Which I plan to build at some point) but the 4-1 collector should make a nice power increase on these N/A engines. I'm doing my best to make all the Jag guys happy
Certainly as I setup sponsoring this forum and moving towards sales, all members will receive a discount. Early bird specials will be offered as well. As the more material I can order at once, the lower the manufacturing costs. There are no corners that will be cut with these headers. I plan to ceramic coat all of them and offer a range of color options through Calico coatings.
I stopped by and chatted with Kenny. He's wrapping up a few 427's for Superperformance in South Africa. As soon as he is done, roughly two weeks, He mentioned we can start on them.
Ideally the N/A will benefit the most from a Tri-Y design (Which I plan to build at some point) but the 4-1 collector should make a nice power increase on these N/A engines. I'm doing my best to make all the Jag guys happy
I still don't understand why you are pursuing the 4-1 design at all.
It's been tried, the results were not great.
It's been confirmed by the guy who actually worked on the development the AJ-V8 that a Tri-Y design (suitably sized) will be better in several ways.
Again, because of the firing order, cylinders 6 & 8 firing sequentially, loss of volumetric efficiency, charge robbing, etc...
Nobody's stopping you from doing it your way, but it seems a shame to make the same mistakes as others who tried it before you.
please count me in on the tri-y configuration. please give me a rough order of magnitude price as well. let me know what you need from me to get started.
as a note, I will be back in charlotte over the next 30 days. my house is in the lake norman area. it would be nice to meet at a cars and coffee event or such.
Appreciate your concern and input Cambo. The key word here "Tried". Per what I have seen were three projects: Paramount, BatCat, and Buckhead Imports.
Paramount and Badcat designs do not properly control the 6/8 cylinder issue.
Buckhead had the right thought, but improper execution.
For a supercharged motor that is pressurized, a Tri-Y vs. 4-1 shouldn't note a substantial performance difference (when properly executed).
For a N/A setup, we may see more of a benefit with the Tri-Y as we can benefit from the vacuuming effect with cylinder gases.
What Buckhead overlooked was how flow velocity is effected by;
1. Tight radii and
2. The convergent and divergent angles at the collector.
What I noticed in their design is there was no divergent angle from the collector back to the exhaust. They have a straight connection which causes turbulence and flow restriction. The exhaust gases expand as they heat up from the merge, this is why you want a nice (typically 7 deg)) transition back to your exhaust tubing for the expanding gases to flow smoothly.
Additionally, the other issue I noticed was the tight convergent angle. Its hard to tell in the photos, but it appears as though they are at least a 20 deg convergent angle (This angle is usually used in very confined areas). This angle is where the 4-1 angles back to a single round. If you want to make the most power, a 12-15 deg is where you want to be. These angles are critical areas of design.
The other concerns with the design were very tight radii and sharp corners in the primaries as well as the catalyst varying bank to bank by approx 4-5" in location.
The collectors are key to every design, but there is a science to the proper sizing. Thus why I chose to fab a well designed 4-1 with interchangeable collectors to dial it in. From there we can have good numbers to base from.
If we want more power, we will move towards the Tri-Y sooner. The cost vs. benefit isn't that substantial when these 4-1 setups are properly built. Hence the post title. Typically I would have used the referenced data and started with Tri-Y but I like mathematics and saw too many what-if's. Plus the Tri-Y's will cost a little more and I'm frugal
All data will be published before and after, stock with cats/with out, 200 cell options and 400 cell. Collector vs collector alternatives. No fudging, just straight data. This is what I work from and I like verifying my numbers and calculations.
Keep in mind as well Cambo. Some of these past header builds did not adequately address proper data acquisition. One key area is boost level. Before and after particularly. In some cases the boost pressure will lower in the system with exhaust gases flowing more freely and engine more efficiently. When leveling the boost to compare apples to apples, additional gain is seen. You can see this in some 03-04 Cobra engine designs.
Peter,
Sounds good. Shoot me a message and we can certainly meet-up.
Derek I really want to see you succeed with this. So don't ever feel that i'm putting down your efforts or that my criticism is not meant in a constructive way.
Originally Posted by FrickenJag
For a supercharged motor that is pressurized, a Tri-Y vs. 4-1 shouldn't note a substantial performance difference (when properly executed).
Shouldn't? or won't? Won't sounds better, so how sure are you? The best way to answer this question will be to try both and let the results speak for themselves, if that's feasible.
Originally Posted by FrickenJag
For a N/A setup, we may see more of a benefit with the Tri-Y as we can benefit from the vacuuming effect with cylinder gases.
No argument there at all.
Originally Posted by FrickenJag
If we want more power, we will move towards the Tri-Y sooner. The cost vs. benefit isn't that substantial when these 4-1 setups are properly built. Hence the post title.
It's not just about the highest number on a dyno sheet. If a 4-1 makes 10hp more in the top end than a Tri-Y but leaves a big hole in mid-range torque where a Tri-Y has a noticeable gain, I know what i'd rather have...
Originally Posted by FrickenJag
Typically I would have used the referenced data and started with Tri-Y but I like mathematics and saw too many what-if's. Plus the Tri-Y's will cost a little more and I'm frugal
Think about the bigger picture here. I can't imagine that a long 4-1 design will be possible to suit both LHD and RHD cars AND also the different models that run the 4.2 engine; X350 XJ, S-Type, XF, X150 XK all have the same stock log manifolds, regardless of which side the steering wheel is on. If it costs a little more but you have one design that fits everything, it would actually be more cost effective and marketable in the end.
Sure it might cost a bit more to make a Tri-Y, but get it right and you double, triple, quadrouple your potential customers with one design, rather having to adjust a design for the different models which will cost you more and take longer to bring to market.
Originally Posted by FrickenJag
All data will be published before and after, stock with cats/with out, 200 cell options and 400 cell. Collector vs collector alternatives. No fudging, just straight data. This is what I work from and I like verifying my numbers and calculations.
For me, and a few others, this is where Buckhead really fell short. Their data was just not credible.
Keep at it mate. There are more than a few of us waiting for the good news.
Thanks Cambo. I appreciate your constructive criticism and always have taken it that way. Hence why I make sure to answer everything with proper detail.
I mentioned "shouldn't" because the cam profile will have an impact on the benefits of a Tri-Y vs 4-1. The profile differences as I'm sure you know have a strong impact on exhaust flow.
I have not seen data comparison of Cam Cards for the N/A cams vs the supercharged cams. Depending on the overlap vs separation the difference in headers may be negligible. If there is a wide separation angle with the supercharged engine and no overlap, the benefit of vacuuming effect from the Tri-Y will not be noticed. Typically a supercharged motor has very little overlap so that it may build boost and not blow it straight through to the exhaust. Now on the N/A I'm sure they have some overlap , thus why the benefit may be noticed more.
I fully agree with you on the mid-range torque vs hp. That's what I'm pushing for are the torque numbers on the lower end.
The other factor that led me to consider the 4-1 design first was the consideration of fitting the other models. The Tri-y setup (per visual inspection) would be very tight to fit easily. A 4-1 allows for individual flanges and makes for an easier install to start.
I'll certainly publish well collected data to support the findings. Then I'll jump into building a the Tri-Y setup. I'm just as curious as you guys at comparing data. I've already calculated all the dimensions and had my work doubled checked by a few experts Vince Roman at Burns stainless being one. So I know everything is ready to go, just need to get this first set knocked out.
I'm really looking forward to getting some good data to supply to you guys. We shouldn't be too far away.
Side note:
The high-flow cat first production piece is almost complete, just need to fine tune flare to fit to manifold (real sharp 57 to 70mm flare) , and slip fit on mid-pipe. (Slip fit is an odd size of 53.6 mm stepped to 57mm) Then we are off to coating.
Tooling for the carbon engine panels is being milled now. Should have these ready to pick up next week.
I mentioned "shouldn't" because the cam profile will have an impact on the benefits of a Tri-Y vs 4-1. The profile differences as I'm sure you know have a strong impact on exhaust flow.
I have not seen data comparison of Cam Cards for the N/A cams vs the supercharged cams. Depending on the overlap vs separation the difference in headers may be negligible. If there is a wide separation angle with the supercharged engine and no overlap, the benefit of vacuuming effect from the Tri-Y will not be noticed.
Typically a supercharged motor has very little overlap so that it may build boost and not blow it straight through to the exhaust. Now on the N/A I'm sure they have some overlap , thus why the benefit may be noticed more.
Numbers in that table were the "in development" specs of the cams, hence a number of changes. As for the final specs, he said the latest ones in the list... but in any case it gives you a ballpark idea. But there seems to be some conflicting information from the JEPC.
The later 4.2's had VVT on intake cam for both the N/A and S/C versions, and run exactly the same cams (both inlet and outlet) and everything in the top end is identical between them too; heads, valves, cams, the lot. This is confirmed by the JEPC, everything with the same part numbers.
The earlier 4.2 N/A is the same as the later ones so same specs, VVT intake, fixed exhaust.
But the earlier 4.2 S/C had no VVT, so there are different cams according to the p/n's (both intake and exhaust). I expect the overall lift & duration to be the same or very close, just without the variation from the VVT.
The cutoff of 4.2 S/C engines changing to VVT is MY2006, by vehicle;
X350 XJ from G49701
S-Type R from N52048
All X150 XKR's and XF SV8 have VVT, but 4.2L X103 XKR never got it
Count Iblis describes the cam specs of the 4.2 as "minimal overlap";
Originally Posted by Count Iblis
7)Redesigned camshafts: The current Aj27 cams have way too high a ramp- at 0.45mms. I will design cams with 0.32 to 0.36 mm ramps as used on the later Land Rovers. In addition it was always policy to minimise overlap on the SC engines to minimise HC emissions. ......
Originally Posted by Count Iblis
We looked deeply into 4 into 1 vs the 4-2-1 and for the AJ37 the 4-2-1 suits the characteristics of the engine far better. The 4-1 will leave a gaping hole in the torque curve at low speed. You can over come this somewhat using exhaust VVT but neither the 4.7 or the 4.3 has that.
Does the AJ37 have the same volumetric efficiency problem between 6 & 8 (actually, 7 & 8) like the Jag versions?
Yes it will, or similar- the difference is that the supercharged engine has minimal overlap and still suffers from the charge robbing problem- mainly due to unfavourably grouped up intercoolers/plenums and the exhausting. On the AJ37- we tried a 264 duration cam which gave great results but were forced to restrict down to 256 due to this mal distrisbution problem. If I ever bought an Aston I would probably grind that same 264 profile again (I still have it!).
Originally Posted by Count Iblis
9) In the current SC engine layout cylinders 7 and 8 suffer BADLY in terms of charge robbing. Theyre running about 20% less Volumetric efficiency than the others. This needs to be addressed! I would do this by doing a bespoke exhaust header design and looking at intercooler connectivity opportunities.
Many of us are looking at utilising more aggressive cam specifications, closer to the Aston spec in lift and duration (some already have modified cams in their engines) so you need to keep this in mind. Not everyone will be bolting these headers onto a stock engine.
++ on side pipes. Can someone photoshop side pipes on an F-Type?
Would be sexier than a 60s 429 Cobra for sure.
Or are we talking about keeping the stock rear-exit?
Of course, you meant 427 Cobra (not 429). The Ford 427 side-oiler was an engine developed for racing that put out a lot more power than the lower compression 428 and later 429 engines that replaced it because it was very expensive to produce.
As a historical side note, Carroll Shelby put 428s in a number of cars and sold them as 427s because he had trouble obtaining enough of the latter. That didn't go over well with customers.
At any rate, heres a shot of my old 427SC with side-pipes in a common pose for photoshop material. Side pipes were the standard location on the 427SC (street/competition) version. Street 427 versions had the dual exhaust routed underneath in a more standard configuration.
Personally, I think side pipes would look ridiculous on the F-Type.
Thanks for the correction Foosh, your old 427 looks fabulous!
Love your taste in cars.
My 15 doesn't have the side skirts, I love it the way it is.
I think I would prefer side-pipes to side-skirts.
Of course, you meant 427 Cobra (not 429). The Ford 427 side-oiler was an engine developed for racing that put out a lot more power than the lower compression 428 and later 429 engines that replaced it because it was very expensive to produce.
As a historical side note, Carroll Shelby put 428s in a number of cars and sold them as 427s because he had trouble obtaining enough of the latter. That didn't go over well with customers.
At any rate, heres a shot of my old 427SC with side-pipes in a common pose for photoshop material. Side pipes were the standard location on the 427SC (street/competition) version. Street 427 versions had the dual exhaust routed underneath in a more standard configuration.
Personally, I think side pipes would look ridiculous on the F-Type.
It wasn't claimed to be an original CSX. It was a near-exact, replica built in 1987 with an original 1965 Ford 427 side-oiler engine built to original specs, close-ratio Ford top-loader 4-speed transmission, and Jaguar/Salisbury IRS rear end complete with in-board disk brakes. That was the same set-up used in the CSX cars and also the E-Type. In other words, it was built with the same chassis and drivetrain set-up. The interior was also original. It was not one of the ubiquitous, "kit Cobras."
It was factory-built by a company that specialized in the restoration of original CSX cars, of which less than 1000 were built. A lot people don't realize that the original CSXs were built as a rolling body and chassis by AC in the UK, and shipped to the Shelby Shop in Los Angeles for installation of Ford engines and transmissions.
Tony and the guys did a great job with that engine. I'm dying to get my hands on a billet block and heads from them. Nicely engineered set of headers as well on that engine setup. I just noticed it appears to be a 4-1 collector setup. The cams were modified with a new firing order for more optimum flow.
10-12-2015, 07:53 PM
