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What are the max ratings of the stock pre he heads? What rpm does it run out of air stock vs porting? How much could it handle with stiffer springs? Could you get 400hp? 500hp?
I would be interested in something more of this nature. I don't think many people are looking for the full race 700hp engine. But if we could see a 450hp motor on stock heads that are modified I think that a lot more people would be interested in that no?
Read Allan Scott's book about the TWR ETCC racing XJSs. This deals in detail about what is doable under the conditions you mention. 400 BHP is doable on a roadable engine
I realize that the market may well be with lower outputs than I am exploring but that is not where I am going.
Having said that you can get the 450 from a 5.3. You need good comp ratio and preferably something akin to the Group A pistons.
Valves to be stock but with a nice seat job. Cams to be stock or at max road race or 0.415 lift.
Springs, stock will work to 8K but maybe fit new, would be nice to balance the heights and therefore pressures.
You need to open out the inlets to 36mm ie to the gasket. If you are really keen knock out the guides to facilitate the gas flowing. Tapering and shortening the replaced/replacement guide ends is nice.
High pressure oil pump from Rob Beere is a must and cheaper than a new pump anyhow.
Inlets need to be Group A available from me or a TB system, if the former they come as castings or machined, your choice. If the latter you are on your own, if carbs you are wasting my time, they were Ok 35 years ago as there was little else but not today.
Cold air for the TBs and a decent set of headers with longer secondaries if you can.
Got a 6L then its the same formula and the same result, swap the heads / pistons to flats and you can add 50+ with the same formula, maybe 75.
Beyond this you are in my area and need to specify what you want and how much your budget is. If your budget is crazy enough we can even talk about twin cams.
Considerations most people don't think of or realize is that the very formula for working out BHP means it is hard to have big horses below the torque / BHP crossing line just above 5200rpm, the multiplier is on your side above this. The oil pressure needed is generally accepted to be 10psi for every 1k of revs you will be needing, just from this you will quickly see that higher revs means higher oil pressure, uprated pump AND uprated bypass (same source). If you are intent on keeping a slush box there are big implications and maybe forgetting the horses and concentrating on the torque is a better idea. This means upping the cubic inches. Get your calculators out and you will quickly see you need something like a Group A set up to keep the torque curve in the same place with the larger engines.
What I want to know is how I create a new thread; I think redesigning new heads is worthy of its own thread don't you?
Would love to design in direct port injectors but am unaware of anything approaching a cost effective system for doing this.
What I want to know is how I create a new thread; I think redesigning new heads is worthy of its own thread don't you?
I do think it's worth a new thread.
Go to the main page of the XJS forum https://www.jaguarforums.com/forum/xjs-x27-32/ and on the left side above the list of threads is a button that says "post new thread". Click that and start your new thread.
Hi Everyone,
Ive decided to sell these original brand new Group 44 Jaguar V12 race heads and cam buckets.
I had thse flow tested in Melbourne and they flow 643Hp at 550 thou lift stock no head work.
They can do more but due to the rarity and uniqueness of thee I didnt touch them.
They are still bare castings brand new with larger cam buckets still with group44 packaging
I need to buy the house I never bought and am liquidating all my toys including these.
Im after $12k usd
I will accept crypto(BTC or LTC), direct bank payment or even cash in person
The items are in Sydney Australia and im willing to ship them anywhere in the world at your cost.
Im happy to deal with agents or people in person.
This is a VERY rare opportunity
contact me on here or daddycool454@hotmail.com or ph +61(0)481302427
reluctant sale, extremely rare
i see you are inrterested in TESLA,, those cars are encredable ,performance machines ,,whooda thought!
that Plaid S is a beast!
my local eye doc just bought one , its on Utube!
how can you go o- 100MPH in 7 seconds, without any noise?
heads havent moved since i brought them back from the flow testing. the pictures are at the beginning of this thread with the ruler.
Im still tossing up whether to use them. only issues ive had are the cam carriers(need larger than standard) and inlets. Available from xjr005 but pricey, like evrything else performance Jaguar...
Havent given the idea away completely. But i bought a cls55 which has 476hp & 515lbft which is what i wanted from the V12...
So if they dont sell i will get to them in another 3-4 years.... how time drags on....lol
Hi everyone,
as i dont have the funds to replicate the heads, I am offering the dicom files for free to anyone that would like them in order to replicate these. https://www.dropbox.com/sh/zkhn35im8...xXOdOtcXa?dl=0
you will need to download a dicom viewer, there are many free on the internet.
These are large folders totalling 4.02GB
happy birthday
These are original group44 heads unused and not modified in anyway.\
I had them flow tested and they produce 643hp @ 550thou lift
comparison of group44 exhaust comparison of group44 inlet vs standard pictures from supercharged tr6 just before i bought them from him
Last edited by daddycool454; Sep 10, 2021 at 06:06 PM.
Thank you for your generosity in sharing these Daddycool. Just for a quick show and tell with what can be done with the data:
This was done very using the 3rd data series of 25 images very crudely (not much fiddling with settings) in InVesalius 3 (free) and then cleaned up slightly in Windows 10's built in 3D Builder. (I had no idea what InVersalius was until about 8 hours ago.... last time I made 3D's - just views - out of DICOMMS was for a broken shoulder of mine about 12 years ago with ImageJ, when there wasn't much 3D software, and impressed the hell out of my surgeon with it...) Its so much easier now.
This one sufferers from being made of only 25 slices, and these DICOMM images are only 512x512 pixels anyway. Some newer scanner systems can do 2000ish x 2000ish pixels now. I suspect the longer image series folders will fare better, but turning these into a solid (not surface file) w/o professional software (even with) would be a significant and time consuming reverse engineering challenge. Doing a large format print of it, then cleaning it up for a conventional sand mold might be one way to go, but any would be labor intensive. I can see how this would have been quite an investment to try to get outside professional help doing any reverse engineering. They can be RE'd with fairly consumer SW, and a boatload of time and effort though. I wish it had been more affordable for you (well for anyone/everyone) as I know you would have really liked to have made copies available.
wow... that looks awesome. i tried to download some software but have no idea what i was doing. This is the difference when someone has skills. Great work Ferrari Guy.
those exhaust ports are very good , much better than factory exh. ports!
pic of my factory ported , ports you can see the change of side to oval shape , not round!
someplace in my Jag V12 design , enginineers wanted only round ports! round ports!
those exhaust ports are very good , much better than factory exh. ports!
pic of my factory ported , ports you can see the change of side to oval shape , not round!
someplace in my Jag V12 design , enginineers wanted only round ports! round ports!
Engine looks nice Ron, i believe you did a fair bit of porting to yours from previous posts
Still occasionally playing with these files but in so doing I though some might be interested in some of the construction. The water-jacket area was clearly made in at least 2 glued together core sections as you can see by the flashing along the split line. And you can see the ribs used to strengthen the deck (11-12mm thick). How this applies to normal flatheads/HE heads IDK.
