..

we have been over this before, but good to bring it up!

sheet metal, large plenum/Tbs, on a Jag V12,, TBs on front of manifold, and long length runners!

that would be easier to produce than casting and machining inlet manifolds!

 

xjr5006; question,are you saying machine out the HE chamber, and weld /fill aluminum and machine in an LS style chamber, using a factory casting HE head?

you would still have the short turn exhaust port outlet to deal with!

maybe easier to use grp44/ TWR castings, with raised exhaust port! but cost would be considerable more!

no doubt GM /LS has brought pushrod engine technology to the fore front, hard to beat for the money costs!

this thread has reached the ( very interesting) level!

 

I would love to that, but the cost of it is way out of reach for me at the moment. I may look at doing this with my 5.3L heads in the future. Norman has a set of pre-HE heads that have had the chambers machined like this.

Inlet manifolds - I will cut the plenums off and replace them with larger 100x100mm aluminium section as my engine guy has suggested. He uses standard runners with the new section welded/brazed on and the TB's moved to the front. He has much success in the racing V12's he has built with this approach.

Norman has advised me to build the 6.7L with all the stock bits first, cams intake and exhaust manifolds, see how it runs ie its power band

 

.


that is a good looking pre-HE head, chamber resembles mid 90s Ford inline 6 engines!

amazing there is that much meat in the deck surface, or is it milled out and filled with weld, much shorter valve stems, yes that could get expensive, labor wise! but to me, the short turn,on both ports, must be even tighter turn!. Oh well,

if it works for Norman its gotta be good!!,LOL.

seems as tho the big port grp44 and TWR heads are hard to come by in Aus.

course there is the set that just came over from tr6supercharged guy, i reckon.

but the advice from Norm using stock components,to get up and running, is very good advice, there will be a lot of tuning and adjustments to make, before the bugs are worked out.

 

i dont know if this relevant , but when i had my 5.3 inlet manifolds EXTRUDE HONED, i measured the runner diameters before they were done and examined inside plenums and all thru out, was opened about 1/8" larger diameter, best of all all the internal humps and bumps casting flash lines were gone, and surface was very smooth but not polished!

at that time 1994, it was odd most race guys i talked with knew little about plenum technologies , they were mostly into carburators and manifolds.

funny how times change! i wish they had a usable internet back then, i didnt even know that a Jaguar site exsisted.

 

went by the dyno shop on the way home
still 3 pulls for 100
will do that soon...
105k miles
new coils
no codes
stock exhaust
possible restriction (melted cat on bank b) flowing freer lately


let us see what we get out of the old horse


then an exhaust upgrade and re-dyno

 

In 1994
most every thing was BBS and FIDO net and news groups...
I ran one...
arpa net in 1980

 

The head there looks like a special casting made recently by a chap in the UK for a drag race project; He canned the project when he could not break the 800 BHP mark. He had made the inlet ports too too big and put in 2.1" inlets I think, (might have only been 2" cannot remember) basically he had LS7'd the whole engine using Nascar and LS performance parts. He hoped he would get twice the power of an LS from twice the capacity. He put A LOT of money into this venture. But now its gone.
There isn't the meat to machine up a flat head like this but an HE I think could do the trick. I'd also worry about the exhaust when I got to the point when I got too much air through the inlets.
The AJ6 Engineering tube and plenum inlets were far better than standard but some suffered from poor quality and manufacture, on some I saw the manner of holding the injectors in was pretty horrible. They also cost a lot of money and that was 20 years ago!
Opening out the standard manifolds , yes you can do quite a bit, racing XJS's in the late 80's we went as far as spending 2 weeks with long shaft die grinders checking with washers on rods. Thats per manifold, got them so hogged out you dared not lean much on them, Tried removing the outside of the plenum and then banding the runners in half ( tops with head flanges in 1 section and bottoms to about the injectors on the other) then opening the far end of the runners to about 1cm and tigging the lot back together, nice idea but the heat warped the lot all over the place. So just settled for what we could achieve with the grinders. The real problem was very simple. the standard manifold was made for road use on a 5.3L when you go to 6L its over 13% under fed. (do the maths) The racing 5,3L TWR cars had the big inlet castings which opened out from 36mm at the head to 45mm at the plenum (that 45mm is larger than the OD of the std runners and by some) they had a usable power band up to about 7250RPM but could rev to 8K You can reduce this by the 13+% if fitted to a 6L so perhaps usable power band up to 6500RPM and down yet again if you go larger.
All this business about bigger / multiple throttles or moving throttles to the front is just tosh or packaging; sadly it also tempts many buyers even with poor results.
You want cheap, then band the plenum in half in line with the top ribs, the triangular end plates and mastic will put it back together so no welding required. The you can get to those lovely runners and carve away until you get totally totally bored (remember you have a pair to do equally) You will see an improvement. Hunt out the late 90 Degree plastic TB take offs to duct to the front of the car or do what we did before that time which was to get 2 x AJ6 alli TB 90 degree bends and weld to a piece of plate to fit the TBs There is also that 'growler system if you prefer to spend a few hundred bucks.
If you seriously think that you can design a functioning and practical inlet on the back of a *** packet then go for it.
It has taken me nearly 30 years to hunt down and acquire the real McCoy; I have made them available to all. I will not be trying to improve what was designed and produced at great cost by Jaguar and a professional team (TWR). Cost to design test and produce today? I would guess little change if any from 1/4 Mill. I'll even sell you a pair of castings if you think you can save money getting them machined yourself; if you can do it yourself you certainly will too. Now theres and offer.
Just had a chap get 445 from his engine with these manifolds + cast exhaust, not bad for a 5.3L. Thats engine on proper Dyno job, and yes I have asked for dyno sheets and yes he did the testing properly with back to back against std manifolds. He knows his stuff and is a happy chap.

 

i agree, what you are saying is, basicly it is difficult to get a lot of HP from Jag V12, also expensive!

the engine was designed and engineered for a smooth road car, that is exactly what it does!
it has little design for a big HP engine, leave that to most good USA V8s!

one guy said use a Veyron engine, OH yeah, plenty of them laying around,,LOL.

easy HP is forced induction nowadays, anyway!

the antique Chevy BBC (big block designed in early 1960s) still today with modern mods have no problem making 1000HP, thete must be 1/2 dozen around here local!
Austin Texas, and forget Oklahoma, must be 200 of them!

you tube ,Street Outlaws OKC

 

Very interesting. As I know the X-type work to increase fuel pressure by 3.0 bar and more. Will V12 run with the X-type's injector with the stock ECU?
Maybe XJR 4.2 will better?

 

.

warron could answer that question!

i suppose you could measure the Ohms/resistance of each style injector, and if close probably work OK.

basicly there are two common types low impedence, and hi impedence, most jag v12 used low imp.

but if you can beg /borrow some from X type, see what you find out.

and read about electronic fuel injectors, much info online!

a problem that could/may come up is being able to adjust the fuel volumes to run smoothly, i use a standalone fuel ECU, i can adjust injection time by a small cockpit control!


i have seen guys who run injectors with non matched ECU, and surprising they work OK.

 

You could possibly use the Lucas ECU these Injectors are 14.5R and the V12 injectors are around 3R. They are also larger than the stock V12 injectors 24lb as apposed to 19lb. You will also need a 6.0L fuel rail or O ringed fuel rail.

You would need to bypass the resistor pack and wire it directly to the injectors.

The problem I see is running these at higher pressure is going to be getting AFR correct. A programmable ECU would be better.

 

These are the intake manifolds I was talking about. This engine was built by Norman Lutz 6.0L and 500hp @ 7500rpm for a long distance racing XJS, cruised at 300km/h (200mph in the old money) all day long.

I have my own machine shop in the shed....

What would a set of GRPA manifolds set me back?

 

I am not saying its difficult to get power out of a V12, an engine is an engine. But this engine was designed 50-60 years ago with relatively low production figures and is now relatively scarce. Hence no or next to no aftermarket parts are available. This means everyone has to do what in effect a 1 off build which is by design always expensive. The only thing I can think of that is available is the weber conversion and the mangoletsi stubby inlets and good luck to you if you want either. There are also liners available in oversize but no pistons. Everything must be made as a 1 off.
I would give an example applicable to any country. Just go to a good or your fav engine shop and ask them to build you a SBC pushing out whatever power you fancy, they can and will get out the parts books including aftermarket blocks and heads......... Dont need to say more do I.
TWR inlet castings £1000 a pair, machine them up yourself. (2.5 machined with studs) If you can make some money on that supplying others you could be my supplier in the USA! There's an offer for you.
Be careful with chopping and changing injectors, The Pre HE work on upto full race with little problem ( they are also fitted to some Mercs) Yes tempting looking at some Chinese $20 ones but havent gone there yet and dont know if I dare on a customers engine either.
As for the Lutz plenums...........

 

i run 24LB. low impedence,,Bosch made in Germany, O-ring top and bottom.

22yrs now, adjustable F/P regulator, pressure at present 45 psi., i have tried many pressures and best response and overall general driving , is at 45psi.

anytime you change pressure yuo have to readjust complete fuel MAP, that can be annoying ,refinding the sweet spots thruout the RPM/Load areas!

but with standalone ECU , you will learn a lot, mark that as FUN!!LOL.

 

something i have found about V12 Jag engines , is a good running 5.3, using a 3.73 rear gear, and a 700R4, will run circles around a stock 6.0L XJS.

its all about AVAILABLE torque at the tires, proper gearing can make a lot of torque!

we talking street type cars here, not a full on race car, race cars weight around 3000lbs, while a complete street XJS goes over 4000+ lbs.

 

We found the 3.77 a bit high and the 3.54 a better and easier to get LSD. Racing weight for a fully lightened XJS 1250Kgs appx 2750 lbs. but many people struggled to get down past 1350 Kgs. Fully road legal racing cars which we drove to and from the races.

 

Ronbros makes a good point: gear the 5.3 well and it will surprise many, especially if it is in a good state of tune.


The 3.73/3.77 ratio would be pretty high for street use, IMHO. The double overdrive T-56 would be appropriate for this ratio.


I run a 3.54 behind a TKO wide ratio box with a 3.27 first gear, and I think this combination is a bit too short legged (although I can tear out the cage at will with it- that's another thing that comes from driving the torque down!). Having run the numbers again and again and again, I would choose a 3.31 with a 3.27 first, or better still, go to a close ratio box with a first gear in the neighborhood of 3.0, against the 3.54.


Hard to beat a 3.31 with a commonly available 3.27 first gear box though.


The 3.54 is usable with the T-56 provided you are looking at the 2.97+ first gear, and go easy on just how deep that 6th overdrive goes (and you can work out the issues with using this box in cars designed toward T-5 style dimensions, shifter, bell, trans mount, prop shaft, etc., etc.).


But a Jag v12 with a manual box behind it is a joy to behold, and fields a formidable capability to boot.

 

right on Mike , a lot of torque at the tires with good tire grip can rip loose the whole cage and rubber mounts!

been ther done that, i made some steel bars trying to keep it from moving around to much, but after some serious launching/burnouts, it gets squrrily on the 1st to 2nd shift!!

 

nothing like 60 65 mph and the shift to second and the rear end breaks loose... FUN! scary the first time... just fun there after