so has anyone actually made 500bhp from a v12 pre.he
#307
#308
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my choice for something that runs on the road would be something like the AJ6 engineering system but in an aluminium casting. The crossover system looks wonderful but I wonder how well it works, its too low IMHO and the compromise of where and how the injectors and their fuel pipes are located with the necessity of fitting it all with clearance under the hood is problematical.
Injectors in a similar location to standard would allow a better curve, longer runners and higher throttle bodies with bellmouths easily clearing the cam covers and the hood, just my 2p worth. So I think the crossover system shown is a beautiful looking fail.
Injectors in a similar location to standard would allow a better curve, longer runners and higher throttle bodies with bellmouths easily clearing the cam covers and the hood, just my 2p worth. So I think the crossover system shown is a beautiful looking fail.
#312
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i mentioned that the AJ6 inlet manifold system is about the best compromise for an XJS under hood.
i dont think anyone is gonna come up with anything better, except a forced induction setup, and i do know that the simplest would be 2 remote mount turbos and a good standalone ECM, and there is enough room under a lowered XJS to do it!
and i dont do any off road driving, not my style!! lol.
i dont think anyone is gonna come up with anything better, except a forced induction setup, and i do know that the simplest would be 2 remote mount turbos and a good standalone ECM, and there is enough room under a lowered XJS to do it!
and i dont do any off road driving, not my style!! lol.
#313
#314
#315
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I wonder if we are totally missing the point here; the std set up is the best production compromise for a road car. Easy starting smooth low tickover, instant pickup and more than adequate power delivery with as good economy as could be achieved at the time.Also remember the ever tightening emissions issues.
It is a total package.
Yes you can improve the (older) standard set up with modern injection/ electronics.
You want more power then be prepared to make make sacrifices in other areas. More power requires more fuel and more air, it needs to be able to get in and get out, of course it will cost more to do this than a 4, 6 or V8 because you have more of everything in a v12. you are wasting your time if you think that bigger throttles or larger inlets will do much without the matching larger head ports and valves, maybe with a change of cams and a different map.
You need a total package again, if its a bit more you need a bit more in all areas to maximise things. If you require a considerable increase then be prepared to make major changes in all areas, fairly obvious but often there is little difference in cost between going 1/2 way to going the whole hog, If you have to buy new pistons and liners then the cost has little to do with the size; it has to do with what is available. In Europe its 96 mm bore off the self. Cheapest crank may well be an offset ground unit starting at either 70 or 78mm. Rods will therefore be Chevy based most likely at 6" and everything follows on from there.
Might be different in the USA or Australia. What I am certain of is that just the changing of an inlet set up will be a waste of time and money, bringing disappointing results. You need a package.
It is a total package.
Yes you can improve the (older) standard set up with modern injection/ electronics.
You want more power then be prepared to make make sacrifices in other areas. More power requires more fuel and more air, it needs to be able to get in and get out, of course it will cost more to do this than a 4, 6 or V8 because you have more of everything in a v12. you are wasting your time if you think that bigger throttles or larger inlets will do much without the matching larger head ports and valves, maybe with a change of cams and a different map.
You need a total package again, if its a bit more you need a bit more in all areas to maximise things. If you require a considerable increase then be prepared to make major changes in all areas, fairly obvious but often there is little difference in cost between going 1/2 way to going the whole hog, If you have to buy new pistons and liners then the cost has little to do with the size; it has to do with what is available. In Europe its 96 mm bore off the self. Cheapest crank may well be an offset ground unit starting at either 70 or 78mm. Rods will therefore be Chevy based most likely at 6" and everything follows on from there.
Might be different in the USA or Australia. What I am certain of is that just the changing of an inlet set up will be a waste of time and money, bringing disappointing results. You need a package.
#316
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5006, totally agree(a package for performance).
here in the states, for a lowly GM chevy V8, they sell a recomended Package,
it includes a set of Hi-performance cylinder heads, a custom inlet manifold, and a camshaft kit, that includes a cam that is correct for the head and manifolds, a set of lifters(cam followers), and a set of valve springs.
now they will sell any one of the components seperatly, but if you want good results, it is a complete package, and highly recommended!
here in the states, for a lowly GM chevy V8, they sell a recomended Package,
it includes a set of Hi-performance cylinder heads, a custom inlet manifold, and a camshaft kit, that includes a cam that is correct for the head and manifolds, a set of lifters(cam followers), and a set of valve springs.
now they will sell any one of the components seperatly, but if you want good results, it is a complete package, and highly recommended!
#317
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and the old girl aint dead yet!
yesterday went to a car show with her, over 500 kool cars, i was directed to the Exotic car area(nice Ferrari's,porsche, audi R8 types, Lambo's, RR conv. Bentley's,Aston Martins, and more), parked me between a Viper and a Tesla roadster.
well turned out many viewers for my Jag, all kinds of braggin rights, mine you, you know this mod that trans,etc. but mostly about the standalone system, some couldnt believe ive had it 20yrs.
weather perfect mid 70s sunny, car run like a raped ape out on the hiway!
those pesky old Corvettes HUH.
yesterday went to a car show with her, over 500 kool cars, i was directed to the Exotic car area(nice Ferrari's,porsche, audi R8 types, Lambo's, RR conv. Bentley's,Aston Martins, and more), parked me between a Viper and a Tesla roadster.
well turned out many viewers for my Jag, all kinds of braggin rights, mine you, you know this mod that trans,etc. but mostly about the standalone system, some couldnt believe ive had it 20yrs.
weather perfect mid 70s sunny, car run like a raped ape out on the hiway!
those pesky old Corvettes HUH.
#318
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That thing is a joke.
#319
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Frankly, I'm a sceptic. I think it's unlikely you can hit 500 hp in a drivable engine without using forced induction.
We all know how poorly the HE head flows, but the pre-HE was not that much better. Porting the HE head still leaves you with a less-than-desireable chamber shape. Asking a V12 Jag to produce in excess of 1.5hp/ci is going to be a very high bar to reach.
These engines do well in categories of smoothness and panache, but have never been renowned for their power output.
We all know how poorly the HE head flows, but the pre-HE was not that much better. Porting the HE head still leaves you with a less-than-desireable chamber shape. Asking a V12 Jag to produce in excess of 1.5hp/ci is going to be a very high bar to reach.
These engines do well in categories of smoothness and panache, but have never been renowned for their power output.
The Le Mans engines were making 100bhp/L with relatively mild cam timing, peak power before 7000rpm and ran for 24hrs at a time with no worries at all.
The Pre-HE has excellent breathing as it's a semi Heron extremely similar to the famous Ford kent x-flow engine. Those engines make easily up to 200bhp nowadays from 1800cc.
The basic problem always arises, the sheer dreadful thermal efficiency of the thing.
It has about all the worst aspects ever imagineable to make fuel effiency, no matter how jaguar said how wonderful it was.
In this respect, some US V8s are better, i can think of the LS series for instance.
One of the major hangups is the lack of space and the sheer weight of the V12 engine.
This makes it incredibly difficult to make a proper tuned exhaust for it, in anything other than a sports racing car (hence the Le Mans V12 worked).
If you REALLY want to tune a V12 to make 500bhp it's pretty straighforward, but first com up with a huge wad of cash and DRY SUMP the thing with a proper water system.
After that it's just mega money to do the heads & ancilliaries right with a proper inlet tract and EFI system,- in short all the things that were a design disaster on the original factory Jaguar.
#320