10psi boost for extended time can be bad for the engine, detonation and blown head gaskets, most recommend maybe up to 7 psi , altho water/alchohol injection can help reduce tendencies.
old GM idea for production cars, turbo Jet fire oldsmobile 1962, Corvair turbo 65, and Buick Typhoon 1984.

but my father, had a new 1950 Cadillac, and in hot weather made a tinkling sound going up hills(pinging), dealer said they have a kit for that problem, water/alky, had it installed( no more noises,) so it been around for some time!
history was by Ricardo UK, 1920s. WIKI.

NOW for some of those interested, just maybe an HE engine can be forced induction with a variable rate W/A kit , much improved versions nowadays.

like you said, just a thought!

 

You know by asking this type of questions
1) I am going to ask you to buy a book by carol smith called "tune to win"


2) in some forms of racing you are not allowed to balance your engine
if fact some people would go so far as to get car dealer backing and have the parts dept order a large number of connecting rod and pistons excreta and then weight them and make a matching balanced set...
(you see that way when torn down for inspection ... no evidence of balancing on the rods or pistons...)


a balanced engine reduces stress... depending on the engine design depends on which type and where the stress is... 4 and V8 have a inherent torsional stress on the crank shaft and benefit greatly from being balanced... I have seen an spitfire engine built by some one other than me snap the crank between 3 and 4 (that is where the torsional stress is the greatest between 1 and 2 then 3 and 4)


please read tune to win...

 

1st jon , read what i said ,balance your PISTONS!

did not say dont balance your engine!

there is much more to an engine balance, than the pistons.

i have been doing engine modifiing since the early 1950s, have balanced guessing over a hundred engines!

for a true fact most good pistons come outa the box very close balanced, along with a set of con rods from one engine, BUT if you modify either,for lightness, then they should be REbalanced!

at that point you should consider a rebalance of the crankshaft, along with clutch, torque converter,flywheel, any front rotating components!

for my Jag V12 , i use oversize valves,that are lighter than stock, all tulipped, polished , and shaped ,then a final balance of the valves themselves!

i use a special lightweight converter, smaller in diameter, and balanced, along with the light weight FLEX plate.

i use a single piece ALUMINUM drivshaft, lightened and balanced.
, and my transmission is a light weight also.


the list of lightening for my XJS , on a calibrated scale weighs 3365 lbs.

just for comparing, go weigh your XJS ,and think what you could do to come up with a power to weight ratio, even close to mine.

i have certified papers for both weight and dyno sheet.

as you can see ,this is NOT my 1st fast road car.

i have so many engine build books,it could fill a small bedroom!

 

The name of this thread is 500+hp. For that level of performance balancing your engine/pistons is essential. Someone who has been building engines for 50 years should know this.
Your previous post implied that its not necessary and you kinda gave me crap for suggesting it.

 

opps...

so I found the little jewel
Matchless G50 motorcycle which has a 496 cc SOHC air cooled single with 51 hp at 7200rpm


so I am looking at how it has the valve, piston shape, and the cam and valve actuation.... of course the port shapes too...
could easily cobble a air cooled V12 5952cc at 600HP what ever, or apply the knowledge gained to head and valve improvement of the Jaguar V12
and with 5340cc would give about 549hp


parts and the engine...
http://www.minnovationracing.co.uk/115/G50_Engine

 

I think that was directed at me...


I did not mean to offend... as I so offen do

 

SO what did happen to the thread originator...?


did he get it finished and he went and his engine Failed?
and if so what was the failure mode... ?

 

I've definitely played with that idea, but, Bradley already did that nearly 20 years ago. Where's the fun in copying someone else?

As far as I know, nobody has ever twincharged a V12 XJS, and, for me, that's a huge part of the appeal...not to mention that I can get 2 positive displacement superchargers, 2 new turbos, split intercoolers, associated plumbing, bypasses & blowoff valves for about the cost of a single new Whipple SC.

not that I'm serious about doing anything like that

 

There is at least one with twin screw compressors and it was (is) a fantastic car. Try to google for it.

 

Yes, I know the car, and I knew its owner, Bradley Smith, before his untimely passing in 2005. In fact, I almost bought that car in 2009. That's the car I was referring to in my last post.

However, having two superchargers is not the definition of "twincharging". Twincharging refers to a motor that is both supercharged AND turbocharged.

https://en.wikipedia.org/wiki/Twincharger

Perhaps I should coin the term "Quadracharging" for the purposes of this discussion, since you need two of each on the V12.

 

speaking of an engine with 4 turbochargers, check Steve Morris engines .com/devel sixteen

for an unbelievable engine, just might fit into an XJS

this CNC stuff has opened a completely different kind of engine builds.

 

.


OP , i believe he junked the V12 or sold it cheap. he never could make V12 run properly!

ended up putting a GM V6 supercharged, then lots of transmission problems, thats the last i followed his buildup!

this thread seems now, is following the 500hp theme!

 

Calvin is not the super charged V6 guy. I actually got to meet Calvin when I sold him the Pre-HE heads he was intending to use for this project. At the time he was a very young man, 19 or there about. Very smart, knowledgeable and enterprising. He had already converted his XJS to a manual transmission at this point. We spoke some more and he detailed his plans to me in person and we chatted for quite awhile when he picked up the parts. I got the impression he knew what was involved but as a student with a part time Job his ambitions were well ahead of his resources at that time. I don't know his present situation and I wish he would chime in and up date us all. If this project fell by the way side, I wouldn't be surprised. As a once young man myself, I understand its common to for interests to wane and would not be surprised if he moved on to something even more ambitious.

 

OOPS, iscamerica wrong thread, i mixed OP with the guy that was doing a twin turbo V12
i dont know what he did ether.

 

You will find with twin charged the temperature rise at a given pressure ratio is less than either straight turbo or ROOTs blower ( twinscrew excluded, these are THE most thermally efficient).

You will not need split intercoolers. Run the Turbo directly into the intercooler then SC
then water meth injection.

Do not turn off the SC as the VE will be greatly improved by the pressurised input of the TC. Also be aware that running 10psi on the TC and 4psi on the SC will NOT give you 14psi at the manifold it will give you 16.7psi, as the pressure ratios multiply not add.

 

you guys are all about theory and much ideas of what may/could/hope will make more power from a Jag V12! that system you are talkng about,in my opinion, is way over complicated, be a lot of work(and Money) , only to be always unreliable/troublesome.

i do believe a simple remote mount twin turbo system with no intercoolers and a variable rate water /meth system ,would be so much simpler and far easier to tune!

and it would work on an HE engine, without any mods , other than a GOOD set of head gaskets(MLS, or liner rings).

you guys kinda miss some important mods, when flexy open deck engines get into slight detonation, chamber pressures can actually lift the cylinder heads,studs strech, gaskets start to leak and chamber pressures blow out coolant, even tho temp gages say no overheat(YET).

i have personally seen dyno runs where W/M add 75/100 hp over the best tune without it!

simply by adding more timing, boost pressure, and not having to add extra fuel, trying to keep combustion temps down!

 

Ron,

I always find your insight and experience interesting and informative, so I'll bite.

How much boost do you guesstimate can be run on an unmodified HE, with the system you describe, and how much additional power & torque are you talking about here?

 

On the issue of lightness the rotating masses and balancing

Look for these rods is XJR AJ16, two motors ,'95 and '96. It's different and different weight. Wherefore?


I found two companies who are doing lightweight. It's on the video. Do they right thing?

 

nice work,, much weight saved , also how much strength has been lost?
but practice and experience shows well.

DARN i miss my machine shop,(retired 12 years).

 

I was advised by a very experienced engine builder not to completely remove the pad on the bottom of the rod.

Just remove the bottom bit of the pad see pic