WELL this seems like its gonna be another talk show, with little getting done?

 

If you’ve driven both you wouldn’t ask but the Borg Warner was designed for 1950’s cars and efficiency lost to smoothness.
The GM turbo 400 was used in Trucks, Ambulances, and heavy cars so lock up was quicker and power loss was only about 2% compared to the BorgWarners 4%+
Now to be fair, late in 1977 the switch was made but those likely weren’t sold until 1978 and a 2% more efficient transmission really wasn’t earth shattering.
Combined with the other changes though ( and the ending of the fuel embargo ) Suddenly Jaguar had something positive they could market.
Add the wood trim and more classically styled gauges and sales took off. From around a 1,000 units a year to nearly double that.
They could claim efficiency gains because most buyers of Jaguar V12’s were rich older men showing off their success. Not young racers. An extra 50+ miles per tankful was notable.

What wasn’t advertised was Group 44 and Walkinshaw Racing were both using the earlier flat head style to win those races. We can discuss the shallow dome that Lister used much later as to whether that was a modification to the early head or the recessed valve HE head. I’ve only briefly seen one picture and don’t remember if both valves were even or not.

The very first fuel injection system (1975-) based on the Bosch system had an adjustment in the ECU from rich to lean. With fuel prices suddenly shooting up, a fair number of mechanics tried to do their owners a favor and lean out the engine to get better fuel mileage. The problem was it was possible to go too lean. Overheating and dropped valves occurred.
Later leaves and debris blocked air flowing through the A/C and radiator. Achieving the same results. That and it was all too easy to pop the radiator cap off and think the system was full not knowing that’s not how to check.
Finally with enough time passing the lack of proper lubrication in the distributor ( like the owners manual tells you ) froze up the advance in the distributor. The result was more overheating.

So Jaguar got a poor reputation in spite of a fantastic well designed engine. A little knowledge did the rest. Everybody knew a Chevy 350 V8 made 350 horsepower and more while the Jaguar made 262 horsepower. DIN net whatever that was, but it was less than 350.
what they didn’t realize was the difference between SAE net and advertised or Gross horsepower

Suddenly Corvette has 160 horsepower while Jaguar still had 262.
In fact the Chevy SS pickup with the 454 had 235 horsepower. And Jaguar had 262 horsepower. out of a little 326 cu in engine?

 

Honestly it's because not much is known. Right? Some sacrifices will have to be made, like blowing up some poor v12's but hopefully not damaging anything beyond repair. Honestly, with today's tuning ability and new turbo tech, I think 15 psi going into a 6 liter will put it at at least 700hp, that's only IF the May chamber doesn't poop itself when it sees higher pressures! Plans are two gt2871 turbos down below by the cats under the car, have a oil scavenge pump for the drains, and definitely internal gates. For tuning I'm also trying to retain a/c, cruise, and such so I'm trying to keep stock ecu in. And because of that, my known options are some sort of piggyback, or eeprom writing the ECU I have and somehow modifying the code, which is going to be extremely challenging and I will have to find a way to convert the code in the eeprom into tables or maps that I can read and make changes to. Also, it's going to need a gm 3 bar map sensor, and bigger injectors. Anyone have suggestions on piggybacks or tuning the stock ecu? Roger bywater says I'm on my own.

This thread is dead as far as the original topic, since it seems no one has put boost into a HE motor.

 

Boost into a HE motor is not going to work for several reasons
The big one is the Lucas system isn’t easily tuneable.
You can’t just plug your laptop in. Down load a turbo friendly program and fine tune it with a few key strokes. Most HE engines are analog not digital.

Second even self learning ECU’s (Like Megasquirt ) will need a lot of work to get analog Sensors to work digitally. Plus there is no knock sensor on a V12 and that’s not something. Easily added. Can’t just glue one on in a easily accessible place and expect it to work well

Third The reason the HE gets better fuel mileage is because it’s leaned out at part throttle. Just the opposite of what you want when you add boost.

Fourth the high compression is dealt with by a retarded ignition which is near the systems limits and incapable of dealing with even moderate boost.

Fifth you cannot use HE pistons with early flatheads,

Sixth any turbo charged engine will need ring gaps opened up. Typically double the stock end gaps. So no matter what you are going to have to go into the engine.

Having said that if you are willing to rebuild the engine and mix and match components it can be done.

 

I am well aware of all of this. I will come back tomorrow with a massive epiphany I just had lmao.
Found this https://www.motorsportselectronics.com/products/link-knocklink-g4-digital-warning?variant=17037690500

 

Having said all that I built a twin turbo V12 that is still running around here.
This was for Chump car racing. Endurance racing of $500 cars. I used an early (1975)XJS I bought in non running condition added a pair of used Saab (T2 size) under the front fenders but out of the engine compartment.

I kludged it into working. With an $85 FMU I bought used. As the engine built boost it fooled the computer ( not a real computer), the early units were analog and basically used 3 VW Rabbit modules to fuel the injectors. Luckily the earliest injectors were the biggest and the ECM had an adjustment on it that went from rich to lean. By starting out on the rich side I was able to very crudely keep the fuel mixture close to correct. The final “trick” was once the boost exceeded 4 psi the cold start injector came on and added sufficient fuel to get it around 6 PSI.

The stock spark plugs would have been quickly flooded running on full rich except Champion was making Gold palladium plugs for another application and I bought a couple of sets. Gold Palladium can handle rich without fouling as easily and since under full boost that kludged system went from rich to lean on 2 separate spots in the rev curve I was able to get away with it.

My final good deal to keep the cost under $500 was the acquisition of an Rusty smashed up XKE series 3 with the 4 speed transmission. I sold enough parts off that to bring my cost down $100 and then swapped the Borg Warner stuff for the 4 speed. In my opinion the 4 speed improved the XJS more than the twin turbo’s did.

My computer tells me I was somewhere slightly over 450 horsepower. But to be fair I had used a set of 9.0-1 pistons, had ported my intake ports and was using a pair of Isky XM3 camshafts I had laying around. ( the later items I hadn’t listed on the build sheet I was preparing.

Driving it around while I was sorting it a Series 3 XKE still was faster off the line. I never got it much past 50 since I didn’t want police attention.

conversation with the chump car tech inspectors after completion at the time though convinced me I would either be assigned too many penalty laps or simply not allowed to run. Most of the entrants were small Honda’s Toyota’s Saab’s VW’s & BMW’s. In addition the mandatory 5 minute stop for refueling would put me over two laps behind at least twice as often as the smaller more fuel efficient cars.

I sold it at a car event for a modest profit and every few years it shows up again. I should get a picture of it though he still hasn’t painted it or recivilized it since buying it. It’s still a crude junky old car that unless you look under the front fenders looks near stock.

 

So I had an epiphany when talking to Paul Kobres on Facebook on why the he motor doesn't yeild results like other motors when psi is added. Double hp with 15psi applies to cars that have 9:1. Not 11:1, to make a accurate prediction, you must find out what the he motor makes on 9:1, then double that number. A 11:1 6 liter opened up makes 370hp. On 9:1 it makes 329hp. Double 329 and that's 660, which is extremely close and makes sense to the twin supercharged Lister he car with 10 psi making 604hp with no intercoolers. So in order to make big power with an he, it would take some seriously sharp tuning and in order to see big numbers it would take e85 or a higher octane. I'll say it again, it would take some very sharp tuning and some high pressures to make power to compete. So there really isn't anything keeping a he from being boosted, you just have to realize don't expect gains to be huge over the n/a numbers without a higher octane or some more cams and a bit of port work.

 

some added info,, i lived in Daytona bch for 30yrs, and seen many assorted Jag V12 race in the 24hr, most NEVER finished because of OVERHEATING!
90% of those went down because of head gasket sealing, coolant loss!
some had big money backing direct from JAGUAR!

 

also TWR , oil cooling was a big problem! the JAG V12 was NEVER desgned as a hi performance engine , it was a VERY smooth quiet engine!

 

Want to share the rest of the book? I'd love to read more, most motors at that power level can't handle what serious racing will throw at it. Even boosted street motors don't see abuse like that. But extremely valid point on the v12's lacking ability to make power.

 

I have tried to find the info with no success. There was a car featured in Jaguar World magazine where a computer software company owner bought a Lister 7 Liter engine that had never been used in racing. He went through it, and installed the superchargers from the GM 3.8 liter V6 on each side. Twin injection system due to not being able to have a wide enough range of fuel delivery at WOT and idle. If I remember correctly, the car engine produced over 1600HP. Traction at any speed was severely limited. Seems I read that the man that built it passed of cancer. The car was sold maybe two or three years ago for around 23K at auction. As much as 300K invested. Anyone?

 

Only inconsistency I see is 1 of those 3.8 superchargers will never even come close to supplying 800hp of air. They barely do 300hp.

 

By Allan Scott, TWR's engine guru. The best thing you could possibly read before getting into the hardware.

 

Nitrous is the best bang for the buck, by the way, by far. And the HE can take it. Clarkson and the Top Gear team took and old HE, nitroused it, and it blew away everything.

 

Nitrous is by far harsher than a turbo, so that's very promising.

 

I have no idea how long an HE engine will last though under nitrous! But it does work wonderfully - for a while at least. the clip:

And these are the guys who did it.
https://www.noswizard.com/

 

Ron, with due respect the V12’s design and origins were all for racing.
The origins of the V12 go back to 1954 when work was started on sketches for a V12 .for LeMans. The whole idea was shelved until the early 1960’s with the success of the XKE.
The Jaguar factory wanted to go back to LeMans and The XJ 13 was designed using “basically” a pair of heads off the Six cylinder. ( yes I’m aware of all of the difference)
That was designed and built as a Racing motor.

When cancelled work was started on enlarging the V12 in order to be competitive with Detroit’s big V8’s. Since it so easily goes out to 7 liters+ you know they were after the Cadillac market.
After Jaguar bought Coventry Climax one of the engineers they got in the deal was very familiar with the Heron head design which is what they wound up going with. At the Time heron headed race cars were very successful.
That head was much lighter and far more compact, not to mention easier and cheaper to manufacture. In addition up to 5000 RPM it made more torque and horsepower then the quad cam engine did.

 

simply said ,there is nothing in the 5.3L Jag V12 engine related to the early V12 4 cam race engine, starting with cylinder block!
5.3 are aluminum and deep skirt with 4 bolt clamping.
the early block was cast iron, and not skirted!
plus numerous differences !

 

gotta remember JAGUAR spent over a million money with TWR !
are you prepared for that!
they spent close to that with Grp 44 also!

 

There is a world of difference between a factory sponsored development of a complete racing team to compete globally with the most developed and serious racing teams and someone who just wants to go out and have a little fun.

Recently a $ 600. Craigslist of a 1976 Jaguar XJS popped up. An excellent candidate to turn into a tribute race car or just a weekend Vintage track car. With prudent shopping and careful workmanship you could be on the racetrack for around $5000. With a horsepower to weight ratio of better than 10-1 That’s enough to have some great fun.

My own XJS V12 was a $500 Facebook listing. A Southern California rust free example that ran when stored away. While the $150 example I bought in the early 90’s probably can’t be found anymore, there is no doubt there are plenty of low cost candidates available still.


For those wanting silly horsepower out of a street driven car that could be up to 45 years old you had better plan on spending silly money.