Doug,

I dont remember doing a PDF, so I reckon there is nothing missed, coffee maybe.

I had arrive via doubtful means, a pair of XJ40 throttle discs and shafts.

The sizes from 5.3 to the '40 discs, I FORGOT, but the machining came SO close to breakthrough of the mounting holes, that was big enough for me.

Great care for machining, so I found someone that actually knew what I wanted, and could use a lathe properly.

When fitted, you will need to "panel beat" the air filter element flame shield, OR, when you hit WOT, the discs will contact that shield, and you will be stuck at WOT, NOT FUN.
I made my own foam elements., waaaaay back, and did away with that flame shield, never had a flame on a HE, that was only on the PreHE engines.

If you still run the AAV, I reckon 0.015" -0,002" gap will be fine. I dont have an AAV or any other stuff like that, so I used the throttle stops to "balance" the 2 sides, just like the carby days, rubber hose shoved in the ear and LISTEN.

It did wake up that V12, and more so at the 1/2 throttle and up.
It was part of the whole refurb, discs, AAV, Balance pipe removal, PCV removal, advance curve change in the dizzy (I used a PreHE base), cold start infectors gone, rewiring the engine bay, XJ40 TPS, over run valve removal, 16CU ECU, and now I forget, OOPS.

 

Not sure on that one, but if it was possible, the TPS would be ON the throttle body front side, as became a thread here a while back, I
doubt they would be "bolt on" as we understand that phrase.

 

Ok, so the heart of the matter is XJ40 throttle discs. Not throttle bodies. Right?

4.0 litre XJ40 I presume?

Cheers
DD

 

YES Doug, and the shafts if they are there. I got the shafts and TPS, etc all in one grab. XJ40 in wrecking yards here back then were more plentiful than today. Nobody loved a '40.

The existing 5.3 shafts are OK, but the slots may need extending a small amount. The XJ40 shafts just needed the 5.3 arm thingy attached, direct fit, no messing with anything else.

As far as I remember the 3.6/3.2/4.0ltr, all had the same diameter discs.

 

as i remember my TB plates are 75MM dia, and with just a small amount of throttle open a big kick on response!
more air quicker makes better response,.
i,m not quite sure that TWR made a more power with smaller port runners, it dont fit normal engine modifications?
i had my 5.3 runners and plenums EXTRUDE HONED, they measure about 1/8" larger all the way thru, much smoother and humps and bumps gone!
as i was doing the lathe work i also bellmouth the TB entrance shape!
im from the school of (never can get to much air)!
many of my mods probably would NOT be effective if not for the Standalone EFI system, adjustability AF ratios!
ron

 

Not more power, more torque below 5000 rpm. That is what produces a faster 0-60 time. AJ6 Engineering used to make a set of cams that did a similar thing, the peak HP number was lower, but the midrange torque was higher, so in everyday driving that made the car faster, even if the headline HP number was lower.

 

I think that's the design intent of AJ6 Engineering's "Superenhanced ECU". Not more total horsepower. But, more power in the range where it's useful.

Cheers
DD

 

just showin off.
the best way to increase low end torque at the tires(where its needed) is lower the gear ratio, also get rid of that OLD 400 trans!
you have to remember TWR was not interested in low end acceleration , he rarely was below 4000/5000 revs anyway!
this an old pic , but from a rest just hit the throttle 275 tires lite up!
3.73 rear posi, and 700R4 1st gear, now thats how to apply tire torque!
so it runs outta top end around 150MPH!
i can live with it!

 

some of the challengers use the inner of the quad headlights as an intake with a signal marker around it I think. This was the thread, but didn't develop into much.

https://www.jaguarforums.com/forum/x...signal-235677/

 

For the race cars, yes. However, they did a project for Jaguar to see how the standard V12 could be enhanced and remain emissions legal. They did a whole series of dyno tests with step by step alterations and plotted them all together. Larger throttle bodies basically made no difference.

 

Got a 1992 V- 12 XJS. When I got it about 10 years ago it would pre-ignite (ping Pink) on premium gas going up a hill.
Figured the problem was the engine was breathing under hood air which was extremely hot. I put 2 pieces of old rubber radiator hose on to the inlet trumpets and put them on top of the radiator and then put foam all the way across the radiator so the engine breathed cold outside air.
I have run it on regular gas ever since and it never pings. The trouble with British cars is they are designed for Britain where it is much colder.
nofking

 

all the mods here says , Forced Induction has the most potential, !
Force feed the bitch and be done with it!
a subject not brought up, theory says , just a simple positive pressure of 15 PSI in the inlet manifold will double HP, all else being same!
so without much else you may only get 75% more power!
better than these silly 3- or 5% more power, cold air ,ram effect ,etc.

 

How?

 

the simple way would be twin turbos remote mounted!
least expensive, i never said cheap, best bang for the buck!
google remote turbos. try STS remote turbo system!
ron