the v12 he was originally ment to run on 14:1 it just is incapable of being ran on anything lower than 87, which is all thats avalible in many parts of the world circa 1980

 

Can anyone confirm that ALL 5.3 cranks are forged, rather than cast?

 

Confirmed all 5.3 cranks are EN16T forged and nitrided. Early 6.0 cranks are EN40 forgings and later 6.0 cranks from engine number 12471 are cast

 

It's not possible to de-shroud the exhaust by much. The lip in the chamber around the exhaust valve is smoothed, and I agree the exhaust port needs to be venturied.

I know a guy here in Aus running 450hp+ on stock 6.0L with only intake, exhaust and aftermarket ECU. He has just had the engine rebuilt so when I catch up with him next week I will quiz him on HP numbers with the new engine.

 

sounds good! and not the shroud, the port behind the valve, look at how tiny the port actually is.

 

How about the stock HE rods and pistons, cast or forged?

 

pistons are cast, rods are the same as pre He

 

so head flows the only thing holding this big cat back? anyone have the specs or cfm ratings on these? I know a few trick too keep this cat running cool to avoid detonation im planning on a oil cooler setup and possibly making a few small air scoops in the fenders with a fan too keep the motor and future turbos in proper operating temp range.along with a bigger radiator and better electric fans.

 

calvin what size rods/pistons can i get for this thing? looking too bring it too a 5.7 possibly new sleeves (magnesium/nickle alloy?) along with nickle alloy bearings they last longer or soo im told.. higher the nickle content the better!

 

You can get to 5.7L on the 5.3 by boring the stock liners - 93.5mm is max bore on stock liners.

Cal can chime in here- I have seen 6.0" chev rods in a Jag V12, chev rods are also lighter than the jag rods.

High nickle bearings would be very hard, could cause wear on the crank????????? I would rather replace bearings than have to regrind a crank. You should almost never have to regrind a Jag V12 crank

 

thanks warrjon ! I will build this engine for 750 people may doubt these engines and possibly my skills but nothing is impossible its all mathematics. keep the oil too the turbo cold and the oil in the engine cool there's alot of your heat right there. bigger radiator and a good inter cooler 750 is easy too reach . but here's another question.. can the car take it without twisting?

 

the reason why those race engines dont last long is there built too be replaced! they spin easy by hand tighter tolerances and a good oil like royal purple race oil. itll run for quite some time the trick is too over build the engine so if im looking for or using 750hp it shoould be built for 1000hp or more.

 

I know a fellow here in Australia that has a twin turbo XJS V12 race car which if my memory serves me correctly made around 500rwhp on the highly developed 6.8LTT before it spun a bearing. It now runs a 5.3L making less power but is far more reliable.

750hp is doable but be prepared to spend a lot of $$$$$ even with FI to get there. He had to reduce the intercooler size as it affected engine cooling.

The stock chassis will take the power unless you use large sticky tyres. And/or are no sensible using said power.

You will have to brace the rear end other wise you WILL rip it from its mounts. the race car has a brace running along the boot floor and running 300 wide slicks the boot floor has ripples in it.

Problem

 

Soo basically its like a foxbody mustang too much power ill rip the rear end out? any picture of this brace? and do i have too make one or can I buy one. Ive already started making an intake for it simular too a 350 tune port but way better flow. Im a fabricator /Jack of all trades master of none . haha there isnt much I cant do everything from cb radios too wind turbines .

 

Correct the rear end is held in by rubber mounts

here a post of a Lister rearend

https://www.jaguarforums.com/forum/x...2-91287/page2/

The stock V12 manifolds flow around 1100cfm each. The manifolds just need cleaning up and inlet trumpets would not hurt. BMW and Merc use longer intake runners in their V12's if you go shorter the bottom end will suffer.

 

shorter is not what I'm after i want too open up the space for the turbo system this picture is a similar idea but it wont go direct it will cross sides so the right bank ports will be on the left kind of deal

 

Have a read of this from someone that has done TT V12

1977 JAGUAR XJS V12 TWIN TURBO Race car - CAMS LOG BOOK - JAGworks

 

On the old Chrysler "cross ram" 413 motor(one of my favorite motors!) they developed phenomenal torque using very long intake runners and twin 4bbls. I was led to believe that the performance gains were primarily from the carbs being further away from the cylinders. With the Jag motor, will the injectors be retained in the stock location? If so then what is the theory behind lengthening the intake runners?

 

Lengthening the runners increases the velocity and the low end torque, there is a tradeoff in that they will not as well at high RPM, especially if made too long. The idea is to have them long enough to make good torque in the low to mid-range.

A lot of race cars locate the injectors at the entry of the intake trumpet. this allows them to have the injector angle correct and provides cooling of the intake and better atomisation. This is not advisable on a road car there is the possibility of a fire if the engine backfires through the intake.

 

Stock injectors may or may not stay. they certainly wont after its built up with a tt system. they will be put as a direct inject style . the theory on the long intake is it builds torque but heres the thing short intakes are for bottom end power long ones are for t main reason ill do this is space unde hood. after a revamp this year with a lister body kit it will be built up Ill flowbench the heads (I built a flowbench) and do some testing.