Hi All
i am looking to work out the differences between the AJ26 and AJ28...

i have an N-A 4.0 V8 from an S-type that i am planning to strip, rebuild and add an XKR Supercharger...

i have test fitted the supercharger, and everything seems to fit perfectly...

i am binning the old dodgy water pump and going to an electric Davis-Craig EWP150 with controller.

i am also binning off the power steering, and AC. the Engine is going into my Lotus Excel, target is 450bhp with 900kgs dry weight.

any advice on places to buy stuff, and what the differences are in engines between the NA and supercharged and AJ26/AJ28 are appreciated.

i understand my AJ28 4.0 has variable valve timing which the supercharger cars didnt, so i would like to bin that off as well... i assume its just a cam change?
















also any jag parts suppliers near surrey/hants/west sussex borders? and what do i need other than removing the cats, and upgrading the pulleys to get to 450-500bhp?

i will be using an emerald ECU in wasted spark config for engine management.

having an adapter made to take a supra clutch onto the jag flywheel, and mate it to my Toyota W58 gearbox thats already in the car.

Many thanks!
Oz

 

Hi, hope you are getting on with the project ok, as far as I am aware the major differences between the two engines are,
1.lower compression heavy duty pistons
2. water pump
3.different fuelling manifolds (SC different injectors)
4. cam wheels, correct SC does not have VT but should still run with it as SC makes up difference to intake charge to give same effect.
I hope you can get the engine management sorted as the original is a bit of a nightmare with all them sensors etc, same as binning the cats good idea but play havoc with fueling
hope this little bit helps and hope you get it sorted.
regards
rrosscoe

 

The 4.2L SC did get VVT on the 2006-2008 STR's.

I would use the more modern blower off an STR. It's a Gen V Eaton M112 and that currently is the most efficient M112 out there.
.
.
.