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Going from the 2.88 to a 3.31 diff has been one of the most satisfying and effective changes I've made.
I had an XJR as a daily driver for years. Great car in many respects. And fast! But not particularly easy to own at times. I used to call it "The Tormentor".
I've always been interested in power/performance but budget and practicality plays more of a role as the years go by. If I want more power than a few simple mods can deliver I'd be really tempted to simply go out and buya car that has the level of power/performance I want. But that's just me
Cheers
DD
How do you determine your ratio without taking the diff apart?
How do you determine your ratio without taking the diff apart?
If you're wondering about your '89 XJS, it'll have the 2.88 ratio. The 2.88 became standard issue when the HE engine was introduced and, as far as I know, all were built with that ratio.
Prior to the HE, 3.07 and 3.31 were most common, depending on market. Back then you could special order different ratios but I doubt that it was done very often.
still working through the ECU process .... Have contacted AJ6 engineering.
Also came across these fellas .....www.atpelectronics.co.uk ... offering remanfactured ECU's for what seems to be a reasonable price, has anyone had any experience with these fellas or their products.....?
They are in the UK, but skinny in the USA, due to different comp ratio engines.
OK ... still working through the ECU bsiness ... Covid has slowed things down alot ... my question is the My 84 V12 with the 6CU does not have Oxygen Sensors ... do i need them to run the replacement 16CU - ECU's or will the 16CU run OK without them ... The Mistress is a 1984 V12 English Delivered - unmolested.
OK ... still working through the ECU bsiness ... Covid has slowed things down alot ... my question is the My 84 V12 with the 6CU does not have Oxygen Sensors ... do i need them to run the replacement 16CU - ECU's or will the 16CU run OK without them ... The Mistress is a 1984 V12 English Delivered - unmolested.
OK ... still working through the ECU bsiness ... Covid has slowed things down alot ... my question is the My 84 V12 with the 6CU does not have Oxygen Sensors ... do i need them to run the replacement 16CU - ECU's or will the 16CU run OK without them ... The Mistress is a 1984 V12 English Delivered - unmolested.
regards
Darren
No just fit the 16 CU and it will be fine, but it must come from a Lucas ignition car.
Mate fitted a Wolf thingy to his 1988 S3 V12, WITH cats etc.
Mine was a 1985 HE NO Cats etc.
Drove t his house, unplugged my 6CU, plugged his old 16CU and drove home, it was less than 1/2 beer.
Look at your multi pin plug, there are gaps in the plug, found them, good, these gaps are used for various markets that require emissions etc etc, so my thinking, this was 1995, so NO Forums etc to ask, was if there are no wires feeding stuff in, the ECU has no info to process, so just does its basic task.
That ECU is still in that car, and doing what it does, and NO, I did not get the number off the tag, all that info came to my attention much later, but since it was running, and running well, why re-invent the wheel.
HOWEVER
You cannot go the other way. Meaning, if the car has Cats etc, a Cats etc ECU MUST be used.
Last edited by Grant Francis; Jul 2, 2020 at 07:04 AM.
Reason: CRAFT moment
.... AJ6 have a back log of work and want my 6CU to enhance .... i am looking for a 16CU as and interum as is will take a few months at least for the turn around with AJ6... can not get one in Oz unless someone has one in a box under the bench ... alternatively a 6CU to send over .... this is all adding to the delay....!
Mate fitted a Wolf thingy to his 1988 S3 V12, WITH cats etc.
Mine was a 1985 HE NO Cats etc.
Drove t his house, unplugged my 6CU, plugged his old 16CU and drove home, it was less than 1/2 beer.
Look at your multi pin plug, there are gaps in the plug, found them, good, these gaps are used for various markets that require emissions etc etc, so my thinking, this was 1995, so NO Forums etc to ask, was if there are no wires feeding stuff in, the ECU has no info to process, so just does its basic task.
That ECU is still in that car, and doing what it does, and NO, I did not get the number off the tag, all that info came to my attention much later, but since it was running, and running well, why re-invent the wheel.
HOWEVER
You cannot go the other way. Meaning, if the car has Cats etc, a Cats etc ECU MUST be used.
Ahh, so thats the way it goes round, ive been reading up on this and was wondering why a few people had issues with swaps that should have worked. l almost brought a non cat/hi comp ECU for my 82 thinking it would be some easy power, that was a lucky escape.
i went down the path of souring a second hand ecu from just XJS in the UK and getting it shipped across to Roger B at AJ6 engineering.... who was working through a back log of work due to corvid and every one wanting to do their thing while at home sitting through covid ....Roger passed his wand over the ecu and it arrived here in Oz late last year ... and i fitted it early Jan this year .... and yes it was worth the wait .... car runs so much better and so much more responsive..... thanks to all for advice and input.
Throttle bodies will be done in due coarse ... have a few other issues i need to work through first which i will start a separate post ...>!
