Fellas, just bought from eBay a set of Getrag 290 gearbox off an XJR X300, and am planning to start my project to convert a reasonably decent 1995 XJR 4.0 X300 Supercharged in Hong Kong. I asked the seller about the ECU but he said I can reuse my own. I searched the Internet and found some previous comments recommending the need for a manual ECU or remapping an auto ECU to ensure a clean swap. Is replacement or remapping better? Thank you.

 

Well, I believe Andrew would be an expert here, but I remember him saying though that the best would be to actually swap ECU.

 

Thanks. Am quite excited about the project and look forward to learning more about this.

 

And we're hoping for lots of pictures from the conversion!

 

erh, yes. But this is still very early stage. Will formally adopt the XJR tomorrow. Manual gear box still with eBayer awaiting measurements and weight info to help with packaging and shipping (he says collect only) so this would be tricky as I am on the other side of the planet, but I imagine that this is not insurmountable. I then heard about the ECU issue (remapping or finding a manual ECU). Do I have to bother with the differential as well? I hope the speedometer does not need fiddling after the gearbox conversion. I don't have the skill to DIY so would have to look for professional help locally. I imagine parts sourcing will take two to three months.

 

XJR 4.0 X300 Supercharged? Please explain what you plan to do to pull this off and what you will be using. I'm not being a naysayer at all. I'd love to squeeze more power into my x300

 

Car is in pretty good shape. I was just thinking of a simple swap of the auto with the factory original 5-speed manual gearbox, possibly including an ECU off a manual XJR. May need to upgrade the brakes as well at a later date. Tested the car the other day and seems like the rear shocks also need attention. Finding the right parts is my primary concern at the moment. Can't DIY so have to find a local Jaguar mechanic.

 

Hi Qvhk i converted my 1997 XJR 300. just over a year ago to manual as there is only one original one here in NewZealand' not a large population here; more sheep than people. I am still using the same ECU from auto to manual;just occasionaly at lights or stop signs it cuts out but always restarts straight away. from what i have researched the part number from both are the same but the manual is mapped a bit different. XJRENGINEER may help with that. You say your thinking of a simple swap there will be other small issues ' could be quite costley to pay some one else to do it.Iam fortunate in doing my one as i run a Jaguar spares and repares here in N/Z.Willing to help you thru it if you have any problems.but well worth the effort makes an awsome car to drive. Good luck cheers Ray down under.

 

Thanks, Ray. Would be nice to have you as a guide to my project. I anticipate that the ECU will have to be tackled. I am still negotiating with the seller to see if he too has a manual ECU to go with the lot. Otherwise, remapping would be the way to go.

 

Gentlemen, I commend you on your endeavor. Qvhk, I am keeping an eye on your progress as this is something I may very well decide to undertake in the future. I have a X308 XJR now that I am selling. I have always been partial to inline 6 Supercharged but would need something to make up for the fun factor.

 

Hi Qvhk if you a purchasing the gearbox from an actual xjr which there were not to many made' it should be fairly straight forward.You will also need the engine backing plate between rear of engine and gearbox bellhousing ' as this gives you the right amount of clutch travel.Ifound this out because i used a standard plate from a auto 3.2 which i modified. the plate on the XJR Auto is complety different. I never had a manual car for breaking up so most parts were made in workshop. You will also need a pedal box and if you have cruise control yu need the cut of switches on clutch and brake pedals.Also the correct drive shaft would help. The diff ratio is the same for auto and manual both being 3.27 to one' allthough i will be changing mine fairly soon to a 3.58 power lok . the brakes should be okay just use agood quality pad. The wireing in the console wherethe liniear switch for starting with auto wil need sorting as well plus reverse light wire to manual box . My conversion took 4 weeks as i did it of and on and i like a challenge
Cheers Ray

 

HI Qvhk,
In one of your earlier posts you expressed some concern over the vehicle speed input forllowing your auto to manual conversion. The signal is generated from the ABS wheel sensors, so it is indenpendent of gearbox type, ratios or final drive ratio. It is only dependent on wheel diameter.

 

Thanks, Ray and Andy. I have bought the XJR but have yet to find a local Jaguar specialist to conduct a full body check-up before proceeding with the project. Nonetheless, I have seen evidence that this rare find was maintained at the dealer for the past 17 years, and only left idle for nearly a year just now. I shall have a better picture in a few days.

 

Funny thing, on my way home I was wondering if this has been done before and this was the first thread. I am looking to get back into a Jag namely a x300 R, and this is what would sway me.

 

I know of at least half a dozen DIY auto to manual conversions on the XJR6.

 

Qvhk,
Whoever does your conversion will need access to Jaguar WDS, Jaguar IDS, our a good aftermarket diagnostic tool like Autologic, to perform an idle throttle voltage adaption and lambda sensor orientation test on any reporgrammed ECU that I send you for your car after the conversion.

 

Thank you. I have yet to hear from the eBayer on collection of the gearbox - this is a bit odd, it being more than a week after I have paid for the item.

At this time, I am planning what other parts I should find to go with the conversion, but what about other usual maintenance stuff? I already knew engine idling speed is high (O2 sensor?), the rear bounds abnormal (rear shocks?) and there is metal sound after firing up the engine (starter spring not retracted fully?). Other routine stuff would be lower arm bushes, ball joints, etc. as car has to go through MOT before putting back on the road. Engine bay is reasonably clean and dry, despite its age. Would like to know where best to source parts? I would imagine parts for a 1995 XJR6 especially the 4.0 supercharged model would be relatively hard to find, but certainly UK is the place to start looking, it being the country of origin?

Incidentally, during my Internet search, I found a "Jaguar Genuine New Cylinder Head Assembly with valves and camshafts for XJR6 X300 4.0 Supercharged" in factory original wood crate in eBay, listed for US$850 and inviting offers. I imagine cylinder heads are normally trouble free so this one would only be a nice-to-have item mainly for perfectionist trying to beautify the engine appearance.

 

What is the estimated cost for doing such a conversion? Will you be able to do a cost break down as you go?

Many thanks in advance,

Jeff

 

Of course, since these were offered in the UK. BTW, how much would such a conversion run in the UK? I have yet to see a manual X300 in California. Still think this is a great conversion for the XJR6.

 

All but one of the conversions of which I know were performed by the owners themselves, and I have no idea how many man hours it took. Your would have to ask a good Jaguar independent garage how much time and therefore labout costs were involved. If you lived in the UK it would be possible to source all the second hand driveline parts from a nautrally aspirated manual X300. At a guess , I would estimate £500 for the flywheel, clutch, clutch cover, grearbox, propshaft and peddle box. There is an extra brace on the rear suspension of manual XJR6 cars, but the coversion would work without it. Unfortunately, no manual X300s were sold in the US, so you would have to source and import all the parts from the Europe.