58.2 MPG!!

[D_Doran]

It's getting it's 60k service the week after I get the LPG conversion done, so I'll get them to change the plugs and new oil.

Mark, you got the tank fitted in the spare wheel well; did you remove the space-saver, and opt for the tyre repair spray?

[mike020150]

It would be interesting to hear what you think of the finished conversion and how the actual costs stack up against the maths you used to decide in favour of the conversion. Mike.

[MarkyM]

Only really worthwhile if you do in excess of 12k miles a year, I've covered just over 17k in 11 months and the conversion has already paid for itself.

You still have to start in unleaded but for the month of May with a brimmed tank I got through £5.80 of unleaded.

Car is used every day and can achieve the following on a full 60l LPG tank:

200 miles urban
330 miles motorway (steady 65-70 MPH average)
Anything in between for mixed driving

60l now costs me £30 (50ppl) when it used to cost £24 when I had it converted last year. I guess it's on parity with the £1.20 for unleaded now.

So had I stuck with unleaded and 400 miles per 75l fill it would have cost me £3,500 (averaging £1.12ppl)

When it's cost me £1500 in LPG at £28 a fill (averaging 46ppl)

No brainer really!

M

[mike020150]

Interesting results for us all to ponder, thanks. Mike.

[D_Doran]

Well the car is now converted, but with a slight problem still needing to be rectified (The Romano system is bringing on a 'Restricted Performance' warning plus the engine management light. I am assured that a module is already on its' way from Italy which will solve the problem). Another problem has reared its' head which could not have been envisaged before!

My aircon isn't running well and needs gassed up... unfortunately, part of the LPG system is blocking access to the gas charge valve for the aircon, so it will need to be moved!

I have taken before and after photos which I will put on the gallery next week when I have more time, but I am very impressed with the filler being hidden from view, so from the outside, you would have no idea it was LPG converted!

[MarkyM]

Absolutely no such problems with my Prinz system and I've had the aircon regassed since I had it done so no access problems to the valve (which is immediately in front of firewall on the drivers side).

Mark

[D_Doran]

I have put pictures before/after on the XK8 gallery if anyone wants to look.

Damian

[MarkyM]

Damian

Nice job, two points

1) I was advised that for safety it wasn't possible to fit the filler within a certain distance of an exhaust pipe. Clearly not true but since mine's central I can pull up either side of the pump.

2) I can see why your aircon recharge would be a problem

Mark

[D_Doran]

Point 1, it was done by an LPGA approved installer (even checked their website before to be sure!), so I would hope they are working to the correct regulations.

Point 2, Yup!!! That is a problem! Can't get the car back to him to reposition for a few days as I am chokka with other commitments at the moment.

Looking forward to having it all finished, and I will report back in a few weeks to let you all know how it is going. My local Jag independent was very impressed when he saw the work (apart from the aircon problem! ), and has taken business cards in case others decide the way forward is gas.

[MarkyM]

So are you having it done in stages or only going back to have the aircon bit moved? Clearly this is his first XK8 conversion as he'd have known how the space was used.

Have you done much driving in it and if so what's your tank fill capacity/economy like?

I took mine back after 1000 miles for them to check the calibration and it has 3yrs 30k miles free warranty/servicing. I assume your getting the same.

Mark

[D_Doran]

It isn't being deliberately done in stages!

It was supposed to be done in 4 days, but initially the wrong ECU/electronics were sent, so tank, filler, electrical wiring up to engine compartment was installed.

The ECU, switch and sequential injectors were then to be installed the following week over a 1 1/2 to 2 day period.

When it came back, the 'Restricted Performance' warning came on, and Romano have sent a module to cure this problem. Have to drive it on petrol as it runs very roughly as though not firing on all cylinders with that warning.

Coincidentally, my aircon wasn't running well, and it was only when my independent was going to charge the system that the filler was found to be obstructed!


This is only his second XK8 (previous one was about 2 years ago, and also came up against the performance problem which he had forgotten about, or would have had the module already ordered.) My warranty is only 2 years unlimited mileage by the way.

Damian

[D_Doran]

Finally got round to giving the car back to finish the job!... Came back today running sweet as a nut, no performance problems, reducer moved to opposite side of engine bay, and air-con access back to normal!

Not working for next 3 weeks, so won't be able to validate the fuel savings for a while, but will keep very close record of outgoings and let you all know.

(PS Mark at Go-Gas has just done an XKR and they are more awkward, requiring a second reducer due to the higher BHP, and the stainless steel ducting is harder to work with than the normally aspirated, but still workable)

[MarkyM]

Well done!!

Depends how it's driven but you should easily see 300 miles on a full tank of M'way driving.

Would interested in knowing what your emissions test was before and after (they should have done this) so we can compare...I'll dig out mine in the meantime and post on here.

Regards

Mark

[binghama]

Hi Mark ..spoke to you before about air filters and I fitted an Apexi like yours..ran it for a few momths but not convinced there is much impronement...was a bit doubious about not gettin cool fresh air..about amonth ago i opened the bonnet ,after a run, on ahot dat and the under bonnet temp seriously hot I couldnt put my hand on the filter and of course it was drawing air directly from behind the radiator! I have put the origional back until I can get a source of cool air. I am wondering would vents in the bonnet as per the XKR be the ans. a scoop on the bonnet would but would spoil the looks even considered taking out the R H fog lamp but i dont know if i could duct it from ther...any thoughts

[mike020150]

With fuel at £1.20 a litre, It's worth remembering that cold air gives more power but hot air is better for fuel economy. On top of that, the length of the air intake affects cylinder filling (torque) by using the natural harmonics of the inlet system available at particular engine speeds. So, moving away from standard may increase maximum power but it may also reduce torque lower down the rev range where it's actually more useful for real world motoring. In the XK8 with its very high gearing, the gearbox is set up to make the most of the engine's torque curve. Hence, ideally, the box should be remapped to make the most of any alterations to the torque curve. In short, the standard system probably isn't such a bad compromise for most on-road situations. Check out AJ6 Engineering for a good explanation (www.jagweb.com/). Mike.