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LPG cayenne 4.5 V8

moss

Well-known member
Joined
15 Jun 2010
Messages
632
just purchased my 3rd cayenne, its one of those cars that you can't stay away from once you've owned one, in my opinion ! in the past I've lpg converted them, this once was done :) great addition, with returns 28-32mpg you can't fault it ! anyone else got a LPG converted cayenne ?
 
Had mine converted a month or so ago, using the AC Stag system petrol can be simultaneously injected at 10-20% to negate valve seat recession. The amount of valve saver fluid you would need to inject may foul the sensors and/or cat. The system also has a monitoring Bluetooth dongle and app for Android phones so you can keep an eye on fuel trims etc, which coincidentally led me to replace my MAFs. Equivalent mpg which depends on unleaded costs and was working out at about 27 around town and 35 on a run, factoring in 10% unleaded use also.

I originally complained about low mpg which was diagnosed as incorrect injector rating, once changed it's much better. Which injectors did they fit?
 
moss said:
just purchased my 3rd cayenne, its one of those cars that you can't stay away from once you've owned one, in my opinion ! in the past I've lpg converted them, this once was done :) great addition, with returns 28-32mpg you can't fault it ! anyone else got a LPG converted cayenne ?

How on earth do you get 30+mpg out of it? I have to try hard to squeeze that out of my diesel RR, I thought LPG conversions were less fuel efficient than petrol. With that kind of economy how many miles do you need to do to get a return on the conversion with petrol being relatively cheap?

MC
 
At 12k a year about 18 months payback, assuming that when you sell the vehicle people won't pay a little extra for the kit.

The car will slurp about 20% more LPG than petrol but the price of LPG is about 50% less, as a rule of thumb.

52 litres of LPG @ 55ppl, plus 10% petrol will yield 150 'normal' driving or 200 motorway. I'm not sure how that equates to diesel.
 
That makes more sense, so about 17mpg. That is what I used to get out of my 4.2 petrol RR. That is why I changed to the diesel.

MC
 
Looking at the figures the drop in diesel effects the equivalent lpg mpg, I'll feel better when diesel goes back up again :D

52l x 55p = £28.6 in lpg
5.2l x 1.10 = £5.72 in petrol

£28.60 + £5.72 / (£1.08 x 4.54) = 7 gals equivalent diesel used

150 / 7 = 21.5 mpg normal or 200 / 7 = 28.5 mpg mway

Out of interest what does the RR do?
 
basadan said:
Had mine converted a month or so ago, using the AC Stag system petrol can be simultaneously injected at 10-20% to negate valve seat recession. The amount of valve saver fluid you would need to inject may foul the sensors and/or cat. The system also has a monitoring Bluetooth dongle and app for Android phones so you can keep an eye on fuel trims etc, which coincidentally led me to replace my MAFs. Equivalent mpg which depends on unleaded costs and was working out at about 27 around town and 35 on a run, factoring in 10% unleaded use also.

I originally complained about low mpg which was diagnosed as incorrect injector rating, once changed it's much better. Which injectors did they fit?


I am currently looking into doing a LPG conversion on mine,
Who did yours, can you recommend them ? And how much did it cost,
I have heard that the TT struggle so to run on LPG any problems with yours ?
What size tank did you go for ?
 
I always tell people in money it does XXXmpg, ie it cost XXX£ to do YYY miles, my 4.4 Range Rover does about 26-30 mpg round town and over 35 on a run in money.
 
I take it you're running LPG for a 4.4 to be getting that type of mpg, I wouldn't do the sums at the moment though with diesel so 'cheap'!
 
basadan said:
Looking at the figures the drop in diesel effects the equivalent lpg mpg, I'll feel better when diesel goes back up again :D

52l x 55p = £28.6 in lpg
5.2l x 1.10 = £5.72 in petrol

£28.60 + £5.72 / (£1.08 x 4.54) = 7 gals equivalent diesel used

150 / 7 = 21.5 mpg normal or 200 / 7 = 28.5 mpg mway

Out of interest what does the RR do?

I can get 30mpg out of mine. It is a 2007 TDV8. 3.6l diesel, about 285hp. Used for carrying and long family trips.

MC
 
basadan said:
I take it you're running LPG for a 4.4 to be getting that type of mpg, I wouldn't do the sums at the moment though with diesel so 'cheap'!

Yes LPG dude, would not own if it was on petrol.
 
FYI out of my gen1 KN turbo, I got 19.9 mpg over 60k driving - no LPG conversion
And I don't have a light right foot....
I was impressed
 
Can any one recommend a good installer for LPG on a cayenne TT :?:
 
You're best looking for one in your area through
http://www.uklpg.org/
I can recommend the AC Stag kit which adds a squirt of petrol with the LPG.
 
Looking around for one the wife's next car.
 

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