Page 1 of 2

Cayenne Turbo awaiting LPG

Posted: Fri Apr 18, 2008 6:51 pm
by drocter
Hi Folks

Some weeks ago I was all set to buy a BMW 645ci and have it converted to LPG. I had a very helpful discussion with Alternatech on your advice.
i sold my previous car and as I was driving back from the valeters, I spotted a Black Cayenne Turbo for sale very reasonably at a local franchise. It was too good to be true so half an hour later the deal was done and Ive had the Cayenne for a week now.

On Alternatechs recommendation, I spoke to Dougie of Martin Motors in Glasgow, my local Prins approved installer - I'm 'penciled in' for 2nd June.

Dougie has converted a few Cayennes before, but never a Turbo. Much Googling has revealed that there are a couple flying around with the Prins kit in Europe. Are you aware of any in the UK?

I drove JE Engineering's Range Rover Sport Supercharged that has been modded to 440bhp and converted to LPG. I was impressed.

The Cayenne Turbo is a 4511cc V8 Twin-Turbo running 450bhp stock. Does anyone here have experience of an LPG'd Cayenne/Cayenne Turbo? I'm told it will take only a 55 litre donut tank in the spare wheel well, any chance of adding a modified floor to accomodate larger donut tank eg 100 litre

Anybody used Martin Motors?

I have read recent posts on ECU remapping and a remapped Cayenne is claimed to achieve 510-530 bhp!!! Should I bother with this or is it likely to put too much demand on the Prins kit? If I do go for a remap which should come first the LPG or the ECU?

Sorry for the exhaustive post, but I'm new to this LPG game and really dont want to mess the Cayenne up with an unreliable conversion.

Thanks in advance

Re: Cayenne Turbo awaiting LPG

Posted: Sat Apr 19, 2008 11:20 pm
by mak-uk
Hi and welcome back..

Some change from a 645Ci to a Cayenne Turbo!!

With any high-powered conversion, what is of importance is the injector rating - i.e. how much BHP each injector can deliver and if it can deliver it quick enough.

The following are the most common injectors that Prins provide along with their ratings:

Prins Code Definition
080/31032 Injector 32cc green
080/31042 Injector 42cc white
080/31052 Injector 52cc blue
080/31063 Injector 63cc orange
080/31073 Injector 73cc yellow

To give you an idea, I have the yellow injectors on my 286-300 BHP 4.4 litre V8.

I have also heard that there are 'brown' (or grey?) injectors which are 100cc but a Prins installer or alternatech should be able to confirm that.

It depends on how many cylinders you have - divide the total BHP by the number of cylinders and you have your BHP per cylinder. Then convert the LPG injector cc to BHP using an online convertor and see if it can provide enough BHP.

In regards to a re-map, it's always best to get it done BEFORE conversion so the LPG system can be mapped to follow the altered petrol map. In this case, however, it will depend on whether the LPG equipment can cope with that amount of BHP.

Such a high powered conversion will always push boundaries for any LPG system and ultimately you will be a 'guinea pig' of sorts as not many (if any?) of these will have been done. It is vital you have a competent and enthusiastic installer in case problems arise and possibly, an alternative method of transport in the meantime.

Good luck and keep us posted!

Re: Cayenne Turbo awaiting LPG

Posted: Thu Nov 27, 2008 10:10 pm
by r9 turbo
Hi , Dont know if you have had the cayenne LPG yet but just to let you know I have a cayenne turbo converted to LPG with no probs at all. I have raised the rear floor by 2" (its easy) and have a 66ltr tank.

Re: Cayenne Turbo awaiting LPG

Posted: Mon Dec 01, 2008 4:40 pm
by mak-uk
r9 turbo wrote:Hi , Dont know if you have had the cayenne LPG yet but just to let you know I have a cayenne turbo converted to LPG with no probs at all. I have raised the rear floor by 2" (its easy) and have a 66ltr tank.
Hi

Would be interested to see pictures of your installation. Who did the install? Are you happy with it?

Regards.

Re: Cayenne Turbo awaiting LPG

Posted: Tue Dec 02, 2008 12:08 am
by r9 turbo
Hi Mak, The install was done by GAS 4 CARS . The owner of the company is a chap called Stewart who seems on the ball and the install was a very good job considering the lack of space he had to work with. I am a bit of a fussy bugger and like to see a job done well, everything fixed down ,nothing flapping around in the breeze ect. I cant complain at all at the job he did. The car runs fine with normal to fast driving, when running flat out and I mean flat out it gives the impression of running out of the gas supply. Its only when you put your foot flat to the floor in 1st gear, as the revs reach 5500-6000 rpm it seens to run out of gas, it changes to 2nd gear and takes off again. May be I am expecting too much ? after all it is a 450bhp car and LPG is an economy conversion. Stewart is going to fit a second vaporiser to see if will solve the problem, It may seem and obvious thing to do from the very start until you see the space available under the bonnet. I will try to send you some photos of the install if I can work out how to do it. I could e-mail you some.

Regards
r9 turbo

Re: Cayenne Turbo awaiting LPG

Posted: Tue Dec 02, 2008 12:43 pm
by mak-uk
Hi

There are several 400+ bhp cars out there on LPG and with the Prins VSi system. The key components are the injectors and the vapouriser/reducer. I have the yellow injectors in mine but you can also get the brown ones which you might have or might need. Also, a single vapouriser runs to about 310 BHP approx so I reckon you definitely need a second one.

To post up pictures the easiest thing to do would be to join somewhere like http://www.photobucket.com
You can upload your pictures there then post the link in your message.

Re: Cayenne Turbo awaiting LPG

Posted: Tue Dec 02, 2008 2:36 pm
by twinturbo
I really don't understand this post, everyone knows that the Prins VSI VAP tops out at around 320-330bhp.... I know this is right! and prins will also tell you this.


Why would he fit 1 vap with 450! no way... I take it you have the latest system with a separate Bosch MAP sensor that prins have ( for turbo cars only) 211-s I think the ECU should be.

Look at the Prins motorsport Focus ST, Turbo and of course 2 vaps. I really don't understand why your car would ever have just 1? get some Brown injectors as well, Yellows may be OK for a lazy yank V8 but not this car





Kev

Re: Cayenne Turbo awaiting LPG

Posted: Wed Dec 03, 2008 8:03 pm
by r9 turbo
Hi , I do understand your comments and 2 vaps is obviously the best solution. However if you have ever seen under the hood of a cayenne turbo and look at the lack of space to work with , you will understand why its worth a try using 1 vap. The hole idea of going gas in the first place was to help the wallet out with the normal day to day driving. This type of drive does not use all 450bhp so in this case 1 vap is OK.
Its only now ,after I have lived with Gas for a short while that " I want the lot" , Maximum BHP and cheap fuel and big smiles !.
If this means 2 vaps then so be it.


Regards
r9 turbo

Re: Cayenne Turbo awaiting LPG

Posted: Thu Dec 04, 2008 11:03 am
by twinturbo
r9 turbo wrote:Hi , I do understand your comments and 2 vaps is obviously the best solution. However if you have ever seen under the hood of a cayenne turbo and look at the lack of space to work with , you will understand why its worth a try using 1 vap. The hole idea of going gas in the first place was to help the wallet out with the normal day to day driving. This type of drive does not use all 450bhp so in this case 1 vap is OK.
Its only now ,after I have lived with Gas for a short while that " I want the lot" , Maximum BHP and cheap fuel and big smiles !.
If this means 2 vaps then so be it.


Regards
r9 turbo

If something needs 2 it needs 2, you have to find the space, bumper removal or whatever. If Prins rate at 330 max, it is the only way. it will run lean or cut back to petrol. its not right. go for 2 and feel the power! you will love it!

Re: Cayenne Turbo awaiting LPG

Posted: Mon Dec 22, 2008 9:37 pm
by r9 turbo
Just to let you know that the second vaporiser is now fitted and the result is " THE DOGS NUTS"
Regards
R9