Looking for an LPG installer - Mazda RX8

[buzzmonkey]

Hello All,

Hoping to get some direction to an LPG installer who is able to convert the Mazda RX8, preferably in the Midlands or surrounding area - but happy to travel further if required.

Cheers,

[classicswede]

I'm more than happy to do them but as you are in the midlands perhaps Toby is your man

[buzzmonkey]

I'm more than happy to do them but as you are in the midlands perhaps Toby is your man

Good to hear! I gave Toby a call yesterday evening, great guy, but was little apprehensive with doing the rotary (totally understandable)!

What system would you be using? Pretty sure I also need to get a flashlube system or similiar in there as well

Cheers,

[classicswede]

I would use the KME controller.

LPG is not as bad as some think with the rotary as most of the problems are down to carbon build up on the tips and as LPG burns clean life of the rotors should be longer.

[buzzmonkey]

I would use the KME controller.

LPG is not as bad as some think with the rotary as most of the problems are down to carbon build up on the tips and as LPG burns clean life of the rotors should be longer.

You have email

[Tubbs]

Yes. I'm apprehensive.
In my defence I promised my wife no more headaches and stress until after the school holidays.

[LPGC]

Buzzmonkey - Have you emailed me about this a few times recently and asked a few technical questions? Someone has!

Simon

[Tubbs]

I've had about 3 enquiries about them recently as well. It's mazda season !

[Gilbertd]

Probably because they are now cheap, stylish, a lot more practical than most sports cars, come with lots of luxury and toys (especially if you get the 231 bhp one with full leather, a 6 speed box and 13 speaker Bose audio system), go like stink, make a wonderful noise once the revs get over 6,000 rpm, handle well but if you drive them as they are meant to be driven you are lucky if you can get 20 mpg. Took a brand new one on a holiday to Italy a few years ago and averaged 19mpg.......

[ZiggyB]

Hi Chaps,
Since I converted mine 4 or 5 months ago there has been a lot of interest on the RX8 forum.
Many people were apprehensive due to the usual forum hearsay regarding the negatives of LPG along with 'the weight of the tank will spoil the handling' etc etc.
This may be the reason why you are getting more enquiries than usual and yes the cars are very cheap at present (you may be lucky and get a perfectly usable car with no issues for £1000) and along wth a LPG conversion can have a fantastic car that costs the same to run as my previous company car, a 2011 Mondeo diesel (ugh).
My car runs beautifully on it and produces a little more top end power as RX8's run excessively rich once in open loop at the top end of the rev range. With this richness mapped out on LPG I get about another 4-5hp using the Dyno software on my OBD reader.

[bbstrikesagain]

Fascinating. The Renesis II is amazing in how it fits 3,924cc of lowly strung displacement in such a simple and lightweight package. The taxman doesn't realise he needs to turn the crankshaft 3 turns to get any one of the rotating gas pockets to experience all four strokes, so he thinks it's a 2.6, but the mpg belies the beautiful truth. Three major moving parts for all the torque overlap and smoothness of a six pot, it's closest analogy, but the six pot being huge, heavy, and needing has 30-40 major moving parts. And perfect balance, tiny, light - want one, but wouldn't want to feed it.

From an lpg point of view the six gas pockets, that rotate around the 3 faces of each rotor, each experience 654cc displacement twice on the way round. At the heady 9000rpm crank rpm the rotors turn at 3000rpm and the total displacement (and hence flow) rates are identical to a 3,924cc six pot doing just 6,000rpm. The challenge would be that each rotors' three faces are fed sequentially through one port and injector, so the inlet pulses and injections are at 3x the rate.

In other words, although it genuinely has 3,924cc of concurrent and parallel displacement, from a breathing, fuelling, and sparking point of view it's much more like a traditional two-pot 1,308cc four-stoke doing up to 18,000rpm, or a 2T doing up to 9,000rpm...

Given their single-seal (instead of multiple piston rings) high levels of oil consumption, and hardened edge and tip seals, flash lube seems unlikely to do much, but perhaps it couldn't hurt? I remember reading that with its twin spark, cooler inlet zone and hotter expansion zone, Wankels are well suited to another dry fuel - hydrogen. Did that need flashlube?

Want to hear more.

[ZiggyB]

Don't believe what you hear about 'high levels of oil consumption'.
Under normal driving mine does about 2500 to a litre which is probably less than many current piston engines.
The oil consumption goes up with throttle position and engine speed so on a trackday the oil consumption can be high (as much as 200 miles to a litre).
It is prudent to inject extra 2T as this helps to lubricate the seals and tips (especially the tips which are only lubricated at the ends leading to excessive wear in the centre) and also reduces carbon build up while increasing compression slightly.
If you rely on the oil lubricating system fitted as standard when running on LPG there have been issues with excessive wear not experienced on petrol. This may be down to the lubricating properties of petrol vs dry LPG. The jury is still out.

[rich r]

Under normal driving mine does about 2500 to a litre which is probably less than many current piston engines.

Indeed - Vauxhall quote 0.6l/1000km (or about 1 litre per 1000 miles) for most of their four and six cylinder engines from the last 20 years or so. My 1.8 Vectra Dualfuel uses about a litre every 5000 miles, which I think isn't too bad for an engine approaching 130,000 miles (virtually all that on LPG)

As you say, it all depends on how you drive the Renesis engines as to how much oil they use. Keep the revs down and they're no worse than a piston engine.

[bbstrikesagain]

Wow, 1 litre oil per 2,500 miles not high??

My 40,000 mile Subaru STI will use about 170ml of flash lube and well under 100ml of engine oil in 2,500 miles. My 13,750rpm 50,000 mile Suzuki gixxer thou consumes less oil still. Both are acquainted with their throttle stops, and light up their shift lights often enough,

Perhaps I ran them in wrong (mineral oil, by the book)? I know the stated max limits are high, and since 2008 Honda's Fireblades tend to take take the mickey, but a piston engine with good valve stem seals and multiple piston rings just isn't in the same league of oil use as a Wankel. I'm a rotary fan, but not for nothing is the dedicated cubby hole for spare oil, and the user manual instruction to check oil level at every refuelling.

I like the sound 2T oil - sounds more appropriate lube than flash lube, given the nature of the port and chamber sealing, which is very like a two-stroke. But 2T oil and cats?

[ZiggyB]

Alfa and BMW state that 1l per 1000km is acceptable!
I use about 150ml of 2T per 350 to 400 miles (again about 2500 miles per litre) so this would have a negligible effect on the cat (SEE ABOVE).

[hitman]

2t oil and cats is ok if you use low ash ie 2t tcw3 designated for marine 2 strokes

some use it instead of flash lube products