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RX-8 LPG Conversion

Old 08-28-2011, 04:22 AM
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UK RX-8 LPG Conversion

Well after having my 2006 RX-8 for 4 weeks and taking out a morgage to run it i have opted to have a LPG gas conversion on the vehicle.

This is being completed this week (29 August - 02 Sept 2011) by a professional lpg conversion company near London, England who have converted 4 so far with no problems.

The conversion will be a BRC multi point gas injection system with flash lube to keep the rotors & seals in order.

Based on covering 12000 miles per year and an economy of 20 mpg i will be saving approx £1800 per year by running on gas at £0.68 per ltr compared to £1.31 for petrol, Even though the MPG will not improve because of the conversion the saving is in the cost of the fuel, This will be equilivent to getting 35 mpg out of the car.

The tank will be in the boot and will be a 45 - 50 ltr usable tank (Tank will be 60 ltr) so will give me a range of 200 - 220 miles between fill ups.

I will keep you posted on how it turns out, Feel free to ad to the thread if you want any info
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Old 08-28-2011, 04:28 AM
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What will it do to power output?
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Old 08-28-2011, 11:35 AM
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Originally Posted by Beodude View Post
What will it do to power output?
I would expect it to be about the same. I plan on getting an emergency portable generator that runs on propane. Propane doesn't contaminate the oil and you can store it with out it gumming up the fuel system (gasoline separates with time).
I once had a motorhome that could be switched over from gas to propane on the fly.
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Old 08-28-2011, 11:51 AM
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My work truck runs on propane. Let us know how it works out for you, propane’s minimal sooting, owing to its low carbon content, means increased engine life, fewer oil changes and longer spark plug life. It's a pretty expensive conversion though, isn't it?

Good Luck!
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Old 08-29-2011, 12:30 AM
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what is "flash lube"?
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Old 08-29-2011, 03:20 AM
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The power output will still be 231 bhp, There is no loss of power by running on LPG.

Flash lube is a very fine mist of oil which is also injected when the gas enters the rotors, When the rotors compress the gas under compression the oil liquidifies and coates all the components before it is burnt

Belive it or not the cost of the conversion is only £1300 (gbp) which includes 3 years unlimited mileage guarantee and if you base your yearly mileage as 12,000 the conversion would have paid for its self by the end of the 1st year following installation.

The system is automatic change over and you have no idea when it changes from petrol to gas or vica vera and from cold the car wil change to gas within 3 - 4 mins so i will be using hardly any petrol, The car has to start on petrol and then change to gas, The system does not allow you to start on gas because the lpg is not at the correct temperature to vapourise.
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Old 08-29-2011, 06:21 AM
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Originally Posted by Chad D. View Post
My work truck runs on propane. Let us know how it works out for you, propane’s minimal sooting, owing to its low carbon content, means increased engine life, fewer oil changes and longer spark plug life. It's a pretty expensive conversion though, isn't it?

Good Luck!
How does it work as a cooling agent though?
It only prolongs engine life if you can lubricate the parts properly and keep them at the right temperature. Flash lube systems are designed for valvetrains mostly, seals and seal springs are made of a different material.
Gasoline produces carbon deposits, true but it is also a solvent of sorts. It will prevent OMP injected oil to "gunk up" under the seals. That thing alone breaks the springs over time.
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Old 08-29-2011, 08:29 AM
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I'm actually EXTREMELY excited about this. I was asking Mr Engman about pros and cons of LPG, CNG etc just this weekend. LPG makes a lot of sense.

Paul.
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Old 08-29-2011, 10:24 AM
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I wish there was some company offering this conversion in the US. I'd be very interested.
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Old 08-29-2011, 10:40 AM
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Originally Posted by Suby_1996 View Post
The power output will still be 231 bhp, There is no loss of power by running on LPG.
As the energy density of LPG is only 74% that of gasoline, something has gotta give. Specifically, either your miles/gal of fuel will suffer if you demand and can get the same power from the engine, or the specific power output will be less if you drive so as to extract the same miles/gal of fuel.

If this company has figured out a way around these LPG chemical characteristics, they're definitely on to something... but I doubt it ... marketing hype aside. Beside the conversion adds significant weight (tank/fuel/mechanism) which also has a negative effect on economy and acceleration. Then you've lost the use of your 'boot'. And I'd be hesitant about carring around what is essentially an LP bomb in my trunk, esp considering the excellent braking of the 8 vs. the poor braking of so many vehicles combined with inattention leading to rear-enders. Best of luck to you.

ps. One last thing. There is a 2.38% loss in volumtric efficiency of an internal combustion engine on LPG vs one that uses gasoline. Just add that deficit to the rest.

Last edited by Spin9k; 08-29-2011 at 10:55 AM.
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Old 08-29-2011, 10:53 AM
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we probably end up with two of this in the trunk and praying not to get read ended

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Old 08-29-2011, 11:40 AM
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Originally Posted by Spin9k View Post
As the energy density of LPG is only 74% that of gasoline, something has gotta give. Specifically, either your miles/gal of fuel will suffer if you demand and can get the same power from the engine, or the specific power output will be less if you drive so as to extract the same miles/gal of fuel.

If this company has figured out a way around these LPG chemical characteristics, they're definitely on to something... but I doubt it ... marketing hype aside. Beside the conversion adds significant weight (tank/fuel/mechanism) which also has a negative effect on economy and acceleration. Then you've lost the use of your 'boot'. And I'd be hesitant about carring around what is essentially an LP bomb in my trunk, esp considering the excellent braking of the 8 vs. the poor braking of so many vehicles combined with inattention leading to rear-enders. Best of luck to you.

ps. One last thing. There is a 2.38% loss in volumtric efficiency of an internal combustion engine on LPG vs one that uses gasoline. Just add that deficit to the rest.
It's not just the energy density per se that's a problem, it's the effective volume required for storage. LPG is only L (liquid) when pressurized. As the tank empties, the pressure drops. One can't easily use the full contents of an LPG tank, so overall, the tank volume required is about 3-4 times that of gasoline for the same energy content.
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Old 08-30-2011, 02:50 PM
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Hi All,

Thanks for all the posts and the comments.....

Yes as the pressure drops in the lpg tank there will be some gas left in the tank that can not be used, The lpg tank is going in the boot between the rear arches and will take up approx 1/2 the boot, This lpg tank being fitted will be a 55 - 60 ltr tank which will give me approx 50 ltr use, There is a slight drop in economy running on gas, i am currently getting 20 mpg on petrol, I estimate i should return 16 mpg on gas, Bearing in mind how cheap lpg is to buy comared to petrol pound for pound (Or doller for doller) if i was to put £6 of Petrol i will travel 20 miles, but £6 of gas will get me 32 miles making the rx-8 a much more affordable car to run, Especially when petrol is £1.31 per ltr in England.

The lpg conversion will only add value to the Rx-8, I just hope it works out as planned, I will keep you posted with updates when i get the car back.
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Old 08-30-2011, 05:40 PM
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Lpg is not a substitute for maintenance. If you get 20mpg avg then there's something else to do to the car.
What spark plugs will you be using? How will they retune the pcm?
You know, it's not possible to tune it while running so what happens when you switch fuel?
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Old 08-30-2011, 05:55 PM
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Good Luck with your conversion!

I am using LPG for some time now myself, as our Company is doing such conversions.
It's based on a "5th Generation" Icom JTG System, that in contrary to the BRC or other 4th Generation systems injects LIQUID LPG without vaporizing before.
In all 4th gen systems, the LPG is "heated" up from liquid form stored in the tank to gaseous form and then mixed with air.
In 5th gen, it's injected by a special fuel injector much like the petrol injectors.
It also has a high output Walbro in-tank lpg pump and a return system with a fuel pressure regulator....
In general it's like having normal petrol fuel :-)
I believe that the big advantage is that when injected in liquid form, the charge temperature is around 60 degrees celsius lower than with petrol (around 30 lower than 4th gen system).
The big disadvantage is cost. This system is more than 3000 USD!!

In any case, the economy is tremendous (on all systems), and I pay about half of what I paid for petrol before, for the same kilometers driven.

New project now is to combine the LPG system with my Turbo setup (which I removed in order to see how it works first on LPG alone....).

I might start a new thread with the project.

Congratulations on your choice, I believe at the cost you are paying it's one of the best mods you can do.

Have you considered just reflashing your omp to inject a bit more oil instead of using flash lube?
This is what I am doing currently and believe it's enough lubrication, especially if combined with Idemitsu Premix and Sohn adapter.

Best Regards,
George


P.S. Some photos from the Install....






Last edited by gvang; 08-30-2011 at 06:00 PM.
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Old 08-30-2011, 08:39 PM
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Cool!
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Old 08-30-2011, 09:13 PM
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is your car 4 port automatic ????
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Old 08-30-2011, 10:08 PM
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Originally Posted by gvang View Post

New project now is to combine the LPG system with my Turbo setup (which I removed in order to see how it works first on LPG alone....).

I might start a new thread with the project.
Yes definitely - that would be a very cool project .
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Old 09-19-2011, 01:31 PM
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Any update on this?

you getting the sort of MPG you hoped?

Nothing broken?

Any chance you could PM me a link for the company that did this?

Thanks
~Craig
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Old 09-19-2011, 04:16 PM
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Originally Posted by RXCraig8 View Post
Any update on this?
you getting the sort of MPG you hoped?
Nothing broken?
Any chance you could PM me a link for the company that did this?
Thanks
~Craig
greetings mate !!

the company that does the LPG Conversion is www.Easytuning.gr !!!

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Old 09-19-2011, 04:19 PM
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Originally Posted by sebarx8 View Post
is your car 4 port automatic ????
its a 4port, 5speed manual 192 PS


...meaning a 4port with an MX5 gearbox
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Old 09-19-2011, 07:09 PM
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This is what I've been wanting. It sounds great.... wonder what a kit would cost? What is the feeling their.....we are all wondering how things are?
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Old 10-26-2011, 02:32 AM
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Hi all,

Sorry for the long delay.

The gas conversion was a faliure, i was without my car for a total of 28 days having had 2 seperate gas systems fitted and even then they could not get it to run right, There was a delay in throttle responce from tickover which sometimes the rev's dropes so low it cut out, it would start back up but would automatically be on petrol then swap to gas and it was not a plesent swap over and between 4000 - 5000 reves it was seriously holding back, The 231 is a 6 port engine compared to the 192 which is a 4 port engine and they could not control when the two additional ports were going to open so as a result could not compensate with gas injection, I ended getting a full refund after i told the company to remove there system.

Sorry guys but it was worth a shot!!!!!
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Old 10-26-2011, 04:19 AM
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Tough luck. At least you tried.
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Old 10-26-2011, 10:27 AM
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They can control all that with the AP...

Someone needs to revisit this.
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