Hi Guys,

Has anybody ever heard of an FD running on LPG? I haven't heard or found any place either in the UK or USA that does it or sells the kit.

With petrol prices getting stupidly high again, it is a thing I have to consider.

Also, I like the idea of AI, I wonder if it would work with LPG?

Cheers

 

It won't be worth your time, as you can't store enough fuel to be able to travel for any meaningful distance. We had a LPG fueled F-250, built by Roush Engineering, at work (Car and Driver) a few months back. While it drove like a regular F-250, fuel economy wasn't the greatest, and finding a station that was capable (and had a knowledgeable employee on hand when we needed fuel) was very difficult. It was also quite expensive.

Story:
http://www.caranddriver.com/reviews/...ane-quick_spin

-Jim

 

^^ great info

 

yes interesting reading, however I'd just go for the doughnut tank in the boot (trunk for you US guys!)

In the UK there's loads of petrol stations that sell LPG, and we are miles behind compared to mainland Europe who have LPG stations everywhere.

Being able to find a LPG station wouldn't be a problem.

Still looking for a conversion, been reading about a company thats been doing it in Australia.

There are companies in the UK that do LPG conversions for RX8s, I wonder if that would work??

 

Afaik, LPG decrease performance on NA petrol engines (less power, slower acceleration). I heard it may be different on turbocharged diesel engines but I don't know how it'd be on a rotary engine as octane, carbon build up, detonation etc. are all very important.

 

Propane has an octane rating of about 100 (does not state which method of measurement was used). The biggest issue is that it has a lower energy content per unit volume than gasoline. Propane contains 91,500 btu's of energy per gallon, whereas gasoline has about 125,000 btu/gallon, meaning for the same volume of fuel on board, you'll have a shorter range with propane than you will with gasoline.

http://www.gotpropane.com/p3.html

http://www.generatorjoe.net/html/energy.html

http://en.wikipedia.org/wiki/Gasoline

-Jim

 

ok so LPG doesn't pack as much punch as Petrol (gasolene), but then again it is half the price... and unless I'm wrong LPG doesn't burn with any of the nasty emissions that petrol does, so I wouldn't have to worry about passing the MOT tests.

Come to think of it, why do RX7s suffer so badly with their emissions, is it because they dump fuel or is there something else? How can it be fixed I wonder.

 

suffers badly because many of them arent maintained right....
a few cracked/broken vaccum line could make the emission useless - or solenoids that failed from the high engine heat... all of which will make the cat fail and make it run 'dirty'

emission can be fixed by checking the parts before you install it - or installing new parts...

 

solenoids?

 

Any news on this?

I was speaking to a Rotary Specialist, and he said he had an LPG system running on an FD or 12000miles with no problems

 

really, that's good news. I ve spoken to a few and they couldn't help me, plus I can find anybody that will install one or sell me a kit to do it myself. Did the guy say where he had it done?

 

Super7 autos in Sussex....he offered me the kit, but he said theres a lot of work in fitting and mapping and is not interested in doing it all again!

 

Thanks Charlie, I will check it out asap. These 7's are thirsty beasts so I would gladly go through the trouble to save a whole lot more £ in the long run.

 

Propane does burn a lot cleaner then gasoline. And while it contains less energy per volume that's good in the regard that the extra fuel required will help cool combustion chamber and reduce detonation. Much like e85.

You may want to inject more oil, I've heard that propane drys the "cylinders" out. This is hear say though, I have no personal experience with propane other then diesel injection kits, just a consideration since premix really isn't an option.

I don't see how mapping is a big deal. It's no different then tuning a gasoline rotary. Just use a wideband and the same gasoline afr's you would tune a gasoline rotary. Unless it's using an old school regulator type, maybe it's harder idk. (Shrug)

 

If you really want to save money on gas just get an ls1 hard to argue with 30mpg.

 

Thanks and believe me I have considered it in the past but for one, I think it is a bit strange when you hear a muscle car sound (which is great btw) coming from a sports car.

And secondly, I really admire the technical thinking that goes into the rotary engine and it's workings in the FD. With a grunting V8, although very manly and tough, I feel that the mechanics of it are pretty simple and a bit boring.

 

Will be doing mine, before the summer hopefully, so can give more details then

 

Subscribed, please keep us posted. Will be very interesting to see how it turns out.

 

Not really sure which way to go with this now, I thought that I would read up ablut LPG conversions on an Australian site Ausrotary. They know alot about LPG over there and I couldn't find anything positive about converting an FD. People have done it with FC/12a but none that I've found with the turbo FD. And I haven't found anything about it in the UK.

 

Lol you must be lazy with your searching....
there's a turbo fc in this country on gas, and Couple of companies in Aus have converted fd engines

I will have it done by the summer!

 

One of you Charlies post what you find. It would be interesting if nothing else.

 

LOL yep and by the sounds of it, the other Charlie is the one to watch for now. yes Charlie I'm probably a bit lazy and I'm in no big hurry as I haven't used my FD since 2004.

If I could get a LPG kit then I would be doing mine very soon also, the best answer I had was from an Aussie who would only send me a kit if there was a garage accepting delivery and willing to try to install it!!

Charlie, are you buying a kit and doing it yourself or getting a garage to do it for you? how much and info please etc etc.

 

No looking at getting the people who did my other (V8) car, although he's been warned against it ''because the tips break'' and a load of other rotary myths, he's open minded, and wants me to find out more info

 

I had my old series 2 rx7 with series 5 13b turbo motor running straight LPG almost 10 years ago now.

It was great spending $25 to fill up the tank which lasted all week. It was a very fun car and I loved the LPG. Always had people coming up asking dumb stuff like 'man are you running methanol or something', obviously they didnt know what lpg smelled like! People used to freak out it was cool :P

The setup was basic though, used a carby and mixer style setup, so no injection or anything. This made it hard to tune properly, and the fact no-one had any idea how to tune an lpg car for power (that i could find) back then made things annoying.
I was running 7psi for ages with no problem, had just a high flowed s5 turbo, some very primitive looking front mount intercooler and a full 3 inch exhaust. On the street was a bit quicker than mildy modded skylines, 200s etc. I remember i easily beat an FD, the guy wasnt happy :P.
But then wanted to turn the boost up to 12psi, so went to the place who did the lpg conversion and he said yeh no worries. Little did i know that his idea of dyno tuning was just reading exhaust emissions from some piece of crap instrument he used to tune taxis.

Needless to say, my car was an animal on 12psi, push u right back in your seat performance, beating very quick cars, but on this 'tune' the motor lasted 1 week.
Turned out the carby couldnt flow anywhere near enough fuel to support the extra boost so was running way lean.

I tried finding carbys that would flow more, and fitted a larger unit and found someone with more knowledge tuning lpg and a dyno, but still couldnt get enough fuel to run more than 7psi.

A lack of funds stopped me progressing any further as i was just studying and only doing weekend shifts, so never got to run the car to its full potential which was disappointing.
Had a lot of good times though, and sold the car after a year or so.

LPG does have a higher octane rating, so suits forced induction perfectly.
You dont have to run any emission equipment whatsover if you run straight lpg. No cat, nothing, which is very nice.
LPG does produce less energy compared to fuel. Wind the boost up to compensate
LPG does run dry, so oil injection would be very important.
An engine running on LPG can take more timing advance at lower revs purely because of its higher octane rating and slower burn speed. At higher revs LPG's burn rate speeds up with increasing air velocity making it require less advance than an equivalent Petrol engine.

Yeh id be very interested in going the straight LPG injection route as im buying an FD soon. But just not sure about the kits available at this stage, and they seem very expensive last time i looked, 6k ish...
LPG injection seems to make basically identical power to petrol, and i think uses your petrol injectors, and maybe stock ECU with a piggyback perhaps (been a while since i looked into it so cant remember exactly.
Ill do a bit of research!