LPG and Turbo

[edz]

I am seriously thinking about fitting LPG to my twin turbo setup with the aussie fuel prices looking like hitting $1.30 - $1.50 /litre by the end of the year ($US4 /gal). LPG is 40c/litre!

The problem is I am getting conflicting information. I would like my finished setup to have around 400 kw at the engine (400 rwhp). I have been told that the Lpg systems are fairly simple and would be very risky when used in high horsepower applications? However, ther are a number of dinosaur motors (non ohc) and rotaries getteing 500-800 hp on LPG.

I have talked to gas research aust and my local dyno/lpg man (Gastune in Tuggeranong if you are looking for a fair friendly gas tuner in Canberra).
Initially I will just setup na with gas (but run dual lines staright off for later), using the factory computer as it only has to manage the ignition. Later I will have to worry about a more complex ignition system (maybe Haltech Ignition only) when I add turbo's. I would like to use Kdog's tiptronic system with the auto.

I know I need to run dual converters and lpg lines, run the lpg mixer just before the throttle body (and definitely after the intercooler unless you like grenades!). Has anyone got any info or help on this?

I have to worry about ignition retard etc later, but the haltech or some equivalent should be able to handle it? Also current lpg mixes have a lower octane rating than old mixes (used to be 110 but I hear around 95-100 is the norm.)

 

[Miles B]

FAT did a supercharged LPG Soarer. They used no intercooler, methanol injection, stock compression, twin Gas Research 510 or 480 carbs (not sure), 15psi. Also heavy valve springs and custom cams I think. And a motec.

 

[edz]

Yeah, saw that one in zoom, they invetsed a lot of dollars and used liquid injection. I'm trying to stay simple. Thanks for the tip anyway.

 

[autocol]

i can't see why any of it should be a problem. i believe (don't quote me though) that to get the mixers (converters) to work you need to equalise the pressure with the intake charge or the diaphragm won't open under intake vacuum, because there wouldn't BE a vacuum! so you need to run a line from the intake system just before the throttle body to the top of the converter...

i THINK.

you might want to look into that.


gas rules. the only problem, in my experience, is an occasional "front-fire". makes for cheap fuel pumps!

 

[Mcgee]

Lpg

Thats correct.
I've helped a mate do a 355 stroker using two impco carbies. edit: had two VG30 turbos hanging off the side.
We spaced the converters to flow more gas until we could get it tuned on the dyno.
Also first problem was that the mixers were vented to atmoshpere. Which ment when the throttle was closed it would stall the engine. Anyway a simple tread tapped in the side and this plumbed into the the post intercooler plumbing stoped this problem.
easy to setup.
Gas research has some good gouge on their web site.

 

[71hq]

pls forgive my slow brain:boggled:............do you mean put a threaded hole in the top the mixer and run it back to before the t/b ? :Eyecrazy:
like what you do to equl pres in the turbo when deeeeselerating ?

 

[cribbj]

71 - unfortunately the last post in this thread is 2.5 years old, and McGee hasn't been on the Forum since 2005, so you may not get a reply from him.

FWIW, you're on the right track with this balance line, but the terminology is a bit mixed up in the posts. The mixer is the bit that replaces the carby, while the converter is the bit that vaporises the propane and reduces the pressure.

The converter is where the balance line from the manifold should be connected, same as with a FPR in a liquid fuel system.

 

[Death By Bass]

isn't there a "new" "direct injection" method now available (which wasn't around in 2004) which apparently, leads to MORE power output (on NA engines anyway)

might cost you twice as much as a standard LPG system, but it sure seems like a good idea.

 

[edz]

lpg and Turbo's

I'm getting back into mine this year now the bathroom reno is finished. Look forward to chatting later as problem's need solving.

Cribbj iscorrect on the mixedup bits - from my experience, the main danger with lpg is the backfires - you need a high quality ignition system. The standard system should be ok if it's in good condition, but don't skimp on cheap ignition leads, and definitely run blow through - hate to think of the mess when the lpg backfires in the intercooler! .

I'm running twin throtle bodies with a mixer each and twin converters. The intercooler is designed for a 300zx so basically two single intercoolers joined toether as one unit. I'm running the tubo from one side across the front throught the intercooler to the throttle body on the other side to keep the pumping length as short as possible. Using a pair of VG30 roller bearing turbos.

Mcgee is in the airforce, he left Canberra at the end of last year to go to Amberley in Qld. Think he's gone off the 1uz idea, he was thinking it was too hard to fit the torana, was thinking of a chev. He also got a bit distracted fitting a ca18 turbo to a datsun 1200 ute for a a daily driver.

Look forward to more discussions on this as I get some work done this year.

Edz

71 - unfortunately the last post in this thread is 2.5 years old, and McGee hasn't been on the Forum since 2005, so you may not get a reply from him.

FWIW, you're on the right track with this balance line, but the terminology is a bit mixed up in the posts. The mixer is the bit that replaces the carby, while the converter is the bit that vaporises the propane and reduces the pressure.

The converter is where the balance line from the manifold should be connected, same as with a FPR in a liquid fuel system.

 

[edz]

direct lpg injection

isn't there a "new" "direct injection" method now available (which wasn't around in 2004) which apparently, leads to MORE power output (on NA engines anyway)

might cost you twice as much as a standard LPG system, but it sure seems like a good idea.

There is, you are looking at about $6000 to setup the system (around $2,500 - 3000 for the old vapour system. Seems a great idea now that they are getting it working, uses a fuel pump in the gas tank to pump liquid gas. There was a problem with the iinjectors being small as they were designed for small european systems. I saw one on Tv last year that uses a discharge ring that sits under the petrol injectors, sealessly switching between petrol and fuel - but then you need 2 tanks. I think this is the 'factory falcon sysytem'. Good, no backfires, full power.

 

[71hq]

thanks very helpful ......... would love direct injection lpg but the price not an issue planning, time and money going into this project (still dont want to spend silly cash though) :tongue2: and haven't found any where that can produce a single (per piston) setup that can handle big HP most of the ones i have found are good for 200-300 hp.

i am selfish i wont stop playing till i get around 500+ hp:006:

i did find one place that shows lots of promise but they are still testing, not selling to the public so on so forth bla bla bla onder: cant have every thing i want but i can try:006:

thanks again guys

 

[striker]

LPG injection By prins Autotechniek

A dutch company Prins designed those in cooperation with Keihin, it's the first LPG injector that can be triggered by almost any stock ecu injector output in the world.
It's called LPG-VSI "liquid propane gas vaporized sequential injection"

Volvo and saab are using these on the bifuel cars I'm told (not seen the engines to verify)

anyway www.prins-lpg.com

the best thing is that you will not have problems with knock on LPG, the con about this is that you can run leaner AFR ratio's but the heat generated in that will burn you valve seats in some time.

I have driven on LPG for 7 years now (very common in the netherlands) and ruiend 3 cylinderheads on my renault (did 380.000km when sold it) and no I have a honda which has the more heat resistant cylinderhead, as do more japaneze cars, 1uzfe... I don't know.

Regarding the 2 tank set-up, you will need 2 tanks because the engine starts on petrol and then after a few seconds running switched over to LPG automaticly, In the netherlands we get a road tax reduction for running the emmissions friendly LPG G3 (third gen) systems, they require the start on petrol. anyway my cars have run single fogger systems (both G3 btw) and although a dyno test revealed a los of 12nm of torque on the renault when driving LPG and a little less reactive to the "go pedal", both cars are far smoother in terms of drivability when run on LPG.

grtz Thomas

ps if any translation problems to Dutch (not german) feel free to ask

 

[Death By Bass]

"liquid propane gas"??

our LPG is

"liquid petroleum gas"

hmm...

 

[striker]

It's the same, I believe that in there are more terms used in other countries.

propane is leftover from refining petrolium which is from oil anyway.

in the south of france there are even various pumpstations which provide a mix with Buthane to get prices down further though there's a lot less energy in buthane so that should get power loss.

In the city of Apeldoorn where I live we're getting the first commercial Earth-Gas tank station which I will try out when they're in buisness, even cheaper than LPG but with the same power aboard every molecule

anyway goes to show that LPG has become a sort of group name for gasious fuels for automotive, just as biodiesel. what is biodiesel??? pure PPO (pure plant oil) or a mix of fosile fuel and seed oils? or maybe biodiesel is the stuff you get from a month of backing french fries.... doesn;t matter all diesel engines can burn the all sorts of fuel reffered to as Biodiesel.

grtz Thomas

 

[cribbj]

Have a look at the Prins vapor injection system. Very nice hardware, especially the injectors, which are made by Keihin of Japan. They have a 93cc model injector (don't try to relate this number to anything in the liquid injector world) which should be good for 60 BHP per cylinder - and probably a good bit more if you bump the fuel pressure up more than recommended.....

A mate installed this system on his supercharged Cobra Mustang and did make over 500 RWHP on the dyno, so it's definitely do-able. See photo below.

Just make sure you have enough fuel pressure in the tank to support these systems, as the injectors need 1 bar (relative to the manifold), so at 1 bar of boost, you'll need 2 bar of fuel pressure, which may be tough on a cold day in Oz, with the typical vapor pressure of LPG that you have. I'm told you have a fairly high percentage of butane in your LPG which will lower its vapor pressure. Also you'll need to watch for detonation as the amount of n-butane in the fuel drastically increases a motor's propensity to knock.

 

[striker]

Hey Cribbj

read 3 posts above here, we're on the same route. good stuff!

grtz Thomas

side-note: hahaha now I'm getting really sad, I just had 2 twice edit the post, 1st because of spelling in the message, the then 2nd to take out the spelling faults in the reason for editing line........ hahahaha Oh I feel stupid!

 

[cribbj]

LOL, Thomas sometimes it takes me so long to compose a post that others jump in ahead, so I usually hit the preview before I submit to make sure my post is still relevant. Didn't do that for my last post here, and definitely should have.

IMHO, the Prins is the highest quality LPG vapor system out there. I bought some Italian LPG injectors awhile back and they were junk, but the Prins stuff is top notch (and their price reflects it).

About the valve seat recession that you've had, supposedly FlashLube helps this a lot, unfortunately I don't think they've figured out how to put one of their systems on a FI motor.....

 

[urtwhistle]

a question for ya's if u were going a after market ecu. would u need the prins ecu to still piggy back it??? or could u do with out it and use like a standard lpg carb controller to tell all the regulators and fuel lock offs to open or close???
its probly a silly question but if u dont need it u could probly save a hell of alot of money by going a standard GRA setup with injectors and a LINK ecu.

 

[cribbj]

I had a mate in Oz who used the Prins injectors with a Megasquirt and the AEM P&H driver box. We never did figure out if the system was driving the injectors OK, 'cause he discovered the pressure of his LPG was too low for his application.

I talked with the Prins guys about doing this, and they strongly recommended to use their ECU to drive the injectors as the mapping would be much easier. I believe their current ECU's are "nearly" standalone anyway.

Don't try driving the Prins (Keihin) injectors with an ECU and a resistor box to try to fool the system into thinking they're saturated injectors. These are BIG honkers and they require a true P&H driver with enough current to bang them open smartly.

If you'd want to use an ECU that only has normal saturated drivers, you'd need to invest in a P&H driver box like the AEM and let your ECU drive the driver box.

 

[Deuce]

What's a P&H driver?