Looking at AU's and BA's as a family car with the option of conversion to gas to take advantage of the rebate.
A local gas conversion bloke told me today that BA's and BF's should only be converted using the direction injection method. Their reason is that if you go the vapor route you run the risk of misfire and bending a conrod.
AU's arent a problem on a vapor system.

I am not disputing their information as I am no expert myself. I just like to question opinions...

What do ya'll think?

He wants to suck you into paying $3800

Normally I would agree with you on that point. But these guys dont strike me as the type. They do come across as being the type of mechanics that do everything right and do the job correctly the first time. Unlike many of the auto mechanics I have met.

FFS, don't give bad advice! You were banned from Boosted for being a douche. If swaz was to go on your advice and got a mixer-ring setup for his B-Series, would you pay for his engine rebuild?

swaz, the person/people you have spoken with are correct regarding conrod issues.

BA/BFs differ from earlier sixes when it comes to backfiring. This is due to having 4 valves per cylinder/a different head design so that it "seals" far better. Backfiring in a BA/BF can leave the gas with nowhere to go, and this will cause the conrods to bend or break. Which means engine rebuild time. AU and earlier sixes are far more forgiving with backfires due to the gases being able to escape back out through the inlet, killing airboxes & intake piping & cheaper stuff like that instead of the guts of your engine.

Mixer ring systems can be prone to backfiring if not set up right, or if they're not regularly maintained.

E-Gas B-series have mixer rings but they have stronger conrods to compensate for this. Petrol B-series may be susceptible to conrod failure if converted to mixer ring setup. This is why the gas specialist is telling you that injection is the way to go (injection eliminates backfiring issues)

awesome reply! Thanks for all the info and it makes perfect sense. AUIII's are going cheap at the moment ($7k) so I might go that route with a vapor system.

Would you think it would be necessary or advisable to stick direct injection on an AU?? What are the chances of a back fire? What is involved in servicing? I have rebuilt engines before so am capable of most things mechanical.

I think I kind of repeated myself a few times re-reading my post lol

Direct injection is better, but it really depends on the kms you'll do & what kind of power you want out of the car. I've got a s**t EF wagon with a mixer ring, & I couldn't be happier with it. 400kms to a 50L tank (12.5L/100kms), can't complain with that. Injection might lower that to say 11L/100kms, and would bump up the power a little, but it'd take years to make up the difference in install cost thru the improved economy.

'm not a pro with gas, in fact I haven't touched my system (I've left it to gas experts despite the good info on here), but with regular servicing (which I have started doing on the wagon) you just need to check/replace your plugs more often, and either use good leads or replace them more often. I'm of the "spend little, replace more regularly" ilk. Hell, the last batch of oil chucked in was a $20 no-name special from repco

Going by the many accounts of injection on FFAU and here I'd say the injection system virtually eliminates backfiring issues and improves the power and economy you get from gas. A vague answer I know, but I'm sure someone with experience in gas injection can help you out with their opinions/advice

If I were buying an AUIII, I'd skimp & go for a mixer ring setup, because I'd treat it the same as my EF

If I were buying a B-Series, I'd get injection no questions. Or a model with E-gas already fitted.

If you get a petrol model Falcon, then whatever you do, get a reputable installer to do the job. Helps if they know how to tune gas as well. The installer I went to did a so-so job but had no idea how to tune it. As a result I had a lot of troubles after that, until I took it to another place where it was finally tuned properly, and some other little things were fixed up (workmanship stuff like electrical earths, tidying up wiring, etc)

Thinking outload
BA's are going for about 9-10K at the moment plus a $2800 gas conversion = nearly $13k.

AUIII are about say $7k for a schmick one. + $800 for the conversion. $8kish.


AU is it!

BA uses the same rod as AU...these are weaker than the E series rod...so if their is no issue on AUs then there will be none on BA....

I have NFI what you mean by BAs "seal" better...its only difference is 4V vs 2V

BA uses coilpack so there is no chance of a crossfire causing a bent rod...

IMO the BA would should be fine with a mixer vapour system...if u want a reliable system have a look at what the cabbies run in theirs....I really doubt it will be injection

BA cabbies would have e-gas systems wouldn't they?

They also have dual VCT (regarding 4v vs 2v)

So how about if the mixer system runs lean, a cylinder fails to fire first time around, & next time around boom? Or fouled plugs...

Granted, coil on plug means much less chance of misfiring than ignition which includes leads, but it can still happen.

Had a look at E-gas BA's and they are vapor not direct injection...

2003 they changed the emissions so thats why they use vapour to meet the new laws

u can put mixer ring on any pre 2003 car

do u have a link to these regulations?

So how can the dedicated cars run on a vapor system yet I cant retrofit a BA with it?

because you r thinking of a different system

3 systems

1. liquid phase injection
2. vapour phase injection
3. vapour mixer system (old style)

A lot of cab's are getting around melbourne running the Easyjet Vapor injection system's. Like what i have fit to my EB. Boemo engineering do a lot of cab's, all with easyjet system's.

Much smoother operating engine than a mixer setup, better milage, longer range due to better mileage. Which is why i had it fit back in 2004. I had a basic mixer setup on my torana & it was crap. The initial fitment of my easyjet system was very poor, but after i fixed up the installers faults, it's been running good overall. ( aside fuel quality issues, thanks shell! )

I have read somewhere that post 2003 the LPG converted car's have to comply with certain emissions laws, and the older systems are too hard to make comply. To be honest, if you plan on keeping the car for say 5yrs, the extra for the injection system is worth it in my books. Unless your trying to scrape every penny you can atm, you should consider a lpg injection system. If you have ever had issues with the damage caused by an old mixer system back firing, you will know what i mean.

Even tho the Egas falcon is a mixer ring setup, it's still controlled by the EEC, whereas a aftermarket mixer ring setup isn't as well controlled.

Hell, when i converted, it was $1500 dearer, and no government rebate existed. It was still worth it!

Cheers