Distributer Regraphing

[CanberraMav]

Yes its the same except it doesnt have the gauze.

So from there ill run a pipe back to the air box and see if it fixes anything.

How is running it to the airbox any different to having it vented to atmosphere? (except being cleaner air)

[jessie928]

Yes its the same except it doesnt have the gauze.

So from there ill run a pipe back to the air box and see if it fixes anything.

How is running it to the airbox any different to having it vented to atmosphere? (except being cleaner air)

no, not to your airbox, it must goto the same port on your mixer brother.

Jes

[CanberraMav]

Hey Jes you have lost me on that one.

I now have a breather going from the air box to the bottom of the converter as Fozdick mentioned.

Im booked in for dynotune on monday.

[jessie928]

Hey Jes you have lost me on that one.

I now have a breather going from the air box to the bottom of the converter as Fozdick mentioned.

Im booked in for dynotune on monday.

the balance tube does not run from the airbox to the converter. It runs from the MIXER to the converter.

on your mixer, there should be a hole or a fitting like the one on the converter.

sorry about that, i shoudl have stated it earliyer that it must goto your mixer not your airbox,

Jes

[CanberraMav]

The only fitting on the mixer is a small grub screw which is basically in the pipe from the airbox to the mixer.

The balance tube runs into the top of the air box so is basically in the pipe between the filter and mixer so im guessing it amounts to the same as removing the mentioned grub screw?

Will this setup give me the desired results?

[Fozdick]

The closer to the mixer diaphram the better

So go with the grub screw.

[PGS 4WD]

About your distributor, some of whats posted aint quite right. LPG burns slow at low rpm and fast at high rpm as a result the advance curve shold be shorter and faster while finishing earlier, for instance a std dist will start at 10 degrees and advance quickly to say 25 degrees around 3000 rpm and then continue to advance slower on the heavy spring to around 32 degrees at redline also there will be 20 odd degrees of vacuum advance, total timing on vac plus mechanical will be around 36-38 degrees. Gas being a vapour is less inclined to drop out of the air stream than petrol at low air speeds like cruise so will generally require a little less timing at cruise as the propagation speed of the flame is related to turbulence, or how well the air and fuel mix. Better mixing or more turbulance mean less timing required, this is true for under load at high RPM, mixture turbulence is high so total timing is less than that of cruise as the combuston process is happening faster, as the engine is also reving faster there is less time for combustion to take place hence more timing than idle, the process needs to be started earlier to allow the necessary time for peak pressure to be acheived at the right point just after TDC.
An engine can handle much more timing at idle but when you increae the load it will ping as the increased turbulence speeds the combustion process, LPG is better here as it burn slower at low rpm, so use more inital timing, the advance needs to shorter though as if you screw the dist up to 18 at idle it will now be 41 degrees total, way to much and even if you cant hear it it is killing your motor and costing peak power through detonation. Also as you have now increase the timing 8 degrees at idle over std the cruise timing is up 8 degrees also, again too much and doing harm.

Get your distributor curved to have 15 degrees mechanical advance in crank degrees finished by 3000 rpm and shorten the vacuum advance by 10 degrees from standard, put the dist in at 15 degrees go to a dyno and get it power timed for peak power check your initial at idle and this is your new idle setting.
Best ever is programmable 3D map

Joel

[CanberraMav]

Thank PGS.

Thats heaps of help.

Ill be geting the truck back this arvo so ill see what difference it has all made.

[Jimbo]

Hey PGS thats an interesting read.

If you get the mods done to suit lpg what will the car/4wd be like on petrol (mine is duel fuel)? Can you have a happy medium? Also what is the rough cost of getting your dizzy recurved?

Cheers

Jimmy

[PGS 4WD]

If you run premium 98 from Mobil(8000) or BP(Ultimate), havent tried the new Shell V, you "should" get away with it and reap all the benefits, you need to keep your ear out for detonation at high load low RPM from idle to 2500 rpm as this is the likely problem area on petrol. My advise to my customer is to use premium and I usually put the vehicle through its paces on the dyno with chassis ears on to be sure ther is no detonation, if there is Ill pull some timing out but its usually only 1-2 degrees or sweet FA.
Joel

[PGS 4WD]

Sorry forgot how much. Depends largely on condition of distributor, usually $200-400. Not much point regraphing a knackered distributor as the timing will be erratic and can differ from cylinder to cylinder if the shaft or bushes are worn (plus dyno time). Strongly suggest electronic igniton also as LPG is harder to ignite, it needs more spark output to ionize the plug gap.
Joel