ok 600 is a bit of a stretch...but what your saying is wrong...petrol carbs work the same way (pressure drop)...that would be like saying you cant put a bigger carb on an engine...you can if the metering is good...

im a fan of impco/GRA systems over mixer ring systems...but im open to new ideas...can u show me the figures (CFM) for a std size mixer ring compared to a GRA/impco mixer...

My timing advance kit just arrived so will be good to see how much difference 2 or 3 degrees advance makes to lpg.

Trying to decide if its better to wire up this module in the engine bay, or near the ecu.

Looking at the mechanical design, it looks to be splashproof but not waterproof. Out of the engine bay would be my recommendation. There may be reasons to mount it close to the Dissy however, the installtion instructions may give a perferred location.

You can't compair a gas mixer to a carby. carbies are far more complex.
They start with and idle circuit that as you open the throttle hand an accelerator pump shot, expose normally 3 progression ports until the main circuit becomes active this main circuit then and a non linear flow cruve controlled by jet size, air corrector size, the emulsion tube and the size of the well around the tube, we then have a power circuit. and thats just on a single throat carby.

when you get into the really big dominator stuff there is a third circuit that operates between the idle/progression and main cirtuit.

Carbies also run at least one booster venturi for each main venturi, The primary side of the big carter quads actualy have three booster venturi in each main venturi, the secondary side uses a spring loaded flap and no venturi at all. we adjust the spring tension to change the pressure drop for a given air flow, which let holden/chev use the same carby on everything from the local 253s up to 400+ cube big block engines.


A gas mixer/convert combination is infinitely more basic and simple.

I can show you the flow figures for all the IMPCO gear, A comparison of the pressure drops shows how each flows. A simple water manometer will do, and i can show you the testing needed to properly size a mixer to any given engine. The instructor that I did my training with has done all the testing and he has written and published his own Texts books and his training is recognised in all states. I've got a copy all his texts that were needed to pass his training a*** and I'm sure the testing results are in the gas mixers text. I have all that stuff at work, so I can't post it right now.

the problem with the gas set up is the mixer must be small enough to create a pressure drop from just above idle, (where a carbie does not as at the this point it is still on the progression circuit)

This link is to an impco training manual that goes into detail on sizing mixers.
http://www.scribd.com/doc/17379058/IMPC ... ing-Manual

The basics of it is no mater what the gas system it still needs the same pressure drop to operate efficiently.

I'f I ever get the time I'll do my own back to back test with 43mm ring mixer on my AU and with an IMPCO 200 mixer on the same car. Test would be a simple water manometer test that measures intake pressure between the mixer and the throttle body.
I say an Impco 200 as I have an AU setup at work that was removed from a car a few weeks ago, the mixer would be a simple bolt on. Tests would be run on petrol with the gas ports blocked as that will give a true reading of restriction and would simplify the tests.

Hi guys,

The butterfly I'm trying to pipe around my mixer is about 42mm or 1 5/8 inches...

Anyone think of any pipe that is around that big? can be a mil or two bigger too. Want to make up the pipework and linkages on the quick.

Also, does anyone know if the signal wire from the TFI on an EL goes all the way back to the ECU? The timing advance unit wants me to splice it into that wire, and I'd rather do that in the kickpanel as opposed to the engine bay.

cheers

Frank

Last edited by frankieh on Sun Jul 24, 2011 10:51 pm, edited 1 time in total.

Which timing advance unit did you end up getting?

This one..

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=160616227024&ssPageName=STRK:MEWNX:IT

says it's for ford TFI and the price was right.

AEB gold master.

Last edited by frankieh on Sun Jul 24, 2011 11:36 pm, edited 1 time in total.

my bad.... had a baby on my lap and messed up the link.

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=160616227024&ssPageName=STRK:MEWNX:IT

How did you go with it?

As always when I am doing something interesting, some catastrophy happens to take me away from it. In this case my wife's ef wagon blew its btr 4speed, left a huge fluid puddle a the shopping center and required towing home. As a result I had to pull the spare El into the shed and extract the engine and box.

I have started fabrication of the pipe work required for the flow booster as well as working out the linkages.. and I think I've sussed all the wires I need at the ecu to hook in the timing advance unit. This weekend ill be putting the box I just extracted and cleaned up into the effect and whatever time is left will be for fitting the advance unit....

Will post results when I get some.

Oh , the bbm electric vacuum switch is exactly what I need to switch the vacuum on and off... so. I have all the bits I need to finish it now.

As always when I am doing something interesting, some catastrophy happened to take me away from it. In this case my wife's effect wagon blew its btr 4speed, left a huge fluid puddle a the shopping center and required towing home. As a result I had to pull the spare El into the shed and extract the engine and box.

I have started fabrication of the pipe work required for the flow booster as well as working outgoing the linkages.. and I think I've sussed all the wires I need at thoe ecu to hook in the timing advance unit. This weekend ill be putting the box I just extracted and cleaned up into the effect and whatever time is left will be for fitting the advance unit....

Will post results when I get some.

Oh , the bbm electric vacuum switch is exactly what I need to switch the vacuum on and off... so I ha e all the bits I need now.

J3 Chip w/ switch will solve the spark map issue. I'm sure those ignition modules would be worth more than a DIY Tuning kit...

yeah.. and I would have bought a J3 and tuning kit from you already if I could figure out a way to keep the speed sensitive steering as well.

I'm planning to see if there is some way I can manually control the steering hardness, because if there is, I can probably trigger it from a Jacar speedo adjust module or something..

I really like my speed sensitive steering

Question.. if you had a GHIA ECU, and you put in a J3 with a full Ghia turn on it.. would you still lose the SSS?

You can keep SSPS.

If you use a base bin that has SSPS in it. You can then use the switch to select one of two tunes based on this bin, one with LPG spark maps (could even use the factory tickford ones if you wanted).

If you use a non-SSPS bin (XR6 Manual for example) you lose SSPS.

Pretty sure 6DJC is a 6 cyl bin with SSPS.