stuchizik

iTrader: (2)

Anyone know of an ecu for timing only? I posted in engine management but havent got any bites. Thanks

moremazda

iTrader: (4)

Why don't you use an ecu to control both fuel and ignition??

stuchizik

iTrader: (2)

Because it's for a turbo propane project. Its easier and cheaper to use a propane mixer (carb type setup). I can't seem to find much information on user controlled ecu controlled propane injection. Most setups i've seen are for a particular vehichle (they simply fool the stock ecu to think it's burning gasoline). And there are lots of Impco mixers in the junkyard. I know I can use a 12a dissy by locking the advance weights. However, I think with a programable timing curve I can fine tune more power and better driveability.
Any Ideas?

KrisGXL

Megasquirt is probably cheapest. I've set one up before to run FC style ignition on a 12a. It works well imo.

stuchizik

iTrader: (2)

Thanks. I assume you just wired up the ignition and left the fuel injection out?

bumpstart

i have impco 225 and microtech LTX8 on my FC turbo with 4 x bosh HEC 715
-- previously i used the 12aT dizzy with modded advance curve and DF leading
( trailing timing deleted after trials )
[ deleting the trailing allowed me to use that pickup and vac pot for the DF leading timing,, the trailing vac retard pot has more scale adjust ]

the advantage of the micro is i can run trailing split again without any holdbacks,, and still have relevant retard beyond 10 psi
( which the dizzy cannot match )

all up,, not hugely different,, maybe the micro has the edge below 2000 rpm
( its also fully sequential and no longer wastesparking )

BTW,, am doing same on a 1Jz in a mx73 with impco 200 ,, but instead chose E6S ( wasted spark )
due to price
( regrettably,, as the S has the physical dip switch reluctor adapter that is painful on toyos,, a K would have been MUCH better )

on you LPG car spark is everything
-- the moment its not up to the game,, you will be told in inlet backfires
( the rotary is actually very resilient to the normal LPG bain,, as it has essentially a cold side inlet )

the inlet backfires have potential to smash the hat on the 225
( fixes cheaply in moments,, but avoid the backfire at all cost by getting the best spark you can buy )

BTW,, am very happy with propane and impco 225
-- driveabilty is par and beyond with well street tuned ECU's
( in fact my 5th gear low speed is MORE tractable than many EFI tunes )
and the inlet PD doesn't prove that much of a handbrake
( i rather suspect the combined PD of mixer and new I/C is lesser than the OEM inter-cooler and hat )

stuchizik

iTrader: (2)

Thanks Bumpstart I was hoping you'd chime in I studied your other post about your setup with modified dissy and impco 225. Great stuff.

Do you think an impco 425 is too big for a 13b 6-port turbo? The 225 info i've found says its limited to 200-230 hp (unless these ratings are NA)and the 425 seems to be common in junkyards here. Are these mixers boost ready?

What do you run for sparkplugs? I seem to remember my dad running different plugs/gaps on the propane ford pickups.

I assume your LTX8 is simply not hooked up to or programmed to the fuel system and run as an ignition computer. Are you trigering it with the stock CAS or one of those notched wheel things?

Thanks for the help

bumpstart

the 425 is not so boost friendly as the much simpler 200/225 series
-- the 230 hp ratings are NA
-- the supply of propane is proportional to reference given from inside the hat to the converter
so will step up,, just like a rising rate reg

the limits of this is the heating capacity of the surface area in the converter
-- but also that in cold conditions below about 4 C that anything with a butane content may only show 30 psi supply pressure from the tank

in my situ,, ( i buy propane,, but most servos sell a mix )
the limits are around 20 psi boost,, to keep a minimum differential that equates to the volume of liquid coming forwards from the tank

,, two lines,, and two lockoff is the preferred solution for a little more boost
( singles lockoff can trip with sudden flows in excess of 350 HP )


from what i have learned,, it pays to err smaller,, this brings response and easy starting and stable low rpm mixes
this includes the primary ports as well as the mixer
( my motor is a 6 port hybrid )

-- the only mods to the standard 225 set up i have is
-a spacer to raise the UIM to clear the 225 entry on the oil filter
( i use modded turbo manifolds )
( 200 with side entry and different pipework will clear )

and also an air bleed around the mixer ,, about an 8 mm pill ,, i use the stock ABSV to switch it
( pipe from intercooler pipe around the mixer,, but not stock TB )

to start cold i close the bypass,,,, after that it stays open,, and mixtures are steady at an indicated 14.7
( its actually a 15.3 in LPG,, just cause the ECU thinks the probe is lambda 1 in petrol )

NB... i am using the magic black feedback box and convertor solenoid to suit
-( mine is lambda feedback corrected )

i strongly suggest this setup,, its cheap,, and easy,, and works very well

i use B9EG,, and gap them to 0.55 /0.60 mm
i use the stock CAS,, and a bit more timing down low ,, and normal retards i would see on a 13bt
( though mine is 9.4 and 6 ports )

injectors are simply not hooked up,, the ECU is AOK with this
( they are there while i get the WI tank made up,, and will return with an AI mix )

stuchizik

iTrader: (2)

Thank you so much. You just gave me more info than I've found in two weeks of searching

Is the black voodoo magic box part of impco's "feedback carb" system? Use stock O2 sensor?

Are you running 20psi on high compression rotors and limited by a single converter? Wow, I cant wait to hear what you can do with AI.

What did you use to control the ABSV when you had the 12AT dissy? Or is this controlled by the impco feedback system? I may have to learn about mega squirt or source a 12a turbo dissy as the cost of a microtech will almost double my cost. I'm kind of leaning towards the dissy to get it running at first as it's not my daily driver. Another benefit of propane is I can park the car all winter without stale, varnished fuel.

What are you running for a turbo?

Thanks

jagass

Thanks for the input...

bumpstart

turbo is a 58mm highflow s5 with a 3.5 inch exit and dump
the black box is the impco feedback box,, it works by attenuation of the vac signal to the convertor
-- ie
the tune set rich,, and the feedback solenoid from the OEM lambda output will lean down the convertor by shortcutting it more vac to achieve lambda
-- and they work surprisingly well !!!!!

the ABSV is simply a manual switch under the dash for starting
--- i planned to hook it to the aux out,, or even a hobbs switch
( when i had the dizzy )
to allow it to shut under boost ,, but found the AFR was steady anyhows with it open for all conditions but coldest start,, and also during rad overtemps

ie
the over hot water makes for too much gas expansion which can effectively lean the mixes at overtemps
,, the shut ABSV restores the idle down from 1400 to 1000 in these conditions
this problem only occurs when coolant temps are above 100 C

stuchizik

iTrader: (2)

Thats good to know. I like the manual switch although I think with the right selection of temp senders and a relay may be able to close it below 5 C and above 100 C
Unfortunately for me a lot of my mornings are <5 C snowed here last week -I'm still pissed

Thanks for all the help, I think its time for me to go shopping.

bumpstart

same shoes,, but on a different leg
this is the 1jz GT3582 with impco 200 and 3 mazda FC coils , 3 BIM137 and E6S that i have set up
( locked timing and true timing calibration yet established )
-- a similar combo to what i would suggest you follow,, and also on an engine with similar potential

http://tinypic.com/r/2808fus/5
http://tinypic.com/r/2qnbltk/5
http://tinypic.com/r/dnkcus/5

stuchizik

iTrader: (2)

Looks nice, too bad I have no sound

Have you ever tried those propane tanks that look like an air mattress? I think they are made in NZ. They look like a bunch of thin cylinders stuck together like a package of hotdogs. I cant seem to find their webpage.

bumpstart

http://www.propaneperformance.com/

stuchizik

iTrader: (2)

Thanks, those sure look nice. I bet they are spendy.