Crank angle sensor for 3T GTE

[turbo ke20]

TA22 GT,

would your modified dizzy setup work on a 2tgeu. ive turboed mine and i think i will need a adjustable ignition timing setup as at the moment i only have a fuel only ecu.

justin

[TA22 GT]

What do you mean by compatible?

I have a ecu that can either use a halleffect or a magnetic sensor. Is that what you mean?

I mean you need some type of ECU that can use a signal from a crank angle sensor. Eg this system is no good with the stock 3T GTE computer. Its ok with Microtech, Haltech etc.
Just about all CAS have a 24 tooth wheel and a reference point.

Cheers,
Simon

[Grega]

justin - no - simons will run from the 3T (head) vs your 2TGEU which will run from the dummy cam...

[turbo ke20]

is there anyone out there who has done this setup for a 2tgeu then???

[gearb0x]

turbo_ke20: with the amount of trouble the toyota CAS's/VR sensors cause when using aftermarket computers its probably easier to go to a crank wheel arangement, where you just have either a toothed crank wheel with 1 missing tooth, or magnets set into the crank wheel. It really depends on what ECU you will be using.

One thing i was investigating was transfering smallport bits into a 2TG dizzy, but i couldnt get the shaft off it. Apparently you can use 22R's pickups etc in 18RG dizzys (???) never got around to trying though as ive gone off the CAS/dizzy idea

When i get around to it ill be running toothed wheel + wasted spark, much easier

[The Witzl]

turbo_ke20: with the amount of trouble the toyota CAS's/VR sensors cause when using aftermarket computers its probably easier to go to a crank wheel arangement, where you just have either a toothed crank wheel with 1 missing tooth, or magnets set into the crank wheel. It really depends on what ECU you will be using.

The problem lies mainly with Wolf3d and EMS ecus from experiences i've encountered.

What I will be doing with my 18R-G is using the crank pulley as the crank angle triggered, with a hall effect sensor bracketeered into position. A couple of 180deg opposed "notches" will be cut out of one of the v-belt grooves in the crank pulley (the 18R-G pulley has 3 belt grooves) and the sensor will be positioned above that groove.

For the reference (or home) signal, the stock electronic dissy (VR sensor) will be used, and the 4-tooth wheel modified to a 1-tooth wheel to trigger at TDC no.1 compression.

This will work fine with the Autronic

[turbo ke20]

damm karl looks like someones been doing lots of homework.

[The Witzl]

indeed yes.

I didnt want to end up with the plethora of problems a lot of people have been running into in the past with "dissy flex" - a name i've given to a condition where the chain/gear drive for the dissy has enough play such that at high RPM the signal can vary enough to cause the ECU to go into "misfire" protection.

Triggering directly off the crank removes this potential gremlin completely.

[turbo ke20]

i agree.
what sensor are u gunna use. maybe like a bommodore style on the crank pulley.
they have a bit of problems with them but when you think about it.......... there a s#*t box.
i would be interested in this upgrade for my 2tgteu.
post up how it turns out.
justin

[Grega]

the commodore style with the 18x and 3x interrupter wheel on the back of the crank pulley would be a pr1ck of a think to sort out, given, the pickup has to run between the teeth on the pulley, and, any misalignment bye - bye CAS. and these CAS do fail even on the commodores (i've had 2 fail)

another thing you could do is (open to flames here ) is mount them on the flywheel and put a pickup on the bellhousing (bit more complex)

[Norbie]

FWIW my plan for the elimination of my "dissy flex" problems is to use a generic chopper wheel which you can buy from Motec, and machine it to fit behind the crank pulley. As for the sensor, poking around at the wreckers it would appear that AU Falcons have a crank-mounted sensor which should work nicely. Then all you need is an alloy bracket mounted on the timing cover and voila, no more dissy flex!

Karl's plan to use a modified factory VR trigger as a home signal is a good idea, but my experience with the VR trigger so far has been a total disaster (well the Haltech doesn't seem to like it anyway) so I'm casting around for other options at the moment.

[gearb0x]

another thing you could do is (open to flames here ) is mount them on the flywheel and put a pickup on the bellhousing (bit more complex)

or cut a hole in the bellhousin an use the flywheel as a trigger might need a home signal somewhere else as im not sure how flywheels go with 1 tooth missing

[Norbie]

Hmmm that's not a bad idea actually, except that there are probably too many teeth on a flywheel ring gear - most ECU's expect something like 18 or 36 teeth. But then again maybe you can configure some ECU's to work with any number of teeth?

[gearb0x]

I know you can use any amount of teeth + missing teeth on the Megasquirt (with megasquirtnspark-extra), all software configurable. But not sure what the limit is, im sure there must be a ceiling of what the ecu can decode properly at high rpm.

[The Witzl]

the problem with the dissy being used as a home/reference signal is redundant. The reference signal doesnt have to be absolutely precise, it just has to be most accurate that the number of degrees between your crank angle signals.

Like i've said before, the reference signal is only used to tell the ECU what cylinder the engine is up to.... the crank angle signal is what the ECU uses as it's accurate measure for ignition timing.

Using the dissy for this crank angle signal is where problem can arise - thanks to flexes and "play" in the timing chain and gears giving an end result that isnt 100% accurate - it can vary an amount either way. I call this DISSY FLEX.