Diesel Tach Idea.

[dennis]

Is there any reason alternator revs are less accurate than engine revs?
I'd bet on the instrument being the leas accurate part of the system either way.

Probably not except at least with my truck the pulley ratios probably don't match up with the doner alternator. I guess it could be dialed in with a variable resistor once the tire size gear ratios ect.. are calculated to determine rpm at a certain road speed to have a reference to adjust to.  Mechanical engine rpm is engine rpm. Im gonna make this work without modifying the tach. Im already thinking that Tectonics Tuning sells a crank pickup to change CIS 16 valve engines to EFI.

Here is a 16 Valve crank trigger set up from 034 Motorsport. The sensor wheel looks a lot like some BMW stuff I have seen. The crank sensor used I think would like an ignition module. (More expensive all the time) I was thinking a two pin sensor and a regular BC12 Ignition coil could take the place of the module. Maybe I could even light some black smoke in the tail pipe with a well placed spark plug or two.
http://www.034motorsport.com/product_info.php?cPath=28_65&products_id=454

[Smokey Eddy]

Maybe I could even light some black smoke in the tail pipe with a well placed spark plug or two.

Heh, I've always wanted to bleed propane through the exhaust and light it with a spark plug. I have dual exhaust out front of the rear tires so it would look siiiickkkk. Something to note though is that the enviroment in the exhaust pipe is too O2 low to light very well in the pipe so you need your spark very close to the end of the tail pipe.

I saw Stacy on TRUCKS install a pretty wicked set up on a hot rod.
It would cut off 2 of the 8 spark plugs and just let raw gasoline pour through those two cylinders. Once the gas rich ehxaust hit the spark at the end it would light up.

His second method was a more conventional injector in the tail pipe that just drew gas from the tank with the push of a momentary button, the same button also sent sparks across the spark plug that was about 12-14 inches down from the injector.

Only real issue with these less hard-core non-flame thrower methods is that there needs to me some decent flow going through the pipes for it to not just look like a fire ball and lick your nice paint on its way up the side of the car ...

[dennis]

Maybe I could even light some black smoke in the tail pipe with a well placed spark plug or two.

Heh, I've always wanted to bleed propane through the exhaust and light it with a spark plug. I have dual exhaust out front of the rear tires so it would look siiiickkkk. Something to note though is that the enviroment in the exhaust pipe is too O2 low to light very well in the pipe so you need your spark very close to the end of the tail pipe.


Only real issue with these less hard-core non-flame thrower methods is that there needs to me some decent flow going through the pipes for it to not just look like a fire ball and lick your nice paint on its way up the side of the car ...

Paint Schmaint. Check this ebay auction out http://cgi.ebay.com/ebaymotors/05-Kawasaki-Ninja-ZX10R-ignition-trigger-wheel_W0QQitemZ260536644365QQcmdZViewItemQQptZMotorcycles_Parts_Accessories?hash=item3ca931b30d

[Smokey Eddy]

Paint Schmaint. Check this ebay auction out http://cgi.ebay.com/ebaymotors/05-Kawasaki-Ninja-ZX10R-ignition-trigger-wheel_W0QQitemZ260536644365QQcmdZViewItemQQptZMotorcycles_Parts_Accessories?hash=item3ca931b30d

Yes, but that is just the wheel... you could use a cog off a bicycle to do the same thing. What is really valuable and saught after is the sensor that counts the rotations.

[truckinwagen]

auberins.com has hall senders that put out a pulse avery time a magnet goes by them, I am going to be putting a pair of magnets on my crank sprocket and attaching the sensor to the block(or lower timing cover, not sure yet) to get a clean two pulse per rotation signal.

[dennis]

auberins.com has hall senders that put out a pulse avery time a magnet goes by them, I am going to be putting a pair of magnets on my crank sprocket and attaching the sensor to the block(or lower timing cover, not sure yet) to get a clean two pulse per rotation signal.

I ordered an air-cooled Beetle kit used normally to replace the ignition points. Only requires two pulses per rev. Im just gonna epoxy a couple of magnets from the rotor in the kit to the crank pulley, and bracket the pick-up to the correct air gap from the magnet.

[NintendoKD]

haven't seen this one yet:

http://www.pegasusautoracing.com/group.asp?GroupID=MCM3

good luck,
Kevin

[Kudagra]

I figured the best way would be to find a sensor that would count metal passing by it like just about any Ford (very available in yards) or the Kawasaki one in the post above. The best place to use that would be on the cam sprocket. I believe it has 6 holes so there are 6 hunks of metal spinning at 1/2 engine speed that would trip this sensor.  What needs to be known is what the output on a sensor is, what the input of a tach would be and how many pulses equal a revolution. I cant seem to find this information.

Ford v8 applications are plentiful in the yards here and they all use crank sensors.

[Runt]

The best sensors to use for this would be the hall effect style, that just sense whether there is metal nearby or not.  I intend to (as in haven't yet) use one exactly as you describe, on the cam pulley.  I'd like to mount it through from the back (nearby the valve cover), and count the holes/spokes.  A hall effect sensor (usually) has a power, a ground, and a signal out.  The signal out will be one pulse (high, as in +12v) for each metal tooth, or in this case, spoke.  This would mean that we would get 6 pulses for every rotation of the cam, which would be the same as a 6 cylinder gasser (and _should_ drive a 6 cyl gasser tach).  It would read 1.5X actual rpm on a 4 cyl tach, and I have no idea what it would do on the diesel tach.  Since I want to turn 5000ish, I'd like a 6000 rpm range, which would work well with something like Meister's 9000 rpm tach face modification, if it were rescaled to 6000 on the face.  What I have not done yet is actually tried driving a VW tach with a 12v square wave to make sure it behaves properly, or actually fitted the sensor to the backplate so that I know it fits.  I will likely do one or both fairly soon, I just have to find a VSS that I think will fit and work, and a gas tach somewhere to play with.  Anyone in the GVRD got a gas cluster to donate to the cause?
PS. the VSS has to be quite close to the steel to work effectively, on the order of 0.5mm, and the implications of having it catch in the pulley are UGLY, so mounting would require a little finesse, and I would NOT mount it through the plastic, as the plastic is not stable enough.
PPS If you are still reading this far, I am going to start another thread in the troubleshooting section to discuss some tach wierdness with my diesel tach, and I'd appreciate some advice.