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#40996
Hi, Newbie here. I am considering speeduino based efi (fuel & ignition) for my Ford cvh XR2 engine in a kit car. Currently it is NA using Weber twin choke carb and the standard electronic breakerless distributor ignition (Bosch I think).

I have had a quick look thru the docs but am slightly confused by the setup/requirements of 2nd rotational sensor (phase) to run sequential. There are references to custom missing tooth timing wheels, modified distributors and single pulse triggers (1/2 moon).

I can fit a 36-1 crankshaft pulley/trigger wheel easily for crank position sensing. The distributor uses a hall sensor which I guess gives 4 pulses (4 cyl engine) per revolution of distributor rotor. So question is to be able to detect phase/sync in speeduino what distributor output do I need and best way to achieve?

Thanks
#40997
Hi, and welcome

With just a missing tooth trigger wheel on the crank only, you can achieve wasted spark and 2 squirts per cycle.

To achieve sequential, ie 1 spark and 1 squirt per cycle, speedy needs to know which of the 2 revolutions in the cycle the engine is on.

So all the phase signal needs to do, is basically say this is this revolution of the cycle.

So all you really need is to detect something at cam speed, once in the cycle.

Its sometimes easier to thing of it as a one cylinder engine.
#40999
@LPG2CV
I realise I could run batch with just a missing tooth crank wheel but for various reasons I would like to go sequential.

As you say logically I would have expected a single pulse/signal from cam/distributor sensor to be sufficient to correctly sync phase for sequential. However looking thru Trigger Patterns & Decoders section of manual nothing seems to fit the bill.

Missing Tooth (cam) - quote from manual
"The wheel must have at least as many teeth as cylinders, not including the missing tooth. This generally requires double the number of teeth as cylinders or more. As many teeth, slots, or other readable features (sensor targets) as possible in the limited space is recommended in order to satisfy this requirement, and to maximize resolution. The sensor must be capable of reliably reading smaller or closely-spaced teeth."

Dual Wheel - quotes from manual
"The primary input should contain no missing teeth. Both pulses can run at either cam or crank speed, but sequential operations requires that the secondary pulse is located on the cam. The design of the secondary trigger can vary (Eg a single short tooth, half-moon wheel etc), provided it only provides a single pulse per revolution."
"Tooth #1 is defined to be the first tooth on the primary wheel AFTER the pulse on the secondary wheel."

So my understanding from this is:-
1. to use Missing Tooth (cam) I would need to construct a distributor wheel with at least 8 teeth.
2. to use Dual wheel I would need to use a crank wheel with no missing teeth and a distributor wheel which generates a signal pulse per rev.

I was expecting to be able to use Missing Tooth on crank in combination with single pulse on distributor but this does not appear to be supported for some reason?
I was also puzzled why the Dual Wheel uses a non missing tooth trigger wheel and then uses cam wheel to work out crank toot #1 - why not just use missing tooth wheel?
#41000
Welcome!

I have a efi cvh in my quantum kit car.
I have a 36-1 trigger wheel on the crank pulley, I modified the hall effect distributor to give a single trigger per revolution of the dizzy in preparation for going sequential ( I ran wasted spark until then) but have pulled the engine in preparation for its new turbo setup so didn't run it yet.
#41002
@dazq
Well coincidence or what :D - my kit car is also a Quantum (saloon) - the engine is a big bore 2.0 cvh which has obviously had some work done on it in the past - so my thinking is it should definitely benefit from going tunable efi.
Looking at the thread LPG2CV pointed to I guess you will be using the Dual Wheel config. Will be interested to hear how you get on when you get it up and running.

@LPG2CV
Thanks for the pointer to that thread. I am obviously not the first person to wonder about using this particular setup. Good to know it should work. Maybe the manual should mention this to make it clear for others.

Thanks both
#41008
I used a fiesta turbo inlet to convert my carb cvh, though you need either cutouts for the injectors ,an adaptor plate or as I did swap to an efi head.

I have a video on you tube of the very first run on speedy ( fuel only with sparks from the dizzy).

ric355 what car is this on? TVR Chimaera

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