hall sensor

[miniminor63]

I bought the Hall sensor (honeywell) from the web shop. http://sensing.honeywell.com/index.cfm?ci_id=128151&la_id=1

In the pdf I linked to it claims that max rpm is 3600.... Thats a bit low?! I am going to turn around 8500 rpm on the engine, thats 4250 rpm on the cam.. Will that work?  (I am using it as a secondary sensor on the cam to allow sequential injection).

My engine is a tri-cam  as its a converted A series using a twin cam head. The old underlying camshaft is still there to drive the oil pump. That old cam will have this on it:



That will go the same speed as the other cam sprockets and I thought about boring a hole in the front of that one and inserting a ferrous bit of metal for the hall sensor to sense on, will that work?

[rob@vems.co.uk]

That max rpm value is for the trigger arrangement described in that document.

A single tooth will give you a lot more scope for higher RPM.
 
You'll not see any advantage in sequential injection the only reason to use cam sync is for individual ignition coil control.

[miniminor63]

that was what I thought. Thanks!

what I have now is a ford (EDIS) coil that I was going to use in the same manner as I am now with megajolt. (wasted spark).

I am just going with what the guy mapping the car wants, and he told me to get a secondary cam sensor for sequential injection.

If its no point, why did he want it?

The reason for secondary sensor you mention involves one coil pr cylinder right? Are there any advantages with that? Where can I get a cheap nice solution, and how much would it typically cost?

[rob@vems.co.uk]

Theres no point because theres no gain in sequential vs semi-sequential.
When you set the injection up you can fire the injectors in the same order as the ignition.

Rob

[miniminor63]

so there is no point in a second trigger at all? Sorry for being a bit thick...

[rob@vems.co.uk]

Generally you'll not see much improvement in power or response with sequential over wasted spark ignition and semi-sequential injection.
With a Crank only trigger you can fire the injectors in sequence rather than as in a batch and run wasted spark, you can fire the injectors in sequence too but the only difference you'll see is maybe some HC improvements if you fire onto the back of the valve of the cylinder that's firing.
Secondary cam sync triggering is used for driving individual ignition coils (COP or CNP) which are nice to run if they're stock.  You can run Wasted spark with coil on plugs using the IGN_DUAL_OUT option.

[miniminor63]

Thanks Rob!

COP is not stock on my setup, and as I have the wasted spark coil from the ford I think I will use that. As there is no performance, or any other, gain with the secondary sensor I think I will skip it to have one thing less to play with/screw up. The HC gain is not something I need as the car is old enough to be outside of emmision laws in Norway.

Just to make sure, did you mix up some phrase in your text, or am being alphabetically challenged today (not seldom I tell you ):

With a Crank only trigger you can fire the injectors in sequence rather than as in a batch and run wasted spark, you can fire the injectors in sequence too but the only difference you'll see is maybe some HC improvements if you fire onto the back of the valve of the cylinder that's firing.

Should I remove the wire on the underside of the board meant for the secondary sensor if I am not using the secondary sensor?

[rob@vems.co.uk]

If its there you might as well keep there should you get a desire to go COP or CNP.

[miniminor63]

What is the advantage with COP's over wasted spark really?

[Sprocket]

This is how I see it - packaging and electrical consumption

[rob@vems.co.uk]

Its funny one really, COPs offer a good spark with lower charge and dont have leads to generate noise and go wrong.  So for a manufacturer's point of view its win-win as they have better packaging and electrical consumption like Sprocket says.
Wasted spark has the added advantage of that second spark occuring on the exhaust stroke so if you had a misfire on compression you're going to light off the existing charge - meaning you're not dumping unburnt fuel onto the lambda sensor or cat if you have one.

I use wasted spark where ever possible - even with COPs I'll use VEMS' dual out function to drive pairs of IGBTs