Jump to content
Click here if you are having website access problems ×

Xflow ignitions, what would it take


Bill Shurvinton

Recommended Posts

To persuade you to go to a very simple 3D system? Playing with Grahams car on saturday we had a clear problem with getting the butterflies into the correct position for the transition to work.

 

Got me thinking. There is an offshoot of the Megasquirt DIY project that does spark only and requires about £50 worth of components for the ECU, then either a wasted spark module or an ignitor for a dizzy. Certainly should be under £100 for the whole shebang if you get escrot/sierra bits from a scrappy.

 

Not fit and forget and requires user intervention, but certainly doable for anyone with a few skills with a soldering iron.

 

If anyone is interested let me know and i might order a few kits up.

 

Bill

Link to comment
Share on other sites

Could be interested but would like to understand what you are suggesting a bit better. Our car has a Twin Cam and is still running with points! The ignition systems of the orginal Xflow is not much different but from your comment about an "ECU" I assume this modification you're suggesting is in addition to some other type of ignition control system, what do you actually mean?

Would it still use the rotor to distribute the spark? Getting good re-manufactered rotors is a problem.( Always carry a spare!).

How far is it 3D? how does this system take care of the different maps needed for the different states of tune etc?

I know systems like Weber offers might be adaptable but the cost is a barrier, hence the interest in this idea.

Sorry for the novice questions but when you are starting with points you have a long way to go to 3D!

 

 

Edited by - deanteam on 28 Apr 2004 08:18:15

Link to comment
Share on other sites

If you have control of spark via engine timing ( crank sensor ) and throttle pot, you will have a major improvement over clockwork or basic electronic positions which will provide a smoother delivery and also the by-product of improved fuel economy.

 

would system off late Escort work ? They had Kent type engines from recollection albeit with chambered heads

 

Regards

Link to comment
Share on other sites

Well its just in the planning phase, but your options are:

 

1. Use the existing dizzy, with mech advance locked up and a simple ignitor

2. Go full wasted spark with a Fraud EDIS module. These are readily available

 

The only issue with 2 is the crank trigger wheel. This is a 36-1 toothed wheel (36 tooth wheel with 1 tooth cut off). The standard parts bin one is quite large (see Dave Walker's book for a picture). You can have a little one machined to go behind the crank pulley, but I have no idea how many would need to made for it to become economically viable.

 

The kit contains everything for a 3D igniton using either MAP or TPS as a load sensing method. Its adaptable to any engine, but the Xflows seemed in most need, and having 1 engine means that it would be feasible to get a batch of looms made up.

 

Bill

Link to comment
Share on other sites

Hi Bill

 

I like this idea and have been thinking about it for a while but I simply don’t have the electronics knowledge to take it forward…

 

I like the idea of keeping it simple and retaining the distributor (advance mechanism locked) and using a MAP to sense engine load. (Simple take off from manifold?)

 

Is such a box available to do this? I have looked at the Megasquirt site before but all the jargon puts me off! its all very confusing!

 

If it’s as simple as wiring in an electronic box that interfaces with the distributor and senses RPM and engine load to produce a 3D programmable ignition map, then count me in. I would be very interested to do this!

 

Tony

 

Link to comment
Share on other sites

As it is likely to be my xflow as the guinea pig, I guess you had better count me in. Any help putting the bits together and setting up the map would be appreciated. I would guess that using a TPS would be easier to detect load than a sensing airflow or a vacuum sensor.

 

Low tech luddite - xflow and proud!

Link to comment
Share on other sites

I've been thinking of 3D mapped ignition for a while. The Megasquirt web site wasn't very encouraging about the Megajolt ignition, but I guess they don't update the web site very often.

 

Here are a few thoughts:

As it's a wasted spark system, you don't a distributor. In many ways this actually makes it easier to change back to points, as you can leave the distributor alone.

 

The system will need a good crank sensor, and this will take more effort to fit than anything else.

 

Ignition mapping requires only a very crude throttle sensor to give respectable results (unlike mapped injection).

 

How do you download the maps?

 

Is it a constant energy system, with a variable dwell period.

 

Does it handle cranking conditions to make starting easy. This is the most difficult situation, when battery voltage is low.

 

I'm certainly interested, and have an oscilloscope and bench power supply for troubleshooting.

 

SEP field working, not spotted in 100,590 miles. Some photos here

Link to comment
Share on other sites

The documentation is a little out of date, especially with respect to the spark derivatives. however I know all the designers so can keep up to date.

 

The crank sensor is a standard Fraud unit. the mount as you say will be a little bit tricky, which is why I am only looking at Xflows at the moment ( that and they are the most needy).

 

Programming is via laptop just like any 'proper' ECU. In terms of dwell that's all handled by the EDIS module in wasted spark mode which has a built in smart coil driver. In fact the EDIS does all the crank decoding and timing. All the ECU does is send a control pulse to tell the EDIS what the advance should be.

 

In dizzy mode it uses a slightly different set of rules that I won't bore you with.

 

I'll get some prices together and get back to you.

 

Bill

Link to comment
Share on other sites

  • 4 weeks later...

What's wrong with the simple solution? An electronic Bosch dizzy from a 'Valencia' engine (Fiesta, Escort Mk4). About £15 from a scrappie. Side entry cap £5 from Halfrauds. 3 wires to connect.

It's a straight drop in, OK, not programmable but when I fitted one to my original crossflow it instantly made a world of difference. The engine immediately ticked over very smoothly and pulled cleanly, before this I had trouble setting the points Motorcraft to take advantage of the twin webers.

It's also a smaller diameter unit so easier to turn under the carbs!

 

Rob Lane

Link to comment
Share on other sites

News...

 

I have 10 PCBs and processors. Guy Hill has done a BOM for the rest of the parts and we will be ordering up soon. Then its a case of finding a suitable (i.e. cheap and available) trigger wheel and I can start guinea pigging on someones car.

 

Rob: the only reason for this is to get 3D again. The 'valencia' dizzy is in fact 3D as standard, but getting the vac reference right for it can be a problem, so most people disconnect it.

 

Oh and the idea of a wasted spark setup on a Xflow is subversive enough to make me want to do it just for the hell of it.

Link to comment
Share on other sites

I was thinking on doing this with an omex ststem but this sounds like a cheaper option. I race my xflow and i am only allowed 2D mapping so no throttle potentiometer, this would presumably make it simpler but less good! I alos like the idea of a crank sensor (no distributor, less weight, less to break and easy to convert back if needs be). i am aware that alot of people have had problems with the emerald system due to underbonnet temps,, if this is not too big a wish list count me in too! mark

 

 

Link to comment
Share on other sites

Gents,

being a complete numpty I have no idea what any of this means...but, I hear the standard ignition on my 1600 x flow could be better, I get flat spots pulling away from rdbts sometimes and the prob with the unleaded dizzy advance etc. If anyone can point me in the right direction and explain, Count me in *thumbup*

Any upgrades to make her more temperamental must be good.

 

Owner of *thumbup*The Wombat *thumbup*

L7OC member

25,500 so far

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...