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Ignition advance curve:Update:
GL1972 - March 24th, 2005 at 07:56 AM

I'm in the process of fitting a Mitsubishi Magna Distributor and Jaycar programmable ignition to my 2110. Has anyone out there had any experience with various advance curves with programmable ignitions. I'm looking for a starting point until I get it on a Dyno.

I'm presently setting total advance of 30 deg at 4500 RPM (I think I could set it at a lower RPM but I'm being conservative). I have the ability to set a mid RPM advance point. ie: 20 deg at 3000 RPM. This would give a positive curve. This is the point I'm not sure about for a VW engine.

Both mechanical and vacume advance are disabled although I am building a vacume to limit switch unit to trigger a preset amount of advance on acceleration probably around 5 deg.

I'm open to your thoughts.

Brendan

[Edited on 13-4-05 by GL1972]


Andy - March 24th, 2005 at 10:20 AM

I have no experience on performance engines. On stock motors vac/mech advance gives best drivability.
As a start you can get an idea on stock curves from workshop manuals. Some show when advance kicks in and max for both mechanical and vacuum, so you can get a map from that. I only have this info for type 4 motors.

You might also do a search on after market dissy's, some may have advance curves on their web pages.
:)


GL1972 - March 24th, 2005 at 10:55 AM

Andy,
Thanks for the response. It's essentially the advance at the middle of the curve that I am after. That's a good tip regarding the aftermarket dizzys. MSD, Mallory.

Regards

Brendan


68AutoBug - March 24th, 2005 at 11:11 AM

Hi Brendan...
Sorry, nothing done here as yet...

My Son & I are both still thinking about doing the Mitsubishi thing with their Vacuum-centrifugal dizzy...

I also have built the Jaycar unit but haven't put it on My engine as yet....

I'll be very interested in any information that You have or find

I've only substituted a normal coil for My GT40 Bosch coil..
so far...

Someone did contact Me last year regarding the Jaycar unit,
He had a few questions and measurements He wanted as He couldn't get the correct reading when adjusting the Jaycar unit... It wasn't far out, and I told Him it would still work OK... Didn't receive any more emails so I presume it did work OK...

Lee Noonan

http://community.webshots.com/user/vw68autobug 


http://community.webshots.com/user/vw68autobug 


barls - March 24th, 2005 at 12:03 PM

i have run 2 such units in a bug, the first i fried within 5 seconds of turning the ignition on the second ran for about 12 months before dying. when it was running it worked well but it just died one day when i came back i think from water ingress


GL1972 - March 24th, 2005 at 12:07 PM

My observations of the Jaycar Programmable Ignition coupled with a Mistubishi Magna distributor in a VW engine.

1. You don't need the external control unit on the side of the dizy. You do need it to work out the polarity of the reluctor coil to be able to connect it to the PI.
2. Don't use the 10 deg mechanical advance of the distributor as well as the PI. Coupled with a long dwell the PI after a while will struggle with the change in computations and your motor will slow down and cut out. Disable the mech advance and let the PI do the work.
3. "measure twice and cut once" this refers to the drilling of the shaft for the dizy drive. Mine ended up 40 deg out for some reason (too many late nights). No problem just that 1 lead starts around the back of the dizy.
4. If you modify the rotor button for 22 deg of sweep and only a trailing edge (I think you need to do this as when you rev there is cross arcing to the next HT lead) get your brass from a balsa section of a hobby shop. I purchased 1.5mm x 25mm x 300mm for $6 from HobbyCo.
5. Double insulate the lead from the PI to the coil. I used a sheath of another cable.
6. I wired the car for both styles of ignition. Mitsu and PI or Bosh 009. Allows for a quick change on the side of the road should one fail.
7. Even though the text says it probably wonth work with reluctor systems the Tacho works very smooth connected to the designated output.
8. Make sure your minimum programmed RPM is well below you actual idle RPM.
Overall it starts very easily and idles much smoother than the 009 GT40 setup. I'll let you know how it drives once I take it for one. Hoping to have it stable for the drive to the nationals. Even if it is not installed I will have the bits there for anyone to have a look at if they ask.

Regards
Brendan


GL1972 - March 24th, 2005 at 12:13 PM

Barls,
I have mounted the PI and the HEI in one box internally in the car so hopefully water ingress won't be a problem. I might buy another eeprom ($27) in case I stuff the other one. All the other parts you can buy for mere cents at an electronics wholesaler.

I will always carry the 009 and GT40 as a spare in the car in case of failure.

This is a cheap fun exercise.
Distributor from wreckers $45
Machining work $40
Jaycar Programmable Ignition and High Energy Ignition $140
The fun in making it and getting it to work successfully ... Priceless

Regards

Brendan


barls - March 24th, 2005 at 12:27 PM

yeah when the hei failed i just disconected it and went bugger it. so i have 2 units sitting in the shed waiting till i can be bothered again


squizy - March 24th, 2005 at 12:46 PM

Hey Brendan this looks interesting. Just what advantages are you expecting from this type of setup?


GL1972 - March 24th, 2005 at 12:56 PM

Squiz,

I'm looking for a hotter cleaner spark and programmable curve to closer match the torque curve of the engine. In other words the greatest possible efficiency.

009s do the same thing unless you play with the weights and springs ....yech!

If I change things like exhaust and venturi size like I will do in the near future I can reprogram to match the new engine configuration. Wish I had a dyno at home!

Regards

Brendan


GL1972 - March 24th, 2005 at 12:58 PM

Found and interesting read on http://www.centuryperformance.com/timing.asp 
Good allround document on ignition systems.


Jeza - March 24th, 2005 at 06:49 PM

Looking good Brendan

Its a shame that they don't do a MAP sensor version, as it would be nice to have a play with one of these when (and if) I get to fit the turbo.

I had a look at the details a while ago and decided it wouldn't work with the turbo- however someone more creative may be able to come up with something!

Keep us informed.

Cheers
Jeremy


68AutoBug - March 24th, 2005 at 08:22 PM


Hi Brendan,
If You are NOT using the Mitsubishi Distributor for mechanical advance... what about the Vacuum advance???

If You aren't using it either....
why change to the Mitsubishi Dizzy??

what advantages over a 009??

Lee


GL1972 - March 25th, 2005 at 10:45 AM

Found something interesting last night.
When you are using a timing light with the 12v+ lead connected to the pos of the coil the strobe for a split second shows 7 deg BTDC (which is pretty much what I wanted) then it shows erratic between 50 to 70 deg BTDC.

It appears that the Jaycar Programmable ignition picks up the interference of the strobe and tries to compensate causing pinging.

I will make a lead to a different 12v source and see if it improves. Perhaps I need a better quality strobe with greater internal resistance to earth.

Found some settings that are pretty reasonable. Drove the car last night. Was smooth on acceleration and idles reasonable. Seems to pull away from low revs easier.

Setting I currently have are
Min RPM: 500
Mid RPM: 2800
Mid Advance setting: 25 deg
Max RPM: 5200
Max Advance: 30 deg
Dwell: 50 deg
No vacume or mechanical advance. Locked up the mech advance last night for an immediate improvement. Also made the extended rotor contact.

Dose not appear to be any cross arcing however the dwell still needs to be adjusted (the instructions don't say to enter a deg ammount but indicate minimum dwell is 1 millisecond and that the setting you enter is for the length of time that the coil is OFF so from this I think you enter the deg subtracted from 90 to get the dwell required??).

The setting I have are still fairly conservative I think (I could change both the Mid RPM to 3500 and Mid Advance to 30 deg which should improve performance on acceleration but it would run hotter so I'll work my way up to that)

Lee
The magna dizzy uses a reluctor system instead of points which is quite robust and also the overall diameter of the dizzy is larger giving less chance of cross arcing in the cap for these type of systems (high HT voltage). Even without a vacume advance the engine does not stutter at all under acceleration. I'm making up a vacume to limit switch to trigger the unit for 5 - 10 deg on acceleration but will need to be carefull with the Dellortos with the ammount of vacume at high RPM could introduce too much advance.

I've got the bits to make a remote programming module so I don't have to sit on the back seat to program it.

When it's all finished and running ok I will take a series of pictures including the dizzy mods and programming configuration and post it on here.

As I said before this is the fun stuff!

Brendan


68AutoBug - March 25th, 2005 at 01:02 PM

Hi Brendan,
Yes. I know about the reluctor and the size of the dizzy,
having owned a Magna years ago...
I knew both of these were advantages...

but I thought someone was using the vacuum advance...
as it seems to be the item most treasured by people with an original type dizzy... instead of the much used "crappy" 009..

I see CIP1 now selling a New Vacuum/centrifugal German made dizzy for $99 US.... Not Bosch another company...

thanks for the information Brendan...

much appreciated and good to see the results You are getting.... I only have the High energy ignition system and will use it with the 009 & points... until My Son & I get a Mitsubishi dizzy... He has a friend with a lathe...
I would really like to see a pic of the modified rotor button that You have made..... very interesting that....
I have seen rotor buttons actually made like that, I don't know what they were used in......

cheers
Lee


GL1972 - April 14th, 2005 at 08:53 AM

Bloody Bosch!
Coming home from the kids soccer training last night I come off a roundabout and accelerate out of a tight righthander in third (my favourite corner for experiencing the torque of the engine) then BRRrrrr r r r r r .......nothing. Cant be out of fuel as it's showing 1/4. The guage has been sticking lately (actually sender). Ring the wife to bring me a tin of fuel. Put it in let pump take up, pump the pedal and crank it over. .. Nothing, no go, nada! Check fuel out of all 4 pump jets ... ok, must be electrical then. Check fuses are ok...yep. Check programmable ignition.... yep it's on and program is still there, punch a new one in anyway, nope still no fire.

Bugger this I want to get home. Pull the Magna Dizzy and bolt in the 009 (I keep it in the car just in case), connect it up (I wired 2 sets of connectors originally just for these occasions), swap one wire on the coil, unplug the din plug on the HEI/Programmable Unit and then hit the key .. .. Brrrrmmmmmmmm schweet!

Jump in and take off.... burp burp crack burp...what the hell? I thought I could get away with leaving the Bosch 716 coil in (designed for elec ignitions)...nope. Swapped to the GT40 now and got home no worries.

So what the hell was wrong. Here's what I think..
Car ran faultlessy to and from the Nats and the 10 days after.
Started to become hard to start as though it was compressioning on one cylinder when cold.
I thought it was fuel leaking down overnight although no smell in the oil. Once started the car ran perfectly and started easily once warm. On the way to soccer it was a little rough as though the HT was breaking down to earth.
Dizzy if fine and I can test with a multi meter the Reluctor output.
Programmable Ignition does not appear to have any burn marks on the tracks or components and still holds it's program.
Due to the fact that the HEI has a protective circuit for overcurrent on the coil trigger I think the coil died! Brand new and only used three weeks!
Perhaps the voltage put out by the HEI was too much for it?
I'm thinking this because it got progressively worse.
I dont think it was the HEI/PI as it would have just stopped or let the smoke out (a little pocket of smoke makes all electronic equipment run).

Perhaps I need to select a coil that can handle the HEI output.

Any suggestions? I want to get it going again as is was way smooth and had good power delivery.

Brendan :)


Jeza - April 14th, 2005 at 09:55 AM

I fitted my HEI circuit the other day, and its a great bandaid for my old tired engine. I'm currently using it with a 009, points and a bosch blue coil but I used to have trouble with plugs fowling during warmup (too rich at a guess) but this time it had no troubles!

However the only thought I have is that they mention using a coil with a ballast resistor. However like you say their is a current limit on the coil circuit.

Can you test the HEI/PI with another coil (but not the GT40 as they don't recommend using these).

Other than that all I can suggest is progressively removing parts to work out which one maybe faulty.... but this could require a bit of rework on the HEI/PI boards.

Good luck
Jeremy


GL1972 - April 14th, 2005 at 10:01 AM

Thanks Jeremy,
That will be the plan. I'll pick up a standard coil tomorrow. Lucky I made it an easy changeover so it shouldn't be hard to test. I'll let you know how I go.

Brendan


ratty 63 - April 14th, 2005 at 11:53 AM

Hmmm. this will be interesting - I am running an EFI system that also controls the timing on my Baja engine.... as yet the car has not been driven so I don't have the advance curve sorted, but its all laptop tunable so I will be able to fiddle with this once on the road.... not that any of this will help you with your problem, however I would be interested to see any graphs of advance curves from various dissys....

Good luck and let us know how you go.....

R :)


Doug Sweetman - April 14th, 2005 at 12:08 PM

Hey guys, great work !!! good to see people experimenting to get around the standard 'weak as piss' VW ignition system.

A little off topic I know, but I'll ask all the same. Does anyone here know how to tap Kadron carby's for a vacuum signal ? They dont have a vacuum port standard, and I know AJ simms in the US drills and taps them for vacuum, so it can be done.

Reason is, I'd love to go the magna dizzy / HEI route but have no vacuum signal to use for the vacuum advance (which kadrons really should have apparently).


GL1972 - April 14th, 2005 at 03:14 PM

Ratty,
When I get all this sorted I'll post a "how to" for the whole thing with pics and various curves.

Doug,
I removed the vacume can from the distributor and do not run vac advance. The programmed curve works fine even under heavy acceleration with no hesitation (2110cc with dual Dellortos). I will setup a vacume with trigger switch to add 10 deg adv to see how it goes though.

Just bolted on a 1 1/2 merged header and am waiting for delivery of some 36mm venturis before I go any further.

Brendan