I think women think the same about men when they have a baby.

Harley

Brilliant!

This evening I did a quick testdrive doing shopping for next week, together with my wife.
I asked here do you feel any diffrence in the driving of the car and she didn't.
But I did, cruising along I need much less throttle then usual maintaining speed through town.
So it works, giving more advance when cruising along. I think this will save a lot of fuel
when not at WOT.

Now I need to work evrething out....

p.s. let my wife read the last posts, well I'm still married

Today I was searching the internet, on how much degrees of vaccum advance there is when the engine is idling, or cruising along, as you now my ignition can go as far as 45 degrees advance but here is an article mentioning about 60 degrees.......

Here the article that exaclty tells what I'm doing at the moment.

This was written by a former GM engineer.


As many of you are aware, timing and vacuum advance is one of my favorite subjects, as I was involved in the development of some of those systems in my GM days and I understand it. Many people don't, as there has been very little written about it anywhere that makes sense, and as a result, a lot of folks are under the misunderstanding that vacuum advance somehow compromises performance. Nothing could be further from the truth. I finally sat down the other day and wrote up a primer on the subject, with the objective of helping more folks to understand vacuum advance and how it works together with initial timing and centrifugal advance to optimize all-around operation and performance. I have this as a Word document if anyone wants it sent to them - I've cut-and-pasted it here; it's long, but hopefully it's also informative.

TIMING AND VACUUM ADVANCE 101

The most important concept to understand is that lean mixtures, such as at idle and steady highway cruise, take longer to burn than rich mixtures; idle in particular, as idle mixture is affected by exhaust gas dilution. This requires that lean mixtures have "the fire lit" earlier in the compression cycle (spark timing advanced), allowing more burn time so that peak cylinder pressure is reached just after TDC for peak efficiency and reduced exhaust gas temperature (wasted combustion energy). Rich mixtures, on the other hand, burn faster than lean mixtures, so they need to have "the fire lit" later in the compression cycle (spark timing retarded slightly) so maximum cylinder pressure is still achieved at the same point after TDC as with the lean mixture, for maximum efficiency.

The centrifugal advance system in a distributor advances spark timing purely as a function of engine rpm (irrespective of engine load or operating conditions), with the amount of advance and the rate at which it comes in determined by the weights and springs on top of the autocam mechanism. The amount of advance added by the distributor, combined with initial static timing, is "total timing" (i.e., the 34-36 degrees at high rpm that most SBC's like). Vacuum advance has absolutely nothing to do with total timing or performance, as when the throttle is opened, manifold vacuum drops essentially to zero, and the vacuum advance drops out entirely; it has no part in the "total timing" equation.

At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15 degrees of spark advance, on top of the initial static timing setting (i.e., if your static timing is at 10 degrees, at idle it's actually around 25 degrees with the vacuum advance connected). The same thing occurs at steady-state highway cruise; the mixture is lean, takes longer to burn, the load on the engine is low, the manifold vacuum is high, so the vacuum advance is again deployed, and if you had a timing light set up so you could see the balancer as you were going down the highway, you'd see about 50 degrees advance (10 degrees initial, 20-25 degrees from the centrifugal advance, and 15 degrees from the vacuum advance) at steady-state cruise (it only takes about 40 horsepower to cruise at 50mph).

When you accelerate, the mixture is instantly enriched (by the accelerator pump, power valve, etc.), burns faster, doesn't need the additional spark advance, and when the throttle plates open, manifold vacuum drops, and the vacuum advance can returns to zero, retarding the spark timing back to what is provided by the initial static timing plus the centrifugal advance provided by the distributor at that engine rpm; the vacuum advance doesn't come back into play until you back off the gas and manifold vacuum increases again as you return to steady-state cruise, when the mixture again becomes lean.

The key difference is that centrifugal advance (in the distributor autocam via weights and springs) is purely rpm-sensitive; nothing changes it except changes in rpm. Vacuum advance, on the other hand, responds to engine load and rapidly-changing operating conditions, providing the correct degree of spark advance at any point in time based on engine load, to deal with both lean and rich mixture conditions. By today's terms, this was a relatively crude mechanical system, but it did a good job of optimizing engine efficiency, throttle response, fuel economy, and idle cooling, with absolutely ZERO effect on wide-open throttle performance, as vacuum advance is inoperative under wide-open throttle conditions. In modern cars with computerized engine controllers, all those sensors and the controller change both mixture and spark timing 50 to 100 times per second, and we don't even HAVE a distributor any more - it's all electronic.

Well you should know the advantiges of a mapsensor in the electronic ignition by now....

1) extra advancing ignition under light throttle gives you more torque, less fuelconsumption,
less heat so lower oiltemperatures.

2) retarding ignition under boost for turbo/supercharged cars........

Well 1-2-spark can do this and you can even tune the numbers again by laptop/computer..

Iv'e programmed also a lagfactor 0 to 100% to smoothen eratic (spikes) in the mapsensor do to the inletmanifold........


Also I changed the homescreen a little to host a airtemp gauge and an oiltemp gauge.

So when oiltemp goes up the ignition can be retarded to prevent knocking (a hot engine knocks easier then a cold engine)........
This is the next thing I'm going to programm, but first I've got to finnish the Map behaviour.


It starts looking like real tuning bussiness doesn't it.

So when I have realised oil and airtemp, I have everything I need to make injection work, so when I am programming the software I already am integrating things for injection!!!!!!!!

So I think in a year by now I've got a working injection (for a 2cv).........

So in the next 2 or 3 weeks I do some more testing of the mapsensor......first tests are impressive, you can release the throttle but the engine goes on as strong as under heavy throttle.... meaning giving you more fueleffyciency.....

2cv,s don,t have a vacuum advance just the centrifugal weights behind the cam
btw i couldnt be bothered to read all of that previous stuff

So now you can have vacuum advance in a 2cv, it improves fuelconsumption up to 20 percent
(NOT MY WORDS BUT MARK 4X4 LEWIS, 1-2-SPARK TESTDRIVER #1)........

he wrote.... You've given me 20% improvement on MPG for free.

whats that about,?

If you cant be bothered to read why bother clicking?

Ipgo is creating an ignition system from scratch, give him some due credit!

Ipgo. None of what you do makes sense to me because im stupid, but does interest me v much, and i learn from reading

I aggree James!

@ ayjay, if you're not interested in these things, please don't foul topics with stupid remarks! obviously you really don't know what you are talking about! (you might know if you would read everything) buy a modern car and bring it to the garage if you have problems, then you will never be bothered with technical things you don't understand, just get a big bill!

@ LPGO, I read every update on this, all sounds too good to be true! I still want one! (just have to finish my project first ) keep up the good work! I love it!

Rusty

I've been following this thread with interest and now the system is up and running (and with some success), I'm seriously considering ditching the 123 I have installed (which I've never really been happy with), and buying this. What's the price for the set-up, Lpgo?