Food for thought, camfire ignition system?

[jlinfert]

The CIS E GTI ignition box and the Digi ECU both have an inbuilt processing delay of about 60*. (If you bypass them, your timing will be over-advanced by that amount and will need resetting to fixed total timing of your choice (31-33* generally for 8v)
With a new distributor there is very little ignition scatter at any rpm. Crank-fire is nice if you build a hand-grenade 14/1+ GT motor which is very sensitive to over-advance. One degree of scatter/timing off by 2* in this app=virtually no power difference around proper setting.
If you set your timing with locked/no advance setup and see several degrees of retard @6k, it's probably your light and not the ignition that is late. (search MSD ignition info which put me present to this and their recommendation for a specific Sears Penske light which made me a believer when I saw my Volvo motor was overadvanced 4* @6500 if I timed it with $$ Snap-On light!)
And, yes-for IT app, advance curve is unnecessary/no help to power in usable rev band.

Since when? I just had an ITB mk3 Jetta on the dyno Wednesday,(one of our megasquirt customers) and we saw gains of 4whp and 6 wtq to the AVERAGE power across a 4000 to 6500rpm powerband. The peak numbers were only improved by 1 or 2 but the curve flattened out nicely and wide power curves make your car very easy and fun to drive.

[Flyinglizard]

Jeff, are you a diplomat in training?? Phil has shown to know of what he speaks. I have known Phil for about 17yrs, from a distance, but at the same tracks, mostly Watkins Glen. He has shown to know the higher tech areas of making slow shit go fast. like Volvos and VWs.
What are you saying in your post?? It is not clear, not informative. Please elaborate your found data.
I have found no advantage to more lead than about 32 degrees on this ( Non IT legal ) engine. at any rpm that this car runs at( 4700- 7300). More than 35* seems to shorten head gasket life, and often distorts the chamber squish area. I run fixed timing to deal with the vacuum rules at my local circle track. I have found no timing varience, ever.
The car pulls the same with the advance dist also, just idles poorly.
The IT cars run the advance curve for now , but If i find any bounce , will go fixed on them also.
Thanks, MM

[jlinfert]

Jeff, are you a diplomat in training?? Phil has shown to know of what he speaks. I have known Phil for about 17yrs, from a distance, but at the same tracks, mostly Watkins Glen. He has shown to know the higher tech areas of making slow shit go fast. like Volvos and VWs.
What are you saying in your post?? It is not clear, not informative. Please elaborate your found data.
I have found no advantage to more lead than about 32 degrees on this ( Non IT legal ) engine. at any rpm that this car runs at( 4700- 7300). More than 35* seems to shorten head gasket life, and often distorts the chamber squish area. I run fixed timing to deal with the vacuum rules at my local circle track. I have found no timing varience, ever.
The car pulls the same with the advance dist also, just idles poorly.
The IT cars run the advance curve for now , but If i find any bounce , will go fixed on them also.
Thanks, MM

I'm not suggesting that more than 32 to 34 degrees total advance is going to make more power. However with a standalone ecu that allows you to control timing precisely and customise your actual curve, a fair amount of power can be found, typically "under the curve" ie below torque peak. This effectively widens the powerband of the engine making it easier and more fun to drive. Example playing with the timing curve on a GTL motor found 15ft/lb wtq at 5000 rpm (numbers went up 15 ft/lb) and 10whp at 7000 rpm. the power curve and torque curve used to be bell shaped and now they are both pretty darn flat. The same thing can be done with any motor when you can truly adjust your timing curve. Of course the amount of gain will vary but the average gains tend to be decent.

[pfcs]

Hogwash. To see those kinds of changes your fueling curve would have to be terrible.

[jlinfert]

Hogwash. To see those kinds of changes your fueling curve would have to be terrible.

1: I have the dyno sheets to prove it.
2: Never touched fuel, afr was hovering around 13:1
3: Just because say 32 deg timing works best for peak power (at say 6700rpm) it doesn't mean it's best at 5000rpm or at 7200rpm. If you've ever monitored timing with a scan tool on a modern efi car you'll see that the timing is very dynamic. Even above 4000 rpms. The manufacturer does it for economy and emissions but it can be tuned the same way for power.
4:A year ago I would have said the same thing. but after 9 megasquirt installs and hours of tuning them on the dyno I know differently.

[pfcs]

"found 15ft/lb wtq at 5000 rpm (numbers went up 15 ft/lb) and 10whp at 7000 rpm. the power curve and torque curve used to be bell shaped and now they are both pretty darn flat"
Since HP equals torque @5250rpm, sounds like you gained about 15hp@5000! and 10@7000-- and that seriously flattened the power curve? Only if you started with a disaster (quite possible w/DIY TuneItYourself systems-where do I start?) But then you say a/f was 13/1 thruout. I hear that you have "data". And I know what I know. Somethings wrong with this picture. For these values to flatten the curve, you would have to start with a huge hump in the middle; if timing was locked at some sensible value thru-out, you wouldn't get this result-what was your timing control and what were your tq and hp peak values and rpms? What dyno?

[jlinfert]

Bell shaped is a bit of an exaggeration but the torque rose rapidly and steeply to peak at 5300 or so and the hp dropped rapidly after peak at 6800 or so. Torque at 5000 was 115 it's now 130. Hp at 7000 was 130 it's now 140.

Timing has never been outrageous 30-34 degrees max but small changes of 1 or 2 degrees above where a tradional curve would be constant seems to work well.

This is an SIR motor so that may have something to do with the unusual gains. But I still have seen gains on IT motors of 2 to 3% by messing with the timing above 4000rpm.

As far as timing control, the megasquirt is directly driving an Electromotive 4 cylinder DFU (waste spark coil pack). It's using a 36-1 tooth crank trigger for rpm/tdc. Timing is very accurate and contollable to .5 degrees.

All of our testing was done on a portable dynojet, outside air and it's VERY consistant.

While I'm well aware of the fact that standalone systems can create a disaster, I have a lot of experience with megasquirt (as I said 9 installs with tuning in the last year) and once you know your way around it it's very friendly.