Dyna Ignition Curves -- Ya got any?

[BansheeGuy_IV]

Hey Guys,

 

I have a dyna ignition and a dyna programmer. This weekend I am going to start tweaking my timing curves. I was wondering if anyone has spent any time dappling with their timing curves and if anyone has any suggestions.

 

I've been running +5 timing advance with my stock CDI. So I am going to start there, but I am going to increase the timing advance through the midrange and decrease it a little through the upper RPM ranges.

 

I've got a 12 port stroker and rocket pipes for those of you wondering -- with all the bells and whistles to go with it.

 

 

BG

[wesw]

well it the dyno

 

i have them throw several curves at my bike.

 

they told me it really didnt do much of anything for some reason. no hp gains

 

they let like a +5 curve in i think, but they box gives you more spark so thats nice

[Rare Scottish Tree Badger]

I've got the DynaFS, but have only use the standard curves. (Not invested in the programmer box yet).

 

I'd be interested to know how accurate the stock curves are to the graph that comes with the Dyna. I guess you've got the graph?

 

The curve that's supposed to be the same as stock, according to the graph, stops retarding at 10k RPM (12.8 degrees BTDC). ... The (non Dyna) info I have shows that @ 10k the timing is 8 degrees BTDC and continues to fall to 2 BTDC @ 12k RPM.

 

The other 3 curves take their variations on stock, but all stop retarding at the same point. .... 16 degrees BTDC @ 10k RPM. (That's about 1.7mm BTDC which seems like too much advance at those RPMs).

 

Sorry to be answering your question with a question.

 

Rare.

[BansheeGuy_IV]

Rare,

 

You read my mind. I actually fired off an email to Dyna earlier today, asking them them if the stock curve is in fact the REAL stock curve from the CDI unit. The stock timing curve, in the MSD ignition, ends up about 10 degrees of advance at 10K, not the 13 the stock curve shows from Dyna.

 

It matters greatly to me, to have a true, stock baseline. If I advance 5 degrees across the board, on the dyna stock curve, I am at 18 degrees of advance in the upper RPM ranges. I suspect that much timing will produce excess cylinder backpressure and ultimately hinder the overrev potential. I run VP C12, but even then I'm a little hesitant to start tweaking without a verified baseline.

 

What I'd like to do is advance +7 very early in the curve... Then have it retard across the midrange so that at around 7-8K I'm at +5 and then by the time I'm at 12k I'd like to be in the +2 range... And beyond 12K... I want little to no advance at all.

 

Once I tweak it, play with it with seat of the pants, I'll see about making some dyno runs...

 

Hopefully Dyna will email me back with a straight answer.

 

BG

[Rare Scottish Tree Badger]

BG,

 

Dynatek were quick and informative when answering my emails before I got mine, look out for a fairly quick reply.

 

I thought you could plug it into the programmer and view the curves via your computer screen. Hmmmm .

 

These following numbers are from the graph in my 'Yamaha Genuine Service Manual'. But it's referenced to the YFZ350T and the date of printing is 1987. I'm not sure if the CDI curve has changed from 1987 upto the present date:

 

17 degrees from 0 - 2000 rpm, then straight line to 22 @ 3500, straight line to 9 @ 10000. ... That's the edge of the graph at that point, so no idea if it continues diagonally or turns horizontal from there?? ... They must think we don't take our bikes over 10k .

 

These are the numbers I found on the web a while ago, but I don't know what year they're referenced to:

 

RPM Banshee

0 17

500 17

1000 17

1500 17

2000 17

2500 19

3000 20.3

3500 22

4000 22

4250 21

4500 20

5000 19

5500 18

6000 17

6500 16

7000 15

7500 14

8000 13.5

8500 12

9000 11

9500 9.5

10000 8

10500 6.5

11000 4.5

11500 4

12000 2

 

So that's 3 variations, and 4 if you count the MSD! ... (8,9,10 & 13 degrees advance @ 10k rpm depending on which curve you look at).

 

Is the date on your Dyna graph "11-2-00"?

 

I think you might want a bit more than 5 degrees BTDC @ 7-8k.

 

I'd be interested to hear your response from Dynatek. And in the meantime, I'm going to get a hold of Yamaha and get some up-to-date specs for the present day CDI curve.

 

Rare.

[BansheeGuy_IV]

Rare,

 

So far the first curve I made, I took the stock curve, and advanced the whole thing an additional 5 degrees and tapered it down in the upper RPM range.

 

Well... My "logical" approach completely SUCKED. So mimicking +5 timing advance via the stator plate and stock CDI is not accomplished by just adding 5 degrees to the stock dyna curve. So far Curve #3 is by far the best, so I am going to start tweaking, very gently, from there.

 

And yep my Dyna is stamped 2000.

 

BG

 

P.S.

 

They have not emailed me back yet.

[Rare Scottish Tree Badger]

Well...  My "logical" approach completely SUCKED.

398754[/snapback]

It's usually hard to read the 'tone' of words put over the internet. ... No problems there!

 

Yeah, that curve three is quite a favoured one. ... I went from stock to curve 1 and blew the crank apart. (There were a few other contributing factors).

 

Good luck 'tweaking', you'll get there.

 

Rare.

[BansheeGuy_IV]

Rare,

 

Buddy, Pal... Compadre... You hooked me up. After several unsuccessful attempts, I went back and looked at this thread. I took your information from the stock banshee curve and I went from there.

 

Basically, the true stock cruve, goes down to 9 degrees of advance at 10,000 RPM. Well the Dyna Stock curve goes down to 13 at 10,000 RPM's. So when I would advance the timing +5 across the curve, at +18 in the upper RPM, it wouldn't rev... PERIOD. So what I did was... I advanced the timing +5 from your numbers.

 

So

 

100: 22

2000: 22

3500: 27

10,000 14

11,000 14

12,000 13

13,000 13

14,000 12

 

 

And HOLY cow... Basically, it runs like it did with my stock CDI and +5 timing advance at the stator. The only difference is that it revs out MUCH cleaner.

It's beautiful. I never would have figured it out without your help.

 

 

As an aside... If you want any custom curves programmed... I'd be happy to hook you up, free. The dyna timing curves aren't very good as I've come to discover. ;-)

 

Thanks Bro,

 

BG

Edited July 30, 2005 by BansheeGuy_IV

[bradrs]

Rare,

 

Buddy,  Pal...  Compadre...  You hooked me up.  After several unsuccessful attempts, I went back and looked at this thread.  I took your information from the stock banshee curve and I went from there.

 

Basically, the true stock cruve, goes down to 9 degrees of advance at 10,000 RPM.  Well the Dyna Stock curve goes down to 13 at 10,000 RPM's.  So when I would advance the timing +5 across the curve,  at +18 in the upper RPM, it wouldn't rev... PERIOD.  So what I did was...  I advanced the timing +5 from your numbers.

 

So

 

100:  22

2000: 22

3500: 27

10,000 14

11,000 14

12,000 13

13,000 13

14,000 12

And HOLY cow...  Basically, it runs like it did with my stock CDI and +5 timing advance at the stator.  The only difference is that it revs out MUCH cleaner.

It's beautiful.  I never would have figured it out without your help.

 

398873[/snapback]

 

Try pulling more advance out at the high RPM, possibly even to single digits before 10,000 RPM. Another thing to try is holding the timing advance high a little longer in the midrange, like the Dyna curve 3. Then have it drop quicker in the upper RPM. Look at your dyno runs, I'd be real surprised if you are getting anything by adjusting timing in that 11000+RPM range. Focus more in the 8-9K range.

 

As an aside, the Dyna curves are all designed to work with a pretty broad range of mods, giving performance gains while staying in a pretty safe operating area. As you can see, when you tailor a curve to the exact needs of your engine and fuel, your going to get a lot more gains out of it.

[Tedder]

BG, Did you ever get the REAL CDI stock curve numbers from Dyna?? I've got one of the new ignitions from Wilburn motorsports and was looking for a baseline..Thanks

[rjatv]

Anybody ever find out a really good curve to use? I am getting a wilburn ignition and would like to know a good baseline to start at.