Ignition Curves

[John Denman]

As programmable ignition has become woven into the shifter kart fabric, how many of know what that curve really looks like?

Each motor takes a slightly different curve to reach optimal performance. Very few people who own a PI have the required programming hardware.

Anyone know how their curve really plots out in RPM and advance numbers?

For example;

RPM ADVANCE
1000 10
2000 20
3000 30
4000 30
8000 25
9000 24
10000 22
11000 18
12000 12
13000 6
14000 4

If your game, let us know what the curve that works best for you is. Since each motor is different it won't be like giving away a competition advantage.

[Brandon Schroder]

This is the stock curve off a cr_00.

4000= 26
6000=20.6
8000=12.8
10000=9.5
12000=3
14000=8.1

I think that these are accurate.

Brandon Schroder
Southfort Motorsports

[John Neilson]

Brandon,
Where did these numbers come fron and also, which box is this?
I have a couple of different ones, all '96 to '00. All give different results.

John

[Patrick Hubbell]

[QUOTE]Originally posted by John Denman:
[QB]As programmable ignition has become woven into the shifter kart fabric, how many of know what that curve really looks like?

Each motor takes a slightly different curve to reach optimal performance.

Anyone know how their curve really plots out in RPM and advance numbers?

For example;

You hit the nail on the head. Each motor is different and the modified curve for one engine will not be optimum for the next. My engine builder can modify any part of the curve but which part he modifies depends on how he ported the cylinder in conjunction with the pipe and combustion chamber configuration. I'll tell you more once I get the curve for my current engine and the one after it's(the engine and curve)been massaged.

[Brandon Schroder]

This curve is in a vortex box. The curve came with the software to program the box.I got it rate from vortex in australia

Brandon Schroder

[Mark Watkins]

Donnie Bootes, Rotax engine builder non-pariel(sp) showed me the 4 built in curves in Rotax's digital box (which is WAYYYYYYYYYYYYY more expensive than anything else on the market)for the 130. Rotax kindly publishes their curves. I'll xerox a copy and post it next time I see Don.

Mark

[Bob Chiras]

Just a note:

Most of the stock boxes seem to have only up to 15 points selectable in the program.

The reprogrammable boxes allow for up to 50 points to be programmed into the curve.

The difference in granularity is one of the large differences in the two boxes.

In either case you still have to know where the curve belongs.

[Mike Speed]

FYI, Speed Concepts SPI products have 200 points adjustable to .1 deg

[Matt Kull]

quote:

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Originally posted by Mike Speed:
FYI, Speed Concepts SPI products have 200 points adjustable to .1 deg

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Does Speed Concepts SPI have a web site or a catalouge?

[John Wehrheim]

So Mike, does this mean we can buy your programmable ignition boxes and change the curve ourselves, like you do? If so, what is the cost and what advice can you give us. Today, 99% of the karters are at a disadvantage because we can not change the curve based on our port heights, pipe, silencer and track. This is why I am against these PI's.
I have been considering buying the Vortex kit, but waiting to see what SKUSA and WKA decide for next year.

[John Denman]

quote:

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Originally posted by John Wehrheim:
So Mike, does this mean we can buy your programmable ignition boxes and change the curve ourselves, like you do?

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In defense of Mike, he builds a superb PI for the 80 and gives some pretty good curves out of the box. But either buy 10 boxes or spend another $750 to get the programming cable & hardware.

The PI genie is out of the bottle. But the genie will have many masters. I would guess the last master standing is the one who can sell a full featured PI with programming HW/SW and a comprehensive set of instructions for less than $350. I might even put my money on SPI for a while....

[Mike Speed]

Sorry for the lack of WEB site, I have one but its not to date. (speed-concepts.com)

My SPI-CR125 is being track tested now it will be out very soon.

John $350 for both is not going to happen for a while, at least not from me (made in USA) I don’t get the benefit of the foreign exchange rate.

[John Denman]

Mike,

Will the new PI be programmed via PC? It would seem to make the most sense to use a PC and a serial port connection along with some VB or JAVA software to write to the PROM on the PI. That way programmability would be within reach of the users as it should be pretty low cost.

[Dave Stevens]

quote:

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Originally posted by John Denman:
It would seem to make the most sense to use a PC and a serial port connection along with some VB or JAVA software to write to the PROM on the PI.

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I agree, doing it from a PC would make sense for most folks, though I'm still surprised at the number of people I meet that don't have laptops.

Not knowing all that much about the market for something like this, or the chipset used in the PI, (I assume it's a flash PROM) it may make sense to use an existing PROM programming environment. There are a ton of them out there, though I haven't seen one for this purpose.

The hard part's not flashing the PROM, but having a way to define and interpret usable data. My guess is the bulk of the racers using a PI, don't really know how to set up a curve without some help.

What would be slick, is to have a program, that "talks" to your data aquisition hardware, and determines the curve based on real data, from the track.

Perhaps Mike could comment on the feasibility of such a program.

Dave

[Bob Chiras]

The PI solution does not have to be in the $350 raonge to be cost effective. Just look at the stock boxes at about $160 each. We would all have to own 5 or more. The new stators/rotors to match the boxes at $300+

We easily get to over $1000 very rapidly and this assumes that you have cylinders with port height for each box and pipes for each stock box.

Several times the $350 target may still be a bargain.