Launch control

Vetal · Post by **Vetal** » Tue Nov 27, 2007 9:42 pm

I probably already asked this.
Is is possible to implement launch control feature on CA18? When switch fitted to clutch indicates that clutch is off, then rev limiter changes to some lower value (5000 let's say), when clutch pedal is released - normal rev limiter is acting?
It was possible with emulator using 2 128K maps...

Matt · Post by **Matt** » Tue Nov 27, 2007 10:44 pm

It could be possible by two methods -
1. Special ECU programming to adjust the rev limit when an input was enabled
2. Putting an input into NIStune software to then control it, but then you need the laptop hooked up to do that

At this stage I'm not adding enhancements like this yet. Too much other work to get finished in the interim

Vetal · Post by **Vetal** » Thu Nov 29, 2007 12:35 am

Surely input to ECU would be faster and more convenient,
but I would drive with laptop connected if that would allow me to get 2-step limiter

I could designate one of TechEdge inputs to clutch switch - then I guess it would be easy enough to implement in software automatic rev limit change when selected input receives some voltage?

2-step rev limiter would be very good for dragracing

Matt · Post by **Matt** » Thu Nov 29, 2007 11:18 am

These updates are something I would like to add in the future. It requires updating the firmware code to change the rev limiters when certain inputs to the ECU are set

The code would be specific to each ECU type and would take about two weeks to implement

At this stage I have Type 4 / Type 5 boards to get working which is quite time consuming. Once that is all over then I can have a look at future enhancements like this

Its added to the list however

crans · Post by **crans** » Mon Dec 03, 2007 4:14 pm

Im working on something to sort this our.
Embedded computer permantly hooked up to ecu. Press a button it sets the rev limiter to the desired setting.
It then monitors vehicle speed to determine when to take limiter off.

Also does anyone know what rev limit 2 and 3 are for?

Vetal · Post by **Vetal** » Mon Dec 03, 2007 7:07 pm

crans wrote:It then monitors vehicle speed to determine when to take limiter off.

That's a great idea - no clutch switch, and we could get away with just software

Fusion Ed · Post by **Fusion Ed** » Mon Dec 03, 2007 9:37 pm

This wouldn't work if you were monitoring speed form the wheels you were using traction control on!

Vetal · Post by **Vetal** » Tue Dec 04, 2007 3:27 am

Fusion Ed wrote:This wouldn't work if you were monitoring speed form the wheels you were using traction control on!

Sorry didn't get.
Idea is - you stand at the start, pedal to the floor, but Nistune software sees that speed is 0 so it sets rev limit at preset value, say 4800. Once car is moving, limit is set back to 7800

Fusion Ed · Post by **Fusion Ed** » Tue Dec 04, 2007 7:43 am

hmm I see your point not too sure how well it would work in practice (espec on a fwd car)

GZ@hybridka · Post by **GZ@hybridka** » Tue Dec 04, 2007 9:10 am

There is no need for any sort of external unit to do a speed sensor based launch control. It is relatively simple to do and the original MCU can handle it quite easily.

Ive done it on the ka24e, and it is common on modified honda and mitsubishi ecus.

Let me know what ecu you want to try get it working on, I would be glad to help. You must be running an emulator or eprom though and not a Nistune board for initial testing.

Fusion Ed · Post by **Fusion Ed** » Tue Dec 04, 2007 9:42 am

Another thing for me to talk to you about soon then GZ

crans · Post by **crans** » Tue Dec 04, 2007 10:01 am

I will be doing mine by sending commands to the nistune board real time.
When i get the board programmer i will probably do it the other way so an external controller isnt needed.

Vetal · Post by **Vetal** » Tue Dec 04, 2007 7:17 pm

GZ@hybridka wrote:There is no need for any sort of external unit to do a speed sensor based launch control. It is relatively simple to do and the original MCU can handle it quite easily.

Ive done it on the ka24e, and it is common on modified honda and mitsubishi ecus.

Let me know what ecu you want to try get it working on, I would be glad to help. You must be running an emulator or eprom though and not a Nistune board for initial testing.

I have CA18. I can do it fairly easily with emulator by using 2 maps with different rev limiter and switching them with the clutch switch

But I want to be able to do it with Nistune.

GZ@hybridka · Post by **GZ@hybridka** » Tue Dec 04, 2007 8:39 pm

Well, Nistune can certainly do it, using two basic methods that Matt described.

The speed sensor based function would fall into the first method (ecu mod), instead of using an additional input to the ecu via the clutch, you would use the speed sensor variable vs. a threshold to "trigger" a rev limit toggle. It just has to be made a function of the ecu which is actually quite simple.

What you do is convert the original REV limit code to compare the current REV to a RAM threshold instead of a ROM threshold. You then add an external function to stuff 1 of 2 different ROM thresholds into this RAM byte depending on current speed.

Here are a couple videos of the limiter I coded in for the ka24e ecu, the first one is a ka24e U12 TRX and the second is a ka24de S13 240sx (running a ka24e ecu). The videos dont show very much, but if the vehicle speed was raised beyond what the user set their threshold, the rev limit would return to normal.

http://youtube.com/watch?v=XzhbK9e5y0Q
http://youtube.com/watch?v=ieBeEaYu3Cs

Matt · Post by **Matt** » Wed Dec 05, 2007 12:04 am

Trust me ... I would love to do this and get it running.

But I have current commitments which I need to get done first before adding anything else in... these are currently the Auto Tune feature and getting ER34 / Y33 boards running for customers who have sent their ECUs here and been waiting for months to get them working

so I must attend to those firstly