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Old 03-30-2008, 09:03 PM   #1
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Default learn me on some launch control!

i wasnt worried about building boost with the 13g, but with my t3/t4 install almost done, something to build boost is probally a good idea now. but i am a tad confused on the circuit to build.

http://www.msextra.com/manuals/MS_Ex...al.htm#launchC

here is the curcuit, i was plaing on the low input
http://www.msextra.com/manuals/MS_Ex...l.htm#launchin

so i take the clutch switch wire, put a 5v and diode to it, then take that to JS11? but wouldnt that just give JS11 5v all the time? can someone clear that up for me so i dont short my board and i know to put a inline toggle so i can turn it on and off without the laptop.
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Old 03-30-2008, 09:48 PM   #2
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basicly you just are grounding out the JS11 when its activated. You DONT need that circuit, it just helps protect from noise and voltage comming in. it will work fine without it. I bypassed the original clutch loop and then just used the OEM clutch switch connected to ground on one side and js11 on the other..... completing the circuit to ground when the clutch is depressed. Be sure not to EVER send 5 volts on the line, or else you will fry the chip. i had a wiring issue and fried 3 chips.

Essentially you are just switching a ground....thats all. if you choose to make the circuit you need to make the active low input
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Old 03-30-2008, 10:20 PM   #3
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so i just take the clutch switch wire that went to the stock ecu and take it straight to js11?
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Old 03-30-2008, 10:31 PM   #4
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You run a jumper from JS11 to one of the input/outputs and then run a wire to that pin on the DB37 and then tap the clutch switch wire at the ECU. You don't need any circuit or anything, the MS just needs to see the clutch ground.
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Old 03-30-2008, 10:38 PM   #5
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Quote:
Originally Posted by cjernigan View Post
You run a jumper from JS11 to one of the input/outputs and then run a wire to that pin on the DB37 and then tap the clutch switch wire at the ECU. You don't need any circuit or anything, the MS just needs to see the clutch ground.
i cant beleive its that simple. thanks guys.
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Old 03-30-2008, 10:44 PM   #6
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Used it for all my launches at the autocross today. I have it cutting fuel and spark, 5 degrees I believe at 3000 rpm. Works great so have some fun with it.
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Old 03-30-2008, 11:48 PM   #7
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also... flat shift is the **** if set up well... even on a stock miata

Last edited by 240_to_miata; 03-31-2008 at 01:02 AM.
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Old 03-31-2008, 01:39 AM   #8
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I'd say flat shift would be even better for a Turbo miata, all the better to stay in boost.
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Old 03-31-2008, 09:53 AM   #9
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Quote:
Originally Posted by cjernigan View Post
Used it for all my launches at the autocross today. I have it cutting fuel and spark, 5 degrees I believe at 3000 rpm. Works great so have some fun with it.
i tested mine on jackstands....not as cool.
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Old 03-31-2008, 11:22 AM   #10
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I was pondering setting up the launch control / flat shift on the hydra. haven't got to it yet.
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Old 03-31-2008, 11:35 AM   #11
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Worthless without video!!!!!!

C
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Old 03-31-2008, 08:08 PM   #12
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sorry for the ignorance, but to make it work all I need is tapping the clutch switch with a 18gauge cable or so and solder and heatshrink it to the js11 on my middle connector on MS PNP?
that would be simple, why didnt I do it before
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Old 03-31-2008, 08:12 PM   #13
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Quote:
Originally Posted by 90turboMX5 View Post
sorry for the ignorance, but to make it work all I need is tapping the clutch switch with a 18gauge cable or so and solder and heatshrink it to the js11 on my middle connector on MS PNP?
Not even that. The clutch switch in question (the upper switch, not the one which engages the starter)is already brought to your ECU harness. It's the Brown/White wire at position 1V. Closes to ground when the clutch pedal is moved from the upper stop.
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Old 04-01-2008, 12:55 PM   #14
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Quote:
Originally Posted by Joe Perez View Post
Not even that. The clutch switch in question (the upper switch, not the one which engages the starter)is already brought to your ECU harness. It's the Brown/White wire at position 1V. Closes to ground when the clutch pedal is moved from the upper stop.
SO you are saying all I need to do is go to Megatune and activate launch control and it'll work?
Wow
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Old 04-01-2008, 12:59 PM   #15
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Quote:
Originally Posted by 90turboMX5 View Post
SO you are saying all I need to do is go to Megatune and activate launch control and it'll work?
After having connected the wire, yes. I was merely pointing out that you need not go all the way back to the clutch pedal itself to find the wire- it's right there waiting for you in the ECU harness.
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Old 04-01-2008, 01:06 PM   #16
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Quote:
Originally Posted by Joe Perez View Post
After having connected the wire, yes. I was merely pointing out that you need not go all the way back to the clutch pedal itself to find the wire- it's right there waiting for you in the ECU harness.
Yep, 1V on harness, into MS to JS11. turn it on in mega tune, the end.

It if have/had cruise control, you need to remove the neutral switch circuit, as it causes the the signal to ground at the wrong time, ie not in gear.
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Old 04-01-2008, 02:24 PM   #17
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I just tapped the brown-white clutch wire to JS11. Doesnt work....
I had cruise control maybe that's why, it's removed now. I checked for the neutral switch, according to the Miata manual (page F-141) it's located in the transmission. It has two plugs, if I disconnect these wires, would it work?

NEVER MIND. ACCORDING TO MSPNP MANUAL, TO ACTIVATE LAUNCH CONTROL, SOLDER PINS 12 AND 13 ON THE MIDDLE CONNECTOR TOGETHER.

Last edited by 90turboMX5; 04-01-2008 at 02:32 PM. Reason: Wrong information
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Old 04-01-2008, 02:35 PM   #18
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not quite sure. i didn't play with it, new one doesn't have

the clutch switch breaks the circuit when the clutch is off, however, the neutral switch completes the circuit when in gear

so no matter what, when in gear, the launch control light should be on...something like that.

but yes. it seems, if you simply disconnect them, it should work.
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Old 04-01-2008, 02:37 PM   #19
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6-speed + pucked clutch + 80lb.ft buffer between power output and clutch rating = FFS and LC for me.
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Old 04-01-2008, 03:14 PM   #20
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Ok, I just soldered pins 12 & 13 together and the launch control works.
It doesnt work well though. When I accelerate the rpms go to 2300-2400 the timing drops to 5 degrees and the rpms drop to 1200rpms...wtf??
The settings are:
Start retarding at: 2500rpms
retard to: 5 degrees
Hard cut at" 2700

I tried retarding timing to only 15 degrees and raising the rpms to 3000 retard and 3100 hard cut and it does the same? ANY INPUT
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