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Old 09-13-2007, 10:22 PM   #1
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Default Launch Control w/ Linear TPS

Looks like launch control can run w/o having a dash mounted switch if you have a linear TPS.

The box says enter a RAW tps value, I assume that means ADC. My WOT ADC is 255, so I could enter in say 200... That way I could always leave launch control active, not have an extra switch in the dash, and it would only activate if the clutch is pressed in AND I'm at a pretty high throttle position. Seems to me it would work great, with the only potential issue being that variable launch might be tricky or work right. But if I'm right, then I could just leave lc and flat shift on in software all the time.

Gonna try it.

In case you guys couldn't tell, this is really my first time actually going through every one of the menus in MegaTune. It's good stuff.
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Old 09-15-2007, 08:41 AM   #2
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suprised no one's tried. i'm gonna go out and give it a shot since the streets are still wet from last night's rain. figure that will keep my diff safe.
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Old 09-15-2007, 09:04 AM   #3
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I didn't think this would work properly, because say you rev to 7k and go to shift, which (just hypothetically) drop the revs down to say 5.8k in the next gear, and you have the limiter set to 5k then the MS will be trying to limit the revs down to that limit and you will be loading up the driveline heaps letting the clutch out at 5k when at 5.8k road speed.
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Old 09-15-2007, 09:51 AM   #4
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It's a TPS limit, not an rpm limit
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Old 09-15-2007, 09:55 AM   #5
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I'll also modify my harness to wire in the clutch switch as well.
Though i noticed I have two clutch switches. One for the interlock and the other for... I don't know. I do know that my stock ECU has a wire going to it so i figure that is the depression switch, not the interlock one.
Any input for me while i'm doing all this today?
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Old 09-15-2007, 10:08 AM   #6
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cj, anything that goes low (goes to ground) when the clutch is pressed is what you need.

LC seems to work as promised, as does flat shift.
I took it VERY easy on the old girl, one for empathy and two because it's still wet out. Flat shift sent me sideways.
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Old 09-16-2007, 11:23 PM   #7
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What are your settings? I just ordered a TPS and would like to try it out.
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Old 09-17-2007, 02:14 PM   #8
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Quote:
Originally Posted by Ben View Post
Flat shift sent me sideways.
What, no video of this?!
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Old 09-22-2007, 10:16 PM   #9
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Ben, care to share a screen shot of your launch control settings?
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Old 09-22-2007, 11:25 PM   #10
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The female has been hogging the laptop all night

Most of the settings are pretty car dependant anyway.
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Old 11-20-2007, 02:27 AM   #11
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Man launch control is fun. Makes taking off soo much more fun. Just need to mess with the RPM a little to make it hook a little better, my 205s don't like to grab even though they're rt615s.
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Old 11-20-2007, 03:26 AM   #12
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be careful leaving it on all the time. I had it on once and tried to pull out into traffic from a stop and nailed it, and got stuck at 3k rpm in front of a big rig. And dont forget to turn on spark cut for this, flames will make ther ricers jealous and scare small children.
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Old 11-20-2007, 04:02 AM   #13
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I've thought about hooking my clutch switch back up and enabling launch control, but why bother if you can't hook 1st gear anyway?
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Old 11-20-2007, 09:21 AM   #14
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Since nobody's answered one of the original questions yet:

You're correct: Raw TPS values are the ADC values.
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Old 11-20-2007, 10:29 AM   #15
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Is flat shift the same as power shifting(letting the engine continue revving while shifting)? Chad and I were discussing this last night and I think I could have given him the wrong information.
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Old 11-20-2007, 10:43 AM   #16
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basically.

you don't lift your foot (gas) when you shift, you tell MS what RPM you want it to hold at and how much timing to retard. Keep the turbo spoolin' better if you set it spark cut and backfire like a **** doing it.
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Old 11-20-2007, 10:48 AM   #17
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Quote:
Originally Posted by Braineack View Post
basically.

you don't lift your foot (gas) when you shift, you tell MS what RPM you want it to hold at and how much timing to retard. Keep the turbo spoolin' better if you set it spark cut and backfire like a **** doing it.
Yea, but letting it backfire like that will prematurely destroy the turbo as the fuel is ignited during the exhaust stroke. The launch control probably works the same way, its cutting ignition events isnt it, and throwing fuel out of the exhaust?

Great for rally cars that can rebuild their engines after every race, not good for a street car.
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Old 11-20-2007, 10:58 AM   #18
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I don't see it killing a turbo. It will kill your cat.

If anything you can keep fuel cut only on and don't shoot any flames. Even without the flames, retarding the timing and increasing the EGTs will spool that baby.
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Old 11-20-2007, 11:02 AM   #19
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Quote:
Originally Posted by Braineack View Post
I don't see it killing a turbo. It will kill your cat.

If anything you can keep fuel cut only on and don't shoot any flames. Even without the flames, retarding the timing and increasing the EGTs will spool that baby.
You have an explosion of fuel hitting the blades of the turbine, everywhere I have read says that it damages the turbo.

As for higher EGT temps, how much higher are they and is it enough to affect the O2 sensor which is downstream?
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Old 11-20-2007, 11:11 AM   #20
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