tuning and how to use launch control

[renxun]

im getting myself a pair of 272 cams and with u guys suggestion and info im setting up myself my fueling system to a parrelel 910 on a stock regulator... now wat i will do next is to get myself an efi fuel preassure metre to monitor the rail preassure and see how it does.....

oh ya... btw im getting myself a launch control unit... it come with mode 1 for the desired ignition cut and mode 2 for the activation by button....so i had set my mode 2 to 4k rpm to launch and 7k rev limit at mode 1.... so about the button thingy ... when i press it and i floor the throttle it will emit those banging sound as if a missfiring system? and how do i launch tis thing..? when should i realease the button after i launch..? i dont know how to use this thing man.....even my frens dont know how to launch a launch control..

[stradlater]

Firstly, it's 'Friends', not frens, and you could use some capitalization....

A Launch control unit is primarily for automatic drag cars that have a high stall converter. Therefore, they line up, press the launch control button, so it only lets it go to a certain rpm, then when the lights go green they let the button go, the converter hooks up and they're away.

Other than that, they are pretty well useless.

In answer to your question when should I realease the button after i launch..? You shouldn't still HAVE the button depressed after you've launched. Enjoy munching things if you do....

[YLD-16L]

Other than that, they are pretty well useless.

The "two step" setup in my mates car that I was setting up last time I went to WSID was definitely worthwhile. It made launching in a manual very predictable and repeatable and as we got the rpm right it got quicker.

Switch it on on the line, push clutch in (which activates another switch) BANG bANganababang!!! 14psi under no load, side step clutch > launch! Then just hold the pedal to the floor the whole run and shift without risk of over revving or losing boost between gears. Cross the line and switch the "two step" off.

It's most useful on slicks, otherwise it just spins the bejesus out of the tyres You can alter the launch rpm to suit the tyres and track suface though.

[Draven]

mmm,,, turbo-munching anti-lag

[Merudo]

mmm,,, anti-lag

My sentiments exactly... that does sound quite nice...

[chris davey]

strad: I was under the impression that antilag (launch control) was mainly used for manual cars. You could use it on an auto but if you have the correct sized converter you shouldn't need to. Go easy on him with the grammar as he isn't from Australia.

yld: how do you mean flat shifting? I would have thought that if you have your 2 step set at say 4000rpm for takeoff you would have to turn it off as soon as you launched. So unless your 2 step limit is the same as your rev limit then you would have to turn it off after launch. This would also make it a 1 step limit rather than a 2 step as the name suggests

To use them, you can experiment but from what I have seen you chuck in an extra 50% fuel or so so it is very rich and retard timing to the maximum (usually static value) so on my car that is 10deg BTDC. (before top dead centre). I haven't done it yet though.

Ash =L=A=N=C=E about it as he has his wired up (microtech) to hix clutch pedal and another switch I think.

And yeah, it probably isn't too friendly on your turbo.

[YLD-16L]

Ask =L=A=N=C=E about it as he has his wired up (microtech) to his clutch pedal and another switch I think.

That's what the one I was playing with is setup like.

yld: how do you mean flat shifting? I would have thought that if you have your 2 step set at say 4000rpm for takeoff you would have to turn it off as soon as you launched. So unless your 2 step limit is the same as your rev limit then you would have to turn it off after launch. This would also make it a 1 step limit rather than a 2 step as the name suggests

The only time the "two step" is activated (once switched on via a dash switch) is when the clutch is depressed (second switch).

So you can do the run with the pedal to the floor and each time you depress the clutch the rpm limit drops to the preset "two step" rpm value (timing and fuel values altered too) boost will not drop below the value the timing/fuel will allow and rpm won't hit the rpm limiter, rather it'll drop a little to the "two step" limiter.

It is only one rpm value that is set by the clutch activated switch.

It works very well and certainly makes runs easier and as a passneger when testing it it felt very good.

The popping, banging and flamage out the exhaust are cool too

Turbo life shortened, by how much though???? Who knows, you never run it that often anyway.

[stradlater]

Woops. Thought that was from australia.

And by launch control, I wasn't assuming anit-lag...

[renxun]

thanks alot for u guys feedback....and for the grammar error i was actually just trying to use short forms of typing... =)

so to set it at 4k, i press down the button , flooring the gas and when i pop the clutch release at the same time n shift while holding the gas down? doing tis can only get me to 2nd gear and on the 3rd it was stuck un less i release the gas to shift.... its hard to get perfect shift while 100% flooring the gas through the way to the finish line...especially on the 2nd where the car might fish tailed due to excessive spins...

[RONA]

Having witnessed both a 2 stage and antilag in use at the last hillclimb I was at I will say one is a much better thing then the other.

Amusingly with antilag lag on the Evo9 ran slower times then it did for both drivers in the car with it off.

The two stage limiter used on a wrx there worked very well though, set at a point at such when the clutch was dump there was just enough wheelspin to keep it on boost. Made for some very efficient launches and probably the reason it pipped the evo on times.

[Joshstix]

thanks alot for u guys feedback....and for the grammar error i was actually just trying to use short forms of typing... =)

so to set it at 4k, i press down the button , flooring the gas and when i pop the clutch release at the same time n shift while holding the gas down? doing tis can only get me to 2nd gear and on the 3rd it was stuck un less i release the gas to shift.... its hard to get perfect shift while 100% flooring the gas through the way to the finish line...especially on the 2nd where the car might fish tailed due to excessive spins...

No you want to setup two switchs which both need to be closed for the two step to activate. One you put on the dash as an arming switch. The other you put on the clutch so that it is automatically enabled and disabled based on pressing hte clutch pedal. The easiest way to do the clutch switch is to replace the normal clutch stop on the pedal box with a brake light switch.

[Rex_Kelway]

Rex may not be an expert, but is curious as to why you would consider launch control to perform an antilag function?

Would it not make more sense that launch control is essentially traction control?

IE you limit the power of the car on take-off to it will LAUNCH and build speed with better traction.

Antilag is only used to keep the boost up at small or zero throttle openings, this would perfrom the exact opposite to a launch control system as the car would attempt to leave the line with an unusually large surge of power.

If you cant get the car off the line with its normal boost curve, then how is a more agressive curve going to help?

Out of curiosity is the car 4WD? does it have a transbrake?

[Joshstix]

Certain terms mean very different things to different people. To me you're describing traction control rather than Launch control. To me launch control is about having the car leave the line with consistent behaviour which requires the revs to be the same etc.

If you buy a B&M Launch Control it is actually a line lock which has even less to do with what you've described.

As to not being able to get the car off the line with it's current boost curve, I seriously doubt he has bought a launch control because he is getting too much wheel spin. The idea would be to get it up onto boost for launch so that it runs quicker 60 foot times.

[-==L=a=N=c=E==-]

Ash =L=A=N=C=E about it as he has his wired up (microtech) to hix clutch pedal and another switch I think.

As chris said, i use the '2 step' feature of the microtech as my launch control. Using a push button literally ziptied to the clutch pedal, so that it engages the circuit when the button is fully depressed against the fire wall.

And then ECU settings, i set it to anywhere between 3000-4000rpm (meat of my torque band), dial in a few more mS of fuel and retard the timing a tad, and then clutch to the floor, and foot on the accelerator rev it out so its banging up against the rev limit.

Settings im still fiddling with, but i've gotten as much as 5psi with the GT35R on my motor. Once i get it 'banging' good, should be able to get a lot more then that.

Also a nice off shoot of doing it the clutch switch way, is a pseudo way of doing flat shifting.

[DX20VT]

Launch control is basically just a Clutch pedal sw activated limiter, nothing more.

Anti-lag is way more advanced and basically retards the timing to contol idle speed rather than closing off the throttle plate.
It's a little bit more technical than that but needs a long explanation, which may bore some people.

I have launch control on my RWD race car, and tried it, but after a little bit of practise I can launch far better without it. As long as I can get the tyres up to temp on the warmup lap, I can usually launch off the line damn near as good as the 4WD evo's etc in my class.