Who actually uses launch control?

[jammapic]

Hi,

I've been asked by a few people for "launch control" in their maps, which I've done and they seem happy with.

However, after setting it all up myself on my own HDi. What's the point? I can get a faster start by just knowing how to drive properly!!

So, question. Who actually uses it? And what rpm do you have the launch set at?

JP

[THE_Liam]

Launch control = clutch ra*e, don't get it myself. Obviously unable to drive.

[Dum-Dum]

IMO it's just a toy. "ooh look, I've got launch control like one of those F1 cars"

[Matt]

Just matt the throttle to the floor, same thing right.....

[Toms306]

When would you use it anyway? I hope there aren't HDi's sitting at traffic lights in town revving their nuts off with launch control..... 306's get a bad enough rep as it is!

[welshpug]

IMO it's just a toy. "ooh look, I've got launch control like one of those F1 cars"

F1 cars don't have launch, and its actually kinder to the transmission than the simple sidestep and mat it approach by far.



Saxo rally car I service for had it on the DTA ecu, fairly primitive thing really, new car should be far better as it has flatshift sequential box hooked up to Motec.

[Welshy_Pete]

There scrap.

[jammapic]

That sort of answers my question, same as I thought really...

[darrenjlobb]

When you have a chronic blower...launch control is a godsent....

Retarded timing / midrange hard cut, full boost from word go, instead of 50 yards trying to wake the blower up....

Otherwise you have to sit there loading the motor up on the clutch...which is going to last about 10 times before you cook the clutch!

[WiNgNuTz]

There scrap.

*They're

[Ruan]

When you have a chronic blower...launch control is a godsent....

Retarded timing / midrange hard cut, full boost from word go, instead of 50 yards trying to wake the blower up....

Otherwise you have to sit there loading the motor up on the clutch...which is going to last about 10 times before you cook the clutch!

This "Launch Control" however isn't doing any of that... It's just a limit on IQ until you get past 2mph or so.

Hence pointless.

[darrenjlobb]

When you have a chronic blower...launch control is a godsent....

Retarded timing / midrange hard cut, full boost from word go, instead of 50 yards trying to wake the blower up....

Otherwise you have to sit there loading the motor up on the clutch...which is going to last about 10 times before you cook the clutch!

This "Launch Control" however isn't doing any of that... It's just a limit on IQ until you get past 2mph or so.

Hence pointless.

I know, hence its not launch control, its just a revised rev limiter in first gear...lol

It should be spitting flames making 30psi on the launch control

[padge]

Come on, it sounds good on a straight pipe lol

[Dum-Dum]

It would be awesome to make it so it was pouring fuel out the open exhaust valves on launch control to really spool the turbo and make some boost and coal.

[ginge191]

but, it makes you look badass mofo!

http://www.youtube.com/watch?v=Tv9WSc54dI0

[Dum-Dum]

I think that ibiza really is a case in point and proves almost all of the above.

[Ruan]

Post injection map anyone?

Multiple post injections (would take a lot of playing with to get right) at varying stages of the combustion process and carrying on after the valve opens to keep temperatures up would help a massive amount - but doing it so you don't ROAST the valves or just pour boiled diesel down the exhaust would be difficult... But can be done.

[jammapic]

It can be done, but it will 100% toast the motor, very quickly.

The IQ limiter is not "launch control" despite what people say, it's simply a hard cut rev limiter, dependent on vehicle speed. Which is why I said right at the start - it's useless.

JP

[Dum-Dum]

I've gotta say I'm not sure how badly it would toast the engine if done right. Your little pre heating/keep the engine spinning at 2-3k injection needs to be nothing more than it would usually need and gives EGT of maybe 400* guessing off peoples EGT gauges and that would be no more than it usually makes then the stuff your firing out the open exhaust valves I'm not entirely sure would combust as your loosing compression all the time and its not a high temperature or much oxygen so you have no chance of burning the valves IMO any more than a coaling XUD

Or is that completely wrong?

[jammapic]

You need big EGT's to spool the turbo dum.

To get the EGT, you'd use very retarded timing, and dump the fuel out mid burn.... queue lots of timing smoke, big egts and boost. Then when you start moving, bring it all back in line.

JP

[Ruan]

I've gotta say I'm not sure how badly it would toast the engine if done right. Your little pre heating/keep the engine spinning at 2-3k injection needs to be nothing more than it would usually need and gives EGT of maybe 400* guessing off peoples EGT gauges and that would be no more than it usually makes then the stuff your firing out the open exhaust valves I'm not entirely sure would combust as your loosing compression all the time and its not a high temperature or much oxygen so you have no chance of burning the valves IMO any more than a coaling XUD

Or is that completely wrong?

To get it spooling properly you need the diesel burning literally as the exhaust valve opens and throughout the valve open stage... As I said, you'd need multiple injections throughout the entire cycle to ensure the gas stays hot and fuel stays burning... That's when you're likely to roast valves etc... Considering I've seen diesels torch pistons with poorly timed fuel, you could quite easily roast some valves given the right timing...

It'll be very harsh on the engine, but IMHO only as bad as petrol antilag with limiting... Antilag you can easily toast components if set up wrong... Best thing I can advise, go and play with injection timing and see how differently the turbo responds and egts move about... Given a few degrees of retard, you can get the turbo spinning like mad and the egts close to 800c just slightly leaning on the throttle...

[jammapic]

I'm pretty sure you could do that actually, by manipulating the injector calibration and the injector duration selection maps. But it would be a lot of work to make sure it only read that (retarded timing and specific IQ limit) particular part when it needed to. You'd have to basiclly use one of the injector calibration maps as a "launch timing" map, and re-lin all the other maps to suit.

I'd like to have a go... anyone got a donor car they don't mind me blowing up? :-P

[Ruan]

See I had an idea of bodging it badly... This was only a wild thought, use a coolant temperature map - since I know they're able to adjust SOI - if you had a switch that could near enough short out the sensor (or known value resistor...) and having it at that temperature read by the sensor - you could then modify the SOI to be very late at that (fake) ect.... Then if you can switch injector calibrations (NO idea if you can do it on the fly) - or at least force it to an area never reached under normal conditions to get the fuel in late... But the thing is, that's not doing it in multiple stages, that just allows you to throw fuel in very late in one hit, you still want a proper normal combustion, but just dropping fuel in later into the cycle when requested... You want to be able to do it as a post injection really...

There's got to be a way of enabling the post injection maps, therefore you have adjustable quantity and soi for them without pissing with calibrations? Surely?

[jammapic]

See I had an idea of bodging it badly... This was only a wild thought, use a coolant temperature map - since I know they're able to adjust SOI - if you had a switch that could near enough short out the sensor (or known value resistor...) and having it at that temperature read by the sensor - you could then modify the SOI to be very late at that (fake) ect.... Then if you can switch injector calibrations (NO idea if you can do it on the fly) - or at least force it to an area never reached under normal conditions to get the fuel in late... But the thing is, that's not doing it in multiple stages, that just allows you to throw fuel in very late in one hit, you still want a proper normal combustion, but just dropping fuel in later into the cycle when requested... You want to be able to do it as a post injection really...

There's got to be a way of enabling the post injection maps, therefore you have adjustable quantity and soi for them without pissing with calibrations? Surely?

Firstly, yes you can adjust injector calibration maps on the fly (it actually does it out of the box anyway, based on requested SOI (based itself on requested IQ/rpm etc). That's how it works out it's whole concept of injector duration.

Your theory is sort of what I meant anyway - but without a switch... use the vehicle speed as a switch. Which there IS a map for. You'd just have to make sure that when stationary, with foot to the floor, the situation it was in could NEVER be reached under driving conditions.

I've just been looking now, and following through how the ECU comes to a concept of "time" and how it then works out all parameters for a particular injection cycle and it could be done - but as I say, would be a lot of arsing about / redoing axis on maps, fudging which maps it uses and stuff.

JP

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oh, and while I think on... the normal injector calibration maps DO allow for post injection too.. they are based on crank angle anyway.

[Dum-Dum]

Some smart ideas guys. I'd be tempted to offer my car for development but its that unknown quantity of how long will it last burning the valves, will you get 1 launch or 100 before lunching an engine.