Any ideas on how to do a 2 step launch contol on a S60

[stevieturbo]

Just one switch on the clutch, the timer starts once the clutch is released, this feature is aimed at grass track cars (wheel speed sensors not permitted) with bike engines using clutch-less up shifts. I can't see it working on a normal car easily. However you could use one of the axillary channels to cut if off from wheel speed or something, but then again if you have wheel speed just use the normal launch.

TBH Ive tried the usual launch feature a few times and found it to be no good. Plus the fact all adjustments are made on the laptop which would make testing a very very slow tedious process.

Using elapsed time would actually be very simple, and via a pot much easier to do some testing to see what works best for that particular surface.
It should be an easy software change to allow the timer to start on either a clutch switch or once wheelspeed has been detected but only after the system has been armed as usual.

Or a lot of ecu's will let launch activate below a speed threshold, and turn off above a speed threshold.

Which I guess I could configure an Aux out to do this, then feed it back into the Launch button input.
Would be a lot easier and more sensible for it to be allowed internally, rather than having to wire as an output back into an input.

[Rob Stevens]

Steve, you have mentioned before that you had no luck with the traction or launch indicating that it didn't work with the amount of power you had. I've used it for years and it's fine, traction is easy. Launch with wheel speed will always be better than time as it auto corrects (once in traction phase of launch) as you are rolling to keep the 20% slip (or whatever). I find it hard to find the right launch rpm however, I have a no flywheel bike engine that will just stop if I get the rpm wrong, I no longer use the full throttle launches but sort of feed it in.

[stevieturbo]

The traction does work. Whether it is very efficient or not, I cant say, but it certainly does limit power. The only real issue I had, is that for some reason it can be slow to detect and react.

And having say a flat 20% isnt adequate. 20% slip at 20mph is no big deal, that's only 4mph over base. Quite safe etc.
However, 20% at 120mph allows wheel speeds of 144mph before any action is taken, which is too late.

Slip based on vehicle speed would be a great addition.

But back to launch. via time would be easy to setup and test. It allows me a few different launch rpm's without having to resort to the laptop. Although I think this is still possible with the normal launch setup ?

I have previously tried different slip levels for launch, but TBH never had any real success. Due to lack of grip on local airfields etc, ideally launch rpm would be very low so there isnt an initial huge loss of traction.
Usually I do just roll off the line and launch manually. In theory though, an ecu based setup should be able to control it more efficiently.

[Rob Stevens]

Steve, I think that the way Allan describes the launch and traction settings is wrong and confused.
For traction the 'Target Slip' isn't actually the target, that figure indicates that the traction will be inactive until that slip figure is reached, the 2nd figure 'Excess Slip To Hart cut' indicates the amount of slip that would invoke full spark cut. In reality the amount of slip will hover around 10% if the first target figure is say 5% and the hard limit 60% Once you know this it should be easier to implement and is almost automatic compensation for speed as the amount of excess power reduces at speed any way
If you are getting 20% slip at 120mph set as above I'd be very surprised unless its wet.

Confusingly the launch slip is actually a target so can be set much higher, I get fair results at 17%
Look at this video, from the start the engine bogged once in the target slip zone of launch, I had the slip target set too low and the motor has no flywheel to help it.
Then out of the last corner the traction is working hard at around 10% wheel spin, you can hear it.
I spend a fair bit of time watching Allan's car off the start line and he has it sorted for sure.
Post up your launch map and I'll see if I can see anything wrong?

[stevieturbo]

If you are getting 20% slip at 120mph set as above I'd be very surprised unless its wet.

Even in the dry with R type rear tyres ( ie 888 etc ) I cant use any more than 30-35% throttle on the road in 1-3 gears. 4th gear just about hangs on with these tyres, although if the surface is any way bad, away it goes..
With normal road tyres, wheel spin through to 140mph is just a tap of the throttle away in 1-4 gears.

When I did the 200+ mile runs, on one run when the track was still slippery ( not wet, just slippery ), front wheelspeed was recorded at 190mph, rears managed to hit 214mph when it broke loose. And yes I thought I was going to die.

20% slip at only 120mph isnt really that difficult to achieve.

I'll maybe have a go at using the launch setup again, it's just a slow tedious process and I have little patience lol

[stevieturbo]

Nice video, one very fast little car !. But I assume you have a fair bit of grip and a light vehicle ?

I'm trying to shift 1700kgs+ with only 255 section rear tyres and silly amounts of torque on tap.

At Santa Pod etc it is no issue. I can literally dump the clutch at 5-6k and it just goes.

At local venues, airfields etc traction is simply non existent. Even at Elvington airfield which is fairly abrasive and using Hoosiers at the weekend, I still struggled to get a 60ft below 2secs, and that's just rolling off the line.

By comparison, Ive seen big Merc automatics on normal road tyres pull off 1.8s 60fts. Obviously auto's always launch so much easier, but I should be able to do better if they can manage that.

Brutal launching at Santa Pod sees 1.5s 60fts without too much trouble.