GEMS - General Engine Management Systems Ltd - Forum

Hi all,

Some of the older GEMS systems use the top speed line of the fuel, ignition, boost, fuel and ignition limit maps for the launch. users can map the engine to be held at a certain RPM and boost using the fuel and ignition limit maps and use the standard ignition and fuel maps to provide the retard needed and the fueling needed to build the amount of boost needed for launch. Remember when launch is active you will be in Full ALS mode as well so always watch the exhaust temperatures.

Because this system uses the top speed line the Speed table should be adjusted so that the 18th site on the map is higher then the rev rpm rev limit during normal operation (say 10,000rpm typical) this will mean the top speed line of the map is used for the launch control only.

Hope this clears things up. I should move it to the FAQ section really.
Thanks
Ed

Thank you, that makes sense now

Where is the launch rpm limit please? I realise the Rev limit L tables do not appear on this version.

Also, can you explain why when TPS ALS SWT is off (ie ALS from a switch on the speed signal wire), why does it show a speed measurement on G2.41 instead of switching ALS?

Not asking much, huh?!

Hello,

In this older launch system the RPM limit is defined by the amount of cut you use in the Fuel cut and spark cut maps on that top speed line.

I'm not quite sure what your asking in the second question, are you using a speed input as the switch pin for the ALS?

Thanks, sorry about the late reply we have had spam problems preventing us from accessing the forum.

Ed

RickS wrote: In this older launch system the RPM limit is defined by the amount of cut you use in the Fuel cut and spark cut maps on that top speed line.

From what I´ve seen you have to hold the engine at the revs you want rather than just flooring the throttle and letting the ecu handle the rev limit. Is that right or am I doing something wrong? Do you have any recommended settings for the ecu to limit the revs to 4500 rpm (where it builds 10 psi boost enough for a decent launch)?

Thanks!

Yes, that is how our (downloadable) base calibration for this ECU is set up. It is not designed to 'plant' the throttle but with Launch switched and the ignition and fuel cut set for optimum engine speed. This can be adjusted by the amount of 'cut' you specify. You'll hear when this is reached and as you state, has to be held manually. To get moving, release the clutch and bury the throttle and the 'cuts' will remain active until the 'Launch Off' speed is reached.

It may be possible to set high FUEL/IGN CUT figures (90% etc.) and a higher than maximum rev limit in the Speed table to be able to floor the throttle prior to launch but we have no set up for this and this is not how we would advise this setup to be configured.

HTH
RickS

I am having trouble with the deactivation of the ALS once the clutch is released. It remains on the limiter no matter what the speed is or gear. The deactivation speed is currently set at 10kph. I also tried 5 and 2kph but still the same problem. Road speed shows that the ECU is receiving a speed signal. This is on the Evo 9.

PBW/ALS 'on' and 'off' speeds are controlled by options PBW_ON_SPEED and PBW_OFF_SPEED and these refer to engine speed. If you are altering PBW_ON_(F)_SPD and PBW_OFF_(N)_SPD then these are road speed limits below which the ALS/PBW will activate.

I would really need to have a look at the calibration to offer further assistance as it sounds as if yours is calibrated a little differently, but don't post it here. Is this for 'full' ALS or the 'mild' N mode? There are full ALS/PBW setup details in the attached document or you can download any of the Lancer Plug and Play manuals available from our website.

HTH

I am so sorry, I used the wrong terms. This is what I meant: when in full ALS/PBW mode and launch mode once the car is launched (clutch released and wheels moving) the launch limiter will not deactivate. The launch mode stays active until ALS/PBW is switched from full to N (mild) mode.

These are my current settings

Launch off: 10kph
Launch once: on
Launch rtd: 30
Launch rtd +: 5
Launch in pin: switch always on

I also tried using a toggle switch on switch #11 but no luck.

Your quick replies are much appreciated as we have a race this weekend.

I would set the 'Launch In Pin' to either the pin location on the switch or set up a timed switch. A typical setup would be.

Launch In pin Swt Timed 1B On
Launch Off 20 (kph)
Launch Once ON
Launch Rtd 33.00 °
Launch Rtd + 5.00 °
Launch2 In pin Switch is Always OFF

HTH
Rick

Ok I tried your recommend settings, but still the same issue. The launch control will not disengage after the car has passed 20kph

OK. Before I call it as a hardware failure, would you please send me the current calibration to tech (dot) support (at) gems co uk..... Thanks. I'll run a compare to see if there are any other differences.

Am I right in assuming that this problem has just started or has it always been this way...?

Regards,
RickS

There are some parameters that I would like some details on. Would you please log VSS count and the road speed parameters and let me know how accurate the figures are. I am assuming that you are using 01v24 as I haven't seen a calibration yet. Many thanks.
RickS