full throttle up-shifting on seq. box

[Marius]

Trying to find another solution for my 7 (240BHP VX):

 

I´ll fit a Quaife sequential 6speed box this winter and try to find out, what chances I have to stay on the throttle when shifting up. I´ve just gone through quite a few mags to find articles & pictures of seq boxes and the gear"knobs".

 

What I found so far, is that quite a few engine managements (DTA for examplae) do have an input pin for a "full throttle shift switch". When this switch is being activated (or deactivated, depending on system), the management sets back ignition to take a bit of force from the drivetrain to help engaging the next gear.

 

After taking a look on some knobs (not what YOU think again.. ) I saw that for example on the 6speed sequential GEMINI box for the Elise (by QED) the gearknob has got some wires coming out of it. I think there might be some kind of switch inside the knob which recognises a certain amount of force when the lever is being pulled back in order to upshift and sets back ignition or similiar.

 

All you technicans: how far am I away from reality ? What chances do I have to get such a thing up & running and mor important - will it work properly or will it split the box apart ? The system would not be used on the road or a two days track day of course. Only on "special occasions" like hillclimbs or Curborough... 😬 I´m quite sure a proper set-up could give a few hundreds of a second. Otherwise they wouldn´t do it in all the touring cars.

 

Technicians, step forward please. Your thoughts, please.

 

Marius

 

[Joost M]

Hello Marius,

 

Here you can find some information:

 

Racelogic

 

The problem with this package is that it is integrated in the Racelogic Traction Control unit. You will need to fit the unit und the "Self Fit Sensors" (because your car has no ABS). I used the system in one of my cars (not a Seven) and I was very happy with it.

I drove a seven with the same system and it was terrible.

 

In touring cars they shift without using the clutch (dogbox). There is a switch that cuts the ignition if they change gear for a fraction of a second.

 

Regards,

 

Joost

 

Edited by - Joost M on 5 Nov 2002 21:13:19

[rocky]

Hi Marius

 

You should be able to flat shift with this type of gearbox Wether it has a cut off or not . So long as it is dog engagement.

Obviously it will cause a lot less wear and tear if You can sort a cut out but if it proves difficult you can make the shift on the first hit on the limiter

 

If in doubt flat out 😬

 

Mark

[Paul Ranson]

I had a device on my Pilbeam made by 'Mecdine Instruments Limited'. It used an LVDT on the shifter and cut the ignition during a range of travel when shifting upwards. So you take up the slack, the ignition cuts, the shift starts, as the lever nears the end of its travel the ignition comes back, because it's an LVDT it knows which direction the mechanism is moving in and doesn't cut the ignition on the return stroke.

 

It started turning the ignition off when the engine was being cranked, so I've stopped using it. I don't think the benefit is that significant and it was tricky to setup correctly.

 

I understand that Bosch do a rather nice unit, but it's more than £1000. Saves on dog wear at Le Mans though.

 

IME you can't flat shift without assistance. The gearbox won't come out of gear under power. I suppose you could use the rev limiter to achieve the effect but this isn't very smooth. I find that the shift goes through very quickly and seamlessly with only a very slight feather off the throttle.

 

Paul

[clarkey]

Speak to Graeme Finlayson (gee_fin on here). He'll be able to talk to you about using full throttle on up shifts with this combo.

[Marius]

Just had a look on the DTA-website. I´m using the E48 system which offers the chance to fit a simple switch, which when being activated sets back ignition for a preset time.

 

What I definitly need now are more informations about these systems fitted to the gearlever. I´ll conctact QED for theirs being fitted to the Geminin box.

 

Marius

 

[Morls]

I'm sure the method used on Coose's hillclimb bike was a £20 soloution.

 

Rider moves gear lever the first 10mm

 

A microswitch detected movement of the gearlever

 

The microswitch started a timer which opened (or earthed ) the ignition lt circuit

 

Rider completes the gearchange.

 

The end of the timer period closed (or unearthed) the ignition lt circuit.

 

Bike surges forward in a higher gear. *arrowright*

 

Sprung Microswitches and Variable timers are very cheap from RS or Maplin, I think Coose ended up with about 200mS dead period. (albeit this was with a fast revving, low inertia 2 stroke bike engine, a big reletively heavy car lump may need lots more).

 

I'm going to try this method on mine.

 

Mark

 

☹️ My Caterham Silver Jubilee No. 7 is for sale ☹️

[westy]

have a look at the bike ones

[EFA]

Any hard cut unit will not work well.

 

The shift switch on DTA ign etc is designed to be used on the clutch pedal!!!! (not a sequential box). The Racelogic option does not work on the majority of their units even though it is documented.

 

The Medcine unit Paul Ranson refers to above uses a linear pot to establish a "map" of the shift linkage (engaged/disengaged/dogs poised to engage etc....) This is the only system that will work very well IMHO.

 

Forget microswitches - environment is too harsh unless you plan recalibrating every 5 minutes.

 

 

 

Fat Arn

Visit the K2 RUM website

See the Lotus Seven Club 4 Counties Area Website here

 

 

 

Edited by - fat arnie on 6 Nov 2002 14:56:32

[Marius]

Just got a mail from QED:

 

The supplier of the gear-knob with the integrated switch has gone out of business. Anyone an idea where to get hold of these goodies ?

 

Marius

 

 

[Chelspeed]

I've got a cunning plan.... MBE has the flat shift facility. I've got a autocad drawing of a knobbie incorporating a proximity switch actuated by the first 1/4mm or so of movement.

 

So you grab the stick and start to shift, as Paul said with the throttle flat it won't change as the dogs hold it in, the knobbie moves triggering the switch and the MBE cuts the ignition, the dogs free and it shifts. X ms (set in the MBE) later the ignition cuts back in and you're off.

 

At the moment I shift without the clutch just with whats meant to be a slight lift of the thorttle. The logging shows that the slight lift is usually more like a 0.2 sec totally off throttle, bury it again. Can you be ham fisted with your right foot?

 

Just got to find someone to make it for me......

[Marius]

Mmmm, 1/4mm seems far to little to me, prone to unwanted ignition-cuts I guess. Regarding the total movement of the stick something in between 10-15mm seems more appropriate.

 

Arnie, I think it doesn´t matter if you put the switch to the clutch pedal or to the shift-stick, DTA cuts Ignition off anyway as soon as the switch is being hit. And: a switch on the clutch-pedal to cut ignition doesn´t really make sense, then I can use the clutch as usually and do not need an ignition cut. Or am I getting something wrong here ??

 

Does Gemini have a website ??

 

Marius