Now, now - no smutty answers from the back of the class, PLEASE!

I'm about to start putting Megajolt on my car, and I was wondering where to put the MJ unit itself. The instructions say to put it inside the cabin area, but those are written for tin-tops. With a Locost, under the dash is almost as likely to get wet as under the bonnet, and will certainly be damp-ish now and again.

On the engine side of the firewall will generally be drier most of the time, but may get too warm. Plugging in the serial cable will be 'interesting' (but certainly not impossible). Wiring will be a LOT easier.

So which side to choose?

David

[Edited on 11/12/06 by David Jenkins]

In cars that get wet etc fairly often I have velcro'd the ECU onto the trans tunnel and taken it out when its likely to get wet

I'm thinking of mounting mine under the dash bolted to a large heat sink but sealed if that makes sense

I put mine on the engine side of the firewall and it hasn't given me any problems. Although I did use different connectors. I also planned to seal the case up but never got round to it.

I am now on the road to megasquirt and I'm not sure if I'm going to put it in the same place as if the MJ dies then the EDIS will still run the sparks in limp-home (unless it kills the EDIS as well). But if the Megasquirt dies then it is a bit of a showstopper.

How's it gonna get wet under the dash (inside the scuttle?)?

I've driven mine every day for 3 weeks and got pretty damn wet in it... the one area I'm sure hasn't got wet has been inside the scuttle area!


Cheers,
James

I can make a nice amount of room after a tidy up middle to passenger side under the dash, more of a tidy up is needed in front of the scuttle for the edis4 and other additions (catch tank/windscreen washer bottle)

Does anyone know if the edis has to be mounted on anything (plinth like) for cooling,or can it just be bolted straight on the firewall ?

I installed mine under the dash to be away from water and damp. It only requires a grommet to feed wires through and makes connecting the laptop easier.
If I was going to install it in the engine bay I would enclose it in some kind of waterproof casing.
My MS will be going under the dash on the passenger side.

quote:

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Originally posted by David Jenkins
Now, now - no smutty answers from the back of the class, PLEASE!

I'm about to start putting Megajolt on my car, and I was wondering where to put the MJ unit itself. The instructions say to put it inside the cabin area, but those are written for tin-tops. With a Locost, under the dash is almost as likely to get wet as under the bonnet, and will certainly be damp-ish now and again.

On the engine side of the firewall will generally be drier most of the time, but may get too warm. Plugging in the serial cable will be 'interesting' (but certainly not impossible). Wiring will be a LOT easier.

So which side to choose?

David

[Edited on 11/12/06 by David Jenkins]

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Hows about sticking it in a Tupperware box? It can go anywhere then!

Found some info whilst googling late at night that said the EDIS much prefers the c ooler under dash area.
As our cars get quite hot under the bonnet i will be moving my EDIS to sit close to the MegaJolt under the scuttle. It is all bolted to an ally plate so should act as a heat sink

Hadn't thought about the EDIS - but it came out of an Orion, where it lived under the bonnet. That's a pretty
tight space, and it must get hot!

Come to think of it, it was on the side of the wing, so maybe it was cooler there. Have to check.

Does the EDIS have to be mounted on a metal surface? I know that it does switch significant currents, so maybe it does... mine will be on the metal firewall anyway, so it's just curiosity.

Thanks to all anyway - the MJ box is going on the dash side of the firewall, under the scuttle. Probably.

David

David

I'm planning to fit my edis to the firewall as well, i will though fit spacers giving a 5mm gap as i have read this elsewhere but if its of any inportance re cooling i dont really know.

I'm sure some of the wise on this forum will put us straight

I mounted both the edis and megajolt inside the alloy pedal box cover.
The Edis should be bolted to a flat surface for cooling, on the donor it is usualy fitted to a bracket that attaches to the wing and acts as a heatsink or the flat bulkhead.
My megasquirt is just under the scuttle above the passengers knees and has not had any problems with water , it is always dry even after driving in the rain.
The Edis is rated for underbonnet temperatures but some megajolt components are only rated to 80c maximum, even so that is actually quite hot.
Paul

I hope everyone is protecting their assembled Megajolt PCB's with Conformal Coating! The solder resist provides reasonable protection for the areas it covers, but solder joints and components leads are all vulnerable to damp conditions.

bolt the edis onto some ally surface/plate,dont forget the heat sink compound....available from your friendly local wlm member

Conformal coating: is that on the underneath only, or on both sides?

Heat sink compound: got a tube of that (from when I put
the ignition unit on my Bosch dizzy).

Thanks,
David

I always spray the board both sides with conformal coating after testing and cleaning. It does help protect from corrosion caused by moisture in the air.
Heat sink compound is an idea on the Edis but I never used it , mine is bolted to a nice flat bit of alloy.
Paul.

If the firewall is metal not GRP then bolt it flat to it , it will then act as a heatsink.I find the Edis on my test rig gets warm after prolonged use and is not driving a coilpack , it is open to the air though.
Paul.

quote:

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Originally posted by bob
David

I'm planning to fit my edis to the firewall as well, i will though fit spacers giving a 5mm gap as i have read this elsewhere but if its of any inportance re cooling i dont really know.

I'm sure some of the wise on this forum will put us straight

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