Jump to content

ID My ECU


need4speed
 Share

Recommended Posts

Been thinking about how I'm going to control my cooling fans. I would like to control them via my MS ECU but for the life of me I can't remember whether or not I specified with Nige to add this feature to my board.

Wondered if someone could tell from the pic below if I need to have it modified or not.

post-4644-0-39361400-1431373474_thumb.jpg

Link to comment
Share on other sites

He wasn't saying DONT do it. He was just advising not to.

Fans draw large currents, and when they short / back feed, there will / can be a LOT of amps hunting for a earth - and a PCB board is a bad one !

Link to comment
Share on other sites

....surely you use the transistor to then switch a relay...?

Not feed the fan directly from the pcb

The fan can then be fused (correctly) and the ms can be seperatly fused (plus with the addition of the diode protected from reverse emf when the relay coil de-energises

Guess you want the ms to switch the fan on and off at the correct temp?

Rob

Link to comment
Share on other sites

not trying to disuade anyone from doing anything (or HfH's knowledge), but just clarify that you should not be driving the fan directly.

Here's an example (yes not V8, just the principle), top LHS corner "fan", below the title... one way to do the external side

http://www.mkosonen.com/mattsmswiring.gif

Circuit board side, same principle as this, but instead of "pump" it will be "fan".

http://msextra.com/doc/ms1extra/MS_Extra_Hardware_Manual_files/water-circuit.jpg

The negative thing is you will loose an output pin....unless you had one spare that is.

Rob

Link to comment
Share on other sites

Think I've just read your post again....

Purpose of the relay is more current load than any emf issue, the diode is there to protect the chips from spikes, could use a Darlington pair to perform a similar function but then the problem is the circuit board trace taking the current

At the moment I've taken to using solid state relays these days when I can (smaller and faster than a traditional relay ).. Just watch the current rating

http://m.ebay.co.uk/itm/121183847014?nav=SEARCH

Link to comment
Share on other sites

I can only imagine that Nige has seen his fair share of damaged boards due to cooling fan issues.

For what other reason would he strongly advise against it?

Especially as I would be paying him money to modify my board for me....

Link to comment
Share on other sites

I must say I don't really agree with Nige on this one, but then I'm not selling electronics to the general public with their inherent capacity to break absolutely anything :ph34r:

I run twin fans from my MS, via relays of course, and it works lovely.

Link to comment
Share on other sites

Having the Fans independent of the ECU can be an advantage is some configurations.
On one of my V8's I had the fans wired independent of the ignition switch, which meant they would continue to run after engine shutdown, to keep air moving over the block (and cool the water in the rad more). Which was useful for it's cooling and not so easy to do with ECU controlled fans.

Link to comment
Share on other sites

The control that MS gives you over the temperature at which the fan cuts in and out is far better and based on the temperature at the cylinder head rather than the temperature in the top or bottom hose. This is preferable to a top hose fitting and similar to a bottom hose fitting.

Being able to adjust the hysteresis allows you to set a lower activation point than the "mechanical" switches/sensors with a fixed hysteresis where you have to set the turn on point high enough to avoid the turn off point dropping below the thermostat close point.

There's absolutely no reason why you can't drive a relay (or two in my case) direct from the MS ECU to control the fans. I use a fan relay and fuse for each fan so I'm unlikely to lose both fans due to a fault in one.

If you want the fans running when the engine isn't then you either turn the ignition on and don't start the engine or have a switch on the dash to operate the relays manually - I have this anyway on mine as I use an off/on/on switch in the MS control circuit for the relays to allow the fans to be turned off/auto/always on.

Link to comment
Share on other sites

Sounds like Dave and I have the same setup, and Fridge very similar again, twin fans, twin relays, with separate fused feed for each, I have an off/on/on switch for 'normal' (MS controlled), 'off' for entering water, and 'on' for forcing both fans to run no matter what the temperature.

No problem with this ever, except the relays seem at their limit and occasionally stick on, despite being 30A Bosch versions.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy