7 replies to this topic

[Turbo Phil]

The Metro Turbo ECU

What does it do ?
This seems to be a fairly common question, so i thought i'd put a post up explaining it.

Firstly to dyspell a common myth. The ECU does not control the ignition in any way. Secondly the ECU, when removed, does not turn up the boost and does not give your car "mega power" or endow it with magical Cosworth beating potential.

So what does it do ? Basically the ECU, or electronic control unit, as fitted to the Metro Turbo is used to control the boost. Below 4,500rpm the boost is limited to 4psi, after this the boost is increased to 7psi. The ECU does this by means of an electronic solenoid, which it switches on and off. The solenoid is mounted in line to the actuator and acts like an electronic bleed valve. So once the ECU senses that 4,500rpm has been reached it opens the solenoid and bleeds off some of the air signal to the actuator. This fools the actuator into thinking there is less boost than there really is, and so it in turn it keeps the waste gate closed for longer, raising the boost to 7psi. Once the revs drop below 4,500rpm the solenoid closes and boost is lowered again.

Why was it fitted ? Leyland fitted the unit in an effort to prolong the life of the transmission and to lower the amount of people claiming under warranty for failures. The ECU limits the amount of midrange torque which the Turbo produces, which was hoped would extend the life of the transmission.

So what should i do with it ? Most people don't bother with the ECU as it limits power potential, and can spoil the rush somewhat.
To run without the ECU is easy. Just remove it and place it carefully on a dusty shelf, making a note to put it on eBAY sometime soon.... lol
The standard actuator is set to 4psi, so if you run without the ECU this is what you'll see. Obviously you don't want to run just 4psi if your engine is ok for 7psi, so you can either install a bleed valve, and open it slightly {and i mean slightly} until you get 7psi, or you can install an actuator set to give this pressure.
Either way you have 7psi constant boost, much more fun !

Word of warning.
Use your head and don't expect that smokey old old engine you dragged out of a scrapped Metro to be able to handle the extra midrange torque. Adding a twin pin diff or at the very least, a hardened diff pin is very worthwhile otherwise,
a PROPERLY REBUILT standard transmission will be fine, a knackered old, rough as sticks transmission will not !

Ta
Phil. :grin:

[cooperlooper649]

I completely agree with everything you have said about this, i've had a few metro turbo's and when i was younger kept rebuilding diffs out of old rubbish, because i didn't know any better and kept blowing them up, usually taking the gearbox casing with it. Lol
and in my mini turbo i built i never used the ecu at all, and even on standard 4psi boost it was a quick little car, until some ******* in a passat smashed it to bits >

[Ethel]

I think the ecu is a handy bit of kit - you forgot it can also run some natty disco lights for in car entertainment

...and if you run it in parallel with a bleed valve you can still up the mid range to 7 psi or more and pile on even more boost at the top end once you're A series is getting asthmatic and you're past making it go pop due to excess pressure.

[Turbo Phil]

I think the ecu is a handy bit of kit - you forgot it can also run some natty disco lights for in car entertainment

Lol !

But if your going to use a bleedvalve to fool the ECU and up the midrange torque, what's the point of the ECU in the first place ?

Phil.

[Ethel]

I think the ecu is a handy bit of kit - you forgot it can also run some natty disco lights for in car entertainment

Lol !

But if your going to use a bleedvalve to fool the ECU and up the midrange torque, what's the point of the ECU in the first place ?

Phil.

If you put your extra bleed valve next to the ecu's - the ecu won't know it's there as it senses off the fuel regulator line. You could get, say, 7psi plus the extra 4 psi when the ecu kicks in its valve.
Yet to test this theory though - depends how the ecu controls it's valve, isn't it supposed to pulse it to generate the flow resistance? Looking at the valve, if it was wide open, it would dump all the pressure from the actuator hose.

Edited by Ethel, 06 January 2008 - 08:16 PM.

[TheRestorer]

thats a nice little wright up phil.

[millermilla]

Am I right in thinking if you just disconnect to electrical connectors to the boost solenoid it will have the same effect as a bleed valve set at 7psi. Certainly seems to be the case on my ERA. It boosts at around 7 psi all the time with the wires disconnected or stepped 4psi then 7 psi at 4500rpm connected.

[blister]

so how do you blank the ecu i bought a turbo converted mg metro engine it hasnt got a ecu but just wondering if anything needs to be blocked?