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464 Views 7 Replies 5 Participants Last post by  Grandad
Now we've got the MP62 installed, thanks to lots of very tolerant guidance from knowledgable Nutzers, and have started on the intercooler, its time to move onto naive questions about the Adaptronics ECU we intend to install.
Will the Adaptronics, when fitted to a Mk2.5 1.8, accept a signal from a knock sensor, and if so which knock sensor is most appropriate please?
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Yes the Adaptronic will accept a knock sensor, however, from reading around and various posts on Nutz it seems that the 5's engine is particularly noisy, especially so in the rpm range where knock might be expected, so much so that it appears that most knock sensors simply cannot differentiate between the "noise" and knock.
So you either get a false knock reading, or knock might occur but the sensor doesn't pick it up.

There's a sticky somewhere about making your own det cans, that's the only foolproof way of ensuring you have a knock-free tune.
The MX5 engine is very noisy in the 4 to 5k rpm range. This makes it exceptionally difficult to use the knock sensor as there is a very sudden noise spike to filter out.

IIRC the stock ECU only uses the knock sensor upto about 4krpm, presumably for the same reason.
yeah it accepts one but i dont think anyones had much joy with the stock knock sensor due to noise like jimbob said............ since m15 fitted mine i have never used it. i am sure Matt will comment shortly but he's done more research on it than most.

EDIT .........Matt commented while i was typing
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Have a look on, I'm sure I saw a few post on this in the Adaptronic section when I was doing my what ECU shall I try and save up to buy reading
.....many thanks for that guys. So its not possible to have the Adaptronics keep the inition timing bouncing off the bottom of the knock threshold by virtue of a signal from a knock sensor? So how do you guys tune your engines? Do you start with a reasonable map and then adjust fuelling until the readings on a wideband are acceptable, and advance the timing until you can detect detonation by means of det cans and then retard the timing a bit?
Hopefully this chart will explain

Essentially you are most likely to get knock as you approach MBT, but you can afford to be several degrees shy of MBT or the knock limit with minimal loss of power.

There are many variables that will affect whether you are knock limited or can achieve MBT, too many to go into here. But essentially on a good, intercooled system, with an AFR of less than 12:1 or even 11:1, you should advance timing to the onset of knock and then back off a 2-4 degrees - for this you need det cans.

Obviously the ambient conditions you are tuning in will affect the setup, tune on a cold winters day and you might get knock in the summer - though the adaptronic has temperature compensation, and using this I've never had an issue.


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Matt....once again that is very helpful......many thanks, Stephen
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