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Microsquirt ecu project

Well, I am now happy all the bugs are gone and the car runs very well and has not let me down.
As fen suggested the ISV is not worth the effort, I bypassed it and adjusted the throttle stop to give a good idle. It just means you have to give it some throttle on cold start.
Is anybody interested in a write up?
 
It wouldn't seem to me to be a particularily difficult thing to implement. Is it just really hard to setup in the software for the MS? I should think a decent PID controller (basic algorithm for feedback control) would control it without much problem....
 
ORIGINAL: JamesO

Well, I am now happy all the bugs are gone and the car runs very well and has not let me down.
As fen suggested the ISV is not worth the effort, I bypassed it and adjusted the throttle stop to give a good idle. It just means you have to give it some thottle on cold start.
Is anybody interested in a write up?
Click to expand...

More interested in a full belt and braces write up than I can hope to articulate at midnight. Im interested in every aspect, problem and solution.

Simon
 
O.k. will start taking pics as I tidy up my wiring. I'm not much of an auther but will give it a go.

I think with my experimenting I damaged the driver circuit for the idle valve. Although there are spare outputs that could be used to drive a simpler valve its not an issue once its been running for a short time anyway.
 
I'd be interested in a write up and if possible can can you include something in the Intro to highlight what limitations of the OEM stuff you were trying to eliminate? I assume that's why you've done it anyway?

Cheers

James
 
One reason is to simplify fault finding as you can moniter all sensors with a laptop.
Also I feel with larger valves and capacity there must be more power to be had from the 2.7 engine.
I can also get rid of the AFM which can be troublesome and create a restriction in the intake. Microsquirt/Megasquirt use manifold pressure to meter fuel, MAF sensors can be used too.

I was going to swap to a 968 engine I have but that needs a new exhaust cam.
Maybe I should try to create a 3 litre 8 valve instead, or just get a more agressive cam. Standalone management makes things like that a possibility.

 
Well done James [:)] I'd be interested to read more also.

My car originally had its ISV removed when the piggyback ECU was fitted, but during really cold weather over winter the cold start was really lumpy and just couldn't be improved by the Piggyback. Re installation of the ISV brought it back to normal
 
No pressure James (O); but Im hoping for a step-by-step instructional guide thatll take my MS off the Stim and onto a car, working, with a manifold absolute pressure sensor and substituted temperature and crank sensors. I have a MS2 kit in the loft somewhere..... [:D]
 
I would love a write up James. I too have been toying with the idea of a new cam...Have you seen the cam profile of the 944 8v yet? Its a bit like a tractor cam and theres basically no overlap on the intake valves. Theres gotta be some easy HP from that. Im going to give piper cams a ring at some point, they quoted me 150 to re-grind my camshaft....
 
Nice work James - I have been reading up on the microsquirt and it looks like a great project.

Does your success mean that anyone else giving this a go would have your map etc. to rely on as a starter? Hint hint!

Its a way off for me, need to do lots more basic work first, but maybe in a year or so...

Congrats!

Eddy
 
Hmmm. This is interesting. How did you interface with the crank sensors? I saw a post on the MS forum a while ago where someone was building a circuit board that could talk to them. At the time it didn't work, is it now working & is this what you use (or does microsquirt interpret the signal?). Regarding idle control - I have never got it to work successfully with a Bosch (2 wire) valve. I suspect the 3 wire valve would be just as bad.
 
At $650US these are excellent cams. You may or should change your springs and retainers though and depending on the cam might need different (longer) valves. Still, you won't regret putting in a bigger cam. It does really transform the engine, making it feel like a 16v when in the upper rpms. Well worth it now that you've gone this far.
 
Very temped by the cam but also I have a 968 engine which needs a new exhaust cam so i'm not to sure which direction to go in.

I just replaced the AFM with a length of gutter pipe, fitted a proper TPS switch and even with a cone filter sucking warm air particuly hot in traffic (although intake temps drop nicely to ambient at speed) it seems to have loads more poke past 4000 revs.
I will put the standard airbox on but I need to source a 2nd hand one as I don't want to hack up mine.
Will hopefully get it on a dyno in july to see how much gain (or losses) have been made.

For the weight loss junkies the afm is very heavy and takes some force to move the flappy thing.
I had to tinker with the fueling a bit after so it must make a difference.

I have done a write up but I am by no means a writer, its in open office format if anybody wants it.
 
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