Megasquirt Update

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luthier

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I'm on the brink of going for a Megasquirt 3 system for my 1986 S2 505 GTI manual.
I've been reading a lot of stuff previously written on these pages but it's all fairly old, so if anyone is still playing with such a combination I would value any recent advice.
To begin I've seen the pictorial fitment of the 36-1 toothed wheel and sensor placement which looks to be within my capabilities, but if I could run that from the dizzy it would be neater and more secure I feel.
I saw mention of a Nissan dizzy swap but not clear on that procedure, model or anything, or if any of that is still available?
Assuming that the original dizzy won't cut the mustard there will need to be a change ?
I want to run sequential sparking as well as sequential injection, so a full management system.
Thinking there'll need to be an O2 sensor, of which I have a new original 505 one by Bosch so maybe that'll talk to the MS3 box.
I made my first enquiry to DIYautotune which resulted in a very detailed reply asking every possible question to get things rolling, so I feel in very helpful hands there, but would like to be ahead of the game to begin if possible before sending my answers.
Thanks.
Dan
 
Thanks guys, OK I'm thinking from this info that the 36-1 mounted on the crank will be a good thing. I'll need to get the mounting holes drilled on a lathe to mount it but that's no big deal.
Thanks for the info about the O2 sensor , so that'll be an added expense.
Now somewhere on this board I read that using the megasquirt system in their 505 they were getting 130hp with economy at 7litres per 100K's.
I wonder who that was and would love to hear from him or them.
 
Almost certainly me for the economy claims (though I think 7.4L/100km is as good as I've done, and more usually 7.8. I've never had mine on a dyno, so I'm not sure who got the 130hp. Perhaps Graham Wallis? Mine is definitely up on standard and doesn't have any bother keeping up with traffic.

Mine is MS2 and still going very nicely. if I were starting today, I'd go with MS3 as it doesn't cost much more and will give more accurate ignition timing. If you want sequential injection/COP I think you'll need the IO expander too.

A wide band O2 sensor with controller is well worth having.

I haven't gone for sequential injection and am still using a distributor for sparks (i.e. not COP or wasted spark). Sequential injection might be nice to have. I doubt COP would do much for me as I don't rev it hard. The other benefit of distributorless ignition would be less electrical noise, but I've had no bother with that anyway.

Mounting the toothed wheel to the pulley was fairly tricky since there's only a narrow face to mount it to (the outer pulley being rubber mounted). I'm sure it'd be possible to mount a toothed wheel inside the dizzy with a Hall effect or optical sensor. This would be very nice for "stealth" (so you could hold historic rego, say), but you might need the skills of a watchmaker to do it. For the sensor, the simple "L" bracket from the aircon rail mount was a lot simpler than my first effort off the cam belt cover mounts.

It is possible to re-use quite a bit of the standard wiring. The throttle switch needs to be changed to a proper throttle position sensor (one off a Hyundai worked for me). The AFM is best chucked out and replaced with piping.

And you'll be wanting a laptop so you can play with all the hi-tech gadgetry in your car. Something you could do right now is load and install TunerStudio and walk through it in off-line mode to see what you're getting into. There's a lot to know.

Enough for now. Happy to go into more details if you want.

Have fun,

Rob.
 
luthier said:
I want to run sequential sparking as well as sequential injection, so a full management system.

Dan
Click to expand...
I'm assuming your motor is a douvrin, the same as the Renault block.
I messed around with both batch and sequential fuel, and wasted spark vs electronic ignition through a single coil via a basic distributer, and to be honest there was no perceivable difference between any version.
The biggest recurring issue I had was with the throttle body, and tuning the beast at fractional throttle opening...ie the difference between no throttle fuel cut and a bees dick of throttle like you would use whilst cruising down hill. I never managed to get that 100% smooth.
I also found out the hard way that less is more on these motors (throttle body size). In the end the best drivability was with a twin choke sequential TB.
As far as tuning at WOT or most anywhere else on the fuel ignition map, the motor was so sympathetic to any degree of tune that it actually became quite hard to tune. You'd be wondering whether you laptop link was working sometimes!!
Even setting up the sequential fuel had to be done mathematically because rotating it a full 360 degrees was making inpercievable differences.

Jo
 
After more reading and the above advice I think it is probably best to leave the ignition system and just manage the fuel in a batch /bank system. DIYautotune then recommends the micro squirt and later if I want I could make a wasted spark system which I assume would then require the toothed trigger wheel. There are some of those that fit straight into Nissan dizzys which seems like a better idea than the big thing on the harmonic pulley. That depends on how easy it would be to graft the Nissan one onto the 505 one.
The microsquirt is also a lot less expensive and may be just enough to cope with for starters. I just need to find out if it can do the ignition later or if I'd need to upgrade to the Mega version then, [what advantage is the Mega system over the Micro] and also I'd like to find out what system is actually used by the Peugeot ECU. However I suppose the main advantage of the new system is the tunability and versatility there. I'm still wondering where maps come from. I know they don't grow on trees but is there a good one already for these cars or are we just using a generic map and tweaking round the edges?
I know with MotoGuzzi there's a bloke who writes great maps for some of the newer models that have enormous benefits in horsepower and smooth acceleration.
I agree that downloading Tuner Studio would be the very best way to put my foot in the water.
Thanks for the insights, I'll ask Mr DIY a few more questions before I make a financial commitment and have a good look at the Haltech. Buying locally has a big appeal though they seem to be a bit pricey.
 
That sounds like a wise plan. As long as your dizzy is in good shape, with vaccum and centrifugal advance working nicely, there's not much benefit in taking the ignition digital. In fact it makes starting worse. Staying standard, the ignition just fires at the reluctor pulse. By contrast, with a toothed wheel, the engine has to crank until the gap is detected and only then does it know where it is in the cycle, and when the next spark is due.

The Microsquirt runs just the same firmware as the MS2. There's no real difference between a standard Mega and a Micro. Because the Micro is built with surface-mount components, it's not as customisable as the MS2, so you have fewer options on sequential injection, multiple coils, etc. The Micro has one big advantage over the MS2 as well -- it has a PROPER connector, not the rather pitiful DB37 computer connector. And, if you do go fuel-only, most of the things you want to connect to will be right there at the old ECU connector (it was fuel-only too after all). Just need to take the garden shears to the wires and get splicing. I took a couple of breaths before cutting.

The Microsquirt doesn't include a MAP sensor by default. You *can* run it without a MAP sensor (Alpha-N mode), but you'll get a better tune *with* one (Speed-Density mode). DIY will happily sell you a MAP sensor. Not sure, but hooking it up may involve some soldering.

As for tuning maps, I'll be happy to send you mine as a starting point. You can tweak it from there. In a way they do "grow on trees". It's a long time since I started, but MegaTune had an option where you entered your engine characteristics and it generated an initial tuning map. Haven't seen that option in TunerStudio (might be there), but this link shows the kind of thing. It is only a starting point, but the generated one did have my car running reasonably well on the first attempt.

You start with a map like that, then adjust it. The best adjustments come from a dyno. Happy engines give more kW.

The popular alternative is to use a wideband oxygen sensor and some rules of thumb about optimum fuel mixtures under various engine conditions. For Megasquirt, you store these rules of thumb in the AFR Table. The default fuelling is in the VE table. MS constantly adjusts the fuel aiming to match the AFR target value. TunerStudio watches these adjustments and can automatically modify the VE table so that it's in the right spot for next time.
 
To start with just do fuel only in a batch system as you say. Don't bother with the oxy sensor. MS1 will cover this perfectly. although the MS3 has a USB connection and works great with Tuner Studio. Normal power for a Euro Spec 505 GTi is 130 hp, local cars have a bit less. Can't imagine getting 7 litres a hundred. Even with the Megasquirt these engines don't start to work until 3500, my first conversion was amazing though, would run to well over 7000, normally they run out of breath before 5500. I hope this isn't an unleaded engine, wouldn't waste my time doing anything to one of those. Early leaded ones have hardened seats still so fine on unleaded fuel.
 
So here's the list to go with the MicroSquirt.
I am very inclined to take the cheapest O2 sensor with it because from what they say it will greatly assist the ECU to tune better. I'll make the order in a day or two.

From Matt Cramer:
Sequential injection isn't that hard to tune, but it is significantly more expensive. A MicroSquirt is a good budget option if you don't need sequential EFI - it can run fuel-only at the start, if you have a vacuum / mechanical advance on the distributor, and you can then upgrade to wasted spark later. Here's what you'd need for fuel only:

$388.00 MicroSqrt8: Assembled ECU (includes 8 ft / 2.4 m harness & tuning cable)
$67.00 GM3bar-map: MAP sensor
$12.49 GM3bar_piggy: Pigtail connector for MAP sensor
$22.49 IATwPiggy: Intake Air Temperature Sensor
$9.49 38NPT-Bung_A: Aluminum bung for IAT sensor (Also available in stainless steel)
$28.99 USB-2920: USB to serial adapter (Only needed if your laptop doesn't have a true DB9 port)
$528.46 Subtotal without wideband

The wideband oxygen sensor system is optional, but a very useful tuning tool. We carry the Innovate line.

Wideband Options:

$189.00 (Special sale price - $166.00) LC-2 without gauge (you can still view real-time AFR and datalog AFR through your laptop)
$219.00 (Special sale price - $209.00) MTX-L Plus digital gauge system
$219.00 (Special sale price - $209.00) LC-2 with DB digital gauge (available in red, green, or blue)
$259.00 (Special sale price - $209.00) MTX-AL analog gauge system
$349.00 (Special sale price - $279.20) LM-2 basic data logger with one sensor
$399.00 (Special sale price - $333.00) DLG-1 dual wideband package with digital gauge
$479.00 (Special sale price - $383.20) LM-2 deluxe kit with one O2 sensor
$669.00 (Special sale price - $535.00) LM-2 deluxe kit with two O2 sensors

I think this will give you a pretty good start in the right direction. If you'd like to place an order, you can do so at www.diyautotune.com/shop/ and it will calculate exact shipping costs (based on weight of your order) and accept all major credit cards securely. If there is anything else I can assist with, please just let me know!
 
I've ordered the MTX-L wideband setup, which does have a gauge but as you say, what use is the gauge? And the rest of the micro squirt stuff for fuel only.
So one foot in the water now.
PeterT, can you tell me anything about mapping the ignition? Is there a map for sale or love anywhere? Does every new punter have to reinvent the wheel or are there some ways well trodden? Personally if I can get stuff sorted I'd like the info to be used by the next guy if possible.
I'll be documenting this journey in case it's helpful. But first step here will be fuel management only.
From your comment and others I expect I'll be paying the dyno crowd before long because I know seat of the pants isn't where it's at.
However I'm not looking for a racer, just a well tuned and efficient engine for fun and satisfaction.
 
I'm wondering what kind of Throttle Position Sensor can be adapted for the 505. Having measured the standard one I find it's a switching sensor rather than a variable resistor type and so is unsuitable for this application.
Thankfully the injectors are the high frequency type [16ohms] so will plug straight in without any modifications.
Also wondering about the tachiometric relay which I'm assuming will be redundant?
 
Hyundai TPS on mine is marked with part number: 35170-22010 9600930001. It fits the spindle perfectly, but I needed to cut out a simple adaptor plate to get it mounted. Electrical socket is compatible.

I didn't bother wiring up the fuel relay from the MS. Tachymetric relay still works in the usual way. If yours is suspect, chuck it out and wire up an ordinary relay in its place.

A dyno is the quickest and most convenient way to tune for performance, but it's arguably better to tune on the road/track. The ECU means it's not really a seat of the pants thing. The Megasquirt's log file records the engine data about 20 x per second. If you do full throttle runs on a straight flat road in second gear (say) from 1500 to 6000 rpm, you can compare the log files with different fuel or advance settings and choose the best (i.e. where the RPM is climbing fastest). You do need to be a bit geeky to delve into the log files.

Have fun,

Rob.
 
Never mapped 505 ignition, used the basic fuel only MS1 both times. I just took the car to the tuner to do the fuel map then drove it. No need for oxy sensor, the tuner supplies that. Of course the tuning is quite expensive, you could spend the money on a wide band sensor and controller and do it yourself on the road?
 
luthier said:
I'm wondering what kind of Throttle Position Sensor can be adapted for the 505. Having measured the standard one I find it's a switching sensor rather than a variable resistor type and so is unsuitable for this application.
Thankfully the injectors are the high frequency type [16ohms] so will plug straight in without any modifications.
Also wondering about the tachiometric relay which I'm assuming will be redundant?
Click to expand...
High resistance not frequency. You can buy sensors and other things from EFI Hardware http://www.efihardware.com/
 
if any of you guys are sick of your megasquirt I'd love to buy one someday ( to fit/tinker with on a Djet injection car) :dance: :dance:
 
PeterT, yes, M164E is the 505 GTI curve (at least for my late '85 model).

speaksgeek, enjoyed the video. What it doesn't describe is how you decide what the target AFR should be. Perhaps that was in an earlier video where they ran it on the dyno. The first part of this final tune session didn't seem like it'd achieve much more than you can get with just driving around with "autotune" enabled.

On the full throttle run, the 505 won't be very troubled with wheelspin (!!) so second gear is fine, and gets the run over with quickly and at safer speeds. That Mazda would accelerate faster in third than the 505 in second.

One thing I referred to earlier is that the log file gives you a "poor man's dyno". This wasn't mentioned in the video. Here's the flat out run in the Mazda:

wd.png


The slope of the red RPM curve is rate of acceleration. You can do multiple runs with different advance or VE settings and choose whichever makes the slope steepest for each RPM range. Not nearly as immediate as happens on the dyno. but, if you have a quiet road and suitable software, you can get quite a lot done in an afternoon.

Have fun,

Rob.
 
robs said:
speaksgeek, enjoyed the video. What it doesn't describe is how you decide what the target AFR should be.
Click to expand...
That's the difference between a factory tune, built for emissions, or a performance tune. I recently did an S16 for Cam85 on here. It had 14.7 everywhere, except the last WOT point, where it goes to 13:1. Having adjustable fuel maps gives you the ability to make that change far more gradual, increasing the driveability and torque/hp in the mid range. For example, at 3000 RPM, you could make the target 14.7 at cruise (say -50kPa), then decrease gradually to 13:1.

eg
-100 to -50kPa = 14.7:1
-40kPa = 14.4
-30kPa = 14
-20kPa = 13.7
-10kPa = 13.3
0kPa = 13

In most ECUs you can make a table of that (similar to the ignition I posted above). On a Haltech Platinum for example, you hit the Q key as your driving along, and the ECU adjusts the mixture for that load cell, as per the voltage coming from the wideband sensor. Other later ECUs are full self learning.
 
Just make sure it's CW or CCW, which ever suits your throttle body direction. I assume you'll do fuel load via the MAP sensor anyway?
 
PeterT said:
In most ECUs you can make a table of that (similar to the ignition I posted above). On a Haltech Platinum for example, you hit the Q key as your driving along, and the ECU adjusts the mixture for that load cell, as per the voltage coming from the wideband sensor. Other later ECUs are full self learning.
Click to expand...
I think all the ECU makers copy good ideas from each other. The Megasquirts all support live keystroke tuning, as well as automatic tuning by the laptop. They dropped the ECU tuning itself some time ago. I think that was over concerns about wearing out flash memory.

The Microsquirt will let luthier define three 16x16 fuelling tables and two 12x12 advance and AFR target tables. I scrape by with one 12x12 for each.

Luthier ordered a MAP sensor, but his TPS will still be useful for accel enrichment and flood clear, and also for detecting closed throttle for closed-loop idle and overrun fuel cut. I think it also comes into launch control if he wants to get silly.
 
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