advice on megasquirt

[MY91MX]

Hi all.

im looking at getting a megasquirt for my 1991 na6. would love any input from people that have used these units.

the plans for the car in the future is nothing massive just, e85 and cams, and i believe the megasquirt will be the best and cheapest unit for the job.

Any advice in buying, installing and using the ms?? Where can i get it dyno tuned in sydney??

thanks

[NitroDann]

You have a couple options, that is

Megasquirt plug and play

Based on a basic MS1 module, prebuilt, ready to go.

DIY plug and play

Based on a MS2 module, far more scope for playing with it and for the future.

Or a brain build MS3, which has many many more features again (like flex fuel ability)

If you are ONLY going to run it on e85, im happy to help you tune it one weekend for free.

The issue is if you want to be able to put regular in it without changing the tune over.

Any specific questions?

Dann

[Steampunk]

...i believe the megasquirt will be the best and cheapest unit for the job.

Not the best, but the best VALUE, as it doesn't have the same functionalities are higher-end units, but you of course pay alot more for them.

I had the MS MM9495 PnP and besides an initial hardware problem (which was fixed in double-quick time by DIYAutotune) it has been faultless. Installing the Plug&Play was very straightforward, and the MegaTune software, although daunting at first glance, is quite user-friendly as long as you read the instructions carefully and don't do anything silly.
I think people now are using Tuner Studio which apparently is more user friendly.

You will need a wideband Lambda sensor to help getting AFR (and to some extent, igntion) where you want it.
I'm assuming you know of DIYAutotune (outstanding after-sales service) and Miataturbo.net?
There is also a site done by some Qld'ers http://ozmx5.com/

[MY91MX]

Thanks for that. From that it looks like I want the ms3.

Iv read multiply post from you in regards to you e85 system have you found any limitations that ms can't fix?? As do you need to run a wideband o2 sensor?? Getting mixed info on this.

Did you diy or pnp?? Would love to know just how complicated it is to diy. From the instructions it looks pretty simple but with lots of tricky bits, but you can save a bit of money.

Thanks again for your help.

[NitroDann]

You need to use a wideband to tune the car, after that you dont need any oxygen sensor, but a wideband is highly recommended, as it allows the ecu to keep an eye on everything and make minor adjustments as you drive to help mostly with fuel economy.

Theres no special tricks with e85, its just a fuel.

The MS does EVERYTHING you will ever need in an mx5. everything. And much more, so theres no point at all spending more on an overpriced haltech or anything.

If you want to just run e85, an ms1 will do it, but an ms3 is needed to be able to run any mixture of ethanol, from 0% to 85%.

Dann

[Steampunk]

You need to use a wideband to tune the car, after that you dont need any oxygen sensor, but a wideband is highly recommended, as it allows the ecu to keep an eye on everything and make minor adjustments as you drive to help mostly with fuel economy.

That's still confusing for someone who knows nothing about what O2 sensors do.
In long-hand:
- you need a wideband O2 sensor to tune the air-fuel-ratios to where you want it to be in all the rev ranges
- once you are satisfied with your ratios and the driveability of the car, you can choose to either remove the sensor entirely and plug-up the hole in the exhaust,
or leave it installed but tell MegaSquirt to ignore the sensor inputs so it doesn't change your AFR settings. Either way, you must tell the MegaSquirt to run on continuous open loop
- open loop means the MegaSquirt runs with only the settings as per what you commanded it, ignoring the O2 sensor;
closed loop means at idle and cruising speeds, ie. anything that is not wide-open-throttle, MegaSquirt receives inputs from the wideband in order for the car to run optimally.

[NitroDann]

Im going to be blunt and say dont try to tune it yourself at this stage at all. Either do a hell of a lot more research, or just pay someone. Or pm me.

Dann

[MY91MX]

Thanks for all the info. I wasn't going to tune it myself but would like to start to have a look at it and have a more proactive experience with who ever does do the tune.

From this info I'm set on getting the ms once the bank balance allows for it. This will get me plenty of time to read up on it more and ask anymore questions

Thanks again.

[jerrah]

I have a DIYPNP in my MX5 and I've found it run my car extremely well. With all aftermarket ECU's you have the ability make your car run really well or really poorly. I worked it out myself with lots of reading and trial and error. Personally I preferred this approach because whenever an issue would arise I know exactly what action I needed to improve things. Otherwise if you have an issue with the car you'll have to wait (or pay) for someone with experience to tweak it for you.

I feel I've had less issues with idle, idle recovery and cold start than the stories I've heard about the MS1 based MSPNP units - once I tuned my car.

I get better economy than stock and I wouldn't be able to run my car with the modifications I have without it.

[NitroDann]

Yeah the mspnp (MS1 based) guys seem to have a few issues idling. Actually it seems most have no issues idling, they just cant get them to idle leaner than 13:1, which truly isnt an issue.

The best part about doing it yourself is the learning. I can diagnose almost anything in 5 minutes, because I know what and how every sensor works, and how the ecu interperets this info.

You can buy the plug and play, install the software and plug it into your car and on the base map it will run. As long as the engine doesnt ping (caused by too much timing among a couple of other things) and its not to lean (the wideband will tell you this), and your sensible, you cant do much harm to anything.

If you stuff something, you just put the factory ecu back in, drive it to someone like me or jerrahs place and get it sorted and some advice, then continue perfecting that tune. And best of all learning.

Dann

[Steampunk]

Yeah the mspnp (MS1 based) guys seem to have a few issues idling. Actually it seems most have no issues idling, they just cant get them to idle leaner than 13:1, which truly isnt an issue.

Not an issue with MM9495, perhaps more with MM9093, as even idle with AC on was fine on mine from the get-go.
Cold-start enrichment (where it ignores the normal fuel map until the engine gets to operating temperature) was on the rich-side, but from memory, this was to compensate for the lack of "decent" RON fuel over in the US. From what I read, at some places it's a big effort to find 91RON as the highest rating gasoline, and people were getting really lean numbers here and there.

[jerrah]

the lack of "decent" RON fuel over in the US.

Ah but I believe in the US they use MON and RON for their fuel not just RON. The numbers aren't actually compatible.

http://en.wikipedia.org/wiki/Octane_rating

91RON is 82MON

Their 91 is actually our 95-98 equivalent.

[Dweezle]

That explains alot.
I was amazed in Cali when i kept seeing V-Power 91

[NitroDann]

This is all correct regarding ron vs mon in the usa.

Dann

[gslender]

Reading up on the MS2 DIYPNP. Seems it supports table switching, so you can switch between e85 and pulp with a switch. Mmmmm, perhaps this ecu module is better than MS1 PNP, and easier than MS3 (plus smaller).

G