MegaSquirt PNP for Miatas

[FoundSoul]

Can anyone comment on the rate of fuel burned with a PNP or other ECU set-ups? I would imagine it has a lower bsfc rating. Might make for a better enduro set-up.

With a standalone such as the MSPNP you have the capability to adjust your ignition timing and AFR at different load/rpm cells allowing fuel consumption to be fined tuned for sure. In any situation you can only go so lean to accomplish better fuel mileage, and in a race situation it's often even more important to err to the side of caution here for reliability's sake on a engine you're running harder than normal. But the fact remains with complete control of your ignition and fuel tables you have complete control. Is there a significant portion of the course where you're at 40% load(*) and 6000rpm? Don't see any reason why you can't lean it out there to get better mileage? You've got the power. And better yet, doing so won't effect the WOT areas of the tables at all. You don't have to compromise economy and power, generally these are sought in different load ranges, hence you can accomplish both.


(*) Load isn't really measured in percentages but in kPa, but it's easier to express this way here...

[wepsbee]

I have a 95 Ford Escort GT with a 91 engine. This is a Mazada BP 1.8 engine which was also in the Miata's. I am having trouble locating a stand alone ECU for this car. Does the Miata MS ECU also work for my car?

[FoundSoul]

I have a 95 Ford Escort GT with a 91 engine. This is a Mazada BP 1.8 engine which was also in the Miata's. I am having trouble locating a stand alone ECU for this car. Does the Miata MS ECU also work for my car?

At this point no-- you're right the motors are the same, but the ignition systems are different which is the EMS's key interface to the motor. We're actually looking at making a minor update down the road a bit to make it support this model as well though. It's on the to-do list and won't be hard to accomplish. We had a working prototype of this running in the GRM $2008 Challenge this year. Different car, but same ignition system and motor you're running.

[FoundSoul]

Alright, Joe must be busy, but he had given me the go-ahead to share everything anyways, I just wanted to give him a head start .



Here's the best of three pulls on the stock ECU as the car arrived. Tweaked MAF, advanced distributor. WAY LEAN as observed during the pulls.



Here's the final pull after we installed the MSPNP MM9093 and tuned it out. I let the dyno auto-scale to show you the exact peaks, I'll post a direct comparison of before/after next with manual/matched scaling to make everything prettier. Right off the bat here though you can see peak numbers improved. 2.7wtq, and 5.3whp. And because it was so dramatic, you'll probably also notice the torque line stayed left and above the HP line after, where it hugged it before and even dipped under. There is a dramatic changed there, but it's hard to really read as part of that has to do with scaling, so let's scale it evenly and take another look:



Here's the direct comparison. Down low that's a 16ft/lb increase (nearly 20% there), that slowly tapers off as he heads toward 4800rpm. Up top there's a 4-10whp increase all the way to redline. You can see where I laid the line on the graph at 6800-6900 there's a 10.2whp/7.8wtq increase. Still making more power there than the stock ECU was at it's peak at 6300rpm.

[rockytenney]

Remove stock ecu and bracket, plug in your new DIYAutoTune Megasquirt PNP MM9093 , bolt it down, run Map line to intake, pull ST SGN 10 amp fuse, start car, goose it a couple of times, hit the kill switch, eat sandwich while looking at the car, congratulate yourself on how clever you are generally, and specifically in this case, how you exceeded your own cleverness expectations. All this for the price of a set of go to the race tires. Of course, an interface in the form of a laptop (cable included) and a dyno (not included) would be required to further optimize for your engine.
The dyno sheets as posted by Jerry indicate that the device as configured by DIYAutoTune does improve torque and hp across the range significantly. The air/fuel ratio is controlled by the unit and the AFM could be tossed for more gain. Someone may notice this missing in SCCA impound.
Jerry and the folks at DIYAutoTune have an impressive product line and development facility, and are definitely focused on customer service.

Joe Tenney
90 Miata ITA.

[tnord]

Joe -

I have little doubt that getting the car to run on the MS PNP is easy as can be. Do you do any of the tuning yourself? The dyno I will take the car to is not familiar with Megatune, and I want to be able to tune the car myself at the track, so it's something I really need to learn.

i think those are pretty good gains considering you had an already tuned AFM. was that an AFM you had tuned at the dyno before? was it an ART? i won't be running a 1.6, but i know someone who is and is considering a MS PNP. i'll be in a 96.

[rockytenney]

Travis,
I was the watcher and not the doer. I am confident that if I had read the manual I could have muddled through. Populating tables is a repetitive function that is easily handled and you would be working from an existing baseline specific to your 1800 as opposed to a cold start. The displays are great and the menus are more intuitive than your basic cell phone. I am sure the folks there will be able to deal with the various install and tuning problems the user gets himself into. The manual and install procs are on the web site. You will need a wideband sensor to tinker at the track.
Mac Spikes has an 1800 and is going to see Jerry on his way to the ARRC. He would probably let you know how he made out with his "supa fly tune".
The AFM was tuned by John Williams with that engine on a dyno. I am pretty certain that he got all he could get using an AFM.

Joe Tenney