importboi22

i was looking at the megasquirt ecu ( DIY fuel management for 120$) i was wondering if i could run this on my series 5 rx7 and still use the stock ECU for timing.... im not shooting for a high goal of hp... mabye 300? i just want to get rid of my MAF and something better to tune with cuz of my high comp rotor motor setup......... my questions are this

if i elimated the maf wouldnt the stock ecu go into limp mode and use different timing maps..... then it would knock everything outta wack.... like my oil metering pump..... or the ecu doesnt need a MAF input for timing and omp operation

let me know what you guys think....

and im gonna use it only for standalone FUEL management.... i know it doesnt work for ignition hence my questions...

heres there website

Black13B

iTrader: (1)

You'll have to modify the stock ECU to work with it. renns has done this, and quite and excellent job I might add..

Not sure what to tell you about the MOP, though..

importboi22

MOP works via TPS

V8kilr

drop in a s3 dizzy and run vacuum advance direct fire to the stock s5 coils.

there solved the igintion problem

as for the omp I havent yet figured that one out yet.

importboi22

s4 front cover...

Black13B

iTrader: (1)

Oh.. so essentially the internal lubrication (MOP) is the same as S4 then? No electronics to it?

renns modified the stock ECU to *think* it's delivering the fuel, but the megasquirt is actually in control of that. So the ECU continues to give it spark.

You running S4 or S5 stock ECU?

23Racer

I have been reading this information and am very interested in the MegaSquirt application. One benefit of the Megasquirt seems to be fully programable fueling to maximize power on the fuel side and eliminating the AFM. I have been thinking of waiting for the UltraMegaSquirt as it also gives ignition control. What do you think?

Is the system flexible enough to handle staged injection and the demands of a race application with an S5 motor running S4 injection? Has Renn developed good power from his application or has relying on the stock ECU for timing limited his results. Please let me know as my crew chief is an electrical engineer (his real job) and wants to build one up for my car.

Does anyone have some base line information on the application with some dos and don'ts. Thanks in advance for any help.

Black13B

iTrader: (1)

renns set his up as more of a guinea pig project on his bone stock S4 base model RX7.

More than succesful for a guinea pig.

He is in the process of setting up the same system on his SA RX7 which is to be turboed realatively soon.

As for running S4/S5 injection, renns setup his SA to work with both low impedance and high impedance, and be able to switch easily. All using the Megasquirt.

He's a very informative guy. I would hope to see him post in this thread sometime soon. He doesn't browse the forums as much as me, but it was him that definately got me into the Megasquirt. It will be setup in my GXL over the winter.

23Racer

Thanks for the information. I am based in Oakville and may be able to assist in jointly putting on the kits this winter. I have some dealership and technical support that would be of help. I am trying to gain access to a chassis dyno to do the initial setup. I will also be building up a Turbo RX7 as a second car this winter and am planning on using a UltraMegasquirt on this car as well. Will wait to see if Renn responds. Thanks again.

Black13B

iTrader: (1)

No problem.

I'm basically just regurgitating what renns has told/shown me with his setups.

He has told me he will help me install mine into my RX7. I'm doing this over the course of the winter (permitting I find an indoor garage with power to be rented before the winter gets too fargone). I'll be sharing the whole experience here. I can't wait to get started.

renns

23Racer,

I'll try to cover all your questions...

Megasquirt is a speed-density based fuel injection controller, and as such has no need for the AFM signals. It is a fully programmable system, and _not_ a 'piggyback' controller such as S-AFC.

UMS, when released, will likely not support the rotary unless someone modifies the code to suit. The market is just too small, and they (Bruce Bowling and Al Grippo) will likely focus on the other 99%. That said, if someone with the desire and programming abilities tackles the project, it will get done. The advantages of 'open source' are many...

The standard Megasquirt hardware can be loaded with different versions of the embedded code to suit specific applications. Most users run the standard V2 code, but there are a number of code variants floating about which provide further functionality such as:
- stepper motor IAC control
- closed loop operation with WB O2 with AFR(MAP)
- dual table code - to allow individual configuration settings for primary and secondary injectors (staged)
- hi-resolution code - to improve idle control when using large injectors
- simple ignition advance control using distributor
- many more....

I'm running a variant of the dual table code in my '86. This installation was done primarily as an educational exercise, and to allow field-testing of the DT code. I have done no mods other than tuning, and have not done any before/after dyno tests. Any benefits that exist when full fuel control is possible should be realized with this system, assuming proper tuning. This would be a much greater advantage in a non-stock application.

I am presently relying on the stock ECU to control igntion timing, and that seems to be a reasonable solution. Sensors inputs that I have 'stolen' from the stock ECU are tps, afm, mat and O2. Coolant temp input is a continuous 180 degF or so due to an added resistor. I am uncertain if ignition timing is affected by the removal of those sensors. Further testing should really be done, but the car runs nicely, and I am focussing on other projects. I should add that this '86 is my daily driver, running MS for nearly a year now.

There are a few other rotaries running the Megasquirt. The only other 2nd gen that I can think of is a guy by the name of Jason Russell. If you search the Megasquirt archives, you should find him. His installation is on a TII.

My SA installation is nearly done, with a 4-port 13B, S4-TII intake modified for four extra injectors. This will allow me to experiment with different injector sizes and locations. I completed fuel system pressure tests tonight. Once the interior is back in, it's test time.

Provide some further details of your application, and I'll try to address the do's/don'ts. I'm not an rx-7 or efi expert, but I'll do my best to fill in the blanks. If you've got an EE for a crew chief, I'd say you are in good hands with this type of project!

renns

Unless it's a track-only car, you should be able to do the initial setup at least on the street. For all the low-load points, you can let closed-loop mode kick in, and use the datalogs to regenerate the VE table in that area to provide you with near-ideal values. I've re-tuned from scratch a number of times during experimentation with different setups. It really is a pretty straightforward system.

renns

Of course, I should add that I live on the outskirts of a village, with lots of country roads and light traffic. Being closer to the 'Big Smoke' may limit you somewhat :-)

23Racer

Thanks for the information Renns, been a big help already. The car is a track only Touring Sedan. Details on engine are as follows: new 91 S5 engine (Mazda rebuild), S4 intake / FI system, no emissions/ solinoids/ BAC/ choke etc..., Racing Beat race only header and 3" exhaust collected into single pipe after 120". Presently seeing rpm curve flatten out after 6500 RPM and in looking at pipe car seems to run lean as it is incredibly temperature sensitive.

Will be building up the MegaSquirt in January and tuning on a chassis dyno. Very interesting information on the V2 varient software for staged injectors. Where is this info for down load? Would the UltraMegaSquirts improved processing speed and capacity be a better fit for the race car? Just some advice, wouldn't hold your feet to the fire if it isn't any better. Interested in traction control capability of the UMS, especially if the programming can be transferred.

renns

UMS is still under development. I would proceed with an alternate if it is for next season. It will be a very capable system, but for fuel only MS is all you need.

Regarding dual table code, it was created by Eric Fahlgren and Guy Hill. I believe Eric has source code copies on his website, but the easiest way to install is use EasyTherm4. This software can be downloaded from the Yahoo site, and comes with the embedded code version V2, DT, and HR. It also allows you to overwrite the thermistor lookup tables in the embedded code with values that suit your vehicles sensors. See:
http://autos.groups.yahoo.com/group/...les/EasyTherm/

I'm just outside Kitchener. If you are ever out this way, give me a yell at renns_99@yahoo.com

23Racer

Thanks a bunch for the info Renn. Just what I was looking for. The car was running this past weekend at Mosport and based on the data logging info it was fine until approx 6200 when the rate of accel dropped off and seemed to run lean. Ran better after removing cold air box and removing fuel pressure regulator vacuum line. Can hardly wait to install programable ECU. Will e-mail you directly as my folks live in Kitchener and I am out there a fair bit on business.