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Discussion Starter #1
I searched the forum and did not see this addressed so if it has been done before please excuse me.

I am running an 85 Supra in SCCA ITS class and very few modifications to the engine are allowed. However since it is nearly impossible to police the programming in the ECU they wrote in the rules that ECU can be modified as long as they use the original connectors and stay in the original case.

So, who out there still works on our "antique" electronics?
 

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Welcome to the CS.com Forum...

There are a few guys on here that autocross, and probably have some good suggestions about ECU mods.

One of them, Don Lew is very active with the SCCA and runs a very successful Mk2 in DSP class. Here's a link to his contact info on the forum: http://www.celicasupra.com/phpBB2/profile.php?mode=viewprofile&u=23
 

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I know Don hasn't had any luck in the past finding anyone that can reprogram the stock ECU.
 

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Not that I'm saying it's impossible, but I've spent so much time and money sending my spare '84 ECU all over the continent ! Always hear that its possible, just gotta get info from Japan, etc. wait 4-10 weeks later, then find out they can't do it. I've given up. Hope to try the Split Second MAF conversion. If anyone gets a reprogrammed ECU that helps, share with us all !

Don L.
 

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Thanks all, I kinda figured I would be out of luck but I had to ask.
 

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Yeah, that's a pretty common trick around here to get past emissions laws... people pull their standalone ECU apart and put the circuit board inside the case of the original ECU. Wire it up to the factory connector and no-one would ever know it's not stock. As long as the scrutineers never pull your ECU apart it might be worth a try! :)
 

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Discussion Starter #8
I have a spare ECU, can't hurt to try.
 

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Sonny,

That was one of the places that couldn't reprogram my '84 ECU. The dealership contracts it out to EL Prototypes, who had my unit for about 2 months before giving up. I've also sent my ECU to Yoshio, at Japanese Automotive in Canada for couple of months, also to no avail. Of course, that was with my '84 ECU. Maybe other years are possible. FYI.

Don L.
 

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re: ECUs

Talk about false advertising. How the heck can they claim the power increases they quote, with a price, yet in the end not be able to do it??? I've also talked to Yoshio in good ol' Toronto several times. Back several years ago he mentioned that he could modify our ECUs by adding a Techtom (sp?) unit with our stock unit and massage the signal that way (piggy back system I suppose). Anyways thanks for the update Don, later.

Sonny
 

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the techtoms work with the 7m and 2jz computers. I imagine they just assumed thats what you had or that it would work with the 5ms too
 

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My company does ECU development for Honda, Acura, Mazda and Ford vehicles. We have recently aquired an 84 toyota supra and will be digging into the stock computer program to find timing and fuel maps so we can adjust them for maximum performance.

To see some of our previous work, check out http://www.squirrelsw.com/finishline

If anybody has any info that could help us to produce a quality product for our cars, please let me know.
 

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If you are willing to try to figure it out we are willing to help in any way we can I'm sure, with spare ecu's etc... Your wideband idea looks sweet too, anyway let us know what we can do to help and we'll get it done. Welcome to the group!!!
 

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SuperChips UK and down under did make an add-on (piggyback) chip for the 5MGE Supra and Cressida recently. I haven't checked their website in a yr or so but maybe worth a look. Increased hp maybe 15hps.
 

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theres lots of piggy back computers that can be made to work with the 5m. The split second kit, the SAFC, probably this too would work...

http://www.perfectpower.com/products/smt6.asp

I went with the split second kit because it was engineered to replace the afm with a maf, unlike others that are just fuel tunning. Hopefully WOT fuel tunning will be doable...
 

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Seamus, Don and others,
From all I have gathered, (I have looked extensively!) there is no hope for our WOT fuel map. It is preset. :(
I do have one idea tho. I would like to see if a stepper or servo motor could bump the fuel pressure on an adjustable FPR when the TPS' WOT setting is triggered. Further adjustment mapped to RPM incease would even be better!
I know its just another piggyback, but it could be a viable option IMO.
Any thoughts out there?
Jamie
 

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Damn, I was afraid of that. I'm going to be using some 210cc injectors with my kit so I'm not too worried about running lean, but too rich. I guess I'll have to hope its close enough. The rrfpr idea might work but it could only add fuel untill the injectors max. Once they max we would have no way of leaning it out at WOT.

Does anyone know if there are any other inputs affecting wot fuel delivery? The knock sensor I imagine, but thats of no use. Temp sensor readings maybe (coolant or airtemp)?
 

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The water temp mod for sure changes the fuel curve (or more accurately to a different fuel map). Mine could rich enough to completely peg the gauge at 8:1 and kill the motor during shifts. Normally it runs about 12.5:1 or so at full throttle. The AFM has an affect as well, mostly at initial throttle tip in. I really wouldn't recommend the water temp mod myself. I felt its was pretty worthless mod overall. You'll have a high idle speed and a deactivated EGR system with the mod as well. I mostly ended up with a crappy running car as a result. I would recommend doing it to the air temp sensor instead.
 

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Within the rules that say you must keep the stock ECU box and connectors, for the money, the MegaSquirt EFI probably is your best bet.

The following thread is a discussion. HemiYoda in Sweden has added a MegaSquirt to his 5M-E (not 5M-GE) that uses a lot of the stock sensors on his engine.

http://www.celicasupra.com/phpBB2/viewtopic.php?t=1902&start=0

Erik Berg sounds REALLY knowledgeable about this and very helpful.

It works. he has included a link to Videos he has running this modified car at a track day.

He also has photos showing the MegaSquirt EFI board fitted into the stock ECU case and connectors.

The down side: No ignition timing. He uses centrifugal advance only on his engine (that's the way they came in Sweden).

The system is a Speed/Density system. I know a lot of people express reservations about not measuring airflow, but the truth is, the 5M-GE air sensor cannot read past about 2/3 of full range anyways, and the airflow door is very restrictive. For rules reasons, one could remove the flapper in the air sensor so that it appears stock.

There are tuning programs that run on a laptop so that you can re-map on the fly.

The real upside is that the system is developed by two gentlemen who are not out to make money. They want to interest people in using and knowing more about fuel injection. The systems are VERY inexpensive, especially since most of the stock sensors are used.

There is going to be a new version of the MS system out in the not too distant future. Ultra MegaSquirt UMS. It will allow the use of a wide-band O2 sensor so you can tune on the fly without having to do any guessing about how close to Stoich you are. It will also probably support a distributorless ignition. I don't know if that will be within autox rules or not.
 
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