I have found a way to modify the stock ND ECU for the GSL-SE (N304) to give the following capabilities:

A) Full remapping, including changing sensor calibration tables. This will allow changing the stock sensors for different ones if required, and should make the car run better than stock even with no other changes. Fueling maps will allow you to take full advantage of mild porting as well as any exhaust mods, so you get your money's worth out of costly power mods (porting ain't cheap, so why screw yourself out of some of its extra goodness?)

B) Emulator-style tunability; this means you can be driving the car, and can see on a laptop exactly which cells in any given map are being accessed. This is a HUGE advantage for those wishing to do their own tuning, either on the track/road or on a quality dyno setup.

C) Real-time displays of all sensor data and engine parameters. This sort of speaks for itself.

D) Data-logging ability, using your laptop. Log all sensor info, engine speed, etc. Great for tuning, racers, and chasing down intermittent injection issues.


There would be some flexibility for adapting the system to handle slightly bigger mods (I wouldn't recommend it for low-boost turbo, but it could be made to safely work), or a fairly easy way to convert your 12A over to fuel injection (using mainly stock GSL-SE components, or the possibility of using something like widely-available GM sensors). I'm also looking into how much trouble it would be to rewrite the ECU code to allow use of speed density mapping (using manifold pressure, through a MAP sensor) and removing the stock flapper on the GSL-SE, which is a MAJOR intake restriction. Because there will be much more work involved on my end, the cost of a unit modded for speed-density will be somewhat higher (how much higher I don't know yet).

In any case, I'm targeting the price of these modded stock ECUs at under $300, and I'll try to get the price point as close to $200 as possible (this is, of course, built on your stock ECU, or with a core deposit (refundable upon return of your working stock GSL-SE ECU)). This will include the modded ECU, an interface cable, and software for your laptop that will allow all of the functions listed. If anyone has any questions, I can answer them privately or in this thread, your choice.

They are totally plug-and play. I will be shipping them pre-loaded with all the stock maps, so all you have to do is unhook the two connectors from the stock ECU, remove the 8 screws holding it onto its bracket, remove the stock ECU, and repeat the steps in reverse order with the new unit (screw onto bracket, connect ECU). Fire the car up, and you're on your way. This is a great, affordable answer for those who want a little more power and smoothness out of their GSL-SE without having to do any soldering, programming, or trial-and-error testing just to get the car running. In addition, you can re-load it with the stock maps at any time, and it looks totally stock to even the most hawk-eyed emissions technicians -- only the extra port for the laptop would be visible as a difference. Both of these factors are great if you live somewhere where vehicles have to be smogged -- it'll pass visual and rolling-road emissions testing. Even better, if you fail emissions, you can sometimes change the mapping enough to get the car to pass the next time around, without having to spend any extra money for repairs.


Note that, unlike standalone FC/FD aftermarket units, or the stock FC/FD units, or the MegaSquirt when used with the "spark" extra code, you won't be able to alter your ignition timting and setup with this mod (since the stock eCU does not handle spark). If you have turbo'd your car, changed the intake and exhaust radically, or done radical porting, you may have to do more than just basic mapping to get the best out of the vehicle; in some cases you may exceed the limitations of the stock eCU, remapped or not. If you want to handle serious boost, or to remap your spark, you will probably find a MegaSquirt to be a more cost-effective proposition, although you'll have to shell out for changes in the spark hardware regardless of which route you go.

I think it will be a great product, and predict a fair number of GSL-SE owners will be really interested, since it is easy to install, cheap, and can handle most mods that are typically done to running GSL-SE cars (exhaust mods, changes in aux. port activation, etc.) If I can get the speed density conversion working at a vaguely reasonable price, I can promise that even on an otherwise bone-stock car, the improvement in power output will be noticeable. So whaddya say?

 

Sounds like a good deal. My cousins have re-mapped their Corolla GTS ECU for turbo application.

 

Sounds good, I would like to see a working product first. Maybe test it out on a members car so we can see if it works and is worth the money.

 

I own an 85 GSL-SE, and am doing the development work as much for myself as for anyone else. I will certainly make some videos and post them, and I'll also loan the unit to another owner for independent evaluation. I will also find a Mustang chassis dyno somewhere around where I live and video before and after dyno runs using the dyno for a tuning tool. My car currently has a stock exhaust, so I don't expect miracles with just a remap, but it should at least show some of the possibilities.

It's unfortunate that in those days, ND was making each ECU to order; this means that, for instance, the ECU we have is missing any hardware for spark control, so "enabling" it is not an option. There's also no provision for measuring any air pressure except ambient, so using the ECU when converting to a turbo setup would be difficult to do well, and certainly it would not be simple. The FC guys have it easier in that regard, since their cars use the same ECU for NA and turbo apps. I gave conisderation to adapting the FC ECU, but it uses differetn sensors, has different connectors, and so forth; while the mod I plan on doing will be very plug-and-play, requiring no development time or money in that regard, the FC unit would have taken a lot of work and effort to convert to a drop-in.

As this project comes together, I'll post screen shots/videos to keep everyone posted as to the state of things.

 

i like the sound of it too! i too am in Nor Cal! keep me in the loop

 

maybe he fix my players card @ indian casino so I can hit the jackpot at the slot machines.

 

An important part for me would be to get rid of the damn flapper. Did you find out you cant do that now? Also is there anything we can do in conjunction with a wide band?

 

I am 100% certain I CAN rewrite the runtime code to use a MAP sensor instead of the flapper. What I do NOT know, at this point, is how difficult it'll be to make that actually happen. There are differences in the signal put out by the two sensors, and I have to make sure the circuitry of the ECU itself can take in the signals from a MAP sensor by using the circuit currently used for gathering data from the flapper. If it's not possible, it may yet be possible to build another daughterboard to process the signal, either preparing it for the flapper input circuit or skipping past that circuit entirely. If I have to develop separate electronics, I can promise it will A) take longer to develop, and B) cost a bunch more, although how much more I do not know. I will make every attempt to keep a complete flapper-replacement kit (which would be modded ECU loaded with a "base" map for an all-stock GSL-SE, a MAP sensor with instructions on where and how to mount it, a wiring harness pigtail to plug the MAP sensor into the stock GSL-SE engine harness where the flapper plugs in now, a piece of tubing and whatever clamps are necessary to put the tubing in in place of the flapper, and the software and interface cable for the ECU) under $400 out the door, and to make it as simple to install and get running as possible.

If I go much beyond that, we'll increase the price even more, and it'll start to make a lot more sense to simply buy a MegaSquirt and set it up for your GSL-SE. The price will be lower, and the amount of work on your end to install and tune it won't be a huge bunch less than with a further-modded stock ECU. The MegaSquirt has very flexible circuitry between the outside worls and the processor itself, plus it comes with pre-written code snippets that can be linked together to get almost any outboard hardware to work with it properly. With the stock ECU, I have very specific limits in terms of how sensor data can be processed, how many sensors I can use, etc. The more I have to build to go around the stock limitations, the closer it'll get to reinventing the MegaSquirt wheel -- and there's already an experienced user base out there with the MS, people who can and will help you get it running right on your particular car (including any rotary), and even people building extra boards to make it much simpler to drop a MS into your rotary. My idea is to make something that won't be too complicated but will give a lot of extra functionality to people wanting to get more out of their $1000 exhaust system, for instance, or maybe want to try and get better gas mileage on the freeway. I can do that fairly quickly, without a huge amount of work on my part, and I can make it very affordable. And the best part is how easy and transparent it will be to install and use; very simple to install, will come with the stock mapping already onboard so you can install it and have your car running in under 10 minutes. Enough people are interested in getting rid of the flapper that I'm seriously looking into that as an "upgrade" from the basic modded ECU I was originally thinking about, and I've got to have a look at the hardware in more detail before I can really say how much time and effort on my part will be needed to make a viable product that can replace the flapper and still be worthwhile to you guys financially.

I'll keep everyone posted as things develop. I'm continuing to reverse-engineer the sensor processing hardware on the ECU, and I'll be sending the ROM dump off to my software guy shortly for his evaluation. He has already reverse-compiled and hacked the runtime code of one or two other early digital ND ECUs, and has seen the code they used for speed density fueling and sensor processing, so he will have a good idea for me of how involved the conversion will be on our end (developmentally).

More news as it arrives, and anyone within a few hundred miles with a GSL-SE, especially those that have been ported or have non-stock exhaust components, are urged to contact me. I will be wanting to do development testing on the dyno to determine just how much usable gain people can expect when installing and tuning with the modded ECU, particularly how much more power is available by ditching the stock flapper. Since dyno time is costly, I can't offer a free system with a full tune to those who help, but I can probably give a massive discount over what the combo would usually cost someone (not sure about how it is for the really serious shops using a four-gas and an eddy current dyno for a complete tune when dealing with cars, but I know for motorcycles the dyno time and map changes usually run between $700-$1500 from start to finish, not counting the cost of the hardware; I should be able to at least halve the cost of the hardware/installation/tune in exchange for using your before and after dyno numbers and the developed maps as a marketing tool for my product).

I'm open to any suggestions, as well, and am looking into things like partnering with companies that offer similar products for the FC and FD so the software and interface will be the same as what many people are already familiar with. It's too early in the project to tell exactly where it will go, but I can guarantee that at a minimum I'll be able to offer a modded stock ECU as per my original post, and it's looking very likely I will be able to offer an affordable plug-and-play solution that removes the flapper.

 

Oh, and as to WBO2... I have a LOT of hesitation about doing anything with that. Aside from the fact that each aftermarket WBO2 kit maker has their own interface, meaning I'd have to do the development work in rewriting the software again and again for each different WBO2 unit, there's the fact that WBO2 can only get you into the ballpark as far as a best-power tune, and far too many people think there is such a thing as a "target" residual O2 number that is the tuning goal. A vehicle tuned for best power will have a residual O2 "curve" that roughly follows the torque curve, and the "best power" mixture will be different for different pistons, engine designs, and so forth (of course we don't have pistons, but you get the point). Add to that the fact that all you're measuring is residual O2 in the exhaust gases, without knowing how it got there (is the mixture burning too slowly? Or is it too lean? Or is my spark voltage too low? Or maybe my port timing is causing too much scavenging?).

So I don't know if it will be as valuable as "conventional wisdom" has it being, even if it was something I could do affordably on my end (and I am sure I'd get a lot of hate mail from those who bought a brand y wideband kit if I only developed my product for brand x widebands...)

I will be doing like DynoJet does, though, and take maps made by users with certain mods, testing them to make sure they meet my standards, and then making them available as easily downloadable files that'll get you 90% of the way to best power on your particular vehicle right out of the box. That should be a big advantage to those who don't have the dollars or a good shop nearby where they can get steady-state full- and part-throttle dyno testing done with four-gas exhaust data (which tell you what's REALLY going on in your combustion chamber).

I wrote a few sections of my book on specifically why four gases are important for tuning, and why WBO2 is not a good tuning tool by itself; I can post them somewhere for those who want to read them (although I'd obviously prefer if you'd buy my book, 1/3 of which is not about motorcycles or EFI specifically, but is about combustion dynamics, and the intake and exhaust components and how they work together). http://tinyurl.com/6o3ze is the Amazon.com page for the book, and of course I sell copies directly (pm or email me if you want a copy, autographed at your discretion). I'm not here to get rich, though; I'm here to fund my terrible habit for modding my RX-7.

 

This sounds awesome, I am especially interested in the FI 12A possibilities of the setup.

 

The 12A is a possibility for sure. The biggest issue will probably be that most folks who want to put EFI on a 12A have probably modded their engines, some perhaps significantly. While the stock GSL-SE fuel injection system can probably fuel you up to maybe 160 bhp at the back tire on a DynoJet dyno, going beyond that, or handling a turbo, will be difficult; further, the more radical the mods, the more the maps will have to deviate from a "baseline" setting, making it more complicated for the end user to get tuned well (you'll likely not be able to download a map that is "close" to your setup in many cases, meaning you'll have to start mapping from near scratch, which can be hazardous to the motor or just a long exercise in frustration if you don't have some good guidelines to start with). There are enough GSL-SE cars that have had their engines robbed or are just turned into parts cars that it would probably be easier to source GSL-SE fuel injection parts and sensors in many cases than getting a MegaSquirt to work with whatever sensors you could find at a boneyard, plus figuring out a crank sensor and doing all your own wiring and so on. I'll have to explore the possibilities with some 12A folks as things shape up toward shipping 13B units, when we have some working units and the software is all debugged. At that point I'll be able to better gauge the difficulties and issues of a 12A conversion (and I'll need someone with a 12A to work with; I can provide the software and ECU for development purposes, and might be able to source a lot of the 13B EFI sensors, tank, etc.; if it works well, I will let the 12A owner buy the whole system from me for a steep discount, same as with the 13B test cars I talked about above).

As always, though, if it ends up being too huge an investment for me, or I would be unable to provide as much or more than a competing product for the same price or less, I probably won't develop in those directions (for obvious reasons!). As nice as it is to have a few bucks, if I was doing this for the money, I wouldn't have picked a GSL-SE as the showcase market for the product.

 

PM sent.

 

I'm interested.

 

is there any progress on this?

 

I haven't made any progress on the main ECU mods, as I have been up to my ears in various other things. I plan on making some inroads in January; I will be dumping the ROM from the stock ECU and decompiling it in January, and I also am working on a potential standalone hot-film MAF conversion. This would use an LT-1 unidirectional hot-film MAF with an interface box, which would plug into the existing wiring harness connector for the VAF "flapper". It would supply the stock ECU with the same signal it would get from the "flapper" for a given airflow, but without the intake restriction of the flapper itself.

If the stock ECU does not lend itself to my ideal resolution (daughterboard allowing real-time remapping), I can probably set up the interface box for the MAF conversion so there would be a decent range of fine-tuning that could be done (basically by altering the output from the interface box to "trick" the ECU into richening or leaning the mixture; I could also add a coolant temp sensor through-function for the interface box which would give a larger range of fueling control, and I'll explore that while working on the prototype for the interface box).

So I should have more news in mid-Jan. sometime. I'll keep everyone posted.

 

Oh, and I forgot to mention, I'll have to look into pricing on supplying the MAF that I'm working with, but the cost of the interface electronics themselves won't be all that much. Looks like the MAF sensors are pretty cheap on eBay, around $25 typically. That being the case, I can probably deliver a good used MAF sensor with the interface box for about $150, and it should be a simple matter of slotting the MAF in place of the stock flapper (I can just attach the interface box to the MAF, as it should be fairly compact) with some tubing and hose clamps (after I prototype it all, I can probably get parts to make a drop-in kit that will have clamps, tubing, MAF, and interface unit).

 

sounds good will be awaiting updates!

 

whered you say you where here in nor cal?

 

Have you thought about mapping it to the S4 AFM and S4 intake system. The Se intake system
lacks in the air flow department.

 

It's been 2 months since he said he did it, with no proof!

 

i would perfer a S4 or S5 AFM myself i know where i can get them cheal and not many would know the differ!

 

The S4 is a AFM, the S5 is a MAF. And they are completley different.

 

you know what i mean id like to keep it within the family of the Rx7. But yes i do stand corrected thank you!


edit speaking of AFM has anyone every noticed how close the one from the SE looks almost the same os one from a 94 4runner?