As of last night, I'm running a switched 27C512 in my ECU. It's currently programmed with standard UK and one of SE's. You simply select by flicking a switch.

 

How it's done (quoted from a recent email)...

 

" The EPROM mod is very, VERY simple. Basically you're pulling pin-1 high or low with a switch to select page-1 or page-0. You'll need a 3-pin toggle switch. It's just for safety that I bent out the address pin (pin-1) because I don't know what effect it would have on the ECU if connected. And besides, you could damage your EPROM programmer if it's not bent out. So... pin-1 of the EPROM you then wire to the common pin on the switch, pin-28 wires to one of the switch select pins, pin-14 to the other switch select. You wanna make the wires long enough that the switch will come out of the ECU, but not so long you won't be able to stuff it all in the eraser. To be absolutely safe, you should really stick resistors in series with the pin-28 / pin-14 wires... just in case the switch gets wet - you DON'T want these pins to connect together because you'll be shorting the ECU's 5V down to ground.

 

To program, select 27C512 (27C256 won't work), import your 27C256 image into one half of the 27C512s memory block - it doesn't matter which, because the switch now defines which half of the EPROM you're programming - then program that half. The verify will fail if you program the full memory because it'll get a mirror image in the second half. If you want to program the 2nd half, flick the switch and do it again. Obviously, if you erase the EPROM, you erase both halves.

 

I wouldn't advise switching maps whilst driving... most definitely if the code versions are different. I dunno what the ECU would make of suddenly having completely different maps, even if the code versions were the same. It might be OK. "

 

And another bit...

 

" Forgot to say... the EPROM mod also needs short wires to stop any potential noise problems, ie. long wires will pick up spikes and, at best, cause the pages to flip about... at worst, damage the ECU. If you wanna dash-mount a switch (I probably will in future) you should really hook up something like an opto-isolator right at the ECU end and run a couple of wires from that. If you don't already know, an opto-isolator is basically an LED and detector in one small package - the input and output signals are electrically isolated from each other so high-voltage spikes and noise'n'crud won't mess with your ECU. "

 

OK?

You lost me at "switched 27C512" Si ! :D :D

Hmmm, I feel a cunning plan coming on .....

Originally posted by AndyP

Hmmm, I feel a cunning plan coming on .....

SE v JWT?

Nah, don't bother with JWT anymore .... fuel is too expensive these days !

Originally posted by AndyP

Hmmm, I feel a cunning plan coming on .....

What? You're actually getting closer to making a dedicated ECU tuning section? :eek: Pushed my luck now, haven't I?!

Well if you write summat and it doesn't infringe any copyright then it could be in there .... ;)

 

 

Originally posted by 51x

What? You're actually getting closer to making a dedicated ECU tuning section? :eek: Pushed my luck now, haven't I?!

I used to have a duel map chip in my s13 & a switch on the dash to swap the map.

 

you could switch it on the fly no probs.

What would count as infringing copyright.

Well if you write summat and it doesn't infringe any copyright

Originally posted by Peter Hood

What would count as infringing copyright.

 

Taking pictures from someone elses website and selling goods based on them ;)

 

Has anybody looked at how the Mines multi-mapped ECU works?

Is this what the info is based on?

Originally posted by ChrisC

Taking pictures from someone elses website and selling goods based on them ;)

 

Has anybody looked at how the Mines multi-mapped ECU works?

Is this what the info is based on?

Eh?! Hold on now. If AndyP was suggesting I simply ripped off a Mines product and was trying to sell it, then I completely missed that.

 

I have looked at an old Mines ECU (as you well know) but this info certainly wasn't based on it. This is a cheap and simple (pin-compatible!) way to run 2 maps in a 300 ECU. I thought it up on my own - it sure aint rocket science. And I'm not trying to make any money from it.

 

Maybe I've got the cr*p end of your stick?!

LOL No I was referring to somebody else on the forum ;)

So yes you did get the wrong end of the stick.

 

I haven't actually seen a Mines ECU which is why I was asking - I've only seen the code and didn't know how THEY do it.

:D Oh, OK. I dunno who you're talking about then Chris (give us a hint, eh).

 

You have seen a Mines ECU because you've checked my rides section ;) I can tell you how they do it in the ECU I looked at, but it's nowhere near as simple as the method I suggested here.

 

Do you want your stick back then, cos it smells kinda funny.

Hosting copies of Nissan ECU maps for download !

 

 

Originally posted by Peter Hood

What would count as infringing copyright.

Originally posted by AndyP

Hosting copies of Nissan ECU maps for download !

That's fair. Could you get in the same trouble for having links to someone elses copies of complete EPROMs?

Anyway, even if this is a problem, if someone wants to share their re-map data (for example) maybe you could host only the differences between that and a standard EPROM? You'd host a small difference file - a bit like hosting patches for console games... which noone's got in trouble for doing (have they?). This would have to be limited to home-brew stuff tho - no commercially available data (JWT, SE, etc).

Seems like a way forward to me.

Well, OK... a thumbs up from AndyP! :D

Just need: a nice little tool that can make difference files (and undo them back to the real thing)... and a bunch of people ready to do some tuning.

John Dixon's made a nice Z32 tuning spreadsheet, and is still adding to it (just now talking about adding import/export of 512kbit (2-page) images). And ROM Editor is OK for a bit of a play.

Errrrrr do you lot NEVER search the net? :D

 

http://www.ztechz.net/turboupgradeforvg30dett/id9.html

 

;)

Originally posted by andyduff

Errrrrr do you lot NEVER search the net? :D

Hahaha! :D And there's me trying not to mention Devins stuff in case someone here gets in trouble for posting a link to modified Nissan EPROMs.

 

Cheers tho Duff... if anyone hasn't looked at Devins ECU tuning page, it's well worth a read.

Originally posted by 51x

... if anyone hasn't looked at Devins ECU tuning page, it's well worth a read.

 

LOL I only linked to it ;) That site really can make you see the light though - excellent :)

So I thought I'd stick up a pic to show /just/ how complicated this 2-page EPROM is to make...

...and another one of the EPROM being programmed in my home-hacked programmer (just don't cut the black wire)...