51x

300z: Phew! Desperately trying not to p*ss anyone off - I've already been banned from here once... for saying *nothing* (I think)! Now I'm sure I'm gonna get banned for boring everyone into a coma. Oh, and there's no need to take the p*ss, saying this stuff is interesting! :P Cool bananas?! LOL! AndyP: Nothing mysterious... I'm a bloke with a car that jerks off over tables of hex numbers. I totally get what you mean about offsetting maps now. Sorry, my brain fell out and rolled under the bed. It's actually quite easy to do with the Z32 ECU data cos each map is only a 16 by 16 table of 8-bit numbers (256 bytes), and the RPM thresholds are defined in a seperate 16-byte list. In your example (not that bad at all) you'd simply lop a couple of lines off the start of the table (32 bytes) then add your new data (32 bytes) at the end of the table. Then you remove the 1st two bytes in the RPM threshold list and tack the two new upper limits on the end. Job done. It has the effect of appearing to move the 3D graph toward you (in ROM Editor) in the rev-range scale and adding new data. But in reality, you're actually shifting the mapping window (away from you). Relativity... hmm. 165? Oops ;) That's kinda what I was thinking about the octane maps. But to add to the confusion (there must be someone who knows about this!) there's actually 3 fuel maps (lo, mid, hi). I did have a brief word with Pete about this in the morning. As far as he's concerned, "safety boost" is not present in UK spec cars - the ECU *can't* control the boost level. But it can (obviously) retard the timing, and that is somehow triggered by the knock sensor. It came up cos I'm kinda thinking maybe my sensor's f'k'd and worth changing when he does all the other work. Maybe there's some clever(?) way the ECU could do it, but it's probably simpler to switch down to a safer map (with retarded timing) and see if the knocks are still present. If they are, switch down to an even safer one. I really dunno. I'm making a big guess. Anyway Mr AndyP, did you wanna host my crud on your site? As if I hadn't already put enough text in this thread, this is the address list with ROM Editor's labels: Breakdown of the Z32 EPROM addresses, from accesses made by ROM EDITOR 1.98.48 ------------------------------------------------------------------------------ Note: these are addresses relative to the start of the EPROM (at 0000). The HD6303 processor sees the EPROM start at address: 8000 - the upper 32 Kbytes of the 64 Kbyte address space. So in disassembly, the following addresses will be found at F000 onwards. The low 32 Kbytes has hardware registers (and RAM? - dunno how much) mapped to it. 7000-70FF *: Low octane fuel map {8bit ON, 7bit ON} 7100-71FF *: High octane fuel map (more than gear position 4) {8bit ON, 7bit ON} (7200-720F: Acceleration increase volume (?!) ...and also...) 7200-72FF *: Regular fuel map (more than gear position 4) {8bit ON, 7bit ON} 7800-78FF *: High octane ignition time (also High-octane ignition time map (more than gear position 4)) {8bit ON, 7bit OFF} 7940-795F: Idol stabilization control MAX [all 0] 7960-796F: TP Limit 79E3-79EB: Knock limit 7A70-7AAF #: VQ map [a nice smooth curve from 48 to 65535] 7AF0-7AFF: Boost 7B00-7B0F: Fuel RPM thresholds (lowest to highest) - steps of 50 RPM [400 - 6400 in 400 RPM steps] 7B10-7B1F: Another set of RPM thresholds (not accessed by ROM EDITOR) 7B20-7B2F: Ignition time RPM thresholds (lowest to highest) - steps of 50 RPM [400 - 6400 in 400 RPM steps] 7B30-7B4F: Water temperature conversion table 7C00-7CFF *: Low octane ignition time {8bit ON, 7bit OFF} 7D00-7DFF *: High octane fuel map {8bit ON, 7bit ON} 7E80-7E8F: TTP MIN 7E90-7E9F: TTP MAX 7F2B-7F2C: K required number (hi-byte, low-byte) [0120] 7F88: Void blast-off time [4B] 7F91: Feedback control [64] 7FA5: Speed limit - steps of 2 KPH [EE = 476 KPH] 7FB4: RPM limit - steps of 50 RPM [94 = 7400] # = 2D map * = 3D map: load-min: xxx0 to load-max: xxxF; RPM min: xx0x to RPM max: xxFx {} = use these settings in ROM EDITOR's 3D edit mode [] = typical settings = ROM EDITOR tab identification

OK. I read something about a "stealth-box" designed for the 300 which didn't take up much space. But AFAIR it was a small fortune. I'm mainly thinking about getting the best efficiency from a small sub by (maybe) using a huge bubble. Probably worth starting with a high-pressure foam-filled beach-ball coupled to an 8-inch sub. It's all theory - I'm not about to run out and buy a pair of cr*ppy speakers. I /have/ gone completely nuts, but I thought it'd be worth putting out to the tefal-heads around who might know something about sound waves and air-pressure and stuff. Inner-tube... hmmm.

OK, it's not an insult. It comes from the expression: "teaching your granny to suck eggs", ie. telling someone all about something who could probably write a book on it already. No offense intended. Ignorance being bliss (another cr*ppy expression), I hadn't heard I could bust the ECU by opening it... so I just opened it! The original EPROM was removed and a little adapter was soldered in place with a 27C1001 (1 Mbit EPROM) sat in a socket. I popped it out, stuck it in my home-made EPROM reader and dumped the contents. The 1001 being 4 times the size of a 256, I assumed they'd made 4 pages. There's some small IC's on the adapter board (with the numbers rubbed off) that handle the page selection. I'm told there should've been an extra box that you use to select the page with - it connects via 3 wires to the adapter board. I didn't have this tho. I've connected it all up since and the ECU is still working fine - on the one page I could run it without the selector. I've not done anything spectacular (apart from the EPROM reader - which is f'kin spectacular! :D ). I don't have a mate at MINE'S or anything like that.

Yeah, alright... stop looking at me like that! So I was watching some afternoon kiddies TV in bed yesterday - it'd been a long night. There's some tasty female presenter waffling on about something or other - I didn't have the sound on to start, cos hey, ya know - I didn't need it. Then she starts demonstrating a pair of inflatable speakers and I'm all: no way! But it seems to me this could be a pretty neat idea. I'm missing some heavy gut-shaking bass in my motor, but I'm not about to start adding tonnes of extra weight just to get it. If anything, I wanna chuck out weight. And besides, I still need enough space to jam in a couple of snowboards. So... an inflatable bass-bubble? Discuss.

I'm pretty sure SE wouldn't have knocked-off the JWT chip. But I haven't seen the JWT contents yet. I know Pete's put in a lot of work to make a good map - lots of testing on rolling roads, and real ones. I'd heard the JWT maps are more conservative to comply with US emissions. But maybe that's a rumour. In both cases, it's only the EPROM that's different - the ECU is the standard unit with a socket fitted. But you know this already and you totally know how to suck eggs (sorry). I've no idea how old this MINE'S thing is. It's probably not their current VX-ROM - I dunno if that's what you've got. Let me have a look at the contents and I'll see what your limit should be ;) I'd heard it's possible to fling an engine above it's rev limit by, say, missing a gear on hard accelleration. It's all momentum and stuff, right?

Dunno if it was as much as 470 bhp Dave. I should've asked Pete this morning - I dropped in to give him the nod (wink and gun). I'm still feeling a bit sick about parting with all that cash. It'll be worth it tho (repeated over and over in my head).

Hey - I /like/ my HICAS... I think ;) I wouldn't mind having the option to turn it off simply to see how the car would handle without it. Must admit, after having a 4-wheel laser alignment check / reset done it handled way nicer. Don't mean to be rude tho - my original question was about the ECU controlling the HICAS. Whether it's hydraulically or electrically operated something still has to make a decision about when it should operate. Re-reading Henri's post tho (found in the archived stuff) he talks about how the HICAS system can't be disassembled like the ECU ROM. So I guess I'm kinda answering my own question. But does that mean it's a seperate box? So where is it? How quick can I pull it apart and start fiddling?! Lemme at it!

It's a quick one... does the ECU control the HICAS system? I read that HICAS is /supposed/ to only work over 30 mph, yet Henri finds it works much lower. AndyP's comparison chart says UK spec has a high-speed version of HICAS. So is it all down to the EPROM code? And can it be tuned?

Offset the maps? I think it was marked: SE_Z32A.470. I don't have it here to check unfortunately. It's for a UK spec auto - maybe that's what the "A" is for? Looking forward to my custom map... and getting my car back in a few months :(

Hey James... This is probably gonna sound stupid, but I honestly don't know. And now I'm a bit nervous. SE slapped the wheels on at the same time they fit the brake kit. When I dropped in they were cr*pping themselves a bit cos the offsets would've been fine with standard calipers, but the AP's slightly fouled on the back of the spokes. So they had some thin spacers made up (a couple of mm). They didn't mention anything about the studs being short. I've had the tyres turned since then, and the tyre guys didn't say anything either. So I've never thought it was a problem cos I'd never thought of it. Until now :( I can't check either ATM cos I haven't got the car. It's... um... being *modified*.

Hey wow! A switch! I'd try flicking that thing and seeing what happens. Be a bit careful tho - maybe it's to optimise it for different octane fuel. Look out for pinking! Don't fuq your lump just cos I said flick it! Wot you need is someone who knows something about your ECU. S'pose it's a bit obvious, but have you searched the net? Maybe there's a label on the lid of your ECU that might help?

Well, I'm gonna tell you anyway ;) There's a nice mailing list at: http://www.diy-efi.org - lots of interesting stuff. If you do a search for 300zx or Z32 you'll find there's been some discussion about the Z32 EPROM. From diy-efi I find the main processor in the ECU is a Hitachi 6303, which is an 8-bit Motorola 68xx derivative with some extra functionality, in particular: multiply and divide instructions. They also mention a suitable disassembler: DASMx 1.3 which can handle 6303 disassembly (among other things). From much fiddling around with ROM Editor (cheers Henri), then later simply looking at the Z32 ADR file (doh!) I made a list of what addresses in the ROM relate to what maps and other settings. There still seems to be some large data areas in the ROM that the editor doesn't address. I don't have a clue what these are for (does it matter?). Next, I mess around with the disassembler. From the address list, I make a rough SYM file so the disassembler can code-thread it's way through the ROM and sort out what's code and what's data. The SYM is based on the MOT 6803 (mainly for the hardware entry points), but the disassembly seems to look OK with ROM Editor based labels for the data sections. Then I try looking at some ROM dump disassembly in more detail. Specifically, I'm comparing an SE chip to 3 switchable pages from a MINE'S ECU - it has the potential for 4 pages, but the 3rd and 4th are the same. And so... a few (possibly) interesting points: .the "useful" data section of the ROM is the last 4 Kbytes (of 32K). There's some small data entries embedded below that, but mainly it's code (or reserved for code). .the 1st MINE'S map has the speed limit set to 184 kph (114 mph). This makes me think it's based on original Jap contents. The 2nd and 3rd are set to 510 kph (317 mph) - a bit ambitious maybe ;). SE set theirs to 476 kph (296 mph). .all the MINE'S maps have a rev limit of 7000 rpm. SE's is set to 7400. .MINE'S do something rather strange with their low-octane ignition time map - there's a big peek at 800 rpm for some reason. Maybe it's a hangover from the original (Jap?) contents? It's not in the SE ROM. .all the maps have 16 programmable rpm thresholds. All are set at 400 to 6400 in 400 rpm steps. They don't /have/ to be tho. Theoretically, you could concentrate more detail around a certain rpm range by closing down the thresholds. There's actually two of these threshold tables, although ROM Editor only accesses one of them. .In the SE ROM the first 3 fuel maps (low, reg, high: F000-F2FF) are identical. In the MINE'S ROM these are each different. The 4th (FD00-FDFF) in the SE ROM is different to the first 3 maps. I don't fully understand why the ECU would have different fuel octane maps, but maybe the ECU attempts to select an appropriate map (or pair of maps, including the timing map) based on knock-sensing. How would it know the fuel octane rating otherwise? .Most surprising to me: the *code* in the MINE'S and SE ROM is different. The MINE'S pages all have identical code, but relative to the SE ROM they have stuff missing (1st free byte in MINE'S: DBFA; SE: DCE6 - just after the SWI and NMI entry points). It's a bummer really, cos it means you can't switch pages between MINE'S and SE on the fly without running the risk of crashing the processor. I s'pose it's only a matter of doing a cut'n'paste with the code from one ROM and the data from the other. But still, I'd like to know why they're different. And that's about it for the moment. There's still a lot I'd like to know, particularly about all the (non-map) stuff ROM Editor can edit. If anyone's willing to host it, I'd happily share my address list, the disassembler, my SYM file and the ROM Editor (although it's probably best just to post a link to the main host). I was also thinking of doing a: "how to make a 2 page switchable ROM" based around a 27C512... and a switch. It's /real/ tricky stuff (not). I bought some the other day cos they're actually cheaper than blank 27C256's (wot the ECU has already got), and they're pin-compatible. Might be nice to have a "conservative" map built in (with speed limit set to 70 mph and rev limit set to 4000 rpm) for those times you /have/ to leave your motor with the missus - and a second key like Corvettes used to have ;). Anyone still awake?

You'll /way/ like a Z. I lusted after a 928 S4 before I got my Z, but got taken out in a 928 on a track day a while ago - I've never been so disappointed! Nice rumble. But where's the power? OK, so it was a bit wet, but I still reckon you get a lot more for your cash with a Z.

I wouldn't mind a look in the EPROM to see what they've done differently. I've been looking at a few other ROMs lately. Not heard of that one tho.

I spent ages deciding on a set of alloys. But IMO, you can't beat a classic 5-spoke design. So I got Kahn RS-R's. Some fuzzy pics... http://www.300zx.co.uk/rides/51 . And a set of AP 6-pot / 343's to fill in the gaps :D I also considered Anterra 143's and Radius R1's. But RS-R's look that bit bigger than other 18's. And I'm not gonna be buying new alloys in a years time cos they've gone out of fashion. It's all down to personal preference of course.

Hey. Thanks for the replies. I'll try to keep this short so you're not all bored sh*tless (unless you already are of course). Dave: Can't sleep. Too much to think about. Between doing a bit of work, I had actually been comparing sections of data in some Z32 EPROMs... which should've been boring enough to send anyone to sleep. But didn't. I think I still have a bookmark to your site. I remember your car. Probably like everyone, I don't really expect any mods to increase the value of the car. It's just for fun. Which is why I need value for money. I don't mind forking out (so much) if I get a lot of fun. Hopefully, a rebuild with forged pistons should also give me some peace of mind. I have a whole relationship thing going with my car. I've had it a while now, and it's just starting to get good. I've no plans to get shot of it any time soon. So yeah, I think you're right about me knowing I'm gonna spend the cash. Maybe I wasn't prepared for having to spend it this soon tho. I'll pass on your regards to Pete. Trey: I've been a loyal (and long-suffering) customer of SE for a while now. The first few bits were done at the dusty old place they had - however long ago that was. They've done me quite a few favours in the past - fitting me in for small jobs whenever they could cos I work locally to them. I trust Pete to get it right with the big jobs. So honestly, no... I haven't considered anyone else. And I'm not sure I would at the moment, being the sort of paranoid android that I am (maybe read: blinkered, short-sighted fool). I have a complete breakdown of the price. It's all inclusive of parts, labour and VAT. In short (or did you want full detail?), it's: engine out, rebuild labour, rebore (to 3.1L), forged pistons and rings, port and polish the heads, cam belt, oil pump, head gasket, crankshaft main and big-end bearings, associated sundries (injector seals, coolant hoses etc.), AVCr boost controller, 550 injectors, custom EPROM. Estimated BHP: 500 (odd) at 25 PSI. I haven't looked at buying a second-hand lump, but may need to if mine's badly damaged. I don't expect it is, and hopefully the rebore will sort out any bore damage. I'll find out when it's pulled apart. Paul C: I need this more than I need both kidneys. Or a missus. I think. paulg: Wow! If someone had made a suggestion like that to me 10 years ago I would've jumped at the chance. Well, if I'd had a job and some money. With all due respect, even with a lot of fantastic help available, I just don't think I have the sort of ambition to take on a job of this magnitude. I'm a chicken. I know for sure I'd cock it up. In the longrun I dunno if I really would save a fortune. Maybe I'm better off earning enough cash doing something I'm really good at, then paying someone I trust to do a decent job. Thanks for the alternative suggestion tho.

Not sure I'm doing the right thing here. Actually, I've pretty much convinced myself it's the best thing to do, but I'm hardly being objective because I'm telling myself what I want to hear (schizophrenia is b'stard like that). I'm waffling. Does anyone else find their 300 calling them a pussy and demanding more modification?! Fantastic motor that it is, I knew it had potential for reasonable improvement, which is why I bought one. But it seems to be never ending: I drive it a while, I'm happy, then something doesn't feel right - usually "it could pull harder". Up til recently I was pretty happy - SE's coilovers, some phatt 18's and big f*ckoff AP brakes had me flying around (and stopping!) with a permanent stupid grin. Now, you have to bear in mind I'm not made of money. So when I get a mod, I need to get value. I'm not lucky enough to just *out of the blue* go for (eg.) a top-spec engine and huge turbos. OK, so I was lucky and got a set of SE hybrids for near on nothing (don't ask). Should I get to the point? I'd run out of affordable(?!) engine mods to do: filter, exhaust, turbos (@15 PSI), big intercoolers - they're done. Probably not a good time to mention the secondary injector computer I made for SE, cos nothing came of that - shame. The ECU EPROM was the last thing, and that got done a couple of weeks ago while hunting around trying to work out why it just didn't feel very quick. Then one day last week it started puffing burnt engine oil. Only little puffs now and then. But it got worse, fast. I fully expected to see 300 sightings here, but you wouldn't have seen me for smoke - seriously! SE ran compression tests - 2 cyls with virtually none. Bollox! Noone knows why - it hasn't been pinking, I haven't been pushing it hard. But it's f*cked. So, what to do? I had a big long chat with Pete R in his office. He shows me a few quotes for jobs that the big boys have had done - woah!... serious money! I sit there thinking: well, this is gonna cost, so while they're at it, let's do it properly. Forged pistons please. Ooh, and some bigger injectors so I can wind the hybrids up to what they should be pushing. Ooh, and a decent boost controller so I can keep it all under control. Hmmm. I'm still getting Christmas butterflies talking about it. He taps away on the keyboard and prints out the quote. Six and a half thousand pounds. I take the paper. I get in my (borrowed) car and drive home. I've been staring at that paper ever since. I don't know what to do. I know what I /want/ to do - scrape up the cash from somewhere and get all the work done. But 6 1/2 grand is a lot of cash to me. I could dress my girly in a heck of a lot of sexy underwear for that. I could get p*ssed every day for several weeks for that. I could probably buy a few Nissan Micra's... but I wouldn't. I need to know this is kinda the right thing to do, so I'm putting this question out to a bunch of petrol-heads that I fully expect to say: yeah man! F'kin do it! Surprisingly, my girl said, without hesitation: do it! It's only money! But then, she's slightly crazy. Some level-headed advice might help. Maybe.

OK. I've got it now (cheers guys). I got it sent to a different account. Something weird going on there, but never mind. So... it does look pretty good! It even has a compare mode and 3D editing! This is what I was after. The English translation is fairly entertaining too. Not sure it likes Win2K too much, but I can probably dig up a Win95 machine from somewhere. Cheers for the link H. I'm off to play with some numbers :D

H, The software that link points to looks promising. But, unless I'm just not waiting long enough, they haven't sent a username and password for the download. Now I'm worried it's a hoax and I'm gonna get a ton of spam. Have you had any better luck with it?

Crikey... I was gonna make me own. But for that price why bother?! Where from?

...he could only offer limited advice because he makes money from custom mapping. I s'pose it's fair - he's gone to a lot of effort to disassemble the ROM contents. Any other techie guru's around?

Wow! The guy is completely bonkers! Top site tho. Thanks for the tip.

Hi all. Not trying to make my first post particularly controversial... does anyone have any information about what locations do what in the Z32 EPROM? I recently had the chance to dump out a couple of non-standard chips, one of which has 3 selectable maps. If it's likely to be a help to the 300 community I'd like to propose posting these dumps somewhere for all to examine, maybe building up a database to see who's doing what in their "performance" mapping. If anyone's worried about piracy, I can list these in a format that can't be directly imported into an EPROM programmer. I s'pose, technically, anyone making a new map is infringing Nissan's copyright anyway by starting with the original ROM contents. So... thoughts?