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Ae92, Supercharged Khanacross Car.


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Only just got back to this today, took the Easter long weekend off and have been messing around cleaning up the shed in the last day and a bit. I've found an AE93 SX Cluster pinout from the net, seems as though I was looking at the wrong wires before and had picked up the illumination lights. So not sure why there's such a low resistance to ground, must be something a bit weird going on there.

Pulled more of the dash to bits as I found a few damaged wires and was still walking the wrong path. Taped everything back up now and got the multimeter on the right plugs. The earth for the temp guage is fine from the plug onwards, 0 ohms so no issues. But if I go off the screw that appears to lead into the back of the temp gauge (just following the tracking along the board) I get a 270ohm resistance between that and ground. Investigating this further, if I wiggle the plug in the back of the cluster, I can get this down to about 10 ohms. Wiggle it again and it'll jump straight back up to 270 ohms. So seems there's some issues with the connection to the cluster. Looks like the copper colour is gone in one spot, bit dark out there at the moment and my Narva LED trouble lamp just packed it in. So will come back to it tomorrow, but think I'm on the right track.

I might be able to repair the track with a bit of solder, or I'll run a terminal off the back of the screw and splice that directly into the wire. Will have to investigate further as the fuel gauge is permanently reading half tank (think it was doing that before the roll) so not sure if it's a connection issue there or whether the sender's got issues.

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Success !!

Practiced on an old standard dash I had here, and it's not real pretty, but you can lay a bit of solder onto the track. The track actually didn't look that bad, but the pin was sitting as proud as the others and still not getting proper contact... apparently. Soldered it up and tested with a multimeter. Even wiggling the plug, best I could get was 0.7ohms resistance down to Earth.

Plugged it all back together and started it up (just now, ran out of daylight last weekend) temp gauge behaves like normal. Sat there idling for a while, came up to half gauge and held there, even with a few limiter bashes to get some real heat into it. Still got the dash in enough pieces that can't drive it anywhere yet, that will be the real test I guess.

Now I'll chase the fuel sender, while the dash is out, see if that's an issue. Then put everything back together, give it a wash, strap it down to the trailer and on Monday, organise to have a new screen in the front of it. There's an event on the 24th of May with another Car club, but it's only $60/yr to join and a day membership is $15. Might be able to get this thing back out on the dirt !! ... and see if I can roll it this time :D

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  • 4 weeks later...

Another gap between posts, but this time I've been doing things (WARNINFG: Marathon post). After getting the temp gauge issue sorted I was pretty stoked gave it a wash and parked it on the trailer ready for a windscreen replacement. Took some 'glamour' shots to show what the beast now looks like.









Me being me, got a bit carried away at work and forgot to call the windscreen people, so by the time I made the call on Wednesday, they couldn't fit me in and it would have to wait till the next weekend. I used the time wisely and contemplated my navel, or close enough to. Stripped all the useful bits off the old shell so it's ready to go to scrap and messed about it in the shed.

Finally the big weekend came, starter motor was still messing around, so was pretty nervous and very happy when it started up first go off the trailer. Unfortunately it then wouldn't start again in the workshop after the windscreen was fitted. A couple of taps on the starter got it going, so loaded back on the trailer and bought it home to fit the wipers and plastic trim.




All that was left was the sump guard and I could go racing. Unfortunately the old throat at been a bit scratchy since Friday arvo so, yep. Came down with the man flu for the 4th time this year and only a week and a half after having the flu shot. Soldiered thru Sunday but devoted to my time to gardening (waste collection coming up) before taking Monday off work while feeling pretty sorry for myself. With the Autocross the coming weekend I wasn't sure if I could find the inspiration to finish the car and get it there. I didn't want to push on thru and then end up feeling crook at the event, kinda ruins it.

Fortunately by Wednesday morning I was starting to feel better, not great, but better. Decided to go hard on Wednesday night and get this thing finished, didn't spend all this time and money to have it sitting in the carport. The sump guard hasn't fitted all that well for a while and the rollover put a few more kinks in it that I had forgotten about. I got screwed on the material and got given regular aluminium rather than the marine grade I asked for, so beating it back into shape isn't that hard. But the two bends are close to each other and without some big equipment you can't hold/support it to effectively get one bend right without upsetting the other. Thursday morning dropped in on a fabricator I used to deal with many moons ago, they looked after me pretty well and took the time to put it thru the plate roller to straighten it back out in several spots, then put the bends back in, lined up perfectly. So Thursday lunch break was spent picking the guard up from them and then driving to the other end of Perth to get a new fire extinguisher as mine had just reached the end of it's life. All in all, a 2hr lunch break, pretty thankful work are easy going as long as the hours get done. Thursday night spent bolting up the sump guard and loading the truck. Hard to get to sleep that night as I had a million thoughts running thru my head and pretty excited (and nervous) about the Autocross.

Friday night, car onto the trailer and then start stressing as I haven't got a blue triangle or any tow stickers and get worried about being pinged at scrutineering. Mercy dash to Bunnings for some coloured electrical tape and then back home for a relatively early bed time.

Saturday, 5am up and at them, 6am on the road and heading off to the track. Got there at 8:10, car started up off the trailer easy as. Clean the windscreen, mount the Go Pro and present to Scruitineering. Zero fugs given. Didn't see them even look at the Fire Extinguisher, they shook a few things and that was about it, signed off. Why worry ? It's in the supp regs about having mudflaps behind the driven wheels, though I saw cars there without any mudflaps. A pair of cars that rocked up didn't even have functional wipers and it was raining. Oh well.

Event went really well, never had a problem with the starter, must have had a bit of rust or gummed up a bit from sitting. Car handled really well, now have rally tyres (though pretty worn and old) on the rear, but I think the bigger changes are from the softer spring rate and the lack of swaybar. I actually had to use the handbrake a bit to unsettle the rear to get it around the corners as tight as I wanted. Track was awesome, unfortunately the bottom of one of the loops was boggy as all hell and I know I lost a fair bit of time down there, even spun once. But the rest of the track had a lot of grip, it just took me all of the runs to work out how much grip there actually was. Even after the last run I felt as though I didn't commit enough to some corners and could have gone quicker. My times started off at high 2min 17s and I got down to near a 2min 9 dead, so an 8sec improvement, I'm pretty happy with that. Cars that put in the fastest laps were of course 4WD, 2min 1. Next 2wd's were at 2min 5, so I'm still 4sec off them, but anyone in front of me had been to the course before and a couple of them are known as gun autocross drivers, so I was pretty happy with my 7th outright.

Car came home absolutely covered in mud, there was even mud up under the rear door handles ...how the hell ?




I've got it mostly washed down (couple of hours with the hose) and today I'll back it off the trailer and park it back in the carport. Nut and bolt and an oil change and it should be ready to go for the Khanacross on the 15th of June.

This hopefully marks the end of the development of this car, I've got an old Datsun 180B sitting in the garage, taking up space and it's going to get some loving, seeing as I've owned it for near 7yrs and driven it less than 100kms. It will get finished off as a tarmac car, hopefully seeing a lot of motorkhana's with the occassional track work. The Datsun needs to move out of the shed as plans are already under way for a Hyundai Excel rally car, I've already started purchasing bits like an LSD and lower final drive ratio. The Corolla will keep seeing duty as the gravel car until the Datsun/Excel's finished, but hopefully no more full on rebuilds are required in that time.

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It is a damn nice feeling. I had a lot of fun that day, definitely worth all the effort to get the car there in the end. Just looking forward to the next one now. Car is parked back in the carport, ready for an oil change and nut and bolt check.

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  • 4 months later...

Alright, putting the call out for help, I know there's some experienced 4AGZE people out there.

Car has been doing pretty alright, been to a couple of Khana's and another Autocross, getting further up the order and starting to come to grips with the car and up till the last Autocross it performed flawlessly.

I forget whether I mentioned it before, but I did have an O2 sensor failure, showed up on the diagnostic codes when I checked and was able to pinch one from a mate and connect that in, all been fine since.

Last Autocross it was hauling like a trooper and I was driving reasonably well, despite the stupidly slippery conditions (Ended up 5th behind two buggies and some much more experienced drivers, so pretty happy with that). Part way thru the 2nd last test, it went a bit limp. Still drove, guages were fine, no lights, but just lost it's punch. Came out of the test, turned it off and on, checked a few things (thought I might have spat a supercharger belt) but all seemed to be OK. Took the car for a quick test drive and when you stood on the throttle it still wanted to go, so thought maybe I was imagining things, so carried on and lined up for the last test. Nup, this thing is definitely off it's game, it goes, but not punching anywhere near like it should, particularly noticeable up the slight hills, so I just kept my foot buried and kept the corner speed up and got thru the test. Fortunately it was the last test and I got a reasonable result, if it wasn't the final test I was going to have to withdraw, so thankful for the fact it made it thru.

Back home and after chatting to a mate, figured because I was pulling some revs (not at rev limit on this track, but had tickled the rev limit in the past) and I do have the big pulley, probably melted the vanes off the charger. Check the supercharger oil, it's at the right level (have heard they'll pull the oil into the charger with bad seals) so attach a boost gauge and give it a few blips at idle. 0.7bar boost as a spike, so I'm fairly confident that the charger is working well. Up till now it's started and run fine, moved it on and off the trailer and around my yard, no problems. While it's sitting there idling and I'm scratching my head as what to check next, idle note changes (similar to when the O2 sensor died) and when I check the dash, I've got a check engine light. Start to think perhaps the 2nd hand O2 sensor has died. Search the internet again, find the pins I'm meant to bridge, switch on the key and the check engine light doesn't flash at all. Odd, I got a code out of this thing in the past. Disconnect the battery for a minute or two, plug it all back in, Check engine light comes on with bulb check, bridging the test ports still doesn't yield any flashing. Decide to start it back up (it's still warm at this stage after I had it running before) starts up fine and idle's away, fairly happy, but still got a check engine light. Blip the throttle, does not like that ! Basically tries to stall out any time you give it any sort of throttle, if you play with the throttle I could bring it up to ~4K, but it's popping and farting and really not happy about life, but will sit there idling with no problem. Time to phone a friend, talk it thru, decide on MAP sensor. Had seen on the internet that the engine should stall if you unplug the MAP sensor, makes no difference to mine, still idles fine, still won't rev. Even tried disconnecting the O2 sensor, also didn't seem to have an effect (not surprising, but I'm grasping at this stage). So, back to my mate, he hasn't got a MAP sensor from a 4AGZE, but does have one from a Turbo MR2 of similar vintage. Internet search seems to indicate that all those MAP sensors of a similar vintage will yield the same result. Decide to check the harness with a continuity tester as it just so happens that the Diagnostic pins are on the same plug. MAP sensor checks back to the ECU plug all OK. Plug in the new MAP, try to start it. Hopeful, but won't go. Because it's now dead cold, doesn't want to play the game. I did get it to run a couple of times for all of 5 seconds, but it starts to idle and then trails off, blipping the throttle results in instant stall, so it seems as though I haven't made any progress. Decide to check the next option, TPS. 5V to the sensor. IDL to E2 goes to infinity with very little throttle movement, so it means it is switching off the idle map. Plug it all in, 0.4V from the signal wire at closed throttle all the way to 4V at full throttle (which seems to be in spec ?), doesn't jump or skip, all seems quite OK. I haven't checked the TPS wires back to the ECU, I'm assuming they're all good as I have ground and 5V connection there. SO now I'm really stumped at not sure what to go chasing next, hopefully someone out there might have come across something similar, or have a helpful idea. Little worried that the Check Engine light won't go away and I can't get it to flash when bridging the Diag plug, don't know if that means there is something more sinister going on or not. Any thoughts ?

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  • 2 weeks later...

And the answer is ... dead ECU !

Found another ECU for sale on Gumtree, had a 'remanufactured' sticker on it, but the dude had tested it on a working engine. Swapped the plugs over. bit of a splutter and it fired up. Was hesitant on the throttle initially, but I think it must have been slightly fouled plugs, once it had some heat into, no problems, revs nice, all good.

Just to double check, while it was still warm, swapped the plugs back to the old ECU. It started, but threw up a CEL straight away and same messing around with the throttle, have to play with it to get any sort of revs and popping, farting and carrying on.

Swapped back in the old MAP sensor as well, still no problems on that.

Bit of a weird problem, but at least I can now park the beast under a cover, confident in the fact that it's ready to go for next season.

If anyone know's of someone who 'fixes' broken ECU's, I'd be interested in getting this one looked at, they are getting a bit rare.

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  • 10 months later...

Alright, so I'd mostly been doing what I said and just trying to wear the thing out. Couple of small issues, busted gearbox mount and things like that, otherwise had been enjoying just taking it out, throwing some spanners at it when I got home and then taking it out again. Guess that can only last so long though ....



Everything seemed like it happened in slow motion, felt like I was heading for that tree for 3 minutes, but the video shows the real time it took. You can hear the tyre on the guard right after the bump, so that along with the half turn of lock that did nothing as I headed for the tree, leads me to believe that this happened before I got to the tree and possibly even before the bump and I just hadn't realised.




I seriously expected the front of the car to be destroyed, fortunately the tree was dead and mostly just disintegrated on impact. The front bumper developed some big cracks, but I'd already bounced it off some tyres at an autocross, so wasn't that devo about that. The bumper brackets had copped a hiding as well, so replaced the left one. There was a small dent in the front of the bonnet, but it's so small I'm not doing anything about that. Unfortunately part of the tree fell down on the rear spoiler and got not just the spoiler, but the hatch itself. Again, not bad enough to be too concerned about, so going to get the fibreglass fixed by a friend, a dash of paint and that will be it.




So the major bit to sort out was the strut top itself, which wasn't exactly repairable;




I'd seen some minor cracks developing in the rubber, but hadn't figured on this sort of catastrophic failure, thought I'd get longer out of it. Crazy thing is, didn't break apart where I saw the cracks. Had a look in stock and didn't seem to have another good strut top, they all showed suspect signs that I was game to put back into the car. Never researched the price of the new ones, figured they'd be ex-japan, but perhaps there's an aftermarket version. Either way, I figured they'd be exxy and there was the option to improve things and given the recent (and now timely) purchase of a lathe it seemed a good idea to go custom. There are versions from XYZ and the such that you can buy and just bolt in, but I didn't want to mess around with caster angles and camber angles for each wheel alignment. And I already new the camber/caster was pretty close to the same on each side from a previous wheel alignment, though maybe the hit to the left hand control arm might have changed that, anyway I decided to go with a fixed design.






I didn't want to increase the camber, after discussing with my mechanic mate and remembering back to pics of the FWD Honda competing in the local ARC round, camber seemed unecessary, even detrimental, so I just tried to dial in as much caster as I could.




The keener eyes may notice the shock absorber shaft doesn't stick thru the nut, but I've actually stepped the nut, so the thread is down inside the uniball, I've got more than a nuts length of thread in there. The reason it's jacked up so high is to try and get as much of the shock absorber travel as possible. The standard arrangement does that by having a pressed metal spring seat and the 'turning' bearing bonded into the middle of the flexible rubber. Because I now had a spherical and needed to fit the 'turning' bearing in the spring hat underneath, I basically ran out of space for everything. In the end I've compromised on losing less than 5mm of suspension travel. If I had access to a milling machine, I would have turned the top nut and then milled a hex into it. As it was I was stuck by hex bar sizes and to fit over the spherical I needed at least 24mm, so 1" it was. Thinking about it now, I guess I could have done it with a smaller hex and sleeves and what have you, but this works and was a fun little project to turn out on the new lathe.

Unfortunately work and other comittments have got in the way, so I've already missed at least one event, about to miss the next event and from there I think there's only one left for the year, so bit disappointing, but that's the way the cookie crumbles I guess.

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I'm surprised you didn't use a circle instead of a triangle as the spherical ball mount and drill holes all around the edge to get some adjustability. ...or does the spring hit the turret if you move it around?


Spring wouldn't hit, I'm just not a fan of those type of mounts as you can't effect a camber change without also affecting caster. I'd also resolved to keep the camber as stock, any additional camber pulls away contact patch, which on a front wheel drive, doesn't just affect your braking, but also takes away drive patch. The loss of braking on a RWD car is offset by the potential gains, but 0.75-1º is about all you want to run on a FWD and the AE92 has that standard. The only thing left to change then is castor and my experience with castor has always been more is better, so I looked at how far I could move the top of the mount, left some room for the weld around it and then went the maximum distance. As it stands I could of crept a little more as my Brother's TIG welds were smaller/neater than the MIG welding I was originally planning. Still, with the offset I think that now gives me nearly 4º of castor, plus I'm running the Nolathane Castor offset bushes in the lower control arm, which has the effect of pushing the arm/wheel forward and adding castor as well.

The car handles pretty well on the short, sharp twisty stuff that I typically see on a Khanacross, but when it comes to the Autocross I'm getting OK turn in with a mid corner understeer/push that's affecting my corner exit. I'm also seeing a fair bit of wear on the outside edge of the tyre. Camber would fix the outside edge tyre wear, but at the expense of braking/drive. Castor effectively camber's up the wheel only as you're turning, which is exactly when you need it the most. There are potential negatives with running excessive castor as well, but power steering solves some of them and the rest tend to sort themselves out in the practical world.

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