280zedx

Eureka! Finally running sweet! the moment i put a 22k resister in line the problem was solved. after about ten minutes of driving i got a few tach flicks on the high end. a 33k had a rare flicker and a 47k was perfect! the fuel map is definately in the ball park and the blower is working awesome but it's killing me that the car is finally running sweet and it's almost time to park it here in canada.

thanks, it should also be an easy test to determine. I'll just disconnect the fan (and keep an eye on the temp) and see if it acts up still. very information link- Mike

which 12volt are you talking about? The MS relay board's switched 12v is under the dash connected right near the ignition. the coil's 12v is the factory wire (untouched). I do have a fan relay tapped off the coil 12v and i noticed the fan ground is grounded at the alternator. Could that cause a weird loop signal? sidenote: couldn't get a resistor in this small town so the other mods will have to wait. I couldn't. i figured it sputters less the faster you go through the gears so.....i did some wot runs (with Bernardd's zx egging me on ) The wideband readings are almost perfect and the supercharger launches it out of the hole with an evil whine and killer torque

i'm ready to snap! My megasquirt supercharger project is so close!!!! The tach signal is still jumping around especially between 2500 and 3200 RPM. You can see it on the tuning page and it is really evident on the datalog table. This i'm sure is causing the bad sputter it has everytime i drive around those rpms. I'm fairly confident i have the fuel mapping in the ballpark, as i'm also using the LM-1 wideband. I can't fine tune it till i fix my tach signal. So far i've: replaced the coil replaced the signal wire with a direct shielded wire. tried a couple different Ed caps (.01 &.1mf) and the latest- installed the Dave cap (22mf) no difference, it even seems the sputtering is worse since i got it on the road. Outside these tach areas the car runs and hookups great. Tonight i'll try a couple of different resisters in-line with the tach wire itself. If no luck then i'll try wiring a HEI module in. It's a bit of a pain as it needs to run parrallel and connect directly to the VR sensor itself (not the ignition module). Question: has ANYBODY had these type of tach problems with a non-turbo setup? or has anyone even successfully got the megasquirt working on a 81-83 non turbo? other info- it runs the exact same with the supercharger unbelted. Sparkplugs look good. Wideband readings are often "perfect" when it sputters (12 - 14 AFR). other wierd tidbits- i couldn't get the MS tuning page to work properly, it appeared to be backwards with the "ball" off the table. I eventually tried setting up my VE table backwards (high kpa at the top, low kpa at the bottom) and the car ran the same and now the tuning page works right! also- the datalog after the Dave cap was installed shows the rpm incorrectly. the rpm numbers seem to be 1/100 of the actual. (idles at 8-9 and when its in the 20s it jumps around like 50, 80 100 etc. This is probably right where it sputters like before. what gives. I know this a lot to take in but i'm so close i can taste it.....argghhhhh p.s. i'll be posting this on the MS forum as well. thanks, Mike 1983 supercharged ZX

Well i finally caught the last electrical gremlin in my MS install and it fired up and idled sweet! It was running real rich on a wideband LM-1 and i ended up with a required fuel setting of around 8 to keep a perfect idle. (thanks for the startup settings Moby and Sims) This was i'm sure due to the supercharger and piping not hooked up, air sucking right in the throttle body. Next step was to try the megaspark as well. no luck. With a GM HEI between my MSS and coil, and tried both my ignition module and a HEI module to get a signal but still nothing. I'm assuming it might be my magnetic pickup type of distributor '83 N/A(not the optic CAS type). Has anyone been succesful with one of these? A swap to a turbo distributor would solve this but it'll have to wait till winter. I'm waiting on a BOV and will be hopefully be welding that on next week, but i temporarily hooked the piping and I/C up, belted up the supercharger and fired it up. Adjusted the fuel back to roughly Moby and Sims stock turbo tables and voila...a blown 280! I'm only going to adjust the idle until the BOV is installed since this setup with a roots style of blower before the throttle body is dangerous without it. Paitence is tough when its been on jack stands for 2 and a half years. Other little gremlins now include my alternator packing it in, an air leak at the top side of my throttlebody gasket (really weird, but maybe caused by me not waiting for my BOV, i had to at least test to see if it was boosting heh heh), and my doorlock keylight staying on continuous, hmmm. I still have lots of megasquirt settings work ahead and a suspension to setup, but the fun has begun! -stay tuned-

(This Megatune settings file is ....) -Sims, the file you posted doesn't seem to open and can't be saved as a file either. Are these the N/A injector settings? I'll be trying to play with the enrichment settings some more today. thanks all, Mike

I'm getting near my wits end! It fires up like a champ then dies. It took a while but i found my lack of any tach signal was due to the tach pin in the relay box to MS harness being out by one at one end - doh! Still no signal, just a few ticks that shows that it's connected. That was eventually found to be the IC module (little black box on the side of the distributor) failing. arghh! It worked fine just before the megasquirt swap. I've put the "spark" part of MS&S on hold for now until i can get it running. Just the stock N/A distributor (not the CAS style). The GM HEI directly off my pick-up coil didn't seem to work but i seem to get a good signal now with a new (used) same stock IC module. Everything has been multichecked and appear to be working perfectly. Dead on timing. Good spark to all plugs. all good sensor readings. Stock L28 turbo req fuel and constant settings etc. The priming pulses obviously work and it fires right up but then dies right away. I'm borrowing a fuel pressure gauge this weekend and also will buy a set of injector test noads to verify that all injectors are getting a good signal. The turbo (259cc) injectors are the only other variable thats changed since it was running last. (and they are suspect since i didn't get them tested or cleaned) As far as tach signal quality, what are the symptoms? A friend's of mine's got an oscilloscope, what kind of data or waves should i be looking for? It sure sounds good for the 2 seconds at a time i can get it running! Has anybody else had this "simple" problem? It's tough being so close and so frustrated... Mike '83 - 280zx

i'm taking the signal off the coil "-". Moby are you telling me it should be the "+"????? The car was running fine before the MS swap so i can assume the zx components are good. Connections were tested completely and there is a signal getting to the MS, just how much and how well is hard to tell without a scope. Tony, are you running your MSS like the sticky diagram? thanks for the added info on regulation, i'll keep that in mind. I'm tempted to go shopping for the HEIs for the full MSS and work on that at the same time...it's not running now so i have nothing to lose.LOL. I just hope i'm not in over my head already.

step by step...the supercharged L28 is coming together. i want to get the MS up and running before i move onto the MS&S setup. the latest frustration and conclusion after 12 hours of wiring and testing- It seems that it's not getting a good tach signal. Anybody with a non-turbo (variable reluctor dist.) have this problem as well? so far: -all the standard MS tests (spark, fuel, TPS, MAP, base settings, etc) were thoughally checked and working fine -The priming pulse width seems to be working, if i give it a couple shots, then try it, the car will fire up then die right away. -there is the very odd "flicker" of life (100 to 400 rpm) on the Megatune while we were testing and cranking. I'm assuming it is firing up on the residual fuel from the priming pulse, but since it's not seeing a good tach signal, then it shut's down. My electronic guru, Jeff, will try a few capacitor changes to help clean up the signal, and next testing night we should probably try a shielded cable as well. My big question: does it sound like i need a MSD type of amplifier/conditioner? or should i make matters worse and experiment with the MS&S at the same time. (remember: non-turbo distributor) thanks, Mike (1983 280zx soon-to-be-on-the-road supercharged L28)

...i'm sure every one has a few "words of wisdom" from similiar experiences! I know i do... Keep up the good work.

sorry about the size of the pictures...next time i'll post links instead! Mike

ok, it worked (posting a picture) sort of...the picture is a bit big. I'm assuming that his has to do with high resolution. anyways- here's another couple pics. I finished mocking up the intercooling pipe and mounted the adjustable thermostat for the new fans. gotta put the fuel rail back on with the new turbo injectors, rebolt the supercharger back down and it'll be ready for some MS&S management.

I guess i put it all back together right! I fired it up stock (no supercharger) and ensured everything worked, all the new belts and fabrications lined up great. The supercharger was belted up but had no piping yet. Blows like a champ! Just mounted the new 10 inch fans and the thermo and they worked like a charm. 1 leaky injector but that's ok as i have to pull the whole rail it off now anyways to put in the turbo injectors. I should have put them in to start but i chickened out and decided to "break in" the motor first. Now after running it up to temp a half dozen times it's time to ditch the afm and do my megasquirt homework. Bernardd was kind enough to donate the required throttle position sensor and I'll hopefully have the harness spliced in in the next couple weeks. I'm cutting up the intercooling pipe this weekend. That has definately been an eye opener, both aquiring and the price of steel and alluminium mandrel bends and pipes! Bernardd and myself have also gone splits on a LM-1 from Innovative Tech that should give us the required wideband readings to fully tune. We'll hopefully be testing it on his turbo this upcoming week. As far as the MS&S goes, Tony D, do you or anyone else have the non turbo reluctant pickup type up and running? The plans that Mobythevan proposes (awesome sticky -thanks) seem straightforward but i would appreciate any assistance with this part.

The exhaust piping is mild steel of also aluminixed coated. Both aren't as good as stainless steel. The last thing you want is rusting on the inside going into your intake.

A forced induction engine is just that. So yuor stock turbo setup should work just the same assuming you keep your pulley ratio in the same psi paramater. If you go higher boost you can modify just like a turbo, ie. intercooler, bigger injectors, a Z31 ECU setup etc. It's the creative fabricating that's required to make it fly. Mike

fun times will be had soon! (although sometimes the journey is half the fun) -when you say your HEI module is getting hot...why, is it as simple as adding heat sink or relocating it, please elaborate.

"anodized-look" spray paint. 8 bucks a can. you spray a metallic primer on first then the color, supposedly good for 500 degrees. Time will tell how well it sticks. Mike

Bernie, you did however provide the "mental" support for the project...heh heh. All this is still a bit premature since it hasn't ran yet! Ken, i've calculated that the boost should be 8.7 pounds @5800rpm and it has a vacuum actuated bypass valve instead of a BOV. Jersey, how did you attach the pictures? If anyones interested i'll attach some more pics with details of the modifications. thanks all for the compliments. Mike

thanks Bernie....the cat's out of the bag! If someone can clue me in (or Bernie) on how to attach big pictures i'll post some more of the whole project. In case you're curious it is a supercharged L28! An Eaton supercharger with homemade brackets and numerous modifications...i'll keep you all posted as it comes together. Mike

I'm hooking up the control for a new electric fan setup and was wondering if i could substitute the wire for the auxilary fan (the one that blows on the intake after you shut the car off-which i have ditched) for the AC control (which overrides the fan control when you turn on the AC). I beleive the aux fan only turns on after you shut off the ignition and i would like to have the main electric fan run for a minute or so after she's shut down when she's hot. Also would i then have to connect the yellow wire (to ignition circuit) to a constant 12 volt supply? I'm sure lots of people have wired these fan controls, can anybody help? -thanks

i'm looking at running the megasquirt and spark setup and was wondering if anybody has done this with a digital dash (1983zx). Is it possible to replace the ecu completely or will i have to run it as a "piggyback setup" and keep my stock ecu to operate my digital dash? please don't bother telling me to ditch the dash for a analog one. if there's a will there's probably a way!

not to change the topic but...what are the differences in throttle body location in a supercharger application? All stock roots supercharger setups have the TB in front due to the fact that the SC bolts directly to the intake. What is the difference between this and a turbo setup? And if there is none then can the throttle body be between the supercharger and intake (like a stock turbo TB setup)? I'm sure it would have something to do with the bypass or blowoff location. Anybody know?

i'm getting some mixed info about relocating the throttle body and wonder if anybody can give me a solid reason why (or why not) the throttle body has to be on the intake side of the supercharger. It would sure make it easier keeping the TB in it's stock location and my thinking is it should operate just like a turbo setup. The SC has a built in vacum activated bypass. Any clarification on this would surely help!

the stock v-belt wont work on the supercharger setup because of belt slippage (lots of torque required to spin the SC), also for the fact that it's easier to mount/fabricate a new crank pully than change the SC pulley to a v-groove pulley. -i do like the idea of a "super-turbo" setup! good luck!