An ill-advised 300ZX build

a_florida_man said:

Man,

I am LOVING this history thread...

My son and I have a 300zx TT thread going on here:

https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/a-build-thread-in-search-of-a-project-car-jacks-first-daily/273141/page7/#post3975660

 

I mention our thread because we are looking at buying an OBD tool for the data stream and other Consult functions.

We have a Wolf modified ECU and a spare we assume is OEM. We don't really need to tune at this point,  but having that option (additional hardware likely needed) as a part of the future expansion of the system would be cool.

Right now we are looking at drive-ability and maintenance stuff... lots of parameter plotting etc..

I've seem a few and have an idea or two... but I'm guessing these are roads you have been down.

I like my advice backed with expereince. :)

 

I'll look in my backlog of garbage and see if I have the adapter I bought to do that job years and years ago (but can no longer use because I'm running the standalone now).  If I do, I'll just give it to you.  I used some very old tools, one called "Zcontrol".  I've got 'em all on a drive somewhere, probably.

Feel free to ask whatever you want.  I've bled on most of my Z32 from one hole or another.

I'll get back to this thread this afternoon, I was out picking parts for my kids' Datsun Roadster last weekend, and it's been a hot couple days.

Around 2019, I'd started dabbling in autocross, which this car is absolutely terrible for, because 1) it ruins 200TW tires just backing out of the driveway, and 2) the choices I made building the motor put me into classes where I as a driver have absolutely no business being (and even in the best hands, it would be uncompetitive).

So, I did the right thing and went out, had fun, and blew the shocks into complete oily oblivion.  Not their fault, I'd been running Napa "OESpectrum" struts for a while with some cheap Eibach lowering springs.  My friend had given me a set of HKS coilovers that needed rebuilt, and I figured that I'd just do something temporary to tide me over until I got them shipped out to Feal.  However, nothing's as permanent as a temporary solution, so it wasn't like I was buying top-shelf suspension parts, and the HKS stuff never got sent anywhere.

I decided again, to burn some money on the altar of bad decisions, and bought a set of Powertrix ultra-light (aluminum body, pillow-ball upper joint) coilovers with Swift springs (8kg/mm front, 6k/mm rear), and the associated rear upper suspension links to allow corrected camber and caster.  I also put in some things called "subframe collars", which are small pieces of steel that essentially lock out the bushings in the rear subframe.  This was to combat wheel hop off the line.  In the picture, but not really visible, are all of the bushings on the knuckle, replaced with polyurethane.

I also printed some sacrificial nylon spacers onto the rear toe ball joints.  It used to be HICAS, but now no longer sees deflection loads, so the nylon is there to hold the ball joints out straight instead of allowing them any vertical deflection that the former ball joint boots allowed.

In the front, I didn't bother with an adjustable upper arm, because the two designs I know of are both prone to failure.  Instead, I put a spacer on the inner joint of the upper control arm that allows me to take the 1" drop that I wanted and keep camber around -1.5° and -2° using eccentric lower control arm bolts.

So in the end, I'm still in a terribly uncompetitive autocross car, but at least it's fun to drive!

The subframe collars in particular really help the car communicate what it wants to do.  It's tail-happy as hell whenever you apply power, but the collars help let you know before the rear end tries to become the front.

And because I don't like taking apart all of the interior in the back, I 3D printed up some things to dress up the holes I up and drilled through the panels to get to the damping adjustment on the top of the rear struts.

Getting ready to head out to points north of Durango this morning. I think the loop is Silverton, Ouray, Ridgeway, Mancos, back to Durango.

There's some stuff I haven't really covered, like the lip, the new 2.5" intercooler piping, and the new intercoolers on this thing, but for the moment, I'm a little stalled since I have basically no pictures of it.  The notion was everything was supposed to be temporarily test-fit, and I was supposed to remove and repaint the front bumper (since it got curbed pretty hard by the wife on the way to Zcon 2021).  However, since nothing's more permanent than a temporary fix, here's some pictures of what I did with the car last weekend.

One of the kids and I went up to see the fall colors in southern Colorado with the NM and CO Z clubs.  I actually didn't drive much, instead leaving the ridiculous overpowered, underassisted car in the hands of an amateur with two weeks left before getting his provisional license.  So the kid drove Cuchara pass, Wolf Creek pass, from Durango to Silverton, and then Lizardhead pass.  I took La Veta pass and Red Mountain pass (or more generally from Silverton to Ridgeway through Ouray).

The colors were really something:

Silverton, with the group:

To my everlasting surprise, we did not end up ass-first in a deep ditch (or cliff), which is more than I could say for myself at the same age, when I chucked my dad's Audi 100 into a creek on the way to Angelfire.  The kid took an inordinate amount of pleasure in spooling the turbos just to hear the blowoff valves echo off the rock walls, which 100% came from watching me do it (and then giggle afterwards).

Mechanically, I forgot to tighten a coolant line clamp, so it seeped coolant from the lower coolant hose on the way up into Trinidad from Albuquerque. I also neglected to put the cap on the power steering reservoir after checking fluid levels at home, but it didn't seem to lose any (same time we stopped to tighten the clampulator, I found the cap had managed to settle itself under the plenum, so I didn't have to replace it, just retrieve it).

After the first day, I threw the ol' lappy 486 on it because it was doing more popping and burbling than I was comfortable with, and found that the TPS had managed to misadjust itself to 2% when the throttle was closed. Fixing that brought decel fuel cutoff back into play, so it gained about 4 furlongs per hogshead in fuel economy!

I had a terrible migraine yesterday and the first part of today, but no dayquil (because I think it's sinus/allergy related), so yesterday I took some Nyquil in the morning.  When I regained consciousness yesterday afternoon, I had installed the 3-gauge pillar in my 300ZX, and swapped the radio.  I have no memory of doing it, but it looks well done, so... I'm gonna roll with it.

The 3 gauge pillar now has an AEM serial gauge and two AEM UEGO wideband oxygen sensors.  And I stuck a rivnut into the A pillar where the push tabs have all broken off so that it's installed now with some nice stainless allen hardware.

The old radio (a Kenwood from some years ago) was no longer in favor, because it doesn't have physical buttons for radio presets.  In this day and age, I know that's less of a concern, but my wife absolutely hated that.  So, I this Alpine "digital only" receiver I have from another "right place/right time" purchase, and stuck it in.  Only bummer is that it only has front USB, so my bitchin' iPod Dock had to run through the back of the cubby, not as stealthy as before :(

I still felt like garbage today, but this time I had a fresh pack of Dayquil.

So, I started configuring the old AEM serial gauge to some success.  I mean, it took some looking to dig out my null modem adapter and serial to USB interface, but once I got the hang of it (there are 256 possible values in each byte, 19 data bytes to a frame with a header byte of 0x55, and a checksum byte) and the bass-ackwards software from the late 1990s to write and upload configuration files to the gauge, it wasn't so bad.

I'm having the gauge display manifold PSI, AIT, CLT, flex fuel content, oil pressure, and battery voltage. 

Of those, everything seems to come across well except the flex fuel content.  There's no raw percentage to dump onto the wire, apparently it's two values "Flex Fuel Per", which is something in milliseconds, and "Flex Fuel Freq", which is in Hz.  Of the two, I know that my standard GM flex sensor operates in a window from 50-150Hz (50Hz = 0% ethanol, 150Hz = 100% ethanol, linearly scaled).  I'm not entirely sure how the byte is broken up, though, because the report that's supposed to tell me how it's broken up seems to be full of nonsense (negative values for unsigned datatypes, negative offsets).  I opened a ticket with Holley to just ask for whatever PDF they might have from the mid-'90s about AEM's serial data spec, but I'm not optimistic they'll do anything, and I'll just have to start recording raw serial data on my laptop and see how it breaks into known values (if, in fact, it will do so, I'm not optimistic that 1 byte will hold the data I want at a fidelity I find acceptable).

In the meantime, if anyone here has any idea how to interpret byte 6 of this, please enlighten me:

OK, so I know that the gauge says 31.6%.

In the gauge's lookup table, that corresponds to 81, 0x01010001

The actual value (self-reported by the EMS) is 10.0%.

If I use the top 5 bits, that equals 10. But, 5 bits tops out at 31 for a max value.

I dunno. Maybe it's beyond the capabilities of this EMS to do what I'm asking.