Weekend Update: The SequelWell it is now 9PM and I just got home so no physical progress today but I was able to do some digging and have decided to have the LS ECM control the AC using the above described method. It is the simplest method that allows the ECM to control the fans, idle, and compressor while keeping the HVAC wiring stock except for this one thing. Here's how it works, where the AC clutch wire would have gone to the clutch it will now go to the ECMs AC request pin and the ECM will control the clutch using a relay on a seperate pin. Couple things of note, I have no idea how the ECM will respond to having the AC request cut in and out with the cycling switch, but should this not work, it's as simple as bypassing the low pressure switch in the 12V side of things, wiring in a ground, and connecting it to the ECMs low pressure switch input. This allows the AC request to stay on as long as the high pressure switch is not triggered, and allows the low pressure switch to cycle the compressor on and off as required.
Second thing on the docket, here's a video of the first run, ignore the fact that it rev hangs, the intake has about 4 different open vacuum ports and im using a gen 3 MAP sensor in a gen 4 intake, it's a wee bit loose to say the least. With the harness off the car, I'll be starting the great task of putting everything back together, after I sort out those electrical gremlins of course, but I have a feeling those are related to the big chunky ground I found sitting by the brake booster .
The one I really want to get done with are the C5 headers so I can get the wideband setup and see how things are.

 

It has been a little bit, but I've been busy.
Things I can finally mark as done or very close to done:

The powertrain in its entirety, except for shift linkage, more on this later.
Complete brake system redo including C5 brake upgrade, bias spring is still on the to-do.
Electrical gremlins were all traced back to a missing ground for the ECM, which was a fun one to track down.
Hydro ToB is plumbed and bled, much softer than I thought it would be, but good range of motion and engagement point, might not be a bad thing for driving in NoVA traffic.
C5 headers were somewhat installed, driver side went on without much of a problem, the collectors do have to be trimmed to clear the bell housing. The passenger side also requires some bashing to clear the frame rail, unfortunately, I stopped a bit short of the mark when it comes to the bashing so my headers do not sit on the head correctly and leak out of the top. They are also heat wrapped so I have to undo all of the wraps in order to bash them a bit more.

Now where all the progress breaks down, in my rush I ordered the wrong PS pressure side fittings so when I went to make the pressure side hose so I could bolt up the accessory drive, things didn't work out, and brought the weekend to a screeching halt. I was so close to the first drive too

Shift Linkage:
Alright now the real problem, believe it or not, moving the motor a whole 7/16" forward has no effect on 1-4 shift linkages, but man does it wreak havoc on the reverse interlock and reverse linkage. I will need to do a shift linkage adjustment for sure, but it looks like the reverse rod is too short to reach the new position of the trans, now one of the ideas I have is to switch to heim joints and either threading or welding a stud to the shift arms to make this possible but I need to do more research on this subject. The issue with the reverse interlock seems to stem from a little slop in the 1-2 shift linkage preventing the shifter from completely being in neutral. Jumping under the car and slightly pushing the shift arm back causes the interlock to pop back down and into neutral. Here's the crazy part though, gears 1-4 are as smooth as they have ever been, and I feel like I get deeper into second gear than I did before. It was popping out of second on decel when I did get to drive it with the L98, but the shifter always felt biased towards first if that makes sense. I'll be taking a deeper dive into the shift linkage later on in the build, but my main priority, for the time being, will be getting the engine bay work done first.

 

Weekend Update 1:
First victory for the weekend was testing the Ebay rad, it was able to hold the LS down at 203* sitting on the driveway which gives me hope. The dual fans it came with are a wee bit wimpy, but the shroud is pretty decent, for $185 I'd say they are a good deal. To reiterate, my stock rad was fine, but had a slow leak in the pass side lower corner, this rad was a bit of a gamble but it seems to have worked out well enough. I can't speak to it being a cooling upgrade since this is a smaller displacement motor, but it does/will make close to double the power and similar torque.

Success number 2 was power steering, I decided to make my own -6 PTFE pressure line rather than mess around with the stock hose, the truck pump should be pretty similar in spec to the stock pump but flow much more, so I may need a cooler eventually. My column is a mess, but the Z51 rack feels pretty good on the driveway, it's responsive but not twitchy. Fittings required were M16 to -6 power steering fitting(Pump side), and an M18 to -6 fitting(rack side). I'm using the stock rack return going straight into the pumps reservoir, it's a direct fit, don't even need to trim the hose.

I've got alot I'm trying to get done today, but so far the shifter is hooked up and adjusted, the only problem is reverse is right on the very edge of the shift rod but there is still full thread engagement so hopefully I'm safe. I feel I need to mention, with everything properly adjusted, I get "deeper" into 2nd gear so fingers crossed that was the cause of my popping out on decel.

Sometime later this week I'll post up a full electrical system explanation, it got complicated, but in the end I think I have a near OE product with the best of the modern electronics and ease of install.

 

Weekend Update 2:
It was a sad day yesterday, started her up went to put her in gear and she wouldn't go. Tried reverse and it grinds, so my clutch is either not getting to its full stroke, or isn't shimmed correctly. That was pretty heart wrenching to find out and and soon as that happened an electrical gremlin popped into existence, if I'm sitting in the driver's seat, the key does nothing, if I put the key in the run position and get up everything works. Not a clue what it could be.

Anyway, for the clutch, I'm going to try pulling the 0.3" shim I put in behind the master last year and see if I can get to the end of the slaves travel, thankfully, when I designed and 3D printed it, I slotted the holes so I only have to get the master loose and it'll fall right out. If it is a matter of increasing the masters stroke, I think I'll put in a larger bore master, the pedal as it is, is much to soft IMO, good for traffic, but not for feel.

 

Hey all,
It has been a while and unfortunately not much progress has been made. I partially tore a tendon in my shoulder which has brought everything to an almost complete halt but luckily I can still CAD and somewhat turn wrenches.
I mentioned it earlier that the clutch hydraulics were starting to be a pain and I finally found the problem and came up with a solution. The problem in my case was a bent clutch master push rod combined with an insufficient clutch master. The Howe 82870 bearing I am using is GIGANTIC in the volume it needs to be fully extended, I think the volume was somewhere near twice of the stock LS ToBs, which might mean I have escaped the curse of overheating the fluid and having the pedal drop to the floor. Now the fun part, part break downs, and how I made it all work.

PARTS:
Howe 82870
Wilwood 260-13623 1.125" Bore 1.1" Stroke
3AN to 4AN Adapter
1/2 Bore 1/2" Heim Joint
2x M10X30mm Socket Head Cap Screws
2x M10 Flanged Nuts
5/16-24 Grade 8 Jam Nut
5/16 Thick Washer
Printed Parts(Found in Attached ZIP)
1/2 to 5/16-24 Threaded Bushing
Master Cylinder Adapter and Spacer

Alright, first off, some justification of the printed parts, I printed the adapter in PETG and the bushing in an impact-rated PLA copolymer, I thought these two materials were sufficient given the use case. The bushing is only loaded if the pedal has to pull the piston back through the bore, the actual actuation force is handled by a thick washer and 2x 5/16-24 Grade 8 nuts. The washer is in direct contact with the bottom of the Heim joint, and the nuts allow that position to be adjustable, meaning the pedal position is fully adjustable. I don't think this is sufficient for a car driven hard, but in my case it is an easy and cheap intermediary step until I can source a metal bushing.
The adapter on the other hand, is pretty nifty if I may say so myself. It is just over 3/4 thick and has 2 semi-embedded M10x30mm bolts that are being used as stud to retain the master cylinder. It uses the stock master cylinder bolts to hold the bracket to the car. The load-bearing faces are 10mm thick in the case of the master cylinder, and the spacer itself is held on with nearly 20mm of plastic, I think that is more than enough material to cope with the forces that it will experience, only time will tell.

Now, how it all fits together, the above mentioned MC is a remote kit and that is for good reason, there is not any space for either reservoir to fit, I tried sideways and normal installation and it would not clear the firewall, so I will need to find a place to mount it. The other big thing is in my current state I can't pull the clutch pedal out to be able to drill out the stock stud and weld in a prevaling torque nut so that I can use a 1/2 shoulder bolt in combination with the heim joint, but in some weird turn of luck, the stud on the current pedal is somewhat oversized, by aboiut 5 thou, I am going to try heating up the heim joint and see if it will expand enough to fit over the stud and stay there as an interference fit, its risky, but will work for the time being.

That's all I have so far, I am out of commision till November it seems, so my C4 may end up getting towed to another storage unit for some wintertime progress. I'll add pictures tommorow, it was too dark for me to get any photos since it is all mounted to the car.

 

Well, its been about 4 years since my last post, when I dissapeared from this forum, I had just taken my swapped vette out for a test drive and then life hit and she sat for 4 years, mostly because I fell out of love with my build and had a massive jump in my career. The good news is I've learned alot in the 4 years since I left, I started my own tuning company about 2 years ago and I have slowly fallen back in love with this platform and I'm back with a vengeance!
Unfortunately for this specific car that this thread was about, she's dead and the original car is getting gutted on Saturday and getting hauled for scrap on Sunday (Unless someone in NoVA wants a 85 Z51 roller with a C5 body kit, its all yours for free.99, just come and get it).
I'll be picking up a new to me 85 Z51 in much better condition then my original car this weekend and thats when the real fun begins!
The new car won't be getting the same 5.3 so here's the new build breakdown:
Engine

• LQ9/ High Compression 6.0
• Forged Bottom End
• BTR PDS Stage 4 Cam
• Lunati Link Bar Lifters
• Kong X-Ported LSA Blower with ZL1 lid
• Ported Factory Heads(317)
• 102mm TB
• Gen 3 Block Converted to 58x
• High Volume Oil Pump
• Batwing Oil Pan
• Running Full E85
• Haltech Nexus R3, And a Whole Bunch More Custom Electronics

Trans and Diff

• Initially will be DNE 4+3 until it blows
• ZF 8HP with TurboLamik TCU OR a T56/TR6060
• Evaluating the F10 M5 E-diff as a potential swap option

I enjoy driving a manual but the shift speed of an 8HP seems too good to passup with very similar cost of entry as the T56. I don't think I'll fully be able to leverage the powerplant's full capability with a manual trans but I also don't think I could live with myself if I can't row through gears.

Ive got a few open projects concerning this Gen C4 that I'm also working on, I'll be breaking this swap into phases so some will be a phase 1 project and some will be phase 2 projects:
Phase 1:

• OBD2 Dash Module
  • Connects into the ECUs OBD2 port and reads the sensor data directly off the bus and converts it to an Atari dash friendly signal.
• Solid State Headlight Control Module
  • Eliminates constantly failing relays and uses soft start and stop to reduce wear and tear on headlight motors and bushings.
• Switch Panel Touch Screen Display,
  • Replaces the dumb switch panel display with a modern display, reads data off of OBD2 and displays it as an extension to Atari dash.

• 3D Printed CFRP Bolt-On Hood Cowl
  • I left off with a pretty good fit on my first prototype but with the LSA I am left with very few options for a cold air intake, im working on incorporating NACA ducts into the hood and creating an airbox similar to the 84 hood for a true cold air intake and maybe even a ram air intake if my cowl geometry is good.
• C4 Body Control Module,
  • Gets rid of the ancient fuse box and random relays all over and consolidates it into one spot, also fully solid state with digital fuses, im currently reverse engineering and testing Haltech CAN so this will be Haltech compatible since ill be running a Haltech ECU but this is meant to be a standalone unit, also features some turbo/supercharger features such as heat Exchanger/Intercooler fan control and an optional VSS conditioner for the LS ECU.
• C5 Brake Conversion
  • It was awesome to see that people are using the brackets I published in their builds, I'll do the same until phase 2!
• Heat Exchanger Integration, Second Coolant Loop, and a General Cooling System Overhaul
  • With great horsepower comes the need for great cooling, I'll be redesigning the entire cooling system, switching to a liquid cooled condensor and a ton more to repackage the cooling system in a much more efficient way and leverage some of the empty bumper space.

Phase 2: After the 4+3 Blows or I get Bored

• Modern Atari Dash
  • Replaces the aged and broken Atari dash with a CAN/OBD2 compatible digital dash, Im working on making it plug and play but finding a display element the same size as the center display is proving to be difficult. This will be put on hold for the time being.
• Coil Over Conversion
  • No point in going fast if you cant throw it around curves, thats where the real driving is!
• Brembo/Fixed Calipers
  • This will be a track machine, I love the quick swap of pads I have on my Stinger so I want to bring that to this car too.
• Magnetic Paddle Shifters
  • Assuming I go with the 8HP, I'll be designing and integrating magnetic paddle shifters to control the Trans

Its been a pretty long update but thats everything that you can expect to see from me in the near future and far future unless something else pops into my head.
I should also mention that if the electronic modules I mentioned above have enough desire, I'll be more than happy to list them on my website, if you're interested please let me know so I can get a ball park for how many boards to order.