Updating HVAC - Ambitious (Page 1/1)
Wichita JUL 20, 01:00 AM
I'm starting on an ambitious project to update the HVAC system in the Fiero.

It's a doozy: I will need to change the blower motor, HVAC control, evaporator, accumulator/dryer and lines.

Reason: I'll be using an electric heat pump compressor, which is already installed. The system has a three-way valve able to change the flow where It will have access to both cooling and heating.

I'll be deleting the heater core from use as it's no longer needed. I can keep the condenser on the Fiero, which is probably the only thing in the system that will be native to the vehicle.

The good? I have everything I need from a donor vehicle. I'll figure out the AC lines in all, so that's the least of my worry. The HVAC control is a perfect width to fit. The blower fan isn't far off to the point that I could put the Fiero's squirrel cage on the new blower motor.

I cannot use the existing Fiero HVAC control panel as the donor HVAC control is CANBUS and controls the compressor and the switching valves, and also the blower motor which is controlled by PWM.

The bad: Probably trying to figure out or beg someone to help with a 3D printed stereo HVAC bezel cover for this. My 3D design and print skills are quite sorry.




[This message has been edited by Wichita (edited 07-20-2025).]

rbell2915 JUL 20, 11:47 AM
Looking forward to seeing this
82-T/A [At Work] JUL 20, 11:59 AM
Glad you're still working on this... I was hoping for some updates!
Wichita JUL 20, 05:36 PM

quote
Originally posted by 82-T/A [At Work]:

Glad you're still working on this... I was hoping for some updates!



I've been mainly working on rebuilding and refurbishing everything mechanically. That is all complete. Every bushing, tie rod, ball joint, brakes, suspension, and I even rebuilt the steering rack with the brass bushing. Front and rear all complete.

I've done a lot on this Fiero, but now working on the interior.

I had to comb through some old photos here to show the heat pump/ac compressor on the motor stack looks like, before I installed it in the Fiero. It was already on the assembly, ready to go. I might as well use it. I can't get much of a top down picture of it now, since the motor stack is already installed in the Fiero.



Dennis LaGrua AUG 11, 08:37 PM
Admire your dedication to an interesting new project but what is it about the Fiero heater and air conditioner system that you didn't like? If you turn it up my Fiero A/C will freeze you out of there on a 90* day and roast you on a cold day. In short what was the gain?

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 08-11-2025).]

Wichita SEP 13, 11:07 PM

quote
Originally posted by Dennis LaGrua:

Admire your dedication to an interesting new project but what is it about the Fiero heater and air conditioner system that you didn't like? If you turn it up my Fiero A/C will freeze you out of there on a 90* day and roast you on a cold day. In short what was the gain?




There is no belt driven compressor nor any appreciable amount of heat from the coolant to use. This Fiero is no longer an ICE power vehicle.

This is an EV with an EV electric heat pump utilizing 134A to use a both the heat and the AC, so it involves switching valves and etc.

Though it looks like a traditional motor, it's a full stack from a Nissan Leaf. This gets about 200HP and weighs more than 300lbs less than the Iron Duke and transmission.

The Leaf Stack already had the heat pump installed, and I have all the AC lines, switching valves and AC control for it. So I might as well use it.