So... in working on my daughter's car, I've discovered quite a few things about various years and upgrades that the Fieros have gotten. Specifically on A/C compressors, I've noticed a couple of things:
1984-1985 4 Cyl Fieros ...got the MASSIVE DA6 all-steel AC Compressor which weighs in at over 20 pounds:
... now, there is an IMPROVED version of this compressor which has an aluminum housing, and that one is only 14 pounds, with some other slight internal upgrades was made available in early 1986, but also can be used to replace the ones in 84-85 (basically same thing):
1986-1988 4 cyl Fieros
THEN... the late 1986 model year got the upgraded and much smaller V5 Aluminum compressor which only weighs 8 pounds
1986 Model year w/ V-belt:
1987-1988 Model year w/ serpentine belt:
. Unfortunately, it seems like (from what i can tell / remember), the V6s all got the shitty enormous V-belt DA-5 Compressor... even the 1988 model year?
- BREAK -
For my daughter's 1985 Fiero w/ 2.5 Iron Duke ... how can I upgrade her car to the much smaller V5 aluminum compressor? I just cannot fathom putting on that 20-pound or 14-pound A/C compressor on there. It seems absolutely insane.
Now, from what I understand, the difference between the two is that the DA-6 basically works without any computer control. It has a pressure sensor that can tell when there's too much pressure and properly cycle the compressor. On the other hand, the newer V5 compressor requires input from the car's ECM. If I'm not mistaken, it's a single wire that provides some kind of input (I cannot remember). Anyone know what the ECM does as it pertains to the compressor? As far as I know... one or all of these compressors have a low and high pressure switch. I didn't see anything on Ogre's cave about specifically the different models, and I'd really like to put something together on my page for the benefit of everyone, and also for my daughter's car.
I absolutely cannot fathom bolting up a 20-lb A/C compressor to my daughter's 2.5L Iron Duke just so she can have A/C, when there's an 8 pound compressor available instead. She wants to keep her car mostly stock, but damn, there's no reason to put something back when there's an improved version... and the newer compressor doesn't even require the rear bracket (from what I understand.
Can anyone help me understand this? What do I need to upgrade my daughter's 1985 4-cyl Fiero with the new V5 compressor? Is it just swapping out the compressor and installing a pressure switch in one of the holes where there isn't one already? How do I make up the difference for the length of the HVAC lines? Thank you!!!
(Note, I plan to steal whatever information you guys give me, and when / if it works out and she can upgrade it, I'll make sure she gives credit to the right people).
[This message has been edited by 82-T/A [At Work] (edited 02-28-2024).]
So... in working on my daughter's car, I've discovered quite a few things about various years and upgrades that the Fieros have gotten. Specifically on A/C compressors, I've noticed a couple of things:
1984-1985 4 Cyl Fieros ...got the MASSIVE DA6 all-steel AC Compressor which weighs in at over 20 pounds:
... now, there is an IMPROVED version of this compressor which has an aluminum housing, and that one is only 14 pounds, with some other slight internal upgrades was made available in early 1986, but also can be used to replace the ones in 84-85 (basically same thing):
1986-1988 4 cyl Fieros
THEN... the late 1986 model year got the upgraded and much smaller V5 Aluminum compressor which only weighs 8 pounds
1986 Model year w/ V-belt:
1987-1988 Model year w/ serpentine belt:
. Unfortunately, it seems like (from what i can tell / remember), the V6s all got the shitty enormous V-belt DA-5 Compressor... even the 1988 model year?
- BREAK -
For my daughter's 1985 Fiero w/ 2.5 Iron Duke ... how can I upgrade her car to the much smaller V5 aluminum compressor? I just cannot fathom putting on that 20-pound or 14-pound A/C compressor on there. It seems absolutely insane.
Now, from what I understand, the difference between the two is that the DA-6 basically works without any computer control. It has a pressure sensor that can tell when there's too much pressure and properly cycle the compressor. On the other hand, the newer V5 compressor requires input from the car's ECM. If I'm not mistaken, it's a single wire that provides some kind of input (I cannot remember). Anyone know what the ECM does as it pertains to the compressor? As far as I know... one or all of these compressors have a low and high pressure switch. I didn't see anything on Ogre's cave about specifically the different models, and I'd really like to put something together on my page for the benefit of everyone, and also for my daughter's car.
I absolutely cannot fathom bolting up a 20-lb A/C compressor to my daughter's 2.5L Iron Duke just so she can have A/C, when there's an 8 pound compressor available instead. She wants to keep her car mostly stock, but damn, there's no reason to put something back when there's an improved version... and the newer compressor doesn't even require the rear bracket (from what I understand.
Can anyone help me understand this? What do I need to upgrade my daughter's 1985 4-cyl Fiero with the new V5 compressor? Is it just swapping out the compressor and installing a pressure switch in one of the holes where there isn't one already? How do I make up the difference for the length of the HVAC lines? Thank you!!!
(Note, I plan to steal whatever information you guys give me, and when / if it works out and she can upgrade it, I'll make sure she gives credit to the right people).
I have not ideas on mounting changes, but from what I understand, the v5 is really 5 seperate smaller compressors, that cycle individually to constantly maintain the correct pressure or whatever, it makes it so there is no instant large loads on the engine, like cycling one single large compressor would do (nearly stall a small engine), which would be why the 4 cyl got it but the v6 didn't, it was necessary on the 4 cyl, as it has less power, but in the v6, only benefit would be weight. I would imagine there would be a few things extra you would need to wire up, maybe need a different ECM, but it shouldn't be too hard on the physical mounting side of things.
I have not ideas on mounting changes, but from what I understand, the v5 is really 5 seperate smaller compressors, that cycle individually to constantly maintain the correct pressure or whatever, it makes it so there is no instant large loads on the engine, like cycling one single large compressor would do (nearly stall a small engine), which would be why the 4 cyl got it but the v6 didn't, it was necessary on the 4 cyl, as it has less power, but in the v6, only benefit would be weight. I would imagine there would be a few things extra you would need to wire up, maybe need a different ECM, but it shouldn't be too hard on the physical mounting side of things.
Ok, I JUST found an old post by @Blacktree... hoping he sees this but I haven't seen him on Pennock's in a while. This is what he said from this post: https://www.fiero.nl/forum/Forum2/HTML/000505.html
quote
I did the V5 & R134a conversion in my Fiero several years ago. It was a fair amount of work. Here's a brief list of what's involved:
1) Modify compressor mounts to fit the V5 2) Swap V-belt pulley onto V5 compressor (requires a special tool) 3) Replace receiver/dryer unit and orifice tube with R134a compatible parts 4) Replace all the seals in the A/C system with R134a compatible seals 5) Modify engine wiring harness to accommodate the V5 compressor 6) Have custom compressor hoses made to fit the V5 compressor
On the DA6/HR6 compressor, you have 3 separate switches controlling the system: a low pressure cycling switch on the receiver/dryer, a high pressure cut-off switch on the compressor, and a fan switch on the compressor.
On the V5 setup, there are two switches (high and low pressure). Both switches are on the compressor. So the wiring for the cycling switch needs to be re-routed back to the compressor. And both switches on the V5 get wired into the cycling switch circuit.
Also, the V5 compressor doesn't have a fan switch, because it was used in cars with ECM controlled radiator fans. The V6 ECM can't control the radiator fan. So you have to rig something up. I used the low-pressure switch to double as the fan switch; it activated a relay which would ground the fan switch wire.
The high pressure cut-off switch on the DA6/HR6 compressor is wired into the ground leg of the compressor clutch. The V5 compressor doesn't do that (the high-pressure cutoff is part of the cycling switch circuit). The cut-off switch wiring needs to be deleted, so the clutch is grounded at all times.
Also, the suction and discharge ports on the V5 compressor are opposite from the DA6/HR6 compressor. And the compressor itself is a different size/shape, with the ports in a different location. So custom compressor hoses need to be made, to account for that. Neither the stock V6 nor 4cyl compressor hose assemblies will fit, due to interference issues.
Sounds like fun, doesn't it?
But it's just like you said 85GT... it's definitely variable and therefore does not put an incredible load on the engine like the other compressors do.
Back in the 90s, when the Air Conditioning on my V6 Fiero used to work, the very first thing before I raced someone (look... I was 18-19), was hit that A/C off button on the dash. Because even with the V6, it definitely sapped power. So the V5 sounds like a fantastic swap.
What Blacktree says isn't necessarily so daunting. I think I just need to find some A/C lines from an 86 4 cyl... and maybe an AC bracket from an 86 as well.
Originally posted by 82-T/A [At Work]: But it's just like you said 85GT... it's definitely variable and therefore does not put an incredible load on the engine like the other compressors do.
Back in the 90s, when the Air Conditioning on my V6 Fiero used to work, the very first thing before I raced someone (look... I was 18-19), was hit that A/C off button on the dash. Because even with the V6, it definitely sapped power. So the V5 sounds like a fantastic swap.
What Blacktree says isn't necessarily so daunting. I think I just need to find some A/C lines from an 86 4 cyl... and maybe an AC bracket from an 86 as well.
Yeah my dad's Fiero is more tired out, and AC definitely makes it even slower, my car doesn't have AC, so I'm all the faster haha, that swap sounds fairly easy, half of it is just the r134a swap, hoses and wiring/mounts shouldn't be too hard, especially if your able to piece together all the various parts from cars with the v5 system to start with.
How much work do you want to put into it? The DA6 is a cycling setup, I can't exactly say about the V5. If I recall correctly the v5 is a variable type pressure drop system where as the Da6 develops the pressure drop across a fixed orifice tube. Cycling systems are simple in design, less things to complicate/break. V5's take a fair amount of energy to get the ac charge to fill the system properly. The DA6 also has a bracket that attaches to the block, again can't say for the v5.
Unfortunately, it seems like (from what i can tell / remember), the V6s all got the shitty enormous V-belt DA-5 Compressor... even the 1988 model year?
V6 cars had the DA6 or the HR6, IIRC the HR6 was introduced part way through the 87 model year. Externally they're identical, you'd only be able to tell by the label, or taking it apart.
quote
For my daughter's 1985 Fiero w/ 2.5 Iron Duke ... how can I upgrade her car to the much smaller V5 aluminum compressor? I just cannot fathom putting on that 20-pound or 14-pound A/C compressor on there. It seems absolutely insane.
The V5 compressor is controlled by the computer, and the control valve. The switches in the compressor turn off the compressor if the pressure is too low or too high.
quote
I absolutely cannot fathom bolting up a 20-lb A/C compressor to my daughter's 2.5L Iron Duke just so she can have A/C, when there's an 8 pound compressor available instead. She wants to keep her car mostly stock, but damn, there's no reason to put something back when there's an improved version... and the newer compressor doesn't even require the rear bracket (from what I understand.
I've never seen a steel body compressor on a Fiero? On my early 84, it was aluminum. All the aftermarket replacements I've seen like the Four Seasons compressors are also aluminum.
Trying to get a V5 working in an 85 wouldn't be worth the ~5lbs weight savings.
The Four Seasons new compressor for the car would be part number 58255 with the 4.9" Diameter V-belt pulley, or 58251 with the 5.7" diameter pulley. You can use either if you find one on sale, just change the belt size. I wouldn't even bother with reman compressors at this point, given the small price difference, and the 'quality' of most reman jobs these days.
Thanks guys, I'm going to put some information together and try to get absolutely everything and list options... I appreciate all the information. I'll build a page and reply back to this post when I've got everything on there. It seems like it's not THAT complicated to switch over, the daunting part just seems to be exactly what you need. I'm looking to convert to the 87 belt system for my daughter, so there's some interest there to switch to the V5.
Are you planning on verifying the high & low ac lines are clean? Don't know what you've had in them but you got to flush them, preferably off the car, too many low spots. Lots of good info on four seasons, ac kits, and others. Look up nylog
Ok, so... I'm thinking about how I can go about doing this. There's a LOT of information on Pennock's about A/C, and I want to keep it on Pennocks, but I also plan to build my own page just to keep track of everything that I'm doing... and then will repost all that information to Pennocks (and of course, giving credit to everyone, and then making my daughter do all the work while I pay for it).
I think I'll have four pages:
- What was STOCK in Fieros for all years, all engines. - How to upgrade to R134A from R12 (simple) - How to upgrade from DA6 to HR6 (step by step w/ pictures) - How to upgrade to V5 from DA6.
I look at this picture from CPTSnoopy, and it gives me a cringe:
The DA6/HR6 in my opinion are needlessly large. Great for the time, but unreasonably large when there's a much smaller, much more energy efficient version. One of the things my daughter wants to do is to make the car as efficient as possible (within reason), which means reducing drag on the motor where possible in order to maximize fuel economy. I think the V5 certainly helps with respect to that. It'll take up less space, weigh less, and less prone to overheating from the exhaust and everything else going on there.
Here are the pages I'm referencing (copying for my own benefit so I don't lose them):
Just bumping this again... I bought the 1986 Fiero Service Manual, and spent the weekend (while I was in Miami) reviewing and comparing both service manuals for the 85 and the 86. I intend to put together a wiring diagram for both the 85 and the 86, similarly to how I did with the Fiero's stock ignition system (below).
I think most people can read the service manual wiring diagrams, but I find it easier sometimes when there are pictures that help it make a bit more sense. So I intend to do one for both years (to compare DA6 vs V5) so it'll be easier to understand / compare for someone who wants to do the conversion. Based on what I read so far, Ogre is correct in that both ECMs control the A/C in the same way... (in that it disables A/C when you're flooring it). I guess I never needed to mash the A/C off button every time I was getting ready to race someone when I was 19. Haha...
I'm going to muddy the waters just a bit. I hope someone will correct me, if I have mis-spoken.
I was under the impression that the 86 Duke used the DA6/HR6 compressor. I was thinking that the only V5 Dukes were the 87 and 88. (Probably because of all the other changes made to the 87-88 Duke.)
The second design DA6 was the HR6. Became standard on V6 Fieros prior to 88 MY. I can't speak to the material composition, but the HR6 was designed to accommodate R134 without damage. The DA6 was not. (My 4.9 also uses an HR6 compressor.)
I'm going to muddy the waters just a bit. I hope someone will correct me, if I have mis-spoken.
I was under the impression that the 86 Duke used the DA6/HR6 compressor. I was thinking that the only V5 Dukes were the 87 and 88. (Probably because of all the other changes made to the 87-88 Duke.)
The second design DA6 was the HR6. Became standard on V6 Fieros prior to 88 MY. I can't speak to the material composition, but the HR6 was designed to accommodate R134 without damage. The DA6 was not. (My 4.9 also uses an HR6 compressor.)
So from what I know, the V6s use the DA6 / HR6 for all 4 years, 85-88.
But the 84-85 Iron Duke used the DA6, and switched to the V5 early on in the 1986 Production year.
When you look on Rock Auto, they offer both for the L4... but mostly V5s. The Service Manual only mentions the V5 for the L4s, so they likely switched it over really early in the production year.
Originally posted by 82-T/A [At Work]: ... When you look on Rock Auto, they offer both for the L4... but mostly V5s. The Service Manual only mentions the V5 for the L4s, so they likely switched it over really early in the production year.
Fair enough. I stand corrected. That being the case, you ought to be able to find a later set of lines for yours, so that you don't have to have custom lines built.
Fair enough. I stand corrected. That being the case, you ought to be able to find a later set of lines for yours, so that you don't have to have custom lines built.
Yeah, I think that's the last thing I need. I need to take a look, but if there are any interim connections, all I'll need to do is replace the ones coming directly off the compressor to the hard lines.
