Griffith's AC upgrade for '84 911 install thread

[kuehl]

Skip,
Just to confirm for any readers that brushed passed most of your earlier posts.
The reason you are mentioning the "heat duct work, the support bracket on the engine, mufflers, etc". is because you were missing a compressor bracket and you needed to move something around to attach the compressor bracket.

[kuehl]

Originally Posted by wwest

These days we specify PM blower/fan motors as having ball bearings and brushless commutation.

Ball bearing are a bit noisier than sleeve type but service life seems to be quite a bit better

I can't quite agree on a ball bearing shaft support as being 'noisier' than a bushing support. At least not at a noticeable frequency or decibel level to the human ear; we test and run various motors all day long here. Maybe from an 'electrical' noise aspect? Then again I've never seen the later scenario have any interference with either electronics in the 911/930 such as a radio, stereo amp, nor the DME.

My question to you was 'efficiency' for the hp calculation. But that's Okay. You don't need to take up any more bandwidth on Skip's thread here. You almost have more posts than he does.

[wwest]

PM vs powered field....?

PM is clearly more efficient.

"for the HP calculation.."

One would need to know the "inplace", under load, CFM to answer that.

Most of our blower/fan purchases go into server/enterprise class computers where if they are in "standalone" situations, even desktop now and then, the extra mechanical noise can be annoying.

For constant/fixed speed applications the brushless commutation PM motors are clearly more efficient over the mechanical/brush commutation type.

[Skip1]

Originally Posted by kuehl

Skip,
Just to confirm for any readers that brushed passed most of your earlier posts.
The reason you are mentioning the "heat duct work, the support bracket on the engine, mufflers, etc". is because you were missing a compressor bracket and you needed to move something around to attach the compressor bracket.

Indeed thanks.

[kuehl]

Skip,
Occasionally there are 3.2 (84-89) owners out there that never had AC in their cars. It would be interesting if you could summarize how to install the AC compressor brackets onto the engine console in the easiest fashion. Maybe a 'looking back' 1-2-3 scenario.

[Skip1]

I don't see why not. Perhaps I'll start another thread (and link to it from here) so as not to detract from the main AC install itself. Then I could insert more pictures as well. Will try to remember all the steps as I go.

[Skip1]

This evening, I was able to complete the electrics for the relay on the LH side of the engine bay tucked in behind the fuse / relay cover. Very simple really, and I was able to neatly place the fuse and wiring together.



As my panel wasn't grounded, I ran the ground wire to the same point as the ground wires for the rear defroster, which are attached to one of the ignition coil mounting bracket bolts (the one on the far side of the coil) keeping all the ground points in one place.

I ran the power wire across the top of the engine bay as suggested in the instructions and covered it an electrical conduit to protect as well as hold it in place. Finally I installed the last hose (much rejoicing ) from the RH side of the condenser to the compressor (still to be installed). I removed the air box cover for ease of installation.



This allowed me to complete the wiring for the pressure switch and connect the relay line as well.





Next (this weekend) will be to reinstall the protective plate under the evaporator / fuel pump I forgot, and work on the installation of the AC support brackets on the engine itself (which was removed some time ago when I had the engine rebuilt due to no compressor / functioning AC anyway).

[wwest]

Skip, were I to FEDX you a trinary pressure switch, Red DOT 71R7500, would you be will to install it before charging the system?

No need to put it to use, just go ahead and follow Griff's instructions otherwise.

This would prevent the need to evacuate and recharge in the future if you should decide my theory has legs and wish to add condenser effectiveness.

Other than having the 3rd element function, the only possible/probable difference might be the R-134a "safe" high pressure cutout level of 325 PSI vs whatever Griff supplies.

1. I suspect Griffiths is seriously under estimating the adverse effects to the fender well condenser due to RADIANT HEATING from the HOT catalyst.

2. The high side gas high pressure doesn't just disappear when the compressor stops so it is a definite benefit to have the condensing process continue until the high pressure abates.

3. On the other hand Griffiths may well be aware of the adverse effects since they seem to have a "ready" answer... buy/install a second condenser/fan for the front of the fender well. One must wonder, in light of the single condenser/fan used in the 964/993, why Griffiths doesn't approach the problem with a front fender well mounted fan initially.

4. The 0.08 HP, 60 Watt, rating of the fan Griffiths uses, absent knowing the actual loaded CFM, seems low. Probably an effort to keep the electrical load as low as reasonable. Using the 3rd element switch would likely improve the condensing efficiency enough that a higher CFM fan could be used without additional electrical load.

5. The condenser fan might not run at all "at speed" when the engine RPM is consistently high enough to cool the refrigerant before it reaches a high enough pressure to "trigger" the switch.

[Skip1]

My intent is to maintain my current path of installation as per equipment / ancillaries provided in the package I purchased. Thanks anyway.

[techman1]

1. I suspect Griffiths is seriously under estimating the adverse effects to the fender well condenser due to RADIANT HEATING from the HOT catalyst.

ww, I believe your theory regarding heat soak raising pressure is familiar with us all.
Have you put a pressure gauge on a system and verified this does, in fact, happen?

[wwest]

Originally Posted by techman1

1. I suspect Griffiths is seriously under estimating the adverse effects to the fender well condenser due to RADIANT HEATING from the HOT catalyst.

ww, I believe your theory regarding heat soak raising pressure is familiar with us all.
Have you put a pressure gauge on a system and verified this does, in fact, happen?

Digital temperature guage installed/inserted into the rear lid condenser at multiple points, before and after, indicated a substantive temperature rise post engine shutdown.

Don't remember the actual measurements that I posted at the time.

And it isn't simply a matter of "heat soak". Griff's fender mounted condenser is CONSTANTLY affected adversely whenever the catalyst is at operating temperature. The result is that it takes EXTRA air movement(***) to both overcome the radiant effect AND cool the refrigerant.

The same is true of the rear lid condenser but to a lessor effect since the engine does not get nearly that HOT. On the other hand once the engine is shut down and the fan cooling is lost the exhaust heat begins to rise upward to heat the engine and thus the rear lid condenser.

Which is why the 964/993 series, even without the rear lid condenser to be of concern, has a 15 minute cabin heat blower after-run relay/circuit otherwise the fuel within the engine compartment might boil and/or there is the electronic components to consider.

Which is why I wonder if the proper approach, at least initially, is to bypass/discard the rear lid condenser in favor of a rear fender front condenser with a high CFM fan and both front and rear fans controlled via the fan/vane/louver pressure switch section.

*** Quite possibly more air movement than Griff's 70 watt fan is capable of, thereby making it an easy sales job for the second fender well fan.

[GH85Carrera]

Originally Posted by wwest

Digital temperature guage installed/inserted into the rear lid condenser at multiple points, before and after, indicated a substantive temperature rise post engine shutdown.

Don't remember the actual measurements that I posted at the time.

And it isn't simply a matter of "heat soak". Griff's fender mounted condenser is CONSTANTLY affected adversely whenever the catalyst is at operating temperature. The result is that it takes EXTRA air movement(***) to both overcome the radiant effect AND cool the refrigerant.

The same is true of the rear lid condenser but to a lessor effect since the engine does not get nearly that HOT. On the other hand once the engine is shut down and the fan cooling is lost the exhaust heat begins to rise upward to heat the engine and thus the rear lid condenser.

Which is why the 964/993 series, even without the rear lid condenser to be of concern, has a 15 minute cabin heat blower after-run relay/circuit otherwise the fuel within the engine compartment might boil and/or there is the electronic components to consider.

Which is why I wonder if the proper approach, at least initially, is to bypass/discard the rear lid condenser in favor of a rear fender front condenser with a high CFM fan and both front and rear fans controlled via the fan/vane/louver pressure switch section.

*** Quite possibly more air movement than Griff's 70 watt fan is capable of, thereby making it an easy sales job for the second fender well fan.

Wwest, you are just flat out wrong once again. I have a Griffith's system with the two additional condensers in the fender. When I returned from Savannah, GA in AUGUST I drove for several HOURS in over 100 degree heat and high humidity. That will make a real solid heat soak.

For some reason my wife likes for me to stop and eat lunch. I parked for an hour in full scorching sun on black asphalt after it had been driven since morning. We loaded back in the car had headed west right into the afternoon sun. The heat index was over 120. Within a couple of miles we were cooling off quickly and the AC system did indeed struggle in 120+ heat index full sun shining right on our chests and faces. The ultimate test for any AC system much less a 1985 911. Within a few miles we were not sweating and comfortable. The stock system would have been a joke and my wife would never have been in the car with me.

The simple FACT is the system works as advertised. It provides cold air conditioning for a 1985 911. Any heat soak problem of the fender mounted condensers is just in your head. Hey that is a good idea, go soak your head.

[Bob Kontak]

Originally Posted by Skip1

My intent is to maintain my current path of installation as per equipment / ancillaries provided in the package I purchased. Thanks anyway.

Thank you for staying the course.

[wwest]

Originally Posted by GH85Carrera

Wwest, you are just flat out wrong once again. I have a Griffith's system with the two additional condensers in the fender. When I returned from Savannah, GA in AUGUST I drove for several HOURS in over 100 degree heat and high humidity. That will make a real solid heat soak.

"flat out wrong.." Sure, you need TWO fender condensers to do the job of the ONE used in the 964/993...!!

For some reason my wife likes for me to stop and eat lunch. I parked for an hour in full scorching sun on black asphalt after it had been driven since morning. We loaded back in the car had headed west right into the afternoon sun. The heat index was over 120. Within a couple of miles we were cooling off quickly and the AC system did indeed struggle in 120+ heat index full sun shining right on our chests and faces.

"A/C system did indeed struggle..." Just to be sure we both understand... There is NO amount of cooling airflow, or cooled atmosphere, that can compensate, overcome, the effect on the human body of/from radiant heating, the sun, in your case. The A/C may have fully up to the task, keeping the cabin atmosphere at a comfortable 75dF, or even less, and you and your wife would been discomforted, still.

The ultimate test for any AC system much less a 1985 911. Within a few miles we were not sweating and comfortable. The stock system would have been a joke and my wife would never have been in the car with me.

The simple FACT is the system works as advertised. It provides cold air conditioning for a 1985 911. Any heat soak problem of the fender mounted condensers is just in your head. Hey that is a good idea, go soak your head.

"The simple FACT is the system works as advertised.." I couldn't agree more, REALLY!

Just think about how many owners that bought Griff's early tube and fin fender condenser that proved to not be up to the task at hand. And there is the owner group that bought the tube and fin upgrade, which also proved to be NOT up to the task at hand.

So, yes, you have Griff's final(?) design.

But how can any of us say for sure, one way or the other, that simply adding ONE rear fender front condenser with the fan wattage equal to the both of your's wouldn't equal, or even better (***), the performance of your Griff configuration.

A question... Was the second fan an afterthought add-on when the rearmost condenser didn't quite handle the task? And even if not, for how many buyers WAS that the case.

*** Meaning there might be a good chance that the rear lid condenser could be discarded.

[Bob Kontak]

Originally Posted by wwest

Just think about how many owners that bought Griff's early tube and fin fender condenser that proved to not be up to the task at hand. And there is the owner group that bought the tube and fin upgrade, which also proved to be NOT up to the task at hand.

Proved how and where? Because he went to a different design?

This is how you get your tit in a wringer and is a solid basis for a permanent dismissal from this forum.

[wwest]

Originally Posted by Bob Kontak

Proved how and where? Because he went to a different design?

This is how you get your tit in a wringer and is a solid basis for a permanent dismissal from this forum.

Bob, if the "different design", the rear fender mounted plate and fin condenser proved to be not up to the task at hand, then logically the comparatively substandard performance of the tube and fin condenser could not have possibly been adequate.

[Bob Kontak]

Originally Posted by wwest

then logically the comparatively substandard performance of the tube and fin condenser

His business has not been around because his shiet is substandard.

It has never been substandard.

Maybe I am oversimplifying but if you bought a "cost me a left nut" system in 1998 from Griffiths Tech, it kicked the living crap out of stock and you would be comfortable in Texas heat - still.

[GH85Carrera]

I first contacted Griffiths in 2006. I installed the system in 2007. It has worked flawlessly since.

Every manufacturer updates their design. We would all be discussing a 356 if Porsche had not update their designs.

[dos531]

Every time I see any thread relating to AC I hesitate to even look because I know WWEST is going to **** all over the thread. He's really doing a disservice to the entire community with his attitude.

On a more related note, I have the keuhl fender condenser and upgraded lines with everything else factory, and I get vent temps in the 40s in 100+ degree socal weather.

[Bob Kontak]

Originally Posted by dos531

Every time I see any thread relating to AC I hesitate to even look because I know WWEST is going to **** all over the thread. He's really doing a disservice to the entire community with his attitude.

Sad thing is this is his hobby in his sunset years. To "diss" Charlie Griffith.

wwest epitath: I effed Charlie. Hell yeah!

Seriously, Charlie Griffith? Just a smarter than your average bear schmuck trying to make a buck on a good product.

Da fuk?

Really?