Pelican Parts Forums - Griffith's AC upgrade for '84 911 install thread

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Skip, you are cooking right along. Do you happen to have another pic of the fender well cooler just prior to install? Also did you put anything (sealant) on the thru bolts for the Heat shield? Thanks again for documenting your work.

If you mean the condenser itself on the floor or something, then no, never thought of that, but Griff (Kuehl is his nickname on the forum) could probably send you one.

I didn't put anything the the heat shield bolts themselves - I suppose I could have, but doubt any of it would have stayed as the screws were quite snug.

Quote:

Originally Posted by carreradpt (Post 8635709)

Post # 17, decent pictures..

http://forums.pelicanparts.com/porsche-911-technical-forum/176468-griffiths-fender-condenser-dimensions.html

Quote:

Originally Posted by kuehl (Post 2009639)

Phillip,

with the 78-89 930's, with half deck lid condensers, we use a 9" fan, simply bolted onto the unit and the gains are worth the investment (lower high side pressures = lower vent temps), however on the non-turbos' the story is pretty much as we have outlined.

Charlie, you seem to have said that using a 9" "Spal" fan to provide additional cooling airflow for the 930 condenser is well worth the investment, but not the same for the non-turbo condenser.

Can you explain?

Search doesn't find the "pretty much as outlined"

Skip1..
I warned you.. Keep on doing what you are doing.. You're doing fine!!!

Limited work today. All I got done was actually attaching the rear LH wheel well condenser hose to the OEM decklid condenser, but, that's still something. I also cleaned up the mess in the garage a bit (all the dirt piles and stuff - important to keep the work area clean too. Next step is the electrical in the engine compartment panel for the rear LH wheel condenser, including the relay wiring).

I also wanted to add a correction (I'll go back and correct the entry post as well, but the self-tapping bolts that hold the old hose clamps along the base of the car, are in fact 8mm (as it states in Griff's instructions), not 9mm as I had posted - oops! :eek:

Jinjugnb, I expect that shouldn't be too far off - I'm hoping it's not as challenging as it sounds :)

I also wanted to ask a question about reinstalling the large curved bracket that supports the main weight of the compressor to the rear of the engine (fan side, if I'm referring to it incorrectly :)). It was removed when I had to have some significant work done on the engine, and not reinstalled. I have all the parts, as well as the compressor mounting plates that I got from Griff, to complete the set. My question is this, how far do I have to go, in a partial engine drop to reach the necessary bolts to reattach this support. I know as a minimum, I have to support the engine at the rear, so I can remove the cross member and pulley cover as one bolt is only accessible that way, but do I have to remove the muffler as well - I can't recall, but I'd rather not.

Any thoughts?

Thanks.

Ask Griff about this, but depending on the design you now have you may want to use a trinary pressure switch in the same way, method, used in ALL post 1989 911 model years.

Most older, now to be considered obsolete, use a relay powered by the compressor clutch circuit to power the condenser fan(s). Quite obviously the high side pressure does not just disappear the instant the compressor stops, so using the third element of the trinary switch to power the fan allows the refrigerant condensation process to continue unabated, not overcome by the engine and catalyst radiant heating effects.

In addition, once the engine RPM rises enough to sufficiently cool the rear lid condenser the fan would possibly (likely?) remain depowered.

Some Porsche models used a thermostatic switch stud mounted to the R/D, that way the front lip condenser blower need not be functional when underway when roadspeed does the front lip condenser cooling job. Not so sure if this would very effective with Griff's (and KelogGes's) design as it seemingly blocks most cooling airflow due to roadspeed.

On the other hand, as mentioned previously, at roadspeed the engine fan might be sufficient so a thermostatic switch mounted on the R/D could well extend the life of the front blower mower while also reducing the electrical system load.

Quote:

Originally Posted by Skip1 (Post 8636572)

Email and parts diagram sent

Quote:

rear RH wheel well condenser hose

Skip: in your post #107 above, you use this phrase. Do you mean "LH" as in left hand instead of "RH" or right hand? You have used "RH" in several places previously but it seems likely that this is simply a typo.

Or ... what is the "rear RH wheel well condenser hose?"

Enjoying reading your reports. I'm reminded of my installation of a Kuehl system in my car 12 years ago. Still running really well.

Good grief - you're absolutely correct, I'll have to go back and change those erroneous RHs to LHs. Thanks for catching that.

*** Added note: I think I corrected them all now :)

Quote:

Originally Posted by wwest (Post 8636623)

Ask Griff .........

Will, can't you keep still? lol.

1) Not all post 89 air cooled models, nor pre 89 water cooled used a single switch.
2) For Skip's design, a binary is "kiss", less opportunities for failure because there are fewer moving parts and connections inside the switch. The 'tri' function of an aftermarket trinary switch is to turn on or off a circuit at a particular pressure. Since the purpose of the additional condenser is to remove heat from the refrigerant when ever the compressor is operating, rather than to turn on that function at particular pressure, a trinary design is never needed nor wanted (and we don't need to hear why you 'think' we want one today).
3) The reason we "still" use a separate relay to power the Kuehl fender condenser fan is because YOU did not know the circuit you suggested here, and every other thread, can't handle the amp load (go back to the SC and Carrera factory schematic and you will figure this all out; someday).
4) If the factory deck lid condenser could remove enough btu's you would not need additional condensers, and it could do that in any ambient above 85F that condenser would be dumping the heat into the engine. And, someday you might figure out that by modifying the auxiliary engine heater fan with either a wider blower wheel or with a sheet metal shroud, as you have posted in many threads, you are actually blocking the primary air exiting the motor's cooling fan into the duct work to the heat boxers; there is a reason why Porsche left that gap between the blower wheel and the blower housing.
5) A temperature sensor attached to the drier, as used in the earliest of the factory and aftermarket designs in the early 70's is not as concise as a pressure switch providing the same function.
6) The amount of amps required to run the single 12" fan on the Kuehl condenser
is less than 0.008046133 horsepower. If you are concerned about horse power or fuel economy I can think of 1,000 other areas to reduce weight, drag and friction.

Now, Skip has been doing a great job with his project, especially considering that he is not doing a simple R&R, part of his system was a basket case. So, why don't you stay on track here and just let the OP continue down the road he intended this thread to go. Thank you and have a great weekend.

Quote:

Originally Posted by kuehl (Post 8636974)

Will, can't you keep still? lol.

1) Not all post 89 air cooled models, nor pre 89 water cooled used a single switch.

I thought that I stated that all post 1989 911's used a trinary pressure switch, as do ALL modern day automotive A/C systems.

"single switch" from where did that come..??

2) For Skip's design, a binary is "kiss", less opportunities for failure because there are fewer moving parts and connections inside the switch.

So, adding a relay "repeater" for the clutch circuit instead of a third pressure element rated to directly power the fan plus extend the fan life by only powering as necessary is "KISS"...??

The 'tri' function of an aftermarket trinary switch is to turn on or off a circuit at a particular pressure. Since the purpose of the additional condenser is to remove heat from the refrigerant when ever the compressor is operating, rather than to turn on that function at particular pressure, a trinary design is never needed nor wanted

It is well known scientific FACT that heat transfer efficiency rises as the temperature spread between the 2 mediums rises. The 3rd element of the switch will delay activation of the fan until a more efficient heat transfer temperature of the refrigerant gas is achieved. On the flip side the switch will continue to power the fan as long as needed to continue the condensation process beyond the compressor being cycled off.

(and we don't need to hear why you 'think' we want one today).

3) The reason we "still" use a separate relay to power the Kuehl fender condenser fan is because YOU did not know the circuit you suggested here, and every other thread, can't handle the amp load (go back to the SC and Carrera factory schematic and you will figure this all out; someday).

What? Are you now speaking with "forked tongue"? The 3rd element providing "sensory" power to the cabin heat blower module is likely sub one amp.

4) If the factory deck lid condenser could remove enough btu's you would not need additional condensers, and it could do that in any ambient above 85F that condenser would be dumping the heat into the engine.

Wow, are you really behind the curve... It is well known and widely accepted that as long as the engine RPM is consistently elevated the rear lid condenser, along with the roadspeed cooling of the FACTORY front lip condenser is sufficiently effective to provide maximum cooling airflow to the cabin.

And, someday you might figure out that by modifying the auxiliary engine heater fan with either a wider blower wheel or with a sheet metal shroud, as you have posted in many threads, you are actually blocking the primary air exiting the motor's cooling fan into the duct work to the heat boxers; there is a reason why Porsche left that gap between the blower wheel and the blower housing.

And someday you might figure out that I have INTENTIONALLY blocked the engine fan outflow to the cabin heat blower inlet, resulting in the engine getting additional cooling airflow. Plus in heating mode the heated air flow to the cabin is no longer modulated via the engine RPM, less discomfort to myself and my passengers.

5) A temperature sensor attached to the drier, as used in the earliest of the factory and aftermarket designs in the early 70's is not as concise as a pressure switch providing the same function.

As YOU have said, temperature = pressure = temperature. Care to explain "concise"? So you approve of using a pressure switch to control the fan(s) but not a thermostatic switch?

6) The amount of amps required to run the single 12" fan on the Kuehl condenser
is less than 0.008046133(???) horsepower. If you are concerned about horse power or fuel economy I can think of 1,000 other areas to reduce weight, drag and friction.

Worried? Concerned that the fan is not being properly used, taken full advantage of, yes. And why BLINDLY run the fan when it has no function to perform. And if not brushless, as many modern day fans are, there is life service to be considered.

Now, Skip has been doing a great job with his project, especially considering that he is not doing a simple R&R, part of his system was a basket case. So, why don't you stay on track here and just let the OP continue down the road he intended this thread to go. Thank you and have a great weekend.

1 HP = 746 Watts. 0.008 X 746 = 5.968 Watts. Have confused AMPs with Watts?

Charlie, seriously, you need to attend a class on modern day implementations of automotive A/C, and then go back to your shop and "invent" as many of those newly learned aspects to your product set as might be warranted.

Just because our cars or of "yesteryear", doesn't mean we have to live "there", are continue to use, buy, enhancement/retrofit products designed of that era.

Hey Will. Guess what! You got 1 out of 6.
I'll move over the decimal place for you .080 hp for the blower fan motor (at 12vdc nominal naturally, would you prefer a more real world 13.5 nominal?), would you like to comment of the efficiency of pm motors?

Skip, when I was cleaning things up in the engine room I removed the compressor brackets. Had to remove the muffler only to get that bracket off, no partial drop or anything like that. There were a couple of tough to get to fasteners that needed to be removed.

Quote:

Originally Posted by carreradpt (Post 8637773)

As I remember you are right. I think only the muffler has to come off. I had to pull my bracket and put in a heli-coil on one of the fittings.

Thanks guys, I'll be ready for whatever hits me. I'm positively optimistic. This will be a weekend job however. Tonight, I'm going to try to finish the last hose from the evaporator to the engine bay, so the main messy work is finished - then it'll be Molson Canadian time, or in my case here Cologne Fruh Kolsch...

Alrighty then, so this evening I removed the final hose from the evaporator to the engine bay compressor side and solidified the hose on the left to the decklid condenser with the requisite hose clamp. With the exception of reattaching the protective plate under the fuel pump in the front, the work under the car in the dirt should be done. Running the last hose down the passenger side was actually no issue at all, nor was pushing it up into the smuggler's box as well as the other end into the engine bay. Seems like there is a lot more space on this side, which I was pleased about.

http://forums.pelicanparts.com/uploa...1432667824.jpg

http://forums.pelicanparts.com/uploa...1432667864.jpg

I still also have to reinstall the heater ducting, but will do that once I finalize the wiring (likely tomorrow evening if I get a chance to work on it. At that point, it will be time to work the support bracket issue on the engine, before being able to work on any compressor aspects. I took a look underneath the muffler area, and I might be able to get away with removing the heat exchanger cross over pipe that finds it's way up into the engine bay duct work that I've removed. There is a muffler support bracket which is in the way of the bolt I need to install on the base of the bracket, and the two bolts which support it attach to the rounded plate which covers the pulley system. I'm up for that challenge now too :).

http://forums.pelicanparts.com/uploa...1432667981.jpg

http://forums.pelicanparts.com/uploa...1432668013.jpg

Quote:

Originally Posted by kuehl (Post 8637560)

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