Front nose oil cooler - ??box in trunk for air flow?? NEED INPUT FOR BETTER DESIGN

[baloo]

I have an oil cooler with puller fan in the nose of my 87 911 that has a 993 Patritti body. It has a cut out through the trunk floor that leads to an AC condenser lying flat, underneath the car.

This all sits inside the trunk of the car, and there is a rather crudely made steel box that shrouds the oil cooler and directs the flow downward to the condenser, rather than filling the trunk up with heat.

Since I have seen quite a few similar oil cooler setups, my question is:
What do other people's fan boxes look like?
Are they all "custom-crafted" (i.e., homebuilt)?
Are there better setups (other than relocating cooler and condenser to fenders)?

NOTE: I installed two additional pusher fans with their own adjustable thermoswitch to also come on with the AC compressor.

FRONT OIL COOLER AND FAN inside trunk, SHOWING OPENING IN TRUNK FLOOR FOR FRONT AC CONDENSER



BOX IN POSITION OVER FAN AND COOLER



BOX DETAILS



INSIDE BOX



ADDITIONAL TWO FRONT FANS

[wwest]

It seems to me that with the engine oil external thermostat open your oil cooler temperature will be ~180F or above. In that case I suspect that your (front) A/C condensor is operating in reverse, airflow RAISES the temperature of the refrigerant rather than lowering it.

It strikes me that your best "bet" would be a "reversible" blower system. When "at speed" the fans as they are now or even off. Stationary, slow moving traffic, elevated condensor vane/fin temperature, airflow through the condensor first.

Conundrum..that...

Or...Eliminate the front lip condensor altogether and raise the engine lid condensor cooling efficiency. Add 2 12" radiator cooling fans to force air downward through the engine lid condensor. Low speed(series connection), compressor clutch engaged, high speed (parallel fan motor connections) when trinary sensor switch indicates the need.

[wwest]

[baloo]

Originally Posted by wwest

It seems to me that with the engine oil external thermostat open your oil cooler temperature will be ~180F or above. In that case I suspect that your (front) A/C condensor is operating in reverse, airflow RAISES the temperature of the refrigerant rather than lowering it.

Yes, thanks. My similar worries -- that the hot air from the oil cooler will heat up the condenser. BUT, I read that it is simply air flow, not temp of air, that is important to the condenser. It's one of those "stranger than science" explanations -- BUT IT MIGHT BE ENTIRELY FALSE CONCEPT, IMO.

Regarding engine lid fans, yes, I'll get around to that, maybe sooner than later.

[ganun]

What you say then is that the 2 front puller fans work together with the stock oilcooler pusher fan....so air is drawn thru the cond and out thru the oil cooler...OK
if you`re standing still but if going forward fast air wants to go the other way......maybe this is what WWest mentions, and in this situation the cond is getting hot oil cooler air.
If you do city driving i.e. stop &go etc then the 2 rear cond puller fans (or pusher if you have a wing and can sneak then in that space) connected as mentioned is a more modern way to do things.
George
Miami

[baloo]

Originally Posted by ganun

What you say then is that the 2 front puller fans work together with the stock oilcooler pusher fan....so air is drawn thru the cond and out thru the oil cooler...OK
if you`re standing still but if going forward fast air wants to go the other way......maybe this is what WWest mentions, and in this situation the cond is getting hot oil cooler air.
If you do city driving i.e. stop &go etc then the 2 rear cond puller fans (or pusher if you have a wing and can sneak then in that space) connected as mentioned is a more modern way to do things.
George
Miami

Uh, you're talking about WWest's puller fans on the rear wing, right?

Otherwise, if speaking about my nose fans, the two foremost fans are pusher fans; the one behind the oil cooler (on the inside of the trunk) is a puller fan -- so all three force air from front to rear and into the box, which then has its only exit thru the cutout in the floor of the trunk, onto the front AC condenser and out from under the car.

[wwest]

Originally Posted by baloo

Yes, thanks. My similar worries -- that the hot air from the oil cooler will heat up the condenser. BUT, I read that it is simply air flow, not temp of air, that is important to the condenser. It's one of those "stranger than science" explanations -- BUT IT MIGHT BE ENTIRELY FALSE CONCEPT, IMO.

Regarding engine lid fans, yes, I'll get around to that, maybe sooner than later.

"..simply air flow..."

Yes, the FASTER a volume of airflow moves through the heat exchanging structure the less the airflow will be heated. At 70 MPH the airflow reaching the condensor is probably cool enough, but stopped...You'll need a LOT of fan to match that 70 MPH mode.

[ganun]

Oh OK check the rotation of the stock oil cooler fan because it is intended to be a pusher, If rewired to run backwards it not moving much air.
Back to your original question.
Consider flipping them i.e. the condenser in the fron to f the oil cooler(more like a normal car set up with the cond in front of the rad) ...then the stock oil cooler fan can work as intended. The cond get the front air first, aided by the 2 aux fans pushing, then the oilcooler with its pusher fan blowing down. BTW the oilcooler fan really blows!

[baloo]

Originally Posted by ganun

Oh OK check the rotation of the stock oil cooler fan because it is intended to be a pusher, If rewired to run backwards it not moving much air.
Back to your original question.
Consider flipping them i.e. the condenser in the fron to f the oil cooler(more like a normal car set up with the cond in front of the rad) ...then the stock oil cooler fan can work as intended. The cond get the front air first, aided by the 2 aux fans pushing, then the oilcooler with its pusher fan blowing down. BTW the oilcooler fan really blows!

Arggh. May have to remove the "pusher" oil fan. Good to know about its fwd/reverse discrepancy. Many fans on the market push or pull equally.

Ref. flipping the condenser vs oil cooler positions ---- too much labor involved b/c lines would have to be changed. I might, however, have success just moving the oil cooler to the fender. That way, the lines would be plenty good, just curled back somewhat. This would allow full flow to the condenser from top, front, and bottom. hmmm. Need more energy.

[ganun]

Not my car.....

[TRE Cup]

When it comes to oil cooler fans; it is better to push than to pull. Why? the high heat can reduce the life of the pull location fan, and in some cases we have seen melted plastic parts.
the exit is on the small side. I would like to see at least 50% more area for the exhausted air to pass thru

[baloo]

Originally Posted by TRE Cup

When it comes to oil cooler fans; it is better to push than to pull. Why? the high heat can reduce the life of the pull location fan, and in some cases we have seen melted plastic parts.
the exit is on the small side. I would like to see at least 50% more area for the exhausted air to pass thru

Thanks Tre. I just may remove the puller fan and just have the two front pushers.

I am still curious about the box contraption housing the oil cooler and fan in the nose.
Anyone have something similar??

[Sboxin]

Originally Posted by baloo

I am still curious about the box contraption housing the oil cooler and fan in the nose.
Anyone have something similar??

Wow , what a design ! !
Nope, never have seen one of those before . . .

A little more information would be helpful about the car, engine, planned use of the car, etc .

My thought is to take out that stuff -- put in the Carrera fender cooler and move the
AC condenser to the rear engine cover with 2 fans.
I am assuming the engine is a 3.2L and has an engine oil cooler mounted on the engine
along with the front cooler . . . or maybe not . . . We have 3 coolers for a 3.8L in '78 911 race car.

This is what others have said above - - just summarizing here . . .

Regards,

[baloo]

Originally Posted by Sboxin

Wow , what a design ! !
Nope, never have seen one of those before . . .

A little more information would be helpful about the car, engine, planned use of the car, etc .

My thought is to take out that stuff -- put in the Carrera fender cooler and move the
AC condenser to the rear engine cover with 2 fans.
I am assuming the engine is a 3.2L and has an engine oil cooler mounted on the engine
along with the front cooler . . . or maybe not . . . We have 3 coolers for a 3.8L in '78 911 race car.

Sboxin,
The car had been fully set up for some sort of competition in the past, but evidently also for show (rollbar, turbo instruments, brakes, Recaros, competition seat belt attachments) and had had a 750hp turbo engine, purportedly. The engine blew, and it sat inside a warehouse for 10 years (story according to the seller).

It was from south Miami, and it's obvious that there was the need for a lot of show, if you know the south beach crowd, huh. It had a lot of unnecessary luxury and show items: "Turbo" carpets, "Turbo" sills, underbelly full-width condenser with front condenser (no rear condenser due to intercooler), sunroof, heavy stereo system from back in the day, fancy Fittipaldi wheel, white face gauges, fancy anti-theft unit, etc.

They replaced the blown engine with a rebuilt stock 3.2 from a 1987, with tuned headers and what looks like a well-fabricated, non-baffled "Zork" exhaust, which I immediately had to replace due to the neighborhood. (I'm a retired Army guy, so I'm old and conservative and regulation-constrained.)

It has engine cooler and the front cooler. The front cooler is definitely the Porsche fender setup that was put into the front nose instead of the fender.

PLANNED USE? Street driving, although I plan to put a stock turbo setup in (with heat), because all the turbo items were left in the car, like boost gauge, some computer from the 1990's, HKS electronic boost controller. I have about 98% of the items I need to do the conversion -- still waiting for that magic moment and the energy to knock it out in 5 days.

REGARDING THE AIR BOX IN THE NOSE-- I have seen several setups by Pelican contributors that have an oil cooler mounted in the nose and fed by air thru the front nose hole. They had to have some sort of similar diversion box to rout the air flow, right?

[Sboxin]

Originally Posted by baloo

Sboxin,
The car had been fully set up for some sort of competition in the past, but evidently also for show (rollbar, turbo instruments, brakes, Recaros, competition seat belt attachments) and had had a 750hp turbo engine, purportedly. The engine blew, and it sat inside a warehouse for 10 years (story according to the seller).

It was from south Miami, and it's obvious that there was the need for a lot of show, if you know the south beach crowd, huh. It had a lot of unnecessary luxury and show items: "Turbo" carpets, "Turbo" sills, underbelly full-width condenser with front condenser (no rear condenser due to intercooler), sunroof, heavy stereo system from back in the day, fancy Fittipaldi wheel, white face gauges, fancy anti-theft unit, etc.

They replaced the blown engine with a rebuilt stock 3.2 from a 1987, with tuned headers and what looks like a well-fabricated, non-baffled "Zork" exhaust, which I immediately had to replace due to the neighborhood. (I'm a retired Army guy, so I'm old and conservative and regulation-constrained.)

It has engine cooler and the front cooler. The front cooler is definitely the Porsche fender setup that was put into the front nose instead of the fender.

PLANNED USE? Street driving, although I plan to put a stock turbo setup in (with heat), because all the turbo items were left in the car, like boost gauge, some computer from the 1990's, HKS electronic boost controller. I have about 98% of the items I need to do the conversion -- still waiting for that magic moment and the energy to knock it out in 5 days.

REGARDING THE AIR BOX IN THE NOSE-- I have seen several setups by Pelican contributors that have an oil cooler mounted in the nose and fed by air thru the front nose hole. They had to have some sort of similar diversion box to rout the air flow, right?

Well . . . um . . .

Yes, the air needs to go somewhere -- ours has a quarter round cut and welded
to route air under the car. The preferred method is to route air up and thru the
front trunk deck lid. The other method is routing air out a box like yours thru
the side wheel wells -- this keeps the air from under the car. Ours worked very
well with the 3.2L stock engine with engine cooler and 1 front center mounted
cooler = 180-210 even in racing and some warm days here in Phoenix.

Since you are ready to do the add-on Turbo (or is it a 930 engine?) I would suggest leaving the oil
cooler/AC condenser set up as is and see what the engine temps are after the
conversion. As we were advised, more horsepower equals a LOT more engine heat.

You didn't mention what the 3.2L current engine oil temps are running - with
and without the added 2 front fans??
Since the car has been heavily modified, perhaps the fewer changes you make,
the better. And, because I assume you will be mounting an intercooler for the turbo
the rear deck lid is not an option to relocate the AC condenser there?

Regards,

[baloo]

Originally Posted by Sboxin

Well . . . um . . .

Yes, the air needs to go somewhere -- ours has a quarter round cut and welded
to route air under the car. The preferred method is to route air up and thru the
front trunk deck lid. The other method is routing air out a box like yours thru
the side wheel wells -- this keeps the air from under the car. Ours worked very
well with the 3.2L stock engine with engine cooler and 1 front center mounted
cooler = 180-210 even in racing and some warm days here in Phoenix.

Since you are ready to do the add-on Turbo (or is it a 930 engine?) I would suggest leaving the oil
cooler/AC condenser set up as is and see what the engine temps are after the
conversion. As we were advised, more horsepower equals a LOT more engine heat.

You didn't mention what the 3.2L current engine oil temps are running - with
and without the added 2 front fans??
Since the car has been heavily modified, perhaps the fewer changes you make,
the better. And, because I assume you will be mounting an intercooler for the turbo
the rear deck lid is not an option to relocate the AC condenser there?

Regards,

Thanks for the comments. Good advice re. keeping things as is, until other changes made.
The engine is stock 3.2 (not 3.3/930)
As the turbo has not been installed yet, my engine temps are only for stock performance, and with 80degree weather yesterday, the needle was about 3/8 the way up the scale -- and driving 70-75mph for about 40 miles.
After driving about 10 miles at 70mph and stopping immediately, I blindly adjusted temp for fans to come on at slightly higher temp than they would kick on, so that they would not be running while at 70mph.

Regarding rear condenser -- I'll use stock 930 IC, so it would only take up half the space in the tail, so room for condenser back there. I do not like the concept of the underbelly condenser, because it seems too susceptible to stone and high-center damage. HOWEVER, I have seen that they use an underbelly on my BMW Z4 coupe, so maybe this is not a problem.

QUESTION: On rear condensers, has the use of a fan been shown to be effective? I have read several strings on this, and many pro and counter arguments. However, I noticed that Kuehl, Griffiths, and others do not add a fan back there, so this must not have been proven to be useful?

[Sboxin]

Originally Posted by baloo

Thanks for the comments. Good advice re. keeping things as is, until other changers made.
The engine is stock 3.2 (not 3.3/930)
As the turbo has not been installed yet, my engine temps are only for stock performance, and with 80degree weather yesterday, the needle was about 3/8 the way up the scale -- and driving 70-75mph for about 40 miles.
After driving about 10 miles at 70mph and stopping immediately, I blindly adjusted temp for fans to come on at slightly higher temp than they would kick on, so that they would not be running while at 70mph.

Regarding rear condenser -- I'll use stock 930 IC, so it would only take up half the space in the tail, so room for condenser back there. I do not like the concept of the underbelly condenser, because it seems too susceptible to stone and high-center damage. HOWEVER, I have seen that they use an underbelly on my BMW Z4 coupe, so maybe this is not a problem.

QUESTION: On rear condensers, has the use of a fan been shown to be effective? I have read several strings on this, and many pro and counter arguments. However, I noticed that Kuehl, Griffiths, and others do not add a fan back there, so this must not have been proven to be useful?

Current oil temps: This sounds very good for the 3.2L

Condenser Fans: The only experience I have is a friend with 87 911 w/AC --
added 2 fans to rear deck mounted condenser and had cold AC here in Phoenix . . .
his experience was positive . You have consulted the recognized gurus of Porsche AC.

Condenser under car: You might add screening to protect the fins.

Turbo on stock 3.2L : Not something I would do . . . just sayin'

Regards,

[wwest]

Originally Posted by baloo

Thanks for the comments. Good advice re. keeping things as is, until other changers made.
The engine is stock 3.2 (not 3.3/930)
As the turbo has not been installed yet, my engine temps are only for stock performance, and with 80degree weather yesterday, the needle was about 3/8 the way up the scale -- and driving 70-75mph for about 40 miles.
After driving about 10 miles at 70mph and stopping immediately, I blindly adjusted temp for fans to come on at slightly higher temp than they would kick on, so that they would not be running while at 70mph.

Regarding rear condenser -- I'll use stock 930 IC, so it would only take up half the space in the tail, so room for condenser back there. I do not like the concept of the underbelly condenser, because it seems too susceptible to stone and high-center damage. HOWEVER, I have seen that they use an underbelly on my BMW Z4 coupe, so maybe this is not a problem.

QUESTION: On rear condensers, has the use of a fan been shown to be effective? I have read several strings on this, and many pro and counter arguments. However, I noticed that Kuehl, Griffiths, and others do not add a fan back there, so this must not have been proven to be useful?

Just curious, what is your planned method for lowering the engine compression in order to take full advantage of turbocharging. Or do you plan to super-enrich the mixture under boost?

[wwest]

Originally Posted by baloo

Thanks for the comments. Good advice re. keeping things as is, until other changers made.
The engine is stock 3.2 (not 3.3/930)
As the turbo has not been installed yet, my engine temps are only for stock performance, and with 80degree weather yesterday, the needle was about 3/8 the way up the scale -- and driving 70-75mph for about 40 miles.
After driving about 10 miles at 70mph and stopping immediately, I blindly adjusted temp for fans to come on at slightly higher temp than they would kick on, so that they would not be running while at 70mph.

Regarding rear condenser -- I'll use stock 930 IC, so it would only take up half the space in the tail, so room for condenser back there. I do not like the concept of the underbelly condenser, because it seems too susceptible to stone and high-center damage. HOWEVER, I have seen that they use an underbelly on my BMW Z4 coupe, so maybe this is not a problem.

QUESTION: On rear condensers, has the use of a fan been shown to be effective? I have read several strings on this, and many pro and counter arguments. However, I noticed that Kuehl, Griffiths, and others do not add a fan back there, so this must not have been proven to be useful?

Kuehl, Griffiths, and "others" are more in the business of selling snake oil at a HIGH profit margin....take the pure idiocy of the ProCooler, for instance. Promoting a simple and relatively expensive solution is NOT in there best interest.

In some sense they are correct. Selling the fender mounted condensor/fan rather than adding rear lid condensor cooling fans eliminates the possible liability for engine damage blame, FALSE blame.

[baloo]

Originally Posted by wwest

Just curious, what is your planned method for lowering the engine compression in order to take full advantage of turbocharging. Or do you plan to super-enrich the mixture under boost?

WWest and SBoxin,
I did really extensive research on PP and Renn regarding boosting stock 3.2 -- now over one year's worth. I think I have read EVERY thread on PP that involved such a project with the 3.2, and many with the 3.0 SC.

It has been done frequently (and is well described and experienced), and is done extremely extremely commonly on numerous JDM (Japanese etc) cars by people even more inexperienced than I. I got past the voodoo scariness of boosting, and realized that I can get 320-350 hp with a simple .5bar (maybe 8psi boost). I have the Nikasils.

It seems there are two major problems with turbocharging: 1) is the addiction; 2) is the project becoming never-ending, and never completed. I do not think I have read one post where the booster did not want more more more boost, and the temptation to just add one more psi "just for one run" proves to be the downfall. Regarding #2 -- so many of the projects begun with highest hopes and great enthusiasm and ambition, end up biting the dust due to lack of resources, time, energy and interest. (In fact, I buy many of my cars from people who hit the wall and just want to be rid of their uncompleted projects. )

The other reason for turbo is that I am tired of every POS old junky clunky-looking battered spray-painted Japanese car, driven by a carload of teenagers, with a junk turbo kit from eBay, blowing off my $100K (in 2013 dollars) car. While I do not race, I want to at least show up respectably on the street -- otherwise, I should be driving the minivan.

I know this is something that is trivial and vain, but I think it is more a matter of wanting to show pride in the Porsche marque, than something personal.
HOWEVER, maybe it is a matter of not wanting to appear stoopid, paying for an expensive car that does not perform as well as a cheapa** car, huh?