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Posted by: D1A3 Jul 8 2006, 10:56 PM

Just wondering if anyone has tried implementing the 911 rear condenser under the engine lid. Someone mentioned to me today this might be an option if you put a fan or two on it. He even thinks it woudl fit with the rain tray!

Just wondering if anyone else has tried this and any tips you might want to share.

Posted by: So.Cal.914 Jul 9 2006, 01:00 AM

A 914's engine is air cooled, it depends on cool air coming in through the grill

to cool it. What would happen if you put a condenser in the way that is radiating

alot of heat?

Posted by: D1A3 Jul 9 2006, 09:19 PM

My thought was that if I put a fan (or two) on it, that woudl help. Also if it will fit between the grill and rain tray, the tray would help with some of the heat.

If the heat is an issue, then why does Porsche put one on the rear deck of the 911?

Posted by: MBowman325 Jul 9 2006, 09:49 PM

That's still going to be sucking hotter air in to cool the engine. That said, it's a good point on the 911, though I don't know enough... Was it a factory option? I have wondered about the viability of placing it in the rain tray as well, but it seems like not enough room unless you made it deeper to deal with the flow, and a deeper rain tray, I'm not sure how that would affect the engine air flow. (I wouldn't think it would adversly affect it..) {shrugs} Try it, and report to us what happens.

I've never attempted to measure the difference in temp of the air in front of vs the air behind any condensor I have. It wouldn't be highly scientific since all mine have waterpumps. Could give a decent idea though. Or maybe someone will try to measure theirs. Fans or no, the air will still be heated after it passes through the condensor.

Maybe if there were a way to modify the rear firewall into the trunk and mount it there? Draw air in from the lid, and expel it under the trunk where it's already freakin hot? Have to make sure it's sealed well, and a fan would help in that case.

Posted by: gregrobbins Jul 9 2006, 11:00 PM

Dealer install in the front trunk on the floor. Probably recommended by the factory.

Anything that adds heat to the engine compartment is a no no.

Posted by: MBowman325 Jul 10 2006, 10:32 AM

I do wonder though, the guys (or gals) that run three and four condensor setups, what sort of delta there is at the last condensor. Could be it's minor enough to mount on the deck lid, in their opinion, but if that's the case, why have it?

As far as I know, the front trunk is the recommended place. But now that I've started thinking... So long as you maintained a flow through from the engine bay, a condensor mounted in the bulkhead for the read trunk and ducted down towards the transmission/exhaustmay work, but the added work of the fans may only slightly offset the reduced load on the compressor. But, you'd have to be sure that the hot air wouldn't come back up through it into the engine bay, as that'd be much worse than mounting the condensor on the decklid. (I was amazed at how hot the rear trunk gets)

Mounting in the front eleminates the need for super duper fans.

Posted by: brant Jul 10 2006, 10:36 AM

I would theorize that on a 911 the rear engine lid gets more aero flow over it than on a teener...

plus on 911's with the rear condensor, they still run a front trunk one as 2ndary!

this has been covered over and over from the point of cooling oil and mounting oil coolers onto the engine lid. I personally believe its a bad idea all around and would be largely the same for A/C

but what I think isn't all that important.
its what you think that matters.

brant

Posted by: 2-OH! Jul 10 2006, 10:39 AM

Don't some of the tail draggers have the condenser mounted in the left rear fender well...I have seen some kits in Excellence that have a unit mounted there...

2-OH!

Posted by: anthony Jul 10 2006, 11:30 AM

That is an add-on kit for 911s because even with front and rear condensors their A/C systems tend to suck especially when converted to r134a.

Besides what was said above, the 911 rear grill in the rear is a lot larger than a 914 grill. On a 914 two skinny, modern, ribbon condensors would probably work a lot better.

Posted by: MBowman325 Jul 10 2006, 12:52 PM

I've seen kits for 911's that use up to 4 condensors, on in front, one on the deck lid, and one in each rear fender well, behind the wheel. The last two places seem like "dangerous" placed to put something that's suceptable to damage form debris. Maybe they're screened or something...

I've heard that multiple condensors can lower head pressure on the condensor, which reduces the load it brings and extends life. As cheap as some of the condensors are (I've seen the parallel flows ones sale for $120-180), I guess if you're stuck with using small ones, might as well load up.

I sure miss having working A/C sometimes.