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REAR UNDERTRAY OFF OR ON?

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I have recently removed my rear undertray having spoken to several other RS nutters............allegedly improves cooling....must agree having seen the amount of padding stuck up against the engine......................what do you think?
 
I was told that keeping it ON a normal 964 impoved the cooling - can't get that hot, can it ?
 
Take it off!!

It was fitted to help pass stringent Swiss nosie regs at the time.

It's got b*ggr all to do with aerodynamics this far back on the car.

It also, allegedly, can build up hot spots against the engine that could lead to problems.

Removal makes no difference to muck getting blown over the engine because the design of the wing and the fan blows DOWN.

Melv
 
Reliably informed that the heat build up with the undertray led to oil seals hardening and oil leaks..........can't see the logic of insulation/padding stuck up on the engine and can only agree with Mel that it was some kind of sound proofing...............this was completely changed on the 993(RS) which works very well....
 
Car came without it - was originally from Sicily where things can be a bit warm.
Never seen the need to retro fit.
Bruce Andersen in Excellence recommends removal too.
 
Thus all 964 C2/4 should take it off.......................what about 965 (964) Turbo do they have the same arrangement maybe that's why they have all rebuilds every five minutes....
 
I am not 100% in agreement on this one. There is substantial proof that it keeps your engine and box cleaner (don't believe me? just look at the older cars without them!) splashes of muck and road salt when it rains don't plaster the engine's underside with the tray left on.
In Saudi Arabia I might agree that the heat may cause problems, but I am not so convinced about such problems with our more gentle climate. I won't care to comment to strongly on the downforce/ aero effect the tray has as I really don't know. But I do know that Porsche went to great lengths to create a very flat bottomed car and the undertray IS part of that. Though I do agree it was probably more to do with noise regs.
For me I have left mine on solely because it does IMHO keep the engine and box cleaner, if only in a small way and I am all for that. Though I think it's totally a personal choice and in the end causes no great harm either way.
 
One other small point. The heat exchangers are indeed inside the undertray and so cause a degree of heat (which at least is partly cooled by the blower). But all around the outside of the tray are very hot exhaust boxes and an extremely hot cataylist. with the undertray fitted there is at least some insulation from this heat. With the undertray off there is not! Definately never run without the side protection panels they are definately there to keep the heat OUT.
 
What are the side protection panels Laurence........surely with the tray off everything can breath and cool more easily......it would defy physics for an obstruction to aid cooling.......
 
ORIGINAL: Laurence Gibbs

The panels are the ones that the undertray bolts up to. They are insulated. Now Porsche did this for a reason!

And they left them on the Cup Car....

Mel
 

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