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C2S undertray question

tyinsky

Well-known member
Joined
29 Jun 2012
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1,050
Is the undertray for the C2S the same as the NB cars (manual) or is it a different size?

Mine does not have one fitted which I have been led to believe is better for cooling. However, it must also be detrimental to the car at high speeds and increase the amount of dirt?

Toying with fitting one.
 
Old wife's tale ref cooling. Stems from the 964 and it's ability to leak oil. No undertray...... then no signs of an oil leak.
 
Incorrect Wozy and its not an issue related to oil leaks. The problem is a lack of cooling on the cylinder heads. The heat retention when the tray is fitted is enourmous in standing traffic and this means excess wear on the exhaust side valve giudes. A weak spot on the 964 and worse on the 993 due to the smaller valve stems.
 
ras62 said:
Incorrect Wozy and its not an issue related to oil leaks. The problem is a lack of cooling on the cylinder heads. The heat retention when the tray is fitted is enourmous in standing traffic and this means excess wear on the exhaust side valve giudes. A weak spot on the 964 and worse on the 993 due to the smaller valve stems.

With all due respect I ran my car in Kuwait for 15 years where temperatures hit 52C in the summer.
No issues what so ever with the under tray on. I think Porsche designed the cars to run with the under tray in place.


Out of interest how do the "racing " Porsches run :dont know:

ATB :)
 
decgraham said:
ras62 said:
Incorrect Wozy and its not an issue related to oil leaks. The problem is a lack of cooling on the cylinder heads. The heat retention when the tray is fitted is enourmous in standing traffic and this means excess wear on the exhaust side valve giudes. A weak spot on the 964 and worse on the 993 due to the smaller valve stems.

With all due respect I ran my car in Kuwait for 15 years where temperatures hit 52C in the summer.
No issues what so ever with the under tray on. I think Porsche designed the cars to run with the under tray in place.


Out of interest how do the "racing " Porsches run :dont know:

ATB :)

But also very little traffic compared with somewhere like London (at least whenever I have been in Kuwait there appears to be very little). Surely even on the days when it reaches 50ºc, the airflow around the engine if the car is moving provides the cooling?

Suddenly this has become more interesting. All good comments. :thumbs:
 
I ran my car in slow and fast moving traffic, ok I only did 5000 Kms a year but here l am in Spain with 105k Kms on the clock now and not a wiff of smoke on start up or on running. A good mate of mine who is a very good mechanic made comment as my car shot off down the road being driven by his wife "wow not a puff of smoke what a car" Only my personal experience.

ATB :)
 
I hear what you say ras62 but I beg to differ. Bernie29 rebuilt his top end at 100K+ miles and said that there was nothing wrong with the valve guides etc. He only did it because there was an oil leak if I remember correctly.
If you warm these engines up properly, nothing over 3000 RPM until the thermostat opens you should be good for 150K miles plus. These engines are bulletproof if you treat them with a bit of respect.... but not a lot :)

ATB :)
 
Yeh I'm not sure I buy into that theory either Ras, there's a huge fan out front of the engine pulling huge gulps of air over the cylinder heads at all times.

It's not like the engine tray forms an air tight seal or anything close. personally I'd prefer mine to be as Porsche intended.

Trev
 
Cameltoe & Heel said:
Yeh I'm not sure I buy into that theory either Ras, there's a huge fan out front of the engine pulling huge gulps of air over the cylinder heads at all times.

It's not like the engine tray forms an air tight seal or anything close. personally I'd prefer mine to be as Porsche intended.

Trev


I'm with you Trev :thumb: :thumb:
 
This is hardly theory, its a long known fact as any air cooled specialist will explain, and countless videos show. Open the oven door when you next roast a chicken....
The engine capsules and tray were introduced in an effort to make the engines quieter to meet ever more stringent legislation. It worked but as a result it acts to hold heat in just the wrong place which is why its always the exhaust guides that suffer.
 
yep, pretty sure it was to accommodate Switzerland noise regs. Keep mine in the shed
 
so you are saying if you take it off it makes the car louder? That could be interesting :)
 

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