bhp of your 964
04-30-2010, 01:42 PM
#31
Rennlist Member
Yes, you are absolutely right about heat-valve guide wear, but the issue is whether or not the undertray worsens/improves/does nothing to engine temp, which nobody has been able to prove/disprove as yet i.e. conjecture. I doubt anyone ever will. It probably traps heat at idle, but again, nobody has proved this. It is possible that it improves cooling at speed, but we don't know for sure. All we have is personal experience and mine is that my temp gauge acts in the same way at idle or at speed with the tray on or off; all UK weathers, all ambient temps, driven hard and fast and pootling along.
This is why I said 'so much posted on this already, won't repeat it again' - all this has been discussed and disagreed on before.
This is why I said 'so much posted on this already, won't repeat it again' - all this has been discussed and disagreed on before.
Of course i can't prove it however, my mechanic who works on numerous 964's and 993's says he has seen a significantly higher failure rate on cars witch retained their under tray vs not. I personally had much higher running temperatures prior to removing my under tray which to me is proof enough it holds in heat. The factory did not supply the 964 turbo with an under tray because they were aware of the problem it would create as early as the 3.3l motors and especially on the 3.6 T.
04-30-2010, 02:02 PM
#33
Burning Brakes
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Oh well, Anthony, we aren't going to agree; unless I change my mind at a later date, which is always possible 
Any Turbo engined car has major heat generating issues compared to an NA. Oh, and my mechanic agrees with yours, though when pushed, he really doesn't know for sure. My 964 has now done 108k, with the tray on, still has 5% across all six cylinders and no wobbly valves. Damn,now I have said that, you know what I will be f$x$ng next service!
EDIT: Ilko, please don't......
Any Turbo engined car has major heat generating issues compared to an NA. Oh, and my mechanic agrees with yours, though when pushed, he really doesn't know for sure. My 964 has now done 108k, with the tray on, still has 5% across all six cylinders and no wobbly valves. Damn,now I have said that, you know what I will be f$x$ng next service!EDIT: Ilko, please don't......
04-30-2010, 02:12 PM
#34
Rennlist Member
Oh well, Anthony, we aren't going to agree; unless I change my mind at a later date, which is always possible Any Turbo engined car has major heat generating issues compared to an NA. Oh, and my mechanic agrees with yours, though when pushed, he really doesn't know for sure. My 964 has now done 108k, with the tray on, still has 5% across all six cylinders and no wobbly valves. Damn,now I have said that, you know what I will be f$x$ng next service!
EDIT: Ilko, please don't......
Any Turbo engined car has major heat generating issues compared to an NA. Oh, and my mechanic agrees with yours, though when pushed, he really doesn't know for sure. My 964 has now done 108k, with the tray on, still has 5% across all six cylinders and no wobbly valves. Damn,now I have said that, you know what I will be f$x$ng next service!EDIT: Ilko, please don't......
I do feel for average driving on the street it shouldn't make a difference either way. Heat is the killer so as long as your temps stay cool you should be fine.
Another concern is the cat. If it gets clogged over time or allowed to idle sitting still it builds tremendous heat on the left side. So much so that i have seen tire pressures increase on that one tire just from sitting idle staging for Auto cross events. The 100 cell cat did help to reduce these temps I believe that is why the number 3 cylinder is the most common for failing first.
04-30-2010, 02:55 PM
#36
Instructor
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04-30-2010, 03:14 PM
#37
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04-30-2010, 03:48 PM
#39
Agent Orange
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05-03-2010, 06:37 PM
#42
Nordschleife Master
Interesting point that I'm keen to hear more about. The reason being that the P-car specialists I use recommend that the engine undertray is best removed for track work (both for cooling and weight reduction) but the other undertrays (including the gearbox one) should be fitted to reduce turbulence.
