Heat Shield install as easy as it says? Part necessary?

[PDACPA]

Was thinking of buying this part from the "Recommended" section of Pelican.

http://pelicanparts.com/catalog/shopcart/911M/por_911M_911rec_main.htm


It is the Heet Shield.

Is it as easy to install as the instructions say?

Do I have to remove any exhaust components?

Is the part worth putting on?

[Joeaksa]

Would as well love to hear from someone on this if it worked.

I would think that if it really worked, Porsche would have done it years ago...

Joe

[Bill Verburg]

They do work and the factory did use them. Heres' a pic looking backward at the headers and left side oem 3.6 heat shield.



I need to modify/add to it to shield the 'S' hose from the header heat. It needs a horizontal piece which I havn't gotten around to fabricating yet.

Sherwood has some other pics from some older RS or RSR cars with similar setups.

[911pcars]

As Bill pointed out, Porsche used them in some of their race engines as well as the current 993/996 vehicles.

Here's a photo taken a few years ago of a GT2 engine at Porsche Motorsports (next to Andial) during a rebuild ....


.... and a Motorsports normally aspirated engine from p. 193 of Bruce Anderson's Performance Handbook.


BTW, Wayne's (PelicanParts) webpage description of an "up to 40ºF" difference between no HeetSheet and HeetSheet installed is not yet updated. The long-term, road-tested difference is 80ºF (300ºF in front of the shield and 220ºF behind it), measured on my 2.7 "RS" engine (Webers/E-cams). In addition, I've measured the surface temperature of the heat exchanger near the valve cover area at around 380-400ºF. Catalytic converters and turbochargers can get much warmer than this.

PDACPA,
To answer your questions; If I were Wayne, I'd rate it one wrench to install. There are no exhaust components to remove.

Hope this helps,
Sherwood Lee
http://members.rennlist.org/911pcars
www.seinesystems.com

[CamB]

I think I have asked this before, but I'm going to ask again

Are there any (clearance) problems installing the HeetSheet with a twin-plug engine?

Cam

[Superman]

I hope I'm not giving away any secrets here, but I think Warren is fabbing heat shields out of titanium. Apparently, titanium virtually WILL NOT pass heat.

[911pcars]

Cam asks:
"Are there any (clearance) problems installing the HeetSheet with a twin-plug engine? "

Besides the heat barrier properties for the engine, the shields block high temps. that might melt the twin plug wires and connectors. No clearance problems. The shield provides a 1" air space in front of the lower valve cover; two bolts to R&R.

Regarding Warren's titanium shield project: Ti is probably the best as well as least expensive of the exotic materials to use in this application - but still quite expensive. Stainless is right there and more plentiful. Here are some coefficient of thermal conductivity numbers in W/mK. Lower numbers are best. Data is at http://www.seinesystems.com/BrakeFade-2.htm and at http://www.matweb.com/

Aluminum 7075-T6 alloy: 130
Stainless steel 304: 21.5
Titanium CP, commercially pure, Grade 2: 16
Titanium 6Al-4V alloy, Grade 5: 6.7

[Targa Dude]

They are relatively easy to make..I made mine out of Stainless steel.. and they do seem to work.. I noticed a temperature drop of about 7 Deg F after I installed mine.
and easy to install..too.
Now titanium thats a little harder to find in small pieces and costs a bit more than S.S.

Jorge (Targa Dude)

And if you purchase them I feel are very reasonably priced. I have recently seen them around for about $50.00 to $70.00

[Jim Sims]

While not zero, Ti-6Al-4V alloy has about 40% the thermal conductivity of 304 stainless steel; specific heats are about the same. I don't believe that differences in thermal conductivities in the metals used in these applications matter much. The material is so thin that once up to operating temperature there is probably little temperature difference from side to side. What is important is that the heat shields retain their reflectance/absorption properties in the environment they operate in. They need to keep reflecting the radiative heat back to the headers and to do this they need to remain shiny and hence not corrode. The also need to be kept clean; oil dripping and coking on them will degrade their performance as will road grime. Titanium is light and corrosion resistant; fabrication can be difficult because it work hardens rapidly plus titanium is expensive. Stainless steel is a good choice but I suspect anodized aluminum would do well too especially if one could put durable selective surfaces on it: high reflectivity on the hot side (towards the headers) and poor emittance on the cold side (towards the valve covers). Another issue with these heat shields is to ensure they don't adversely block the clearing of the heated fan driven air off the bottom of the engine. One has to be careful one isn't making a scoop that will redirect hot air back up and onto the cylinder and head cooling fins. Cheers, Jim