A&Q about 350Z
Q:
No, have other cars 10 years old with no heat shield. No ill effect on paint.
A:
I live in Palm Desert, CA where its 110+ all summer long and have had my '03 Z Redline since August, '02 and not had any paint problems due to engine heat. Road chips are a different story tho'.
A:
The engine heat should be of less concern than the direct radiant heat load from the sun. On that basis, a heat shield isn't going to protect the paint except for a brief period while the car is standing still and the engine cools down. I wouldn't worry about it.
A:
Stop road chips with a clear bra. Two years on my pre-order Z now, and zero chips. Still looks like a new car.
A:
no problem, we have aluminum hoods
Sportscar = 03 Z SS Performance Pure Stock
A:
aluminum displaces heat alot faster than steal, hence less expanding...steal on the other hand, take a guess
Sportscar = 03 Z SS Performance Pure Stock
A:
joe c - i'm not trying argue with ya, but then why do high-end car amplifiers and motorcycles, if not the whole engine, etc. have aluminum fins, not steal...they do run pretty hot...there is a cooling factor involved.
Sportscar = 03 Z SS Performance Pure Stock
A:
foggy: We're talking two different problems here. I understand what you're saying, and agree with your last point. On a volume-to-volume basis, aluminum will conduct heat faster than steel by a factor or 7 or 8. For an extended surface--like a cooling fin--the combination of very high conductivity and low density make aluminum THE choice over steel unless there are structural considerations that favor the steel. You can get by with fewer cooling fins with aluminum or have greater heat removal capability with the same number and size fins versus steel.
That said, if we take two car hoods that are both brought to the same temperature--hot--and are then left to cool, the steel and aluminum hoods will cool at about the same rate. Why is that? Because both are metals, they have relatively high conductivities. For a thin structure, such as a car hood, the temperatures across the section will have relatively small gradients. The numbers driving the time response are the surface coefficients (same for both), the surface areas (same for both), the volumes (same for both), and the volumetric heat capacities (bigger for steel by about 40 percent). The steel will cool a bit more slowly. From the standpoint of the original question on this thread, the aluminum hood is not going to have temperature issues affecting the paint relative to a stamped steel hood. In fact, the aluminum might just be a bit better.
You could make the argument that, if the two hoods are identical except for the material--same shape, area, and thickness for each--that the inside temperature of the steel hood should be higher for a given rate of heat removal from the engine through the hood. The catch, though, is that for the same rate of heat removal for each hood, the outer surface temps will be the same. That is, the temperature most affecting the paint is not going to be better or worse for the aluminum versus steel.
This discussion could get a lot longer, but I think we will annoy folks if we do that. Feel free to shoot me a line on my email. It's a more interesting problem if you consider both hoods sitting in a sunny parking lot. The aluminum is actually a bit better, but it's not a big deal.
A:
Where does the A/E ratio factor into the equation??