Heatshield Purpose ?!

crankshaft · August 3, 2004, 22:03

Previously I always thought that the heatshields were to shield heat from the engine bay and prevent owners buring themselves, but now I'm not sure !

Could it be that the heat shields are there to keep the heat in the precats and ensure that they get up to temperature as quickly as possible

It may very well be the case that removing the shields would allow air to circulate more freely and that the engine could run cooler

Unless of course you know different...............

Crankshaft

Anonymous · August 3, 2004, 22:07

i think the heatshilds are designed NOT to let heat out, keeping the engine bay as cool as possible. also i beleive the hotter a cat gets, the more efficient it is at its job and the cooler it is will help the performance

Tem · August 3, 2004, 23:49

Quote from: "Tomr2"i think the heatshilds are designed NOT to let heat out, keeping the engine bay as cool as possible.

Yeah, that's what they do. Also, the hotter the exhaust gases are, the faster they move and the less they restrict the movement. If the gases cool off too much, you actually start losing power...

The precats will always be hot enough when the engine is on as the exhaust fumes really have no time to cool off before hitting them.

The main cat does take some time to get hot enough to operate. There are also heat shields after the precats and even after the main cat and muffler, so they can't be there just to keep the cats warm s8)

s8)

Anonymous · August 4, 2004, 00:07

i suspect that some of shields act as extra protection to prolong the life of the main cat as driving through a lot of water wont do it any good

Tem · August 4, 2004, 00:12

Quote from: "Tomr2"i suspect that some of shields act as extra protection to prolong the life of the main cat as driving through a lot of water wont do it any good

Yeah...and I bet one major reason is why it's sometimes called a grassfire stopper s8)

s8)

It gets glowing red after some hard driving s:o

s:o I guess it doesn't normally show, but I took all the shield off while trying to find a mysterious rattle...

Anonymous · August 4, 2004, 00:15

mines all gone aswell now too, as mine had all corroded and were rattling like mad! still got a little clatter at 2000-3000rpm though s:? :? s:?

Tem · August 4, 2004, 00:56

Quote from: "Tomr2"still got a little clatter at 2000-3000rpm though s:? :? s:?

Uh...probably the same I have then s:? :? s:?

I'm 100% sure it's not from the exhaust or its heat shields though, as I now have a PPE header with custom exhaust...and no heat shields.

My first guess after that was the huge heatshield between exhaust and rear bumper, but wasn't that either. Next I removed the heat shields around the intake piping, but wasn't that either. Then the odd pieces from right side of the bay and still got the rattle.

Go figure, I'm out of ideas s:? :? s:? Let me know, if you figure it out...

Anonymous · August 4, 2004, 13:16

could just be the oil thats in there? ive no idea whats in mine. or could it be a loose pre-tensioner belt? or something to do with the vvti as that kicks in at 2000rpm IIRC

Tem · August 4, 2004, 17:23

Quote from: "Tomr2"could just be the oil thats in there? ive no idea whats in mine. or could it be a loose pre-tensioner belt? or something to do with the vvti as that kicks in at 2000rpm IIRC

Pre-tensioner crossed my mind, but I've had it changed for the newer one, which is supposed to be troublefree.

VVT-i is always active, even at idle.
(not 100% sure about stock ecu, but for sure with PFC)