Ok, I took my '97 SSEi to my mechanic today for an inspection. Recently, I had just wrapped the stock intake tube with a heat shield. He just called me asking what was the heat shield for. I had to explain the whole heat shield explanation. He insists that it does more damage than good because the MAF is supposed to work at hotter temperatures and indicate to the PCM the correct temperature. Can someone please give me a more technical explanation as to why we wrap the intake tube with a heat shield? Should I remove the heat shield? I thought a good CAI was optimal for performance.

Your mechanic obviously knows nothing about performance....

Hot air is BAD for performance. It is less dense, and need less slightly fuel to reach the ideal A/F ratio. Less fuel in the cylinder leads to less power. Also, higher intake temps will cause increased KR and hurt performance that way also.

Stock air boxes are not designed for performance, but instead a combination of noise reduction, economy, and performance all at the same time. That also hurts performance.

Cold air is best no matter what for performance. Cold air is more dense and the denser air requires slightly more fuel to reach the ideal A/F ratio. More fuel in the cylinder creates more power. A colder intake temp will be colder entering the cylinder also, lowering combustion chamber temperatures and lowering the chance for KR.

Ever wonder why your car has much more power during the winter???

Did you heat shield the stock intake box, or the tube? What is your setup, do you have a gutted stock air box, or is everything stock?



As for heat shielding the stock intake tube? Probably not going to have an effect. The stock accordian tube disturbs the airflow and does not allow it to flow smoothly into the MAF, so any benefits the heat shield would possibly have, are countered by the stock intake setup.

As far as the MAF working at hotter temps and tell the PCM what the temp is? NO, the MAF is just that, Mass Air Flow sensor. All it does is tell the PCM how much air is entering the engine. The IAT ( Intake Air Temperature sensor ) tells the PCM what the temp is. Together, along with several other sensors, the PCM adjusts fueling to achieve the best economy or performance.

So, if you have a heat shield around your stock intake tube, I would remove it. Not because it hurts performance, but because you are not likely seeing any benefit to it. A good CAI setup is the way to go. Custom ones work, but a FWI is about the best way to go.

Why is this in Forced Induction? I don't see that this is a supercharger issue.

I'll move it to the right section for you.

In the meantime, wrapping your intake CAN be bad:
http://www.bonnevilleclub.com/forum/...ake+insulation

Thanks. I'll print your answer and show it to him. I wish some of these mechanics (excuse me, automotive technicians) would just educate themselves a little better in performance issues. Most kids off the street know more about performance than them. Thanks again!

http://en.wikipedia.org/wiki/Mass_flow_sensor

The 3800 uses the hot wire as described in the Wiki article but outputs a frequency signal proportional to mass air flow instead of a DC voltage.

It does not care what the air temp is. Air temp, regardless of performance considerations, is irrelevant to the function of the MAF.

What about spraying the tube with ceramic engine paint?

That will hold heat IN. The opposite of what you want. You need two things on there. One will slow down the heatsoak, the other will let it cool quickly without storing heat.

That'* because most people dont care about performance, they just want their car to run. And most people that do care about performance do their own work. And if you think that'* bad, I had a tech tell me my wifes head gasket was blown. Asked him how he came to that, he said, the computer said so. Really? Is there oil in the coolent? No, didn't look. Is the oil milky or foamy? No, didn't look. Is the block wet with oil? No, didn't look. Were the plugs fowled? No, didn't look. The head gaskets fine. No it'* not, it could die at any moment. 30k miles later it was still running fine. I've only found a few to be trustworthy and knowlagable. The rest dont know squat.

I actually went and felt around my tube after my hour drive home from work and it was cool to the touch and about the same temp as the surrounding air(70s). Not really any heat to speak of. I am running my stock short flexy rubber intake connector, which was only warm to the touch, clamped to an unwrapped/unpainted aluminum pipe with a fabricated wall and K&N cone filter. Not the prettiest, most effective CAI but cheap and better than stock. Still in R&D for sealing it all really welll.

In summer city traffic, it'* a whole new ballgame. That'* why I did this:

http://www.bonnevilleclub.com/forum/...ake+insulation