Originally Posted by elvisisdead
ANY material will come to equilibrium with engine bay temps. Doesn't matter if it's metal or not. When I did the bwoody experiment, even after 45 minutes - in the summer - in Georgia, there wasn't an appreciable difference in temps.
Umm you might want to check out a lot of data on heat soak. With metal pipes it will raise intake temps.
Here is a great write up on the WKII 5.7
"Well, My other intake thread is getting old and stale and I have new Information that is definitely of benefit to the community here. I have already talked briefly about heat soak, IATs, cylinder airmass and tuning but I would like to expound upon a few things.
First Topic Heat Soak, Intake Air Temps and to shield or not to shield?
Heat Soak occurs when a object is exposed to high temperatures and as a result it's temperature increases. When it comes to making power heat is the enemy because it promotes detonation when means less spark advance allowed and therefore less torque and horsepower output. Hotter air also means reduced cylinder airmass due to the lower density of hot air. The goal when building any good intake setup is to reduce heat soak as much as possible and to provide the coolest IATs possible to the motor so it can make peak power.
How do you reduce heat soak and provide the engine with the coolest possible air? First you move the intake air source as far away as possible from heat sources like the radiator, engine block, and exhaust manifolds as possible. The next and very important aspect is to help prevent heat soak at the IAT sensor as this will skew the IATs up to 100* in some cases.
Now here is what I have found out about heat soak and IATs through data logging different intake configurations.
This may come as a shock to some but there is absolutely no need for a "heat shield" around the intake!!!. In 99% of all cases it will do nothing to reduce IATs.
Why is this? Because 99% of all aftermarket intakes are made of either aluminum or steel which is a giant heat sink and where is the IAT sensor placed on these intakes? Yes, you guessed it, right in the middle of the metal intake pipe!!! Which is right above the radiator. After about 10-15 minutes of engine run time that metal intake pipe will get just as hot as the engine coolant temps (203* in our case) and it will cause the measured IATs to be as hot as 203* which will kill engine performance!!! (The ECM will pull tons of timing advance at 203* IATs). Putting a heat shield around the filter will not help reduce the measured IATs more than 1-2* in this case because the pipe will still soak up just as much heat which will drive the measured IATs way up just the same. Also, our engine bay is sealed up like fort knox (look at all the weather stripping) not much hot air can escape and not much cool air can enter compared to other vehicles out there.
How do we reduce the issues with heat soak? By using less heat conductive materials (nylon crosslink like the factory intake or PVC) or even better by moving the IAT sensor out of the intake pipe and as far away from the engine and radiator heat as possible (this requires cutting and splicing in a couple feet of extra wire into the IAT sensor harness). I have found that by moving the IAT sensor into the end of the airfilter my measured IATs went down anywhere from 25-40* compared to my readings with the IAT in the PVC intake pipe (PVC stays around 40-50* cooler than a metal pipe in the same location). In fact, my IATs are now a mere 6* above ambient which is 10-15* cooler than with the factory intake with the snorkel that pulls air from above the headlight. This is with a open filter in the engine bay no heat shielding whatsoever.
Here is proof. "
This is open filter in the engine bay, no shielding, and IAT sensor in the airfilter. Ambient air temps were 78*. I drove the Jeep 10 minutes before I started data logging and I logged for about 8 minutes then my laptop was low on battery. ECT was 203-205.