The majority opinion among the experts I spoken with is at the main cause of the heat soak is inadequate intercooling from the stock intercoolers.

And that couples with the protections built into the GIAC stage 2 tune to ensure the intake air temperatures don't get too hot and ruin engine/turbos.

It appears that the back pressure of the europipe with its 109 cell cats is not significantly higher than a catless exhaust would be so that does not seem to me to be the primary culprit.

The experts I spoke with also don't think the IPD planning is the major source of the issue either. They think it is the intercooling.

I can't tell you how much I'm looking forward to getting those Champion intercoolers when they come out to see if that solves the problem

 

I agree that data is needed; however your theory that heat soak is "not sensible" is poor. I also think that your understanding of heat soak and how it affects IATs is fundamentally flawed. I never said that the IPD was a heat generator but it does store heat. Champion MS saw IATs of ~180F at full chat with stock ICs. That effectively heats your plenum, charge pipes and ICs to 180 at full boost. When you come off boost, the heat sinks to the air passing through it, exactly as you said. For a period of time the plenum is hotter than the incoming air, exactly as you said. The IPD is indeed a conductor exactly as you said. What you want in your intake tract after the intercoolers is an INSULATOR (unless your engine bay is freaky cold and somehow also free of IR sources). Your "conjecture" only serves to further my point.

When you turn on your hot water at the sink it takes time for the tap to run hot because the water has to heat up all the piping between the heater and the faucet. Now, if you immediately ran cold water through those same pipes it would take time for the water to cool back down because it is absorbing energy from the hot pipes. Nothing about that is "not sensible" or imaginary. This is a perfect model for your intake system alternating between boost and atmospheric pressure. The more thermal energy storage capacity in the system, the more heat soak you get. If you wanted your water to run hot immediately and then cool back down immediately, you would want thin walled plastic pipes. Not heavy metal pipes.

Do yourself a favor and look up the specific heat of ABS plastic versus aluminum. Now assume a 6lb aluminum slug (IPD) and a .5 pound ABS tube (stock). You tell me which stores more total thermal energy. The metal plenum is not "the" source of heat soak as you said but rather "a" source of heat soak as is any material in the entire intake tract including the charge pipes and intercoolers. The idea that adding a 6lb slug of aluminum into your intake pipeline won't affect IATs is ludicrous. It will absolutely extend the amount of time it takes for IATs to drop after coming off boost. You are adding more heat storage capacity to the intake tract which is the diametrical opposite of what you want. In a perfect world, the intake tract wouldn't absorb or store any heat from the charge air. Plastic achieves that goal MUCH better than cast aluminum.

I understand that you have an engineering background from a PM you sent me a while ago. With that in mind, I have a hard time understanding why you continue extolling the virtues of your FVD setup and IPD plenum when your car belches black smoke under load from running pig rich. I don't really trust you as a valuable source of information about what is and isn't good engineering when you are driving a $175k+ car that has been modded to produce soot in exchange for moderately improved 1/4 mile times.

Heat soak is primarily caused by metal intakes. Period. This is why racers ice their intakes between runs and/or install phenolic (insulating) spacers between the upper and lower intake manifolds.

- Patrick

 

It did that on start up on a cold day, what would you expect. If the car ran pig rich, the back end would be black but it's not and it doesn't. I am not extolling anything, I am simply questioning your unsupported claims about the IPD plenum. What I am saying is that my car doesn't really show any significant issues with heat soak given a reasonable cool down interval. The problem the OP has is unique to his car. No one else is reporting this kind of degradation.


The plenum is part of the whole intake, the rest of it isn't metal. However, you failed to answer my point about the temperatures.

Here is what IPD says on their site about the question of heat soak.


So you are agreeing with me and not able to support your own conjecture. You have no theoretical basis for claiming the IPD plenum is a source of heat soak and no data either. I am not defending IPD, simply calling into question your claim.

I am calling for you to support your conjecture about the IPD plenum. Either back it up with facts i.e. an actual heat transfer model and simulation or data from the field or stop making the claim.

My car actually has seen it's trap speed increased by 10mph since I first got it. Those are significant gains. I stand by the configuration. It performed well at the track on a hot day in July while other cars had to quit early because of heat soak. It also performs well at the drag strip with some degradation after four or five runs. However, allowing an hour of cool down addresses that issue as well.

 

Wow. Quoting ad copy in an engineering discussion. I give up.

If you can't understand that hot air flowing through a metal pipe heats up the pipe then I can't help you. If you can't understand that cold air flowing through a hot pipe gets heated on its way through then I can't help you. If you can't understand that telling me your car runs fine if you let it cool down first is just definitive proof that you have heat soak then I can't help you.

- Patrick

 

None of that supports your claim. It's like saying the sky is blue when the sun is out and there are no clouds. What hot air is flowing through the plenum? Where does the air come from that flows through the plenum?

All cars will suffer some heat soak to a degree but not like the OP and you have decided that the IPD Plenum is the source of the heat soak problems with the OP's car. In fact, it's more likely the tune and not the passive element.

The stuff I cited from the IPD site isn't ad copy, it's from the FAQ since apparently this claim has been raised before. They are answering your claim and contracting it.

 

If you can't understand where the air that's passing through the plenum came from and why it is hot then I can't help you. And please stop mis quoting me. I never said the IPD was the only source of the heat soak. This is the second time I have had to correct you on that. Now for the third time... The IPD is not "the" source; it is "a" source.

- Patrick

 

Oh sure, it's a source but not a significant source and not the reason for the problematic heat soak suffered by the OP. Let's hope he gets his problem solved.

 

Thanks. The experts all think that the main issue is the lack of adequate intercooling.