Beho88

Can anyone give me some facts on why our cars are so prone to heat soak? What is an effective way to reduce it? I searched but havent found the reasons why...and as far as ways to help it was just the hondata intake manifold gasket. All responses are greatly appreciated. Thanks!

darcyw

I'm no engineer, this is how I understand things.

To help reduce the power reduction, run high octane fuel to help reduce the ECU's tendency to retard the timing so much. By retarding the timing, the ecu prevents damaging detonation in the heat soak situations. I suppose you could try methanol injection or water injection to cool the intake charge and thereby reduce this effect. Effectively the water/methanol injection raises the octane rating- the resistance to detonation- of the fuel.

am i making sense?

darcy

starchland

The IM does get hot. It may affect the IAT sensor in that its giving the ecu inaccurate info on the real intake air temp. Maybe part of the reason later models had the sensor relocated. Make sure car is maintained/adjusted to limit any possibilities.

mattstryfe

This is interesting. I had never heard of this before. Thanks for pointing this out.

I still feel as though the temp of the IM does affect the ambient air that passes through it. Perhaps though, as you point out, it's not AS MUCH as the readings would suggest. However, regardless of the air's actual temp, the CPU will retard because of the inaccurate reading.

Do you, by chance, happen to have any documentation or links with some information regarding the false readings? I would be very interested in reading them.

IATemps are sort of... well.. an obsession of mine. I have done extensive testing and would appreciate any new information anyone can provide.

As far as the OP's original question:

Quote:

Can anyone give me some facts on why our cars are so prone to heat soak? What is an effective way to reduce it? I searched but havent found the reasons why...and as far as ways to help it was just the hondata intake manifold gasket. All responses are greatly appreciated. Thanks!

There are a few things you can do. Check this post. I replied with a few techniques that I have found that worked.

I am in the process of creating something revolutionary that will solve this "once and for all". However, I am currently moving to a new location and it has slowed me down quite a bit. More to come on this. =)

-Matt

starchland

Me too, I am always watching my IATs from my obd2 reader and thinking of ways of getting them lower. I have yet to try relocating the sensor somewhere less prone to it getting heatsoaked. But then again, I dont really have any need to.

A few things I have done. I have cancelled flow of coolant through the TB and IACV. This seemed to have the biggest effect since now I can rest my hand on the IM after a drive. I don't have any measurable documentation would be worth while...its real tough to test in an uncontrolled environment especially where ambient temps are always changing.

Some observations: Ambient temps have the biggest affect on IATs and whether your moving or not [obviously]. IATS drop much faster after removing coolant flow. Heat from the IM seems to clear out faster after being stopped.

It would be nice to datalog IAT v. Ignition retard

Edit: To the op, rule out any mechanical issue. VA,clean the map, and the small passage,etc.

rob-2

This isn't your mothers family sedan...

The best way to avoid heat soak is not to stop.

On days 100-110f I really notice the heat soak problem when taking off from the light on the way home from work. However on the open freeway I don't notice much of a difference. People are going to debate the density of the air at different temps. By all means. At the track it's not an issue for me either.

xviper

Back over 10 years ago, someone on this forum created a "revolutionary" mod that could have changed the course of S2000 heatsoak history. It was a beautiful design and he was all tooled up to make a bunch of them. He posted pictures which he also sent to me and I still have but since I'm not a member anymore, I don't have the ability to post them here. He did tests and it worked extremely well but back then, S2000 owners were just coming to grips with this thing called "heatsoak" and weren't understanding enough about it to buy into this guy's new invention, even after my 2 extensive posted experiments. He was prepared to send me a sample for testing but I believed him and declined. It was a gorgeous piece of work and very effective.
I had also come up with a very simple and revolutionary invention called the "Radmat" that virtually eliminated this problem. I even made over a dozen and sent them to various people who asked for it. It cost 5 bucks shipped. Unfortunately, it was quite UGLY and most owners didn't want to have such a hideous thing under their hoods. Then came commercially made "cooling plates" that a lot of S2000s now sport. However, though the concept is the same as my Radmat, it didn't have any insulating capabilities and was thus hampered by design and by horrendous pricing.
People know that heatsoak exists but they still don't understand why and how it manifests itself in lowering this engine's performance. It's not a hard concept but it's one that seems to elude most people. I've given lengthy dissertations in the past and I'm just not interested in doing it anymore. People don't care for the explanation anyway. Rob understands the concept and he knows how to deal with it without fancy add-ons. He knows how to drive the car to minimize and eliminate it. So have I. Let's just say that rather than become too obsessed over IATs, an understanding of torque and power curves, what the car needs in terms of Tq and Hp to operate under various conditions and how air temps affect this and how the ECU tries to compensate for it. Everyone should know that X degrees rise in air temp going into an internal combustion engine equates to X Hp reduction. Factor this into Tq/power curves and you'll get the whole picture. It's part rocket science and part Voodoo but most kids these days get some rocket science in grade school, so this shouldn't be a big problem.
Oh, and let's not get sucked into buying those little Radio Shack resister mods that plug into the IAT harness to fool the ECU into thinking the air temp is always low. Those are garbage. They cost 50 cents to make and scammers sell them to victims for as much as 50 - 100 bucks.

cdelena

Driving in city traffic with ambient temps at pavement level over 110F it was easy to have heat problems on my '00 model. I eliminated the issue with a number of changes...

- the radmat or intake to reduce heat from the radiator warming the intake.
- a 180 thermostat can keep the coolant a somewhat cooler but under severe conditions any thermostat will be wide open so it make no difference.
- the hondata intake gasket really does make a difference.

- the thing that totally eliminated heatsoak symptoms was the Mugen ECU that has maps that run richer. Drivability under all conditions is improved and the only downside from me is having to swap in the OEM box every two years to pass the emissions test.

I get the impression that AP2 cars have less of an issue and now that I live in a cooler clime it probably makes little or no difference.

zeroptzero

I definitely agree with this. One of the best ways to get intake temps to drop is to open the throttle on my car, as throttle opening decreases intake air temps increase. Going WOT you will see temps drop quickly. I think the oem temp sensor picks up erroneous intake temps from the heat of the engine/manifold rather than the actual air flowing into the engine. What is happening is that the intake air on my car is very cold and as you open throttle it removes heat from the manifold and the temp sensor temps drop quickly, as the throttle closes the manifold temps increase quickly.

While the ap1 temp sensor measures air temps closer to the intake valves, I think the ap2 measures actual air temps more accurately. I think I could install an ap2 intake arm and ap2 intake temp sensor and just extend the wiring on my ap1 connector, leaving the ap1 sensor in place and disconnected ?. The only issue I would face is that I have the oem air pump system in place. Just thinking out loud here.

I have an ap1 with a J's Racing snorkel on the oem box. My snorkel is always cold, as is the front half of the air box. Everything increases in temp as you approach the intake manifold. Since adding the intake snorkel my car runs more consistently throughout a hot driving day as compared to my previous oem setup. I might be getting some restriction on air flow with the added snorkel but the lower heat soak issues and added performance consistency is worth it to me. My car doesn't seem to bog down halfway through the day now as it used in the past, it runs more consistently from morning to late afternoon.

I also removed the underhood insulation last year as it was rubbing on my expensive strut bar, but I think it also works to trap heat in the engine bay. 1 lb less weight too , lol. Just my opinion.