mattstang2007

Hey guys i was thinkin about this earlier. I think i lost about 20-30 rwhp from bad heatsoak. When i say bad i mean driving for and hour and a half sitting in the direct sun for about 40 mins then getting dynoed, temp was right around 85 or so. So what do u think, how much rwhp do u lose from bad heatsoak.

Blacksmoke

Not sure on common number loss but I do know you DEFINITELY can lose numbers.
Driving that long in hot weather before going on a dyno would really show a loss in my opinion.

Sounds like you are gonna need another run on the dyno without heatsoak to get more accurate numbers.

mattstang2007

Yeah i want to try and find a local dyno and get it dynoed when she is actually at a low temp. I am pretty sure i lost alot of rwhp that day. Thinking about getting water wetter or purple ice to try to help.

Meatloaf of Mass Destruction

Not sure heat soaked is what your describing. Usually when people talk about loss of performance from heat soaking its in a FI application. This happens when the intercooler is pushed beyond its limits and can't cool the compressed air sufficiently (or in non intercooled sc). As a result the air/fuel mixture is to hot and detonates early thus the loss in power or worse.

If your car was operating at normal temps then I think your loss is from something else...

smokestang

Heatsoak effects all motors! higher underhood temps are proven to reduce horsepower.

Nuke

+1

I'd be curious, too, to see some real-life #'s.

GRABOID

Yep and the 5.0 is hot as hell under the hood. Or at least it seems that way to me. I am looking into some venting for sure.

Blacksmoke

Feel free to vent away on this forum.

Get it?

Lifter583

The biggest problem of hot air is the air density... which means as air heats...it expands...less oxygen per cubic foot of air...after 70 degrees F...it really begins to show...altitude and humidity are other big factors...

Meatloaf of Mass Destruction

OP you said the numbers fell short 20-30hp, did you have a base hp from another dyno pull, where did this come from?

Yes all engines can experience loss of power from increased air temp and altitude but that is not heat soak. That is lack of power from changes in oxygen density.

Heat soak results from a cooling component for the engine (intercooler/regular coolant system) becoming overwhelmed by a condition of use. Typically this happens in two ways, 1) you overworked the intercooler so that air/fuel mixture is to hot or 2) you have shut the car down after heavy use. As a result coolant is no longer circulated and the engine block still retains a lot of heat. If you watch on some cars the thermostat on a very hot day after driving for a long time will actually go up for a short period of time after shut off, this is why people pop the hood after runs at the track.

Maybe you experience the second given the long drive and hot day?