Heat soak and what it does to your car's power

  • Thread starter JCE
  • 4 comments
  • 83,882 views
JCE

JCE

6,769
Germany
Little Elm, TX
JCE3000GT
So after looking on google for a while I couldnt get a good answer. How does heat soak actuall affect your powerband. A Honda forum says roughly every 10 degrees F air temp = 1bhp lost. Is this accurate? We all know colder air is more dense and makes a better air\fuel mixture, but, how bad is it really for your engine? Also, does it reduce fuel mileage?

If someone knows of a visual diagram I could use to help explain this go my wife I'd be appreciative.

BTW, this heateave we've had has plagued my poor SVT's power. I feel like I'm driving a Yugo right now. My car feels neutered losing over a second on my 0-60 time. :lol:
 
Not only is it the lower air density, as the engine itself gets hotter it doesn't run as efficiently. My car is meant to be most efficient at like 180-190F I think. If its not in that sweet spot the computer will have to adjust timing away from optimal. You compound the issue if you have a short ram intake sucking in air already getting heated by the engine bay. Turbo cars are even worse, but can be helped with intercooler sprayers.

Edit: And its not a better air/fuel mixture, its that you get more oxygen and thus the computer can add proportionally more fuel. The ratio shouldn't be changing.
 
Eric.
Not only is it the lower air density, as the engine itself gets hotter it doesn't run as efficiently. My car is meant to be most efficient at like 180-190F I think. If its not in that sweet spot the computer will have to adjust timing away from optimal. You compound the issue if you have a short ram intake sucking in air already getting heated by the engine bay. Turbo cars are even worse, but can be helped with intercooler sprayers.

Edit: And its not a better air/fuel mixture, its that you get more oxygen and thus the computer can add proportionally more fuel. The ratio shouldn't be changing.
Click to expand...

Ah ok, that makes sense about the air\fuel mixture. Sounds like my engine is just screwed in a Texas summer! Haha, guess there's just nothing I can do that won't cost me a ton on a new intake and or heat wraps...
 
Heat soak is a much broader term than just air intake temperatures. It refers to the engine bay's heat situation in general - how the engine itself absorbs and dissipates heat, how well the coolant system works, how well the oil stays slippery, and of course how much power the engine makes during all this.

The last generation GT500 had really bad heatsoak problems on the race track. It had an iron block, which absorbs heat slowly and dissipates it even slower. It was supercharged. I made a lot of power. It made a lot of heat too, and all that heat has to go somewhere. It goes into the cooling system - temps rise and heat absorbtion drops. It goes into the metals - temps rise, metals fatigue, tolerances grow tighter. It goes into the oil - it breaks down, viscosity goes down, friction rises. Everything in the general area is hot, so the intake air is also very hot, in that particular car exacerbated by the supercharger's compression - the air is thinner and holds less oxygen, the engine becomes prone to detonation, and the computer retards the timing resulting in a loss of power.

So yeah, it screws everything up.
 

Latest Posts

Back