More HP from cold air?
 

Do diesels develop more power with colder intake air? I swear now that the air is cooler mine ('81 non-turbo) has more pep off the line.:D

I know that colder air is denser and a lot of 60's/70's gasser muscle cars used to have ram-air hood scoops and stuff, but does this also work on diesels?

No, power is determined by the fuel.

What is happening is the barometric pressure is higher which affects the ADA/ALDA the same way a change in altitude does. The engine is not gaining any more power, the injection pump is allowing you to have more throttle (fuel).

A diesel can make more power if it has colder intake air...........the air has more oxygen and can combust with more fuel. But, on most engines.........including yours..........the engine doesn't know the air temperature and cannot make adjustments in the fuel delivery.

Thats exactly what I said in my post.

Surprised FI is wrong on this one....

Any engine needs two things to become closer to 100% Volumetric Efficiency (VE). More oxygen, and more fuel. Denser (cooler) air has more oxygen molecules in it per cubic inch than hotter air.

With a turbo car, it makes slightly less difference, as the turbo heats the air as it compresses it, but, when you start off with more oxygen per CI, you finish that way too. That produces a hotter flame in the combustion chamber, which acts on the piston/rod/crank with more force. That produces more HP.

We're talking maybe 1-2 HP in a standard passenger car with no intercooler.

Ram air is different from a cold air intake. Ram air is a kind of forced injection; the faster the car goes, the more air is forced into the intake, allowing the engine to burn fuel faster. Ram air does give you the advantage of having cold air enter the intake, but I think that the greater advantage is the increased amount of air that's supplied to the engine.

No, I'm not.

Read the first post and you will see the OP has a non-turbo car, the air is not being heated at all on his car.

Not to mention that NONE of the 60's or 70's RA stuff worked. Purely cosmetic..

Then you're doubly incorrect...


Cooler air, more O2 per CI. Period.

Which means YOU are incorrect.

No doubt but it makes ZERO difference when power is limited by fuel quantity, not air volume/density/temperature.

Wrong again, the entire jopb of the fuel pump is to provide a greater volume of fuel given the needs of the engine.

In this particular case, with no electronic sensors, the engine burns slightly lean, which, in turn, makes more power untill detonation.



Ran a fastest street car shootout for a season, been drag racing for 16 years now... Had a low 10 second 70' GTO with a NA Pontiac motor making 700 hp... I know a couple things.

You may "know a couple things", but apparently not about Diesels. There is no such thing as detonation on a Diesel and the pump has no way at all to adjust fuel quantity for air temperature.

What works for a g@sser does not always work or apply to a Diesel.

But in this case it does, and you know it. As do I...

I doubt it based on post 11.

..........and we thank you for your support.........:D