How does a grille block improve warmup time?

[fanamingo]

I've been reading about the benefits of adding a grille block. The two advantages I see mentioned are improved aerodynamics and decreased engine warmup time. The first makes sense to me (air flows around the car instead of through the grille and radiator into the engine bay), but I don't quite follow the second. Obviously cold air entering the engine bay will affect the engine temperature to some extent, but is it really a significant amount? It seems to me an engine working to propel a 2,000+ lb vehicle isn't going to be affected much by a little cold air on it's relatively small surface area.

- fanamingo

[AndrewJ]

It's not the engine that's doing the cooling, it's the radiator. And a radiator does one thing very very well (the thing it was designed for). It takes the heat out of your coolant and transfers it to the air that is passing through your cars grill/engine bay. If you block out most of that cold air, the air coming through your grill (and the radiator directly behind it) then you've just saved a bit of heat from leaching out of your radiator before the engine's warmed up.

Now if you want to get all technical, sure the thermostat keeps your coolant all locked away inside the engine block until it warms up sufficiently, but you must remember that once that temperature is reached all of that cold coolant from the rest of the cooling system has to be cycled through and warmed up. If you keep the rest of the coolant from getting unnecessarily cooled down, you'll get your engine (and all of it's coolant) warmed up quicker.

[fanamingo]

Originally Posted by AndrewJ

...but you must remember that once that temperature is reached all of that cold coolant from the rest of the cooling system has to be cycled through and warmed up.

This was the part I was missing. Thanks!

[diesel_john]

Within reason the hotter you can keep all the fluids the better. A complete block until warm then partial, just so the fan doesn't turn on. For the same reason an air dam and splitter keep the gear boxes warm. The choke equivalent is on until warmed up. O2 sensors must up to temp before ECU goes closed loop.

Too hot and I ruin't the rear main seal. (+250 oil bad)

I am goin'a try heating the gasoline, one of these days, how hot is too hot any suggestions.

[MetroMPG]

I tend to respect what Tony has to say at http://fuelsaving.info - and one of them was that fuel heating - to the point of total vaporisation - gave minimal results:

I have even tested a device that completely vaporizes the fuel on a heated surface*, eliminating fuel droplets altogether, and the economy improvement was tiny (1 - 2% at most).

http://www.fuelsaving.info/atomisation.htm

[Daox]

You should also take into account that most engine components (block, head, tranny case) are all made of aluminum, a very good heat conductor. By reducing the airflow over their surface you'll make them heat up faster as well. It may not be a huge surface area, but its not small either.

Just to clarify, the coolant in the radiator has no bearing on warm up time (other than keeping the engine bay warmer which is a factor too). It is only used for cooling. You will never heat it all up to operating temperature. If you did, you would overheat the engine.

[diesel_john]

I tend to respect what Tony has to say at http://fuelsaving.info - and one of them was that fuel heating - to the point of total vaporisation - gave minimal results:


Quote:
I have even tested a device that completely vaporizes the fuel on a heated surface*, eliminating fuel droplets altogether, and the economy improvement was tiny (1 - 2% at most).

http://www.fuelsaving.info/atomisation.htm

MetroMPG you are awesome. This Tony guy talks pure truth.

[AndrewJ]

Originally Posted by Daox

Just to clarify, the coolant in the radiator has no bearing on warm up time (other than keeping the engine bay warmer which is a factor too).

True, but that cold coolant has to go into the engine sometime. Think of it this way: Its 32 (F) outside and you're driving around, your coolant in the radiator cools down to 15 degrees (F) if you have a just-warmed-up-engine you probably don't want to send 15 degree (F) coolant coursing through it. It won't help. If you can keep that coolant from cooling down in the radiator you'll get into closed loop faster.

Plus, all of this is taking place in *real* cars. I don't know about you, but I've never owned a car that kept all of the "warmed" coolant in the block until it was fully warmed up. I say this because every car I've owned will put out a small amount of heat from the heater core before the temp gauge shows a "warmed" temp.
There's always going to be a bit that leaks past the thermostat and manages to get into the radiator or heater core. So you don't want any of that leaked heat to get dissipated into the atmosphere. Heck, you paid for that heat with your gas money, a grill block just helps you keep hold of your investment.

[MetroMPG]

Originally Posted by diesel_john

This Tony guy talks pure truth.

Hmm. That may be... but I just realized I posted that tidbit in the wrong thread to begin with!

I thought I had posted it in response to someone who brought up fuel line heating and mistakenly put it here instead. And now I can't even find the original thread it was meant for.

Computers! They're hard.

[MetroMPG]

On topic for this thread: another warm-up advantage to a grille block relates to the transaxle in a FWD car. With less cool air rushing through the engine compartment, it stands to reason it will warm up to a higher temperature than it would minus the block. That's a good thing.