Dodge Ram Grille Block: Upper & Lower

[slowmover]

"Hard to read" I finally know the "range" of the stock coolant gauge on the Dodge, that the lower operating limit is 160F due to the Ultragauge.

The grille block makes temp rise rapid and sustained. Hitting the highway on a cold morning used to stop temp rise in it's tracks.

[ron]

I could read the darn thing , if I could see it,Its just past my vision so its a blur, the scan gauge is closer so I don.t have to wear the cheaters while I drive

[ECONORAM]

Originally Posted by Diesel_Dave

I never got the chance to do A-B-A testing and quantify it. I doubt the effect is that large, quite honestly. That being said, it's hard to see how it would hurt.

I did some searching tonight, and it seems the prime benefit of the grille block is the faster warm up time and higher operating temps...which means the engine is more thermodynamically efficient?

Originally Posted by steve05ram360

I did a 75% block in an effort to get a hotter IAT, managed 20*f over ambient. With the grille block in place & hotter intake air I still ran a 20.2 mpg with ambient air temps about the same for both runs (no aba). My truck is real consistent at 20.2 mpg for some reason. I can say though that around town throttle response is noticeably better with the grille bock in place & warmer IATs.

Interesting on the throttle response, and the fact your IAT went up.

[Diesel_Dave]

The grille block should not affect the final operating temp--that should be determined by the thermostat. If the grille block is increasing the final operating temp, then it's too much.

There's basically 3 "stages" the engine potentially goes through:

Stage 1: Thermostat closed.
When the coolant temperature is below the "crack open temp" the termostat is closed and the coolant is not sent to the radiator at all. Usually the "crack open temp" is the temp a thermostat is know as--a "190 deg stat" starts to open at 190 deg F. In some cases, the thermostat is designed to let just a trickle through the thermostat to prevent air build up, but it's basically closed for all practical purposes. The coolant bypasses the radiator and goes right back to the block. In this stage, the coolant is getting warmed up by the engine and the only cooling that happens is due to the air passing through the engine compartent around the engine. This is how the grill block helps the engine warm up faster--less air through the engine compartment means less heat loss, so it warms up faster. The radiator doesn't really matter at this point because there's basically no coolant flowing through it.

Stage 2: Thermostat partially open. Once the temp gets to the crack open temp, the thermostat starts to open and some coolant gets sent to the radiator to be cooled. And some still gets recirulated to the block. The coolant that gets sent out to the radiator comes back to the block and (eventually) lowers the temp up by the termostat. This thus gives closed-loop feedback control--if the coolant temp goes up the thermostat opens more, which lowers the coolant temp, which cause the thermostat to closes more, which causes the coolant temp to rise again, etc. During this time, the coolant temp usually stays a ~10 deg F or so above the crack open temp. There will be some fluctuatin, but it should stay fairly steady. As long as your grille block hasn't over-deminished the cooling capability of the radiator, you should stay in stage 2 after the engine has warmed up. The temperature range should remain the same as it did without the grill block.

Stage 3: Thermostat completely open. This is the situation you want to avoid. If the coolant temp gets very hot, the thermostat has opened all the way, sending the max amount out the radiator--however, the coolant temp keeps going up. If the radiator doesn't have enough cooling capacity to cool the coolant, there's nothing to stop the coolant temp from continuing to rise. Many control modules are set to turn the fan on at this point--the purpose being to pull more air through the radiator and cool the coolant more. Either way, this is not good. If you see the collant temp continuing to rise above the normal range you've got too much grille block.


So, the benefit of the grille block is 1) slightly faster warm up times and 2) Less aerodynamic drag from less air flow through the engine compartment. The final operating temp of the engine should not be changed.

[slowmover]

Well done in clarification, thanks.

[rdefayette]

I see everyone checking coolant temps but (unless I missed it) didn't see anything a IAT.
Intercooler (charge air cooler) requires airflow to drop IAT.
No matter how you cut it IAT almost has to go up.
my 0.02

[skyking]

It will, but it is dependent on boost pressures. At cruise speeds and low loads, my engine will barely break 4 PSI. Under full honk it was 22 PSI, before mods. I have enough cooling air flow for the worst condition, all the time.
What I propose to do is tie the louver control to coolant temp, and have a boost pressure override system that will open things up with a boost pressure servo, as needed. I will monitor pre- and post cooler temps.

[steve05ram360]

Originally Posted by rdefayette

I see everyone checking coolant temps but (unless I missed it) didn't see anything a IAT.
Intercooler (charge air cooler) requires airflow to drop IAT.
No matter how you cut it IAT almost has to go up.
my 0.02

IATs are well within limits. I have been monitoring them as part of all the testing I have done. In fact, with ambient air temps in the 40's I'm lucky to get them up to the mid-upper 60's. I mentioned this elsewhere that my motor runs noticeably stronger the warmer the IATs are. Been looking for an 80~85*f IAT temp to do the test run with but cant get much above 70.

[rdefayette]

Correct if I'm wrong but from my past experience is not the greatest power/effiency achieved when there is the greatest differential between IAT and EGT temps?
ie. The bigger the difference the better.
Understood the IAT is within the "limits" but shouldn't lower temps be better.
Doesn't compute what you are seeing with higher IAT, running stronger.

[steve05ram360]

Originally Posted by rdefayette

Correct if I'm wrong but from my past experience is not the greatest power/effiency achieved when there is the greatest differential between IAT and EGT temps?
ie. The bigger the difference the better.
Understood the IAT is within the "limits" but shouldn't lower temps be better.
Doesn't compute what you are seeing with higher IAT, running stronger.

Not sure about the IAT & EGT temps... as we all know colder is better for a gasser, for diesels I could not find anything that pointed me 1 way or another so I figured I'd raise it as much as I could and see how it runs. I figured with higher temps the burn would be more complete resulting in a stronger feel to it. I was presuming that the fuel economy would go up with it like that but havent proved it to myself yet.

If you have a scan tool of some sort you could experiment with it and see what I mean.