pressure sensors for testing grill blocks?

[jonr]

Ok, I tried it and got 33% drop in mileage for the first two miles after a cold start. At that point, it is warmed up. So a cold start in summer costs me about $.11.

You might get slightly quicker warmup and save $.03 per trip.

Sounds like the total potential for FE improvement relating to engine compartment air flow is about 4%. I expect that covering the entire area below the engine would be the most help.

[NeilBlanchard]

Hello Jon,

Originally Posted by jonr

Ok, so what does this gain you? The purpose of the thermostat is to allow the car to heat up quickly and so you don't need to block radiators to get this.

It gains you several miles per gallon, because of better air flow over the nose of the vehicle. My car improved ~5mpg because of the upper grill block and flush lens on the fog lights.

[NismoMax80]

i completed my grille blocking today. i did it mostly for aero, but my setup should increase the cooling of my radiator as well. i have a large opening below and my radiator is almost completely sealed all around so all air hits it.
check it out:
Help details of my underbody/front

if you're trying to warm your car faster, simply driving it right away like a hypermiler should will warm it far faster than the morons that sit and idle all morning long.
ironic people think sitting there is better for the engine, when it's worse for everything.

[jonr]

I would be interested in several repeats to verify your 5 MPG savings. It sounds like you eliminated approximately 25% of the total wind drag with simple changes.

[Xringer]

"pressure sensors for testing grill blocks?"

What you are testing for is radiator air flow. So, why not cut out the middleman and just measure the coolant water temp?

It works for me. And one of the trip meter parameters you can display is the
max water temp for your trip. When I don't get stuck in traffic, it's always
under 195deg. Meaning the (200deg) fan didn't come on..

Cheers,
Rich

[NeilBlanchard]

Hello,

I've kept a fuel record since I bought the car over three years ago. My average for the first three years was 37mpg, and the highest tankful was 41.8mpg.

Now since doing the mods (and driving a bit better) -- you can see in my sig what my 90 day average is, and my new high for a tank is 46.69mpg. The most recent six tanks have averaged 45.5mpg. So, the improvement is really at least 5mpg, and it could be argued to be 8+.

The interesting thing is that not only does better aero help for steady speed driving -- it also improves coasting, so that you can coast on gentler hills where you could not maintain speed before. So, sometimes small improvements yield better results than you would think.