Idea on Auto Adjusting Grill Block

[wolydotmatrix]

Looking good, I have a similar design I am trying to build (less stock looking with maybe a little less drag) Looking forward to seeing your data. Good luck

[AndrzejM]

Originally Posted by Shortie771

Got my MPGuino installed today and it's working great. After a few tanks of calibration to ensure I get accurate numbers, I will do some A-B-A testing.

Does it matter if it's calibrated correctly yet? Wouldn't it still add up to be the same percentage difference?

Percentage difference will be the same so you can do A-B-A with MPGuino not calibrated at all

[toc]

I don't get why it closes at speed.
I thought the theory of the grill is flow through cooling to cool down the radiator instead of the fan.
Thermostat opens, coolant flows through radiator.
Radiator relies on airflow from front of car to cool down, where idle, the fans do this task.

Down the highway at speed, isn't this also a requirement..?

[RedDevil]

Originally Posted by toc

I don't get why it closes at speed.

At speed enough air finds its way to the radiator, even if the grill is mostly shut.
At standstill or moving with the wind there is no natural flow through the radiator, even with the grille open. The fans will blow the air through, but the grill needs to be open or the air would just circle around under the hood.

The size of the grill is based on a worst case scenario; heavy load, high temperature and low natural air flow, like when climbing a desert mountain road.
On the highway there is much more air and just a partial load all the time.

I measure my air intake temperature because I run a fixed LGB. On the highway intake air is usually just a few degrees hotter than ambient. In the city it rises considerably, it may one day force me to stop and remove some blocking.

Apart from that, the aero benefit from a blocked grill has most effect at high speed.

[Shortie771]

Thank you RedDevil for clearing that up. I just got the notification and was coming to answer the question, but you have explained it far better than what I would have been able to.

[shorty_boy]

Looks nice and good work. I was looking to do something similar on my CRX since my front bumper is already cracked. Can't wait to see the test data. Congrats on making it to the front page.

[FastNLoose]

I have an idea of using an aftermarket fan kit that uses a probe on the radiator and an electric choke of a carburetor. The kit trips a relay at a specific temp, run the lead from the relay to the choke coil. Not sure how much force the coil has, but may work if the pressure is equal across the louvers. The temp probe is pushed between 2 rows in the radiator. This just came to me while reading this thread. I may look into this in the fall.

[Shortie771]

Originally Posted by FastNLoose

I have an idea of using an aftermarket fan kit that uses a probe on the radiator and an electric choke of a carburetor. The kit trips a relay at a specific temp, run the lead from the relay to the choke coil. Not sure how much force the coil has, but may work if the pressure is equal across the louvers. The temp probe is pushed between 2 rows in the radiator. This just came to me while reading this thread. I may look into this in the fall.

The reason I didn't do anything like that is because I wanted to keep things as simple and as cheap as possible. I did not want to rely on electronics or motors to control the operation, because if something goes wrong it is too much trouble to fix. Imagine if the sensor fails and you are stuck with a closed grill block that does not open... These are some things I was trying to avoid. Yes, if you get everything to work properly it will be far better than my simple build. The main disadvantage I have is head winds... If I encounter a strong headwind the grill block will close soone, but at the same time more air is still flowing under the car so cooling has yet to be an issue.

It sounds like you have come up with good idea and I look forward to seeing it come to life. I really hope everything works out with it

[seifrob]

Almost invisible. Great job!

[Shortie771]

Originally Posted by seifrob

Almost invisible. Great job!

Thanks

Sorry that I have not posted any test results yet. I have not been able to drive over the last 2 weeks, due to an eye infection. As soon as I am able to drive without fear of endangering others on the road, I will do some testing on this.