How much of a difference does grill block make?

[jime57]

Originally Posted by AeroModder

If you can also build some ducting to direct the air into the radiator instead of allowing it to spill around it, that will allow you to have an even smaller grille opening.

Very true! On my Insight, I keep the coolant temp under control in winter with only 3x6" grill block opening by carefully ducting ALL cooling air through the radiator. But, one caution, you MUST carefully monitor the coolant temp at all times. Try to design grill blocks which can be removed easily if you get a hot day

You probably have cruise control. If you have a flat section of road, you are well positioned to do relatively easy A-B-A testing and get your own personal answer. My guess is it is of considerable value. Has been on all my cars.

[NeilBlanchard]

Cover the upper grill first - a couple of pieces of black tape (or whatever you have) - and try it for a tank or two! I got a 2MPG increase - almost 5% improvement.

[mcrews]

Originally Posted by Cd

How much of a gain did you see with that grille block ?

Havent run a real aba yet.
wanted to see the temp issues first.