Grill Block Solutions for my 318iS? Inner or outer?Upper/Lower/Both?

[320touring]

I'm about to start modifying my BMW 318iS for better aero/lower Cd..

I've read a bit about grill blocks on here, so was thinking on starting with an upper grill block:

The carr's grills are like this
Front End[/B]


Initially I'd be concentrating on the "Kidney" grills (chrome surrounded shapes with Black vertical infills).

These lead directly to the Radiator, whick is also cooled by the lower grill and a viscous fan drawing in air to the bay.


as per the project thread for this car, I'm keen to keep the mods discrete, and reversible so my initial thoughts are

1. 2 pieces of Clear Perspex cut to size and mounted BEHIND the grills-stopping through flow to the rad

or

2. 2 pieces of Clear Perspex cut to size and mounted N FRONT OF the grills-stopping through flow to the rad

or

3. Individual perspex pieces blocking the gaps between the black vertical dividers.


What would you do?

Any suggestions as to how to mount it?

Thanks!

[Vekke]

I would go for the option 2 and for the attachement little bit of clear silicon. That you can scrub off if needed and the change will be invisible.

[Phantom]

In front of the grill will be best and Vekke using clear silicon is a great idea I will need to try that when I do the final version of my grill block.

[Vekke]

Silicon will work perfectly if pieces are that small and almost flat. If there is lots of curvature its more difficult to clue due to tensions.

[320touring]

Thanks Guys!

I was thinking Silicone would help attach-and as you say, clear one would be almost invisible..

For the grill block I was going to use 2mm Perspex, a it'll allow it to bend slightly- sure I can heat it to get a gentle curve if required.

So In front is the best.. ok-time to get thinking on the botom one, asa the grill is flush with the bumper

[Otto]

Did this with my '95 325is. Covered lower grill with black 2mm coroplast, virtually invisible to the casual observer. Not sure it helped fuel economy, though, so took it off.