Anyone noticed this before? re: front grills

[Jim Bowen 1]

i have two standard front grills and noticed today that one has all the slats open, the other only the bottom one?

 

 

i guess the open one would be much better in terms of keeping bay cool

[VR6 0]

Short answer. Yes :D

[vornwend 0]

I also have both grill types. There is a definite difference with the open slat version cooling oil by up to 10 -15c compared to the closed. Of course a lot depends on ambient temperature and how hard and long you are thrashing the engine but I've kept the open slat on all summer and never gone above 114 compared to 130 one hot day last summer. Might switch when it starts to get consistently colder cos I live fairly close to a motorway and like to see the oil temp above 80 before getting up to speed.

 

My thoery is that the closed slats were from a batch meant for Scandanavia :?

[Jim 2]

I initially thought there was no real difference as I went from a totally open FK grille to a half closed VR grille like the top one in that photo.. now I discovered that my thermostat was stuck open so wouldn't mind getting a fully open grille like the bottom one in the picture for testing out!

[Furkz 0]

cant you just carve out the top one instead of buying another jim?

[Jim 2]

I suppose I could mate but knowing me i'd probably end up butchering it and buggering it up with the dremmel. Probably best to have a safety net / backup in a new one with all the slats open ;)

[Phil K 0]

wonder what the real reasoning behind these grills is?

[Jim 2]

I would *guess* its colder climates..?

 

I bet there aren't many like that in the states...

[Supercharged 2]

Worth hanging onto the closed one for the winter, especially if using a Mocal cooler mounted at the front...

[RS VR6 0]

Interesting...never seen a closed grill before.

 

So it goes to countries that dosen't get above 70F(21C)?

[vwdeviant 0]

Had this dicusion with Bill (VR6) and Yeti a few months ago.. appears all VR's from a certain year got the shut grill...

 

Only idea we can see was aerodynamics as teh VR was supposed to push the 150 envelope, so less air entering the upper part of the bay means less pressure, more slippery car... plus most Rad's air comes in through the lower grille in the bumper apparently.

 

Yeti explained something about the "balling" effect in the front of the car effectivly producing a wedge in front but I'd drifted off looking at Bill's RS's :lol:

[Bojmobile 0]

My VR has the closed one but my 16v had the open version. Always thought it was a bit weird - but I am in a sub-zero climate in Scotland - so I'm probably ok! lol

[Yandards 0]

Interesting...never seen a closed grill before.

 

So it goes to countries that dosen't get above 70F(21C)?

 

It does to get to a whopping 30C here sometimes ;)

 

Yes the car will run colder with more air coming into the engine bay but as already mentioned a lot of the air comes through the bottom grill anyway.

 

As for why, I don't think the pressure wave theory is a sound enough one, also historically a lot of VRs went back to the dealer when they were new for various engine problems, they may well have been tweaking grill design in an effort to get around this.

[Jim 2]

Doesn't the temperature thing hold water if RS VR6 hasn't ever seen one before Stateside...?

[Yandards 0]

Doesn't the temperature thing hold water if RS VR6 hasn't ever seen one before Stateside...?

 

It does, although as all cars in the US also came with aircon, you could say it was an aircon thing.