V8 driver dirt

[sean_V8_914]

I have a question for those of you who put alot of miles on your v8 cars. Does your engine get dirty. My engine gets filthy driving in San Diego. mass amounts of road dirt and grime. it does not leak oil. the K&N gets packed with dirt. I have to clean it every 1000 miles. The intake manifold collects dirt.I wonder if it is an arerodynamic issue under teh car. I have been thinking abaout doing air guides under there ala Lotus Elise, F1, Viper...

[John Rogers]

Since the area behind the rear window is a very large low pressure area, if there is no sheetmetal to seperate the upper part of the engine bay from the lower, the dust and dirt from under the car will actually get sucked up onto the engine. My race car had a dry sump tank in the batt shelf position and the engine sheetmetal had all been removed. The engine was always very dirty so I made a complete set from soft aluminum sheet, what a pain but things were better.

[914GT]

Sean

I have no experience with this yet but maybe the motion the car and tires kicks up dirt which is is sucked into the engine compartment. A front engine car gets dirty too but maybe not as bad as it gets cleaner air straight in from the front. My car had a short deflector next to the fuel pump under the firewall. I don't know if originally there were two with one on each side, but I was thinking of putting a deflector all the way across the bottom. My thoughts this would create a low-pressure zone under the engine and pull more fresh air down through the engine lid. This would give cooler, cleaner air for the air cleaner and help cool the motor. I don't know if this is what you are talking about and if anyone else has done this.

Now I read what John said, maybe it's not possible to create a downward air flow with what he says about the low pressure area behind the rear window...

[John2kx]

My engine gets dirty as well but not to the point the air filter has needed to be changed. I still have both flaps installed under car and think this helps divert some of the grim. Maybe a full length piece would be worth the effort.

I keep up with this by wiping valve covers off about every two weeks. With about 6000 miles logged so far, I have wrapped the carb. and distributor twice and gave a light soaking with Greased Lightning.............spray it down with water and it's all like new again.

John

[AJS]

With this air flow path, I suspect it is a aero advantage by removing air from underneath the car. Of course the down side is all that dirt and debis. Why Porsche chose to pull air from a low pressure area and force it underneath the car seems a curious solution to me, except that they'd suck dirt into the motor. Don't the air cooled track guys vent the area just aft of the motor (trunk area) to reduce high speed lift?

Andy

[sean_V8_914]

john R, thanaks for confirming my susspisisons. I will make tins
2 daays of hard driving at the pca school sure dirtied it up