[Smokeduv]

Many years ago, like at late 70's if I'm not mistaken, some racing teams wanted to exploit just that. The first successful one was the Chaparral 2J, which had a 2-stroke engine from a snowmobile, I think, and connected to 2 big fans from a military tank and then they sealed the sides with skirts. It wasn't very successful because of reliability issues, but it was competitive when it was running.

Some years later, that concept was taken into F1, where the Brabham team put an enormous fan behind the car (The Brabham BT46B or "fan car"), which they said it was to cool the engine, but it was ducted in a way that half of it cooled the engine and the other half sucked the car. The fan was connected to the engine, so the higher the revs, the more the suction. The advantage was so huge that it was banned (that and because the other teams complained, so they withdraw and the next year the rules were changed to ban moving aerodynamic parts). It only ran in just one grand prix, which it won by a very big margin.

For ecomodding purposes, it may work, but as in the Chaparral, I don't think it's going to be easy, or cheap, or reliable and might be too heavy.