What mix are you using?
Have you tried water wetter?
And ebay slim fans SUCK.
I got my fan from STMDSM.com and it was the same as this one
FAL Electric Fan Single 12" Dia Puller 1250 cfm Black Plastic Fits Honda Civic 088657001250 | eBay
You need a QUALITY fan; and a shroud helps out a lot too!
A little creative duct work helps a lot, so does making sure your radiator is CLEAN and free of debris.
Even a hole in the front of your bumper will go a long way!
Also depends on the fans you have. Fans come configured for either a push or pull but if you want to make them do the opposite you switch the blades around AND reverse the polarity.
Hope some of this helps.