Has anyone done any mods for cold air induction to thier 307? I found a mod on the net, but it gets rid of the "thermac" . I wonder how that would affect cold weather starting ect........ Any thoughts?
The stock setup should work the best. As long as you're bringing in cold air from a fender or next to the radiator, you're doing well. Open air elements, while nifty looking, are not the best for performance. You'll see a 1% increase in power for ever 10 degrees you can drop the incoming air temp to a certain point. So as long as your stock setup is in good order, you're alright. Keep the stovepipe from the exhaust, you'll want it for cold starting.
I just simply disconnect the vacuum line to the thermac if I want cold only air.
I made a nice dual snorkel air cleaner for mine, ran dual ducts under the front bumper to get some ram air. Added a thermac to the second snorkel (was on snork from other air cleaner) and hooked both up proper. At WOT vacuum drops and they open up for full cold air anyway. Then you don't have any cold weather drivability issues.
The 307 likes to be warm in the winter. I suspect it is the lean calibration of it. Even the EFE is a help to it.
Duct it for cold forced air, dual snorkels if you can (the more positive pressure you can create, the better power you can get).
Don't disable the thermac, it does help cold drivablility. I DO disable it in the summertime or anytime over 50F or so.
Create a dual snorkel air cleaner, they are sweet!
A simple mod though, is cut off that deflector on the air cleaner that deflects the incoming air from hitting the filter head on. It makes the filter dirty in one spot, but seems to have some small effect on improving power.
IF by chance your air cleaner has that darn charcoal filter inside it, just inside of the air filter, ditch it. It IS unwelcome. It is for evaporative emissions. Which a properly operation thermac takes care of for you.