powderhound should post the data we got from the aerospace core company showing gains from 3.5 to 4 inch cores. if the 4.5 didn't perform as well as the 3.5 then it was not same core contraction or car had issues. the thicker the core, the more heat transfer ability it has.

 

Itguy, any chance you can post some of the data you have between stock ducted and 4.5 unducted? ;-)

Our cars primarily suck air from the bottom, if anyone is deleting that duct they've lost their mind - that one is easy to keep.

 

SRM all Day long. Especially Bang for your Buck you have to be a fool not to go with them. I love mine and the Y-pipe Sean made turned out just Amazing. Fitment compared to what's out there wasn't bad either. But then again some guys don't mind going slow lol

 

Yes but if not sealed into ducting air will go round it rather than thru it, so of course a PROPERLY ducted 4.5" will out perform a 3.5" given equal quality cores. IC's HAVE to be ducted or you are running massively inefficiently. The fact is that at the same boost 1.3 bar my car runs over 10 degrees centigrade cooler than a 4.5" car non ducted measured same place with same ecu.

 

Two different ducts, top and bottom. The aero sucks air from the bottom duct so it's absolutely critical IMO. The top one I believe is important as well but possibly less so. The data I saw was for a car that had lower but not upper.

In any case, I'm running both ducts sealed. My top duct wasn't sealed from the factory apparently, I fixed this. Not 100% convinced the foam I've used is well suited but it's easy enough to change later. Would like to instrument further and test more but I'm happy with good 4.5inch cores for sure.

 

I think both need to be pretty much intact and sealed but a decent water meth kit will make the most difference.

 

Meth is pretty awesome and I've used it but mixture distribution would concern me as might the nikasil liners. I'll hit mine with e85 though lol.

 

Dude Aquamist is your friend !!!!!

http://www.aquamist.co.uk/

Ive seen the atomisation of these kits and the guy has made it an art form.

 

I went with the EVOMs IC kit. Work well.