I have the DF Type R underbody and DF battery undertray with the OEM hood, OEM radiator. But I do have an oil cooler in the rear passenger fender well for my CTSC.
On street driving there is no change in both the oil and water temps, so no overheating. However, I do have an issue with the design of the battery undertray since I don't think it was designed with a 97+ battery tray in mind; it doesn't allow for any drainage as the OEM tray covers most of the punched holes! As posted elsewhere, I suspect the real Type R has the pre 97 tray without the tire pan otherwise those punctured holes in the battery undertray make no sense to me. Sam@DF is checking on this for me.
http://www.nsxprime.com/forums/showthread.php?t=111415
We are talking about vented hoods. The issue in these comments should not be how deep the hood cut must be to be "functional" but how effectively it gets the air flow out. One can easily design an air duct that would achieve the same air volume out of the hood with a less deep cut in the hood (perhaps such as the VIS and DaliRacing's air duct scoop) than the Type R or copies of it. The Type R eliminated the spare because of weight considerations and hence having a deeper cut hood would make sense for the scoop they designed, and perhaps it offered more downforce, or rigidity to the hood, or esthetically was deemed more pleasing. Who knows, we are all guessing re the depth angle of the cut.
The track is a different scenario and most who are buying the higher end hoods don't track their cars regularly - if any. At the track, my experience with ambient temps no higher than low 90s, using the OEM hood as noted above, I didn't see much difference except perhaps 10F more but that can be due to many other factors as well - perhaps running longer at higher RPMs, perhaps there was less breeze, perhaps ........ My water temps got to 215F and oil up to 265F and I was hauling for several laps at the limits - then I eased off just to cool things down. I have come close to those temps before without the undertrays.
Having said this, yes definitely a vented hood will help; common sense physics would say that air must go someplace. But to say the other hoods are "nonfunctional" instead of putting a qualifier stating "
perhaps less effective" (efficiency has to do with cost/benefit) is quite a subjective stretch. We still don't have any data analysis supporting either comparative air volume displacement out of the hood or actual back to back readings re temps from the track to say they are "nonfuctional." YMMV.
Now, do the DF or ProCar hoods "look" better that the cheaper aftermarket ones when looking under the hood, or have better fit and finish when price is not an issue? Well dahhhhhh, we don't need to debate that one .........
