There's been some discussion recently about a CAI not making any power on the Z. Well I have 1/4mi traps that say otherwise. One caveat, my 'test' was between the injen intake short ram w/ a JWT heat shield and the regular CAI set up. I'll say up front that I have no idea if either of theses setups makes more power than the stock intake since I never ran my Z at the track while it was stock. I made 11 runs with my injen as a short ram and my best trap was 100.95 MPH in 53 degree weather. The average of the short ram runs was 100.39 MPH. I switched to the CAI and made 8 runs, my best trap was 102.55 MPH in 70 degree weather. The average of the CAI runs was 101.55 MPH. The actual difference between the highest traps is 1.6 MPH, the differences between the averages is 1.16 MPH. The CAI does indeed add power as evidenced by the higher trap MPH. Again, for the doubters, it IS entirely possible that the short ram lost power and the CAI simply returned the lost power, although I highly doubt it. My mods for these runs were borla headers, random cats, borla dual ex, and the injen intake (short ram & CAI). I'm happy with the gains but will be returning the intake to a short ram for the winter.

 

good results. Makes total sense. You cant prove dyno results of a short ram against the CAI, because the car is sitting still with the hood up.

 

How did you get so many runs, and why was there such a differnece in temps. Can you imagine if you did the CAI runs in 50 degree weather like you ran it with the short ram.?.

 

The short ram runs were done on Oct 3 (53 degrees), Oct 5 (68 degrees), Oct 10 (64-68 degrees), and Oct 24 (43-50 degrees). All of the CAI runs were done on Oct 26 (70 degrees). As you can see the short ram runs were done overtime hence so many runs. I got a lot of runs in with the CAI because I went to the track on Sunday and there were about 30 cars there. I usually go on Friday night when there are typically 275 – 300 cars there. I keep a nice little spreadsheet of all of my runs that includes the time of day, temp and even the lane I was in. A guy I was talking to at the track said the same thing about running the CAI in cooler weather. If I’d just put it on two days earlier (43-50 degrees) I’m sure the numbers would’ve been even more impressive, at least to me. I’m thoroughly convinced that the Injen CAI makes power on the Z as advertised, I’m sure the short ram set up does as well just not as much. I might stick the stock airbox back in and see what happens. I really doubt that the stock air box is as good as the Injen set up. The stock intake is a pretty good design though.

 

Yes I agree, the stock intake is very impressive. But I like the idea of "ramming" the air into the motor. BTW, what you are doing is awesome. Track runs prove alot more than dynos.

Have you done any b4 and after runs with a grounding kit? That would be nice to know. I just ordered a kit today.

 

I had a grounding kit installed for all of my runs. I don't think it adds any HP at all though. I got it because the JDM Z comes with it and it does make it idle a little smoother. Yep, no dyno error here, just time slips and track proven results at the same track, with the same car and driver, in various temps. I'm still debating whether or not to reinstall the stock airbox and see if it truly can give similar gains. It's supposed to be in the mid 40's Friday though and I really want to see what the CAI can do at the track in cooler weather. Maybe if I have time Sunday I'll reinstall it and take it to the track.

BTW, does anyone know aproximately how much HP it takes to gain 1.5 - 2MPH in the 1/4mi traps? That number would be a good estimate of what the CAI added to my setup.

 

Maybe a crank pulley? or make your car lighter. How full was your tank when you did your runs? Try running it very low.

 

I would like to see a CAI vs a STOCK intake on the dyno, a shorty intake means nothing to me, it is stupid to install, because it sucks in hot air and has NO ram effect. They will lose power on the Z compared to stock

 

Well a dyno means nothing to me, it is stupid to compare intakes this way. You dyno with the hood open and sometimes have a fan blowing on the front of the car. How often do you drive around town with your hood propped up? On the dyno you have NO ram effect either. Unless you used one of the wind tunnels that NASA has or something. In fact dynoing this way prevents the heat soak that could occur with the short ram under normal driving conditions. I have 1/4mi time slips showing the differences between traps. The error rate of the average dyno is enough to make it seem like an intake makes 1) little power 2) no power 3) loses power. Just take a look at some of the dyno sheets posted on this board that have multiple runs on one sheet done within a few minutes of each other. They usually vary 5HP or so and thats from pulls a few minutes apart with the SAME mods installed. If I do reinstall the stock intake I will run it at the track not on a dyno, which makes no sense. My times are pretty consistant and I always run the same tire PSI and ~1/4 tank of gas. I will not make blanket statements about short rams vs stock. The next post I make comparing the 2 will have been PROVEN through logical and repeatable methods such as 1/4 mi traps.