I'm currently using an Apex'i intake system. I get noticeably more power on cooler nights (Duh, right?). Summer is coming up and I want to do anything and everything to keep my engine cool. Is the difference in intake temperature enough to warrant switching back to the stock box? Or should I fab or buy a system like pettits that comes with a heat shield? I recall seeing a thread a long time ago about a guy making a heat shield that worked really well. He said he was going to post templates or something. Thoughts or ideas?

 

Cooling the intake temps before the air even passes through the turbos is no going to help very much, you want to cool the air some where between the turbo and the intake manifold. So an upgraded intercooler is your best bet, but something like a vented hood couldn't hurt

 

Thats not true- The cooler the air the turbo charger recieves, the cooler the air it puts out.

just be sure you have good ductwork. Damonb (i think) has a template floating around that works nicely.

 

If the ambient temp is rising, what else is an intake going to do? It's not going to bring in air cooler than the ambient air.


Larz,

No, there won't be enough difference to switch back to the stock air box. If it's 90+ degrees outside, you are bringing in 90+ degrees. The air box is not going to cool it down any less. What the boxes do help is when the car is not moving and the intakes are taking in the warmer engine air. At speed, it really doesn't matter all that much; at that point is more about the amount of air (i.e. what is more/less restrictive).

 

Yes- but if his intakes are pulling air thats been heated by the 180+ degree water temps in the radiator, 90 degrees looks good.

 

At speeds, it really doesn't make a difference. The main difference is when the air flow is low. I've seen many people try different intakes over the years and none of them made any difference (as far as cold verse open).

What did make a difference was removing restriction and allowing more air to flow in (ala the stock air box mods). Considering the amount of heat the stock twins produce, the IC is what needs to be a concern when it comes to intake temps.

 

I'll say that with the pettit 'open' intake and an upgraded IC (CC2) my intake temps are 2-3x ambient in city driving with their heat shield and one i fabbed for the rear of the intake. Not "stuck in traffic" city driving, regular old city driving. I'm going to the asp large IC soon so i guess i'll see if that helps.

The only real comparison I know of is here:
http://www.scuderiaciriani.com/rx7/intake.html#COM

At idle
Stock 147F
M2 137F
Pettit 162F

Highway
Stock 97F
M2 112.5
Pettit 124.2

 

actually my friend and i did alittle comparison between the apexi intake and the m2 stlye box intake.
When driving back from englishtown raceway we both had walkie talkies and consistantly compared our intake temps as measured by the power fc. The ride back consisted of hwy, city, and george washington bridge bumber to bumber traffic. The results were very concrete. On average my (i have the box stlye) intake temps were 10 degrees cooler. The only difference in our setups is that i have the m2 med ic while he has the blitz smic. I would think these ic would perform similarily in these types of conditions. Its not like we were at the track and running on boost for 20 mins straight. Never the less this clearly shows the value of a box design intake. If i owned the apexi i would put it in the foresale section on this data alone.
edit: the power fc displays degrees celsius for those that dont know.

 

Absolutely not. The M2/ASP is one of the most efficient IC's out there. IIRC (from one of Kevin's messages), they are almost at 90% efficiency which no SMIC for the FD really comes close to that.

I used to own a Blitz SMIC and I'm not running the Pettit Coolcharge II (old style which is slightly smaller than the M2/ASP Med) and there is a difference. While I don't have a PFC or any other means to actually monitor my intake temps, the driveability of the car definitely changed.

A local friend has tried the box style, Greddy and is now just running K&N. There was no change in performance between any of them. While there might have been a slight 2-5 degreee difference in temps (as far as I know, he didn't have anything to monitor the intake temps), that translated to ZIP on the dyno.

 

I switched from the Apexi intake to a M2 CAI box. I noticed NO difference in intake temps. In fact, I'm probably going to switch back to an open style intake.

 

Yes, but what that experiment doesn't have is intake temps AFTER the IC to show any real benefit. If you spend the extra money on a cold air intake to only drop your intake temps 2-5 degrees AFTER the IC, then it's pretty much not worth it. Keep in mind that just because you see a 10-20 degree swing in temps BEFORE the turbo, that doesn't translate to the same temperture difference AFTER the turbo.

What really counts is the temp before it goes into the throttle body and that's going to be mainly dictated by the IC.

 

i understand your point. but i was figuring that during hwy cruising and off boost situations the IC wouldnt make that much of a difference. Especially since their probably isnt a dramatic difference between the two. By dramatic i mean soemthing along the lines of comparing either of these two to the stock intercooler.

 

I'm just bitter because I spent $400 on a pettit which is ridiculous for what you get considering you can get a box for <$100 more.

 

So what all of you are saying is "Larz, it doesn't really matter what intake you use. You're good. Get off your *** and but a new intercooler. "
Next question: For my street driven FD, which intercooler would be the most effective (side mount only, please) at keeping them temps down? Is the huge pettit too big for street use? The blitz too small for anything but a paper weight? I'm not concerned so much about the power. I know it's going to increase as the intake temps decrease. I just want something good for in city driving.

 

One thing to remember that I don't think has been mentioned here:

A cold air intake provides cooler, denser air to the turbos. Therefore, if the peak boost is turbo-limited, the cooler air should enable higher peak boost. Even if higher peak boost is not desired, the turbos will work more efficiently with the cooler, denser air, and arrive at the desired boost level sooner.

 

The intake air still runs the same path regardless if the turbos are boosting or not. You are just missing the charged air from the turbos.

I really liked the Blitz when I had it. The Blitz IMO is the best IC that can work with a lot of intakes, doesn't require the battery to be relocated or miniaturized, and mates to the stock IC duct without any problems.

If you want a little more performance, the M2/ASP Med is probably the best bang for the buck SMIC available. Also, the Pettit Coolcharge II (old style) and PFS SMIC's are just slightly smaller and great performers as well. You can usually find those forsale used at great prices.