My fenderwell was pretty closed off from the factory- tire isn't exposed to the fenderwell- I have a plastic inner fender thing that goes around the tire completely, and across the bottom of the fender well- so it really couldn't get splashed. My only recommendation would be to mount it as high up as possible- that way if you drive through a REALLY deep puddle, you won't suck water in. If you put it at the top- its not like you're going to drive through a 2.5 foot deep puddle anyways.

There are actually a couple options here- one is to take your flexible tubing, make the 90* turn down into the fenderwell and mount the filter right at the top.

The other option is to not make the turn- just to take the filter, shove it in the fender well hole in the engine bay (pointing straight into your fender)- and leave it there. Obviously, the whole filter won't fit into the fenderwell, and you'll have some sticking into the engine bay still- so people buy plastic roof flashing, and trim it to fit the opening, and it covers the back of the filter to block it from the engine bay:



Any hardware store carries this- and being regular black plastic, you can cut it with any normal snips. You cut the flat part to fit in the car and line the hole up with the back side of the filter- and you cut the opening to match your tubing size (from what I remember from the one I did- the center was actually a rubber, and the backing was plastic- so you could trim the center to fit very snugly to the piping).

Roughly the same. You're still eliminating the restrictions of the stock filter and box and such. The benefit to a CAI box like the Wiz is the short run of tubing- the downside is, the walls become heated, and they don't necessarily seal 100% perfectly at the edges of the engine bay (although WAY better than the K&N)- so intake temps may be a pinch higher than true ambient. With a FWI, you only get cold air into the filter (well minus the heat transferred through the pipe)- but you have an additional bend and extra tubing length.

So that's why people like to do the thing with the roof flashing I posted- you get 100% cold air (since you can seal the plastic to the car and even screw it in place if you want)- only an extra 10" or so of piping from a CAI box- and for a fraction of the cost.

 

Hey Bumpin,

Does this all make any difference whether it's an NA or Supercharged?
Mike mentioned that it sort of wasn't a big issue about having a HAI in L67 engines since the supercharger would heat up the air (something along the lines).
Will having a HAI in a supercharged engine Okay?, or is it still that much more for the engine to try and get as much cold air as possible? thanks for your replies, its helping me understand the proper care for our cars.

 

Really here is the deal on the HAI. Your not gonna see that much less of a gain. Heck a cai will only get you mabye 5 hp. The downside on an l67 is that they like to knock, and once you stick the hot air in it, it will knock more and hurt your engine more in the long run, and loosing you hp. Also your car will run hotter in general.

 

yeah man, cold air is always better, no matter what engine or what you have done to it, or how you get the cooler air in there its always better than hot air.

 

Yes, it does- the NA engines aren't nearly as sensitive to pipe length. Running extremely long piping (ie having the filter at the bottom of the fender well) on an NA and SC car both will produce the same power drop from suction losses- but the SC car will be even worse off on top of that- because as you make it harder for the SC to suck, the output temperature goes up- which makes it lose even more power.

So for SC setups, I would say to keep your piping length as short as is feasible.

Cold air will always make more power, regardless of which engine it is.

Honestly, I'm not a big fan of a HAI, even on an L67. I know a lot of people do it- some put the filter right on the throttle body, or stick a basic 45 or 22 degree coupler on with a filter on that.

I really think its a stupid solution. For those who stick an angle coupler on anyways- what does another 6" of piping hurt? Really the length of pipe going to a Wizair box isn't that much longer than just sticking the filter on the elbow.

I did run a HAI in my gtp for awhile- before I went to the roof flashing method putting it into the fenderwell- and my IAT's were VERY high, especially at low speeds. I'd come off a stop light- nail it, and the high IAT's would give me extra knock on top of usual (which takes a while to go away, even if the engine senses no more knock once your IAT's drop and you get moving).

I know there are a lot of debates on clubgp on this- but my opinion has always been- adding 6-8" of piping to your short ram/HAI to get the filter to an area where you can build a heat shield isn't going to increase blower output temperatures enough to negate the huge IAT drop from having the air filter only sucking in cold air.

Or, if you're cheap- add maybe 20" of piping, and put the filter mostly in the fender with the roof flashing- it will make a little less power than a wizair or something due to the extra tube length making for slightly higher blower outlet temps- but how much difference will there really be? My bet is very little.

From the couple fluid dynamics classes I took in college- straight pipe isn't particularly restrictive, it is adding bends and such that kills airflow. Here is some good info from zzp:

http://www.zzperformance.com/grand_p...les1.php?id=22

5" of straight 4" PVC pipe = 238 CFM
26" of straight 4" PVC pipe = 220 CFM
26" of straight 4" PVC with a 90* bend = 183 CFM

Now the CFM numbers don't really mean anything alone- but are nice to compare- only an 18 CFM loss from doing 5 times the pipe length! 5" is what many people use on their HAI- so you can see adding even an extra 20" to get the filter into the fender doesn't add much restiction. You can see they lost almost 40 CFM just from adding a little 90* bend.

So the key is to eliminate unnecessary bends- and only use straight pipe with as few bends as possible- try not to do any different size couplers or adapters- keep everything smooth and the same size. Adding a small elbow on the end of the TB is necessary for a big cone filter anyways- so why not move the filter to where you can block off hot air? The lesson here is that you're better off not running all kinds of extra piping and bends- especially on an L67.

For fun's sake- I did some calculations for this guy in the local car club that wanted to put air filters in his foglight holes on his bonneville. He had a 90* bend on the one filter, a T on the other, like 3 other 90* bends to get it up to the engine bay- and then the tubing in the engine bay and the bend on the throttle body. From what I remember, it added up to the equivalent of over 40 feet of straight pipe of the same size! Who in their right mind would attach a 40 foot tube of piping to their intake?

Less is more when it comes to tubing...

 

Great read, thanks. highly appreciated.
If i can bother you once more, and my apologies to the original topic creator
What about changing the thermostat from 195* to 180*, i've seen it here and wonder what's the point of doing this? Is this something recommended for our cars? again any difference whether NA or Supercharged? Would the region of where you live make a difference in doing this?

 

Great read, thanks. highly appreciated.
If i can bother you once more, and my apologies to the original topic creator
What about changing the thermostat from 195* to 180*, i've seen it here and wonder what's the point of doing this? Is this something recommended for our cars? again any difference whether NA or Supercharged? Would the region of where you live make a difference in doing this?

 

A cooler running engine is supposed to be more knock resistant, and make more power. Even some OEM's have started changing to lower tstats lately. Personally, I wouldn't go under a 180*- the engine was really designed to be run at a certain temperature, and I don't like the idea of varying that too much. Not to mention, the cooler the coolant stays, the more heat loss through the heads into the coolant (bigger temperature gradient = faster heat transfer).

If you live anywhere up north where you have prolonged winters, I don't think I'd change from a stock one. Even 15* helps a good bit defrosting windows and adding warmth to the car. I ran a 180* drilled in my GTP in NW Indiana, and it was definitely harder to get ice and such off the windshield than my Impala with a stock tstat. I definitely don't recommend the 160 at all for northern areas- heater output is drastically reduced.

 

Thanks dude!