Cold Air Intake?

I'm looking for a cheap but effective CAI for my 96 RM wagon. I came across this on ebay. What do you think?

http://www.ebay.com/itm/CHEVY-IMPALA-SS-CAPRICE-4-3L-5-7L-V8-COLD-AIR-INTAKE-KIT-SYSTEMS-1994-1996-RED-/180735265972?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3AImpala%7CSubmodel%3ASS&hash=item2a14a94cb4&vxp=mtr

You would be better served by a better quality cone filter 2 pieces of PVC and a hockey puck.

with shipping thats $75.00

buy the cone filter and then don the sewer pipe mod,.

The stock intake is a cold air intake. The two resonator boxes cancel out noises from the engine, and I'd argue that the "homeplate" resonator on top of the motor actually helps partially compensate for the lack of plenum volume in the LT1 intake manifold. Cut some holes in the bottom of your stock airbox and put a clean filter in there and you'll get 90% of the improvements you'd get from any aftermarket intake with no cost and none of the drawbacks of homemade or aftermarket systems.

I can tell you for a fact that you will likely need to get your MAF curve adjusted after altering your intake from stock.

I didn't look at shipping. It's a little pricey. I saw the thread about the PVC mod and it looks like even more of a restriction to me having elbows and such. I agree with Sherlock and I think the stock box is a better location. It draws air from behind the headlight instead of heated air from the engine compartment.

I think the more expensive kits come with scoops to draw air from under the car or behind the headlight instead of under the hood

Never though of having to get the MAF curve adjusted as I though the ECM would make it's own adjustments to compensate for the extra air.

With the MAF, the ECM can make adjustments up to +/- 20% off the base tune without too much drama.   On one aftermarket intake I tested (listed below), the MAF curve was out well beyond this at idle though it came back in line once the throttle was opened.  

If you change your intake, don't alter the PCM to compensate, and then have weird drivability problems, put two and two together and you can figure out why.   I will tell you that the absolute worst intake based on my datalogging is a cone filter hanging directly off the MAF and then that monstrosity hooked to the throttle body.  Guess what 90% of LT1-powered street rods have as their intake setup?

sherlock9c1 wrote:

With the MAF, the ECM can make adjustments up to +/- 20% off the base tune without too much drama.   On one aftermarket intake I tested (listed below), the MAF curve was out well beyond this at idle though it came back in line once the throttle was opened.  

If you change your intake, don't alter the PCM to compensate, and then have weird drivability problems, put two and two together and you can figure out why.   I will tell you that the absolute worst intake based on my datalogging is a cone filter hanging directly off the MAF and then that monstrosity hooked to the throttle body.  Guess what 90% of LT1-powered street rods have as their intake setup?

So have you tested others Joel? How does each fair?

why would the maf curve be out only at idle?

BigBlackBeaSSt wrote:

So have you tested others Joel?  How does each fair?

Yes Tim, I spent $2000 to buy every possible B-body intake made and thoroughly tested each one.  For only a tenth of that I will gladly provide you the results.  

Nick, it's all about how airflow crosses the MAF, how the airflow through the MAF interacts with the pipes on either end of it, and how the air actually flows through the engine's intake tract itself.  If you read MAF sensor product / tuning literature, you will find that MAF is very good at steady state measurement but not so good at transient measurement.  One suspicion I have is that GM intentionally designed the stock intake system with three resonators (yes, three, go count them if you don't believe me) that have a calming effect on the airflow at low rpm and high vacuum.  The other thing is that I suspect idle airflow may consist primarily of crankcase ventilation air and the remaining air goes through the IAC as much as it leaks around the throttle blades, changing the geometry of the airflow.  On a modified intake, if unstable air gets back to the MAF such as the dumbo intake I mentioned above, then you will have screwy readings because those hot wires aren't cooling.

All of this is open to debate, but just to say that someone with a mechanical engineering degree and skilled with fluid dynamics constructed the stock intake setup and to think that one can "improve" it with a few pieces of pipe from the hardware store is nonsense on its face.

One last statement - this is for STREET-DRIVEN, NEAR-STOCK cars whose tunes have not been optimized for modifications such as these.  If you are doing a max-effort build or are far from stock and don't drive in rain, snow, dust, don't care about intake noise, etc, then most of the concerns that drove the design of the stock intake become irrelevant.

Okay I'm going to get down off my soapbox now.

I have a K&N set up with the nice metal box and pipe with logo....everybody knows the one.

I put it on my 94 RMW and lost 2-3 MPG highway on an 800 mile trip. replaced it with the stock airbox for the return trip and instantly regained my MPG. Any comments about uphill/downhill are BS as from Savannah to my house the altitude on the overpass surpasses any in the ground.

The only 'improvement' I found was going WOT around 80mph to pass, the throttle response was quicker as the car would jump when you hit it a little more with the K&N set up. That was 5 years ago and it's been laying on my workbench since.

I hadn't thought about the MAF being the culprit.

Sprocket wrote:

I have a K&N set up with the nice metal box and pipe with logo....everybody knows the one.

[...].  That was 5 years ago and it's been laying on my workbench since.

PM me if you need to make some room.

I always liked the stock box (swiss cheese) and a nice painted pipe. I used a hockey puck too, but modified the home plate so it sat right with the puck installed.

http://www.longroof.info/pdf/lt1intake.pdf

I have a Rammit system on the Roadmaster and a K&N kit with TeamSS pipe on the Caprice.

Chris