I have been in this group for less than a week and have been spending WAY too much time reading old posts (should be working instead).

Anyway, I am researching the pros and cons of a CAI / FWI for my 2001 SE.

So far I have found a lot about pre 2000 Bonnies. When I look at my stock setup, it looks like (on the surface anyway) Pontiac already created a CAI. It also looks like I have a larger TB than all the pre 2000 CAI pictures I have seen.

My question is:
Is there REALLY any advantage to a CAI or FWI with 2000+ NA Bonnies?

Thanks!

(I wish I knew about this group six weeks ago, before I bought my SE. I would have known more about what to look for. I have a mild steering 'clunk', hard upshifts when warm, red poison in my coolant tank, and a wet floor after rain. Thanks for all the info!!!)

There is no difference in size between the throttle bodies from 1995-2005. They are all the same.

The best and easiest solution is a FWI from INTENSE. The design of your inner fender fully shrouds and protects the filter, while pulling the coolest air possible.

Thanks! But will a FWI be an improvement over the stock 2001 airbox? It already takes air from in front by the grill. Almost everything I have found where people say they get an improvement is with DIFFERENT cars.

I have read numerous accounts that SPECULATE a potential improvement. But nobody has the same car as I do. They are pre 2000 Bonnies or Buicks or whatever.

Does anybody have actual experience? It seems that so far it is merely speculation.

There are several 2000 and newer SE'* here with the INTENSE FWI that will chime in shortly with their experiences.

If you do a FWI find some 3" tubing. The 3.5" Intense tubing isn't optimum for an n/a car.

So are you saying that it is similar to the exhaust system down tube, you want to keep the velocity up? And therefore the 3 1/2" tube is too large?

I know there are complexities to this kinda thing but I need more explanation because that doesn't make sense to me intuitively.

I just don't see how the engine would know or care about the tube diameter at that point. The intake manifold, on the other hand is a different story. But outside the throttle body... I don't get it.


Besides, before I even start doing anything, I want to make sure I am actually doing something that will make a difference. There are a lot of myths and there are a few things that Pontiac has really done their homework on. If this is something that ain't broke, I don't want to fix it. I can spend my money and time on something that is documented to give me REAL horsepower like ZZP ER Rockers.

The higher the velocity, the more laminar the flow. Which means your MAF sensor can get a more accurate reading of the incoming air. The non-laminar effect of the larger tube is offset somewhat by the MAF screen. I know the L36'* so far have achieved good results and they're happy with the FWI. You will gain a noticable amount of throttle response, and you will have cooler air. 3" or 3.25" might be more ideal for the L36, and the theory says so, but it hasn't been tested. Everyone that has an FWI loves it, (myself included, but it'* on one of my L67'*).

In a nutshell, it might not be IDEAL for a mostly stock L36, but it'* a definite improvement over stock.

Hector tested a 3" pipe on an L36 and found it to be the best did he not?

The opening to my TB is around four inches in diameter. If I have a 3" pipe and a coupling that steps it out to four inches, that is a DISASTER for laminar flow. The rule of thumb is no more than seven degrees in a diverging duct if you want to avoid flow separation.

Now I am not arguing the pipe diameter here. I am voicing a concern as to how to handle the diameter differences at the throttle body. Due to my knowledge in aerodynamics and my experience designing divergent ducts, I haven't seen any coupler that would be satisfactory for laminar flow.

What engine does Hector have? What year?

I can understand the theory behind the CAI and FWI but I am still wanting to hear of examples that are the same application as mine. I am not familiar with the pre 2000 induction system but the one I have looks pretty well thought out by the factory.

I thought it was closer to 3.5"?