First off, here's a link to BPi's site.
http://www.bpinitiatives.com/

I first read about this stack on HT, back when I was modding my Prelude. It was designed by one of the members and after a few dyno's and review's it became a big hit. I've actually read that Blox ripped off his design, but I have zero proof of this.

I already had this installed on my Prelude before I had S300, so I never got to datalog any differences. Looking back, I should have took it off just to see if it richened out anywhere. Anyways...

I originally ran this with my OEM intake, sense the OEM filter was VERY dirty when I bought the car. I also didn't want to buy a filter sense I knew I would be getting an intake shortly. I felt zero difference, even compared to the very dirty OEM filter. I blame this to the restrictive OEM box(please don't turn this into a debate).

I got bored one day and matted this to the FIPK just to see if it would work. To my surprise it fit inside the FIPK box with ease. The only problem was that the inside of the FIPK pipe was slightly smaller than the BPI stack. Even with the lip, the throttle response was noticeably better. I however felt no power increase but the tone of the intake was slightly different.

I kept it like this for about a month before I found time to get rid of the lip; nothing a Dremel couldn't fix. After that, the throttle response was noticeably better again. But like before, I felt zero power increase. Would I have felt a power increase if I would have done this to begin with? I guess I'll never know. However, with all of the dyno's of H22's and B-series motors, I would expect a power increase with a tune.

On to the pictures.

Here are some pictures of the velocity stacks side by side; huge difference.


And here they are with their K&N filters.


BPi/filter vs OEM filter(sorry old phone picture)


Some measurements. Notice the lip on the inside of the FIPK velocity stack? That's the inside diameter of he FIPK pipe.



Traditional FIPK


FIPK with BPi stack. Notice that the BPi adds a little length to the pipe. The FIPK velocity stack slips over the FIPK pipe, while the BPi buts up against the end of it.


FIPK, BPI stack and AUT plate FTW

 

Hmm, interesting. Correct me if I am wrong, but could increasing the length of the intake tube with the velocity stack be having more of an effect here? I know increasing runner length on the intake manifold can increase torque but hurt peak HP. I know AEM is big on "tuning" the length and diameter of their intakes to get best TQ/HP gains.

I think I would like to see the what the dyno says. Anyways keep us posted!

 

Looks good. Where did you get your aut plate?

 

IheartOEM - The extra length could be part of what makes the stack work but it's deffinently not all. Also, intake length and runner length are 2 completely different animals entirely. Runner length has to do with pulse tuning and longer doesn't always mean low end power. Research pulse tuning and intake resonance tuning.

OMGJDM - I bought the plate off of ebay. It was on back order when I purchased it and it took a month before they got some in stock.

 

Interesting. In the JDM tuning section, I read some big JDM baller company uses dryer hose for the tubing because they say it "swirls" the air and its somehow more efficient.

 

nice work on the fitting

 

2ndTimeAround - Throttle response was noticeably better, sound was slightly different, however I didn't feel a power increase.

Ap2batman - Thanks but it's really not hard to get it fitted right.

IAmTheRealAsif - I seriously doubt that. Swirling air into the plenum would do nothing but disrupt what's already going on in the plenum. Just like the throttle body spacers that swirl the air. Now if it was used on a wet manifold, then it might promote better fuel mixing.

 

In for dyno. Would be interesting to see the differences in power + A/F ratio, even untuned.

 

I won't be getting on a dyno until I get an EMS. I feel like it's just a waste of money without one. Even then, I'll be datalogging and making adjustments by myself, just to see where parts add power(by A/F tuning). Then I'll ether have someone dyno tune it, or I will.

I have some street tuning under my belt, sense I street tuned my H22 with S300(seamless VTEC cross-over, huge midrange gain, 28mpg mixed driving, more part throttle grunt ect). Even with my limited knowledge, I was amazed at the difference. I have sense learned even more.

 

Velocity stacks work on any engine to help straighten out the air flow and it increases the cfm a little.
http://www.turbohoses.com/velocity_stack.htm
Here's mine on a 3.8L
http://s188.photobucket.com/albums/z38/rod...dsintake1-1.jpg
That is a 3 1/2" to 6" velocity stack.

ROD