Second Hole in CAI mod.

[HSVREDSLED]

Hey people,

After wearing out the search button on this forum, today I took broke out the tools to do the second cai hole mod for my VY Clubbie series 1. It all came apart easy enough, then I took off to the Hardware store to pick up some pvc pipe and hole saw. I went in with the 'bigger is better theory' and decided upon about 70mm pipe although not discounting 90mm as a lot of people have said they have used that.

I went to 2 large hardware stores and could only find 50mm 65mm and 90mm piping. Also, the holesaws did not match. I did find a 90mm holesaw, but they wanted $52 for it!! I ended up purchasing 90mm pipe and headed home. (with no holesaw) So there I was...90mm piping on the bench...stanley knife in one hand and CAI in the other. Thankfully, common sense kicked in and I put the CAI back in unmodified.

My questions,

Will I lose induction noise and power if I use 60 or 65 mm rather than 90?

Has anyone done a before and after dyno to see if the second hole cai mod is worth it?

advice welcome...

Sled

[BlueSS]

In this case bigger is better, go the 90mm... see if you can borrow a jig saw (if you don't have one) and use that to cut your hole out.

[jagermeister]

I did this mod by:
1. marking the location of the hole with a white pencil.
2. drilling a series of 2 mm holes around the circumference of the 90mm diameter circle. ie lots of small holes about 1 or 2 mm apart.
3. I then used the Stanley knife to connect the small holes.
4. Insert 90mm pipe and your done.

[markone2]

Or simply hang fire untill its time for edit.......and have it done for you :)

[VX2VESS]

I did this mod by:
1. marking the location of the hole with a white pencil.
2. drilling a series of 2 mm holes around the circumference of the 90mm diameter circle. ie lots of small holes about 1 or 2 mm apart.
3. I then used the Stanley knife to connect the small holes.
4. Insert 90mm pipe and your done.

and a half round file to smooth it out

[Mongy]

I used the largest size on one of those multi size holesaws and then just carefully filed it out to match the pipe size that I had. I used a bit of pipe with a flange on one end that was approx 65mm. I don't know about the actual dyno figures for the second hole on its own but that and the GTS maf tube made a difference of 8rwkw on mine.

[HSVREDSLED]

Thanks for your advice people. I'll go 90mm. Ive got the tools you all mention. I' ll leave it for another day.

Not quite sure about the edit. I would love to, but I am a bit shaky about warranty.

[AllWheelSlide]

Even though this is an old thread, it may get hit with a search.
90mm holesaws can be bought for <$6 at a hardware store. Look for a Downlight Holesaw, all a matter of marketing really.
(Warrior, & Eagle make them. Only need it to last a few holes and then you will shelve it)

[poolkeeper]

normal drill bit will do fine too, go around in circles and punch it through.
You wont get 10hp extra from a straight cut :rofl:

[Phonic]

On my car, I fitted the earlier model heat shield, but instead of cutting a secondary hole in the air box, I cut a large square hole in the lower half of the air box. Then used some foam stripping to seal the heat shield and air box together. The large opening outflows the 2 hole mod, you don't even need PVC piping, and when done properly looks factory from above.

Much louder induction roar then the PVC pipe version (mate has this).