How important is the size of the recirculation tube important when recirculating a blow off valve? I noticed that i could get three different sizes:

http://www.hksusa.com/products/?id=798

And was wondering if there was a specific application for each size, such as maybe needing a size dependant on how much air gets blown off. Thanks.

 

get it as large as practical.

 

Can you elaborate more on this? I'm stuck on this too, but with a GReddy RS BOV.
Does the practicality depend on how much boost is being run?

 

I guess as large as it is practical depending on how much room we have under the hood, the hose sizes we can get and the location after the MAF where we weld on the inlet nipple and what size we can fit in that spot.

 

You are running a map based system (Interceptor-X) so the normal MAF/BOV issues won't be a problem and you won't need to recirculate.

 

large as you can go. I'm using a 3/4" (19mm) bung on intake tube without issues at 10 psi right now.

 

Most of these folks are switching to a MAF-based system.

 

SWEET!

I ordered the 19mm bov recirc attachment for my greddy type-rs bov last week.

 

yeah, my recirculate fitting is 19mm because I had the type-s recirculate fitting from over a year ago. The synchronic bov has a 1 1/4" sized tube, but I do not want to pull the intake pipe and get something new welded on so I used what I had, and it seems to work fine.

 

Bump

I would like to know this also.

 

i don't understand the question. for most people, the maf is on the non compressed side, then after the maf is the turbo, intercooler, then the bov (compressed). anytime the bov goes off, there is unmetered air loss, so we get a temporary rich situation.

 

i did the boost only vacuum fitting on the sychronic bov today. that sucker works well.

without it, the bov releases air at -12 psi, with it enabled, it releases the air whenever boost isn't stable or building. so if i floor it at 7 psi and let off the throttle, it immediately releases the air while it's at 6 psi or so.

the net result of this is that the air is discharged back into the recirculate fitting and into the intake, the car doesn't have a "woosh" and jerk around, it just acts like a NA car when you let off the throttle.

I think I'll keep it setup this way from now on.

 

This is good news for 2 reasons:
1. I don't want to spend $40 for a stupid fitting that probably cost $6 to make.
2. I like the whooshing sound!

 

Yes it would, but I am not sure how well the RX-8 ECU will work on a "blow through" MAF setup. Everything I have heard says its pretty fickle.