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The mkiv Supra Owners Club

Recirculating blow off valve question


j_jza80

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Im currently having a Turbosmart recirculating BOV fitted, and we've run into a slight snag.

 

I wanted to to plumb the outlet on the bov to one of the now redundant oil breather stems on my hks intake pipe, but the installer has mentioned that the stem is a smaller diameter than the valve outlet.

 

There can't be much size difference, so what is tge worst that can happen if its plumbed in this way?

 

I assume it would cause a little compressor stall and cause the bov to remain open marginally longer.

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The BOV might not be able to expel the air quickly enough and you'll build up back pressure which will lead to more compressor stall. If the oil breather line is considerably smaller you might be wasting your time with it as the turbo will take the hit and the BOV will just pressurise. Can't think of any other problems it'll cause.

 

I've removed my BOV as it was fouling the stock front bumper I've put on :(

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Thanks Scott, so no other side effects i need to think about? I was going to run without a bov, but i wanted it to be a little more civilised, and ive heard about people popping off intercooler pipes when running without.

 

Nothing that I can think of. The turbo spinning will draw the air in from the intake and the BOV causing a vacuum which will aid the flow of air. You might not notice any difference at all. Everything is relative of course, it all depends on how good the BOV is to begin with. If it's built to flow off the volume from a 67+mm turbo and you're putting a smaller turbo on it then I would expect even less issues.

 

All that being said, if you want to run without a BOV then I would. I would certainly have the kit bought and planned so that it was a bolt on affair should you decide that it's needed, but I wouldn't have any issues at all at least trying it without.

 

I would be amazed if that tubby blew the doors off mate, honestly. Decent clips holding the pipes on and decent pipe ends will hold anything that turbo can throw at it. Takes serious pressure to blow off an intercooler pipe when everything is good quality and fitted well.

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FYI, the outlet on the BOV is 32mm o.d (probably quite a thick wall), the stem on the hks pipe is 19mm o.d (very thin wall)

 

The HKS outlet is approx 20mm or so, I definitely wouldn't worry about a 32mm to 19mm downsize with the setup involved.

 

You would get compressor stall/noise without the BOV though so I think it's a good way to go for your end result.

 

Out of curiosity, where did you get the clamps? I was looking for them a while back but struggled to find a suitable supplier.

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I got them from SFS :)

 

http://www.sfsperformance.co.uk/hose_clamps.asp

 

If you have a username on the 200sx owners club (SXOC, it's free to join) you get the club discount too. I think it was either 15% or 20% off, but it was a while ago now :)

 

 

My GT35R single ran without a BOV, and I loved the compressor stall noise, it was mental :cool: But I'd prefer this to be toned down a little if possible.

Edited by j_jza80 (see edit history)
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I got them from SFS :)

 

http://www.sfsperformance.co.uk/hose_clamps.asp

 

If you have a username on the 200sx owners club (SXOC, it's free to join) you get the club discount too. I think it was either 15% or 20% off, but it was a while ago now :)

 

 

My GT35R single ran without a BOV, and I loved the compressor stall noise, it was mental :cool: But I'd prefer this to be toned down a little if possible.

 

Superb, thanks very much for that. Everywhere else was charging an absolute arm and a leg :)

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