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View Full Version : SR20DET questions... (not answered in the FAQs)

isdeways
05-23-2006, 07:45 AM
Alrighty, I've searched and searched and have yet to find the answers I'm looking for. I'm just here to help a friend out.

SR20DET in an S13 Hatch.

1) Is there a stock blow off valve on the SR20DET motor?
I would assume there is only because I can see the hose for recirculating the metered air back into the intake tract (turbo tiburons have the same issue with venting to atmostphere type BOVs and the MAF setup). The reason I ask the first question is for the second...

2) Has anyone else suffered from compressor surge on a freshly swapped motor and is this a common issue with the SR20s or are they setup from the factory this way?
The sounds I'm hearing from my friend's turbo is definitely compressor surge and I was wondering if all that needed to be done was an adjustment on the spring on the BOV (if there is a stock one). If this is not the case...

3) If the BOV can't be adjusted (read ?s 1 and 2 first), is it possible that his internal wastegate is shot?
I guess this is what we're looking at for worst case scenario. A turbo rebuild would be a good idea at that point (i think?).


Thanks for reading and for the responses. I'm expecting a mild flaming from the hot shots on the boards (as we get on the newtiburon forums) but hopefully some of the wrenchers will answer up.

Thanks

EDIT: It's a redtop in case that makes a difference.
sblack13
05-23-2006, 08:13 AM
well what kind of setup is your friend running?
And yes on sr20's there is a stock bov. On the s13's it's located next to the smic, and on the s14 it's located by the fuse box.
isdeways
05-23-2006, 08:14 AM
well what kind of setup is your friend running?
And yes on sr20's there is a stock bov. On the s13's it's located next to the smic, and on the s14 it's located by the fuse box.

Stock everything.

That's what I thought. He's gonna need a boost gauge to properly adujust it, correct? And this should cure the backspool (compressor surge) he's dealing with, right?
TheTimanator
05-23-2006, 08:17 AM
1) Is there a stock blow off valve on the SR20DET motor?
I would assume there is only because I can see the hose for recirculating the metered air back into the intake tract (turbo tiburons have the same issue with venting to atmostphere type BOVs and the MAF setup). The reason I ask the first question is for the second...
There is a stock blow-off valve. It is mounted along with factory sidemount intercooler. I'm unsure if it's adjuctable as I never had to mess with it.

How much are you boosting? (or your friend or whatever) Stock is 7psi on an S13 SR. That should help to tell if the wastegate is functioning corectly.
isdeways
05-23-2006, 08:24 AM
There is a stock blow-off valve. It is mounted along with factory sidemount intercooler. I'm unsure if it's adjuctable as I never had to mess with it.

How much are you boosting? (or your friend or whatever) Stock is 7psi on an S13 SR. That should help to tell if the wastegate is functioning corectly.

He doesn't have a boost gauge yet (which I told him is crucial) so he has no idea what amount of psi the turbo is putting out.

With the sound of compressor surge, I'd assume that either the BOV or wastegate is improperly set but again without a boost gauge it's impossible to tell.

EDIT: Haha, it's definitely my friend who should be up here looking for this info but I just want to know it off hand in case it's needed. I drive an NA tiburon that I'm quite fond of. I might build an S13 240 in the future as a project car but we'll see.
g6civcx
05-23-2006, 09:44 AM
This is the S13 SR with sidemount. The stock compressor bypass valve (CBV) is located where the cap is in the picture.



http://g6civcx.angryhosting.com/S13/Tech/SMIC1.JPG

Check your CBV vacuum line. It should be this large vacuum line seen here, and it goes straight to the throttle body. It doesn't go off anywhere else.

http://g6civcx.angryhosting.com/S13/Tech/SMIC2.JPG

You can see the vacuum line here on the TB. It's the larger line on the top, right on top of the b and right where the ' is next to the b. It goes straight to the right.

http://g6civcx.angryhosting.com/S13/Tech/I_AM_SLOW/1.jpg
isdeways
05-23-2006, 10:38 AM
That's the vaccuum hose off of the throttle body to use for hte boost gauge I'd assume.

Thanks.
isdeways
05-23-2006, 11:56 AM
"as for your BOV, the fluttering noise is your compressor surging, i had the same problem. Make sure you run your BOV on its own independant vacuum source and dont T it off of the wastegate signal, this was what was wrong with mine"

I just found this statement and I'm just going to post it in this thread so I can use this as reference later.
isdeways
05-25-2006, 06:40 AM
It turned out to be a vaccuum leak (so the CBV wasn't opening properly) and that's what was causing the compressor surge. Thanks guys for all the help.