BOV location before mas or after?

T28 Joined: 27 Jul 2006 Posts: 215 Location: lockport

i feel like i should know this but does the blow off valve get located after the mas or before it when using a gm one? my guess is after (closer to the throttle body) but im not sure?

Posted: Sat May 01, 2010 9:02 pm

Right before the throttle body if you're using a GM MAF. You can't vent your bov worry free.

Posted: Sun May 02, 2010 5:10 pm

Not that I support blow thru setup anymore, but when I was running a gm maf the bov was after the maf. I was using a hks ssqv.

Here's a pic of it....

T28 Joined: 27 Jul 2006 Posts: 215 Location: lockport

i dont know what other setup to use, i have the latest dsmlink and ive got the harness for a gm mas instead of a translater. Ive been reading alot and finding that its inconsistant? i dont see why but im going to try it

Posted: Sun May 02, 2010 10:59 pm

Sorry I misread your question before. The sensor is right before the throttle body and the bov is before that. If the bov was after the sensor it would be similar to stock and you would have to recirculate it. The ECU is expecting any air that it has seen from the MAF, so you just need to make sure that all the air that the MAF sees makes it into the engine. You can get away with boost leaks much better with this setup as long as they're before the sensor. This doesn't really matter since there's no excuse for having a boost leak pre-throttle body. It's the intake manifold gasket and throttle bodies that leak more commonly. I hate leaky throttle bodies.

Look into speed density. I haven't done much research on it yet, but people seem to like it and you don't need a MAF, so you can also vent your bov and worry less about boost leaks. People tend to hate the GM MAF but the one car I drove with one pulled super hard on a 20g, no tune, and less than 100psi in a couple cylinders; the GM MAF must have been working pretty well then.

Posted: Mon May 03, 2010 8:26 am

nytalontsi wrote:

Not that I support blow thru setup anymore, but when I was running a gm maf the bov was after the maf. I was using a hks ssqv.

Here's a pic of it....

Your BOV is before the MAF in that shot Smile

Posted: Mon May 03, 2010 10:25 am

Yeah I'm probably going speed density when I get my car back on the road. More tuning capabilities and no MAF to limit me.

Posted: Tue May 04, 2010 11:01 am

Lol thanks Jordan I was looking at it the wrong way.

13b Joined: 11 Sep 2009 Posts: 61 Location: palmyra

wait what?.... i always thought you mounted gm mafs in the exhaust system...

Cooter Joined: 18 Feb 2005 Posts: 493 Location: Alden, NY

Carbonfiberhooded wrote:

Yeah I'm probably going speed density when I get my car back on the road. More tuning capabilities and no MAF to limit me.

When will you be back on the road?

T28 Joined: 27 Jul 2006 Posts: 215 Location: lockport

whats involved with a speed density set up?

Posted: Wed May 05, 2010 2:23 am

I know a map sensor is required.

Posted: Wed May 05, 2010 5:36 pm

Ramrodracer759 wrote:

whats involved with a speed density set up?

Speed Density 101 <- good links on the page to follow

ECMLink - Speed Density Setup

T28 Joined: 27 Jul 2006 Posts: 215 Location: lockport

very helpful, i have the break out harness with ecmlink so i need to get a map and iat sensors. so no one else on here is using this setup currently?

Posted: Thu May 06, 2010 9:43 pm

Like I said, I'm not yet.

To answer Cooter's question along with when will I be out and using speed density??? It's anyone's guess really. Could be next month, or the month after, or the month after that, or not at all. If it goes too late into summer, I may just pull the plug on it for this season.

Too many big things going on for me at the end of summer/early fall.