I've got a problem with my BOV.Its a old school HKS Racing Bypass Valve.It works as a BOV and as a Pop-off valve (for boost control)The front vac nipple is for the BOV and the Rear angled nipple is for the Pop-off.Its a white (soft) spring which is 3.5psi - 9psi (Pop-off)Supposedly HKS says that the spring does not affect BOV operation at all.
When I start the car I've noticed that the BOV is open at idle.Not just a little about 3/4 of an inch.I can also feel it sucking air in and when I cover it with my hand I improve the idle quality.When I start opening up the throttle I can feel it go from sucking to blowing and then it closes.
But when I drive it, it idles funny.It will stutter, shudder and hesistate.Its fine while accelerating and engine braking (deceleration)But on part throttle and crusing it stutters and acts up.I can also hear the BOV crack open and whistle too, then the car starts acting up.
So it seems that the BOV is my problem at this point.I've zip tied all the vac lines and it still does it.
I've spoken to one guy who has a KA-T and he says that his BOV is open at idle as well.That its supposed to be.
It kinda makes sense but yet doesn't.Because the BOV opens when it see's vacuum.And uses boost to help it keep closed.
I looked at my Boost/Vac gauge and I'm pulling 22 in/hg at idleWhat is everyone else pulling?Mine might be a bit different because my 20 is bored out a bit.
Also I've got my BOV hooked up to my Vaccum block.Which is hooked up directly to the back of my Top Hat ITM.My boost gauge and FPR are hooked up directly to that as well.
I've tightened down the BOV all the way but I have yet to take her for another test drive.I'll do that tonight.
Any info would be helpful
Modified by Sil240 at 4:48 PM 10/16/2008
RB20DET BOV issues
Ok, I've badgered a whole bunch of people and so far the verdict is either.A- Get a stiffer spring ($27.00 from HKS)B- Put some JDM HDT (Ho-depot) Washers in there
So tonight I'm gonna take her for a test drive see how she is, then take it apart and look about some washers
I'll take some pics and post up later.
So tonight I'm gonna take her for a test drive see how she is, then take it apart and look about some washers
I'll take some pics and post up later.
I took her out last night without putting any washers in.Just with the BOV tightened down all the way.And she's running a shyt ton better.
Just at idle its funny.And I'm looking at my AFR gauge (not wideband).Starting it's CRAZY lean.Then while i'm running at idle its ok, bouncing back and forth, but driving its pegged RICH.I have no idea what exact AFR I'm running but she was feeling pretty good.I don't know how much boost I was running or how fast I was going.
But I did a 1st and 2nd run about 2 blocks and the car is pretty Fockin fast.Very impressed!!!!
I only took 1 run because I popped the fuse (150 amp)But it was probably due to the ghetto rigged battery.I don't have any space up front for the batt, so to get the car home from the shop I hooked up 2 20ft pieces of 4 gauge to my battery and stuck it on the pass side floor.
I'm guessing those small gauge, long power leads were causing a lot of amperage draw and popped the fuse.
So I'm going to scout out some 0, 1, or 2 gauge wires and cop a batt box and mount it in the trunk.
My little Odessy PC680 isn't cutting it.So if anyone needs one LMK
I'm also gonna pull my BOV apart and grab some washers to keep the valve closed at idle.
I have a 15psi wastegate, but stock fuel and ecu.Do you think I should hook up my BOV to work as a pop-off valve also?It should limit me to 9psi. The white spring is good for (3.5 - 9psi)Since its a bigger turbo I think I might do that.
Now that I'm thinking.That screw at the top of the BOV might only be for the Pop-off valve.So the BOV function may not be adjustable.Either that or I might run a piece of hose to re-route my bov and not worry about it.I just gotta get someone to weld a port onto my intake pipe.
Just at idle its funny.And I'm looking at my AFR gauge (not wideband).Starting it's CRAZY lean.Then while i'm running at idle its ok, bouncing back and forth, but driving its pegged RICH.I have no idea what exact AFR I'm running but she was feeling pretty good.I don't know how much boost I was running or how fast I was going.
But I did a 1st and 2nd run about 2 blocks and the car is pretty Fockin fast.Very impressed!!!!
I only took 1 run because I popped the fuse (150 amp)But it was probably due to the ghetto rigged battery.I don't have any space up front for the batt, so to get the car home from the shop I hooked up 2 20ft pieces of 4 gauge to my battery and stuck it on the pass side floor.
I'm guessing those small gauge, long power leads were causing a lot of amperage draw and popped the fuse.
So I'm going to scout out some 0, 1, or 2 gauge wires and cop a batt box and mount it in the trunk.
My little Odessy PC680 isn't cutting it.So if anyone needs one LMK
I'm also gonna pull my BOV apart and grab some washers to keep the valve closed at idle.
I have a 15psi wastegate, but stock fuel and ecu.Do you think I should hook up my BOV to work as a pop-off valve also?It should limit me to 9psi. The white spring is good for (3.5 - 9psi)Since its a bigger turbo I think I might do that.
Now that I'm thinking.That screw at the top of the BOV might only be for the Pop-off valve.So the BOV function may not be adjustable.Either that or I might run a piece of hose to re-route my bov and not worry about it.I just gotta get someone to weld a port onto my intake pipe.