Author Topic: GT2871 with Synapse BOV- Issue at Idle and Low Speeds (Read 45321 times)

spicy3480 · « **on:** June 12, 2011, 04:37:43 PM »

Hey All,
This was getting lost in another thread, so I thought I'd start a new one here. I currently have the GT2871 turbo upgrade with the Synapse Synchronic BOV. At idle, if I rev the engine, the BOV will release two times, followed by a quick drop in RPM's. It then bounces right back to normal.

*I tried adjusting the spring tension to no avail.
*Vacuum at idle is 18.5-18.8 in/Hg.
*The double release of the BOV is only at idle. The drop in RPM happens at low speeds as well.
*The MAF voltage seems to drop to almost zero when the RPM's drop, then it quickly recovers (seen in datalog by Lyndon Wester)
*My car is an AUTOMATIC

Here is the video of what it does...any ideas? I also attached the HP Tuners log in the bottom of this post. The log is when the car is at idle with revving. I am thinking I possibly have a vacuum leak? Thoughts?

http://www.youtube.com/watch?v=PzzPNXeNdh0

I plan on trying to run only one line from Port B and see if it helps, similar to what Elff did.

spicy3480 · « **Reply #1 on:** June 12, 2011, 04:50:58 PM »

Here are some pictures of the lines and where they are run.

Synapse BOV and GT2871 Turbo

BOV

T Section from BOV to Boost Solenoid

Spring Tension Adjustment Screw

Where the line from the BOV is connected (long hose on right)

Critterman · « **Reply #2 on:** June 12, 2011, 06:10:34 PM »

Quit reving in neutral

and I think it is port B not A you want the single line running to

spicy3480 · « **Reply #3 on:** June 12, 2011, 06:16:07 PM »

I meant Port B....thanks Critter....the drop in RPM is not an issue I want, and it happens when driving, so I have to find out what it is:) Vacuum leak maybe?

Critterman · « **Reply #4 on:** June 12, 2011, 06:18:23 PM »

did you try the spraying everything with a cleaner? I wouldn't overthink the issue, but do what elff told you to do and talk to Synopsis.

spicy3480 · « **Reply #5 on:** June 12, 2011, 06:20:49 PM »

Yes, I even cleaned the MAF sensor. I have a port with an open end on it that elff doesnt have...I'm comparing pictures now.

elff · « **Reply #6 on:** June 12, 2011, 07:14:26 PM »

We determined I have the same open port. Mine is just in the stock location as Steve has the Power Steering relocation kit.

Sounds like his connections to the back of the Bov are a little loose and might be losing some pressure

miller11386 · « **Reply #7 on:** June 12, 2011, 07:40:42 PM »

It should not make a difference on the connections. I have nothing to keep the hoses on the back of my Bov.....

shabby · « **Reply #8 on:** June 12, 2011, 08:59:20 PM »

Quote from: spicy3480 on June 12, 2011, 04:37:43 PM

Here is the video of what it does...any ideas?

Thats basically what happens when you vent a bov without relocating the maf sensor, not sure if that synapse anti stall kit will fix it since i never used it but moving the maf sensor to the cold side ic pipe will. Or you can possible try to increase your idle to say 850 or 900 rpm and see if it helps.

spicy3480 · « **Reply #9 on:** June 12, 2011, 09:12:38 PM »

Quote from: shabby on June 12, 2011, 08:59:20 PM

Thats basically what happens when you vent a bov without relocating the maf sensor, not sure if that synapse anti stall kit will fix it since i never used it but moving the maf sensor to the cold side ic pipe will. Or you can possible try to increase your idle to say 850 or 900 rpm and see if it helps.

That's odd because neither elff or miller have that RPM issue and their MAF was not relocated either.

elff · « **Reply #10 on:** June 12, 2011, 09:22:51 PM »

Just to list facts
I have a dejon intake
Miller and steve, what intakes do you have

spicy3480 · « **Reply #11 on:** June 12, 2011, 09:41:07 PM »

I have a ram-air intake by DDMWorks.

elff · « **Reply #12 on:** June 12, 2011, 10:56:43 PM »

Miller?

ihawk95 · « **Reply #13 on:** June 12, 2011, 11:38:50 PM »

I can tell you what Miller has so you all don't have to wait...

*edit* Nevermind...some of you can keep guessing, unless you can zoom in on it!

I prolly have a picture of it!

I do have a picture of it...along with the one of a kind, custom DDM cross bay brace!

Gentleman Jack · « **Reply #14 on:** June 12, 2011, 11:43:54 PM »

Please tell me where I can get one of those braces! I have contacted DDM, but sadly they are closed for the night. I am going to have to get me one of those.... That brace will make a HUGE difference in stability, horsepower, torque and acceleration!

GJ

elff · « **Reply #15 on:** June 12, 2011, 11:44:54 PM »

Will you please untie him and let him post his own reply

Thanks for the info.

ihawk95 · « **Reply #16 on:** June 12, 2011, 11:53:21 PM »

I edited my post to include the pic!

Hey, I'll edit back and leave the guesswork as to what intake he has up to you guys!! I couldn't tell ya if he's tied up or not. My guess is he's been asleep for a few hours now.

I knew the info because I got the story when Dave first sent it to him and figured you'd get a jump on comparing notes. Next time...I'll just tell ya all to look at his signature on the Big Boards. He has a list of mods. I'm surprised he doesn't have the list here.

ihawk95 · « **Reply #17 on:** June 12, 2011, 11:56:07 PM »

Quote from: Gentleman Jack on June 12, 2011, 11:43:54 PM

Please tell me where I can get one of those braces! I have contacted DDM, but sadly they are closed for the night. I am going to have to get me one of those.... That brace will make a HUGE difference in stability, horsepower, torque and acceleration!

GJ

BAHAHAHAHAHAHAHAHAHAHA!!!

But that one is one of a kind! Use a different type of material for the next one!

Arabas · « **Reply #18 on:** June 13, 2011, 04:00:04 AM »

steve 2 things:

1. how come you guys didn't locate the bov on the cold side pipe? this way you could save some space around the turbo and the line wouldn't have to run half the engine bay
2. i believe you have the OCC conected to the "wrong" hose of the engine. can't be 100% sure from these pics but that's what i can distinguish.

sorry i can't help with the actual problem and thx for all the pics, videos

miller11386 · « **Reply #19 on:** June 13, 2011, 05:59:39 AM »

Quote from: elff on June 12, 2011, 10:56:43 PM

Miller?

Fujita intake.

And yes that new cross bay brace makes a HUGE difference. You would never believe it!

(when you posted that I was definitely asleep. It suck being old!

)

miller11386 · « **Reply #20 on:** June 13, 2011, 06:02:37 AM »

Steve,

If you want to try an antistall fitting, I can bring that to canada as well. My antistall was what gave me my codes thrown for the "CBV being stuck closed" ... even though I dont have a CBV anymore...

But maybe the autos need it! Cant hurt to try it. So now will you come to the event in Ajax?

Wartie · « **Reply #21 on:** June 13, 2011, 06:08:30 AM »

Quote from: miller11386 on June 13, 2011, 05:59:39 AM

(when you posted that I was definitely asleep. It suck being old! )

Give me a break!!!!!!!

miller11386 · « **Reply #22 on:** June 13, 2011, 07:39:57 AM »

I am also curious if the hot side is the best side for the BOV to be attached. Im not sure if location is an issue or not.

All the higher HP turbo cars I have looked at always mount a BOV as close to the throttle body as they can. That is what makes sense to me because the air is stopping at the throttle body and needs to escape from that point.

Imagine if you had a constricting intercooler. Why would you really want to make the air in the system run back through an intercooler to escape? I mean Im not saying it cant work on the hot side (obviously elff's does), but if you ever did decide to recirculate the BOV, you would definitely want it from the cold pipe just due to the fact that you wont want to put HOT turbo air back in the intake.

Also think of your system loaded up. Imagine, lets say, 30PSI in your turbo pipes. Now you let off the throttle quickly and begin braking. You are asking that volume of air to be stopped by the throttle plate, and pushed all the way back around and through the intercooler before escaping. Should it? Yes in theory it should be able to push all the way back around. Will some of it push through your throttle plate? I dont know. Is it pushing back around and surging through the intercooler? Maybe the first gulp clears the hot side, the BOV closes then burps the air from the other side of the cooler? Or maybe its gulping the air from the ram air intake?

Not really sure. Now I am starting to see why Dave just LOVES to see your car coming for mods

Kelu · « **Reply #23 on:** June 13, 2011, 08:46:33 AM »

Having BOV on the hot side is not so wrong as it might look except the fact you put extra pressure on IC and pipe joints, when you do let's say 30psi of boost, when the throttle body closes it spikes a lot more pressure like 45psi, this is the only downside imho.

When we are talking about pressurized areas, the statements like "air has to travel back" from tb to BOV located on hot side is wrong imho because no matter where you release the pressure, pressure will be released instantly from starting that point.

miller11386 · « **Reply #24 on:** June 13, 2011, 09:02:17 AM »

You don’t agree that the flow would reverse, Kelu?

I just think you want to release at point of actuation. Think of a long pipe. Let’s imagine a part of a pipeline. It has a volume of water running through it at a pressure (30psi). The velocity of whatever is in the pipe, must be stopped, and travel out at the release point (BOV). If you have a Blow-off valve on the end where you want the flow to stop, would you want to open the valve and release the pressure near the point of use, or a mile upstream? If you release upstream, the volume in the pipe would have some momentum and smack into the closed valve until the pressure drops from the diverter valve that is a mile up the pipe.. Assuming that valve stayed open, the flow would have to reverse and go toward the valve opening that is upstream. The mass would have a velocity to it. I would think just as you open the valve it would have a momentum toward the stopping point (TB).

But maybe I am taking it way too far. Just trying to draw a picture for what I am seeing in my mind. Could be completely wrong, obviously I’m waaaaay new to the turbo scene to claim to have a clue what is going on. I just am drawing from what I know from my engineering background.

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Author Topic: GT2871 with Synapse BOV- Issue at Idle and Low Speeds (Read 45321 times)