Topic: GT2871 with Synapse BOV- Issue at Idle and Low Speeds

[kennysabarese]

Miller. Would like to hear more about this. I get that you are putting hot compressed air back into the sustem, but You only recirc when you activate the bov which is only when you let off so it doesn't seem that you would get a large amount of hot air.

Also you guys are running less pressure than many people with the stock turbo so your IAT should be lower.

[elff]

Kenny

I've been trying to find a good pic of that.

Miller,
I don't see that being an issue. It's done on a ton of turbos and I'd you look at Hahns BoV it's how his is designed.
He hasnt caused issues with that.

[kennysabarese]

Kenny

I've been trying to find a good pic of that.

Here's the stock turbo example: the metal L with the red/black hose
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And this is more like what you would do with the Garrett (it's an efr turbo)
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All wrong again.

[kennysabarese]

Look at a picture of the stock turbo. You can see where it goes. There is an L shaped thing going right to the inlet with a blak hose going to it. The hose is connected to the BPV white plastic cover.

I was wrong about this. It doesn't go from the white cover to the inlet, it goes to the boost control solenoid on the intake manifold.

[miller11386]

Theoretically you are putting hotter air back in, if you have multiple rapid Bov actuations (ie: auto x) you could really build up some heat in the neck and compressor wheel of the turbo. Like I said, not saying its a bad idea, but I would def get an iat gauge to keep an eye on your intake temps.

[elff]

if that was an issue the K04s would be detonating left and right. They recirculate on the hot side because they don't have a separate Bov
Same goes for the EFR turbos

[Arabas]

elff are you sure you don't have a boost leak somewhere?

what about your IC? is it new? have you checked it?

[Arabas]

elff the turkey sound you get is it any of these two?

[miller11386]

if that was an issue the K04s would be detonating left and right. They recirculate on the hot side because they don't have a separate Bov
Same goes for the EFR turbos

From what I understand the K04 and EFR have a bypass valve that dumps to the exhaust. I am not 100% sure how the HAHN bov kit works but it looks like it recircs the hot side. Like I said it may not be an issue at all. I don't claim to be an expert. I would just be concerned  about the IAT's under a large load. However if you log w. hptuners you should be able to keep a pretty good eye on how hot the IAT's get.

If it does recirc to the hot side, and we could find a log of a car with a hahn bov kit from an auto x run, that would give us a pretty good idea.

[kennysabarese]

They definitely don't dump to the exhaust. The whole point of recirculating is that once the MAF reads the air, you can't throw it out of the system or the car will run rich. Also the recirculated air is supposed to keep the turbo spinning when shifting so it definitely is not going to exhaust.

[kennysabarese]

ok guys. so i was wrong with a lot of info here. i've been corrected and i'll try to explain this again. I'm shocked I didn't get jumped all over, shows how little we all know about this stuff

The K04 bypass air is not recirculated by that hose that comes off the BPV. That hose is for the control of it. So the recirculated air doesn't come into the black and red hose. That hose is for wastegate control.

The recirculation is all internal you can see this here in an EFR turbo (k04 does it the same way)
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So to add it to the Garrett setup you would just run it off the BOV and back to the intake side of the turbo.

[elff]

Miller

Let's just leave the AirFlow stuff to iHawk


Arabas,
Brand new DDM LNF Intercooler.
I think you missed this one post

I have a leak tester on the way with both gauge and tire valve. 

So I will be able to know for sure in a short period of time.
It doesn't sound anything like those 2 videos.  The one sounds like it's going to explode  It's only when I let off and it occurs as Air is being released.  At Wot, it's a single split second noise with the release of air.  At low psi, ie 5 or so, it's 2-3 then done in a situation once again where air is being released. 
I took about 5 people for test rides with the car and while Dave was tuning it, it was doing it, and no one mentioned it being an issue.

I've already posted this video with the sound.
Specifically pay attention to the 1:24 period and after.  I do a good job of getting the noise.
Click here

Kenny
So I would basically need to tap into Either my Dejon Intake, or the elbow that connects the Intake to the turbo.
How big of a tube would I need?  In the Hahn kit and in the DV Synapses, it seems like they use about a 1" diameter tube to do this.
Does that mean a vacuum tube would be too small?

[kennysabarese]

Synapse says what you need in the manual for the BOV http://www.synapseengineering.com/pdf/bov-manual.pdf

I would definitely check with Dave before doing this. He says it's not necessary.

[kennysabarese]

Here's a photo of an RX7 with Synapse setup to recirc.

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[elff]

I read that previously which is why I stated where I need to tap into the intake, which then connects to the compressor inlet.
*Changing my reply*
Looking at that picture indicates I need a 1.25" diameter spot added to my intake system somewhere. 
I would need to get something custom made to do that.

[Critterman]

Couple of questions:

1.  Car ran great before you started messing with it correct?
2.  It only fluttered or dipped RPM's when you came to a stop - never stalled, correct?

Now you are getting codes, making rude sounds and generally unhappy with it?

Can you put it back to were it was originally, until you get the pressure test done and HPTuners so you can start scanning it?

If you want to buy the credits, you can borrow My HPT

[kennysabarese]

I read that previously which is why I stated where I need to tap into the intake, which then connects to the compressor inlet.
*Changing my reply*
Looking at that picture indicates I need a 1.25" diameter spot added to my intake system somewhere. 
I would need to get something custom made to do that.

I assume the outlet size of the BOV will determine the size of the hose.

[elff]

I put it back to Port B because like you pointed out, I think I made things worse.
Changing to Port B from Port A+B improved the drive ability. 
As long as I don't get that engine code again, The only issue I have is the drop in RPMs at a stop which I've always had.
The noise is the same from day 1.  It's just different than other's

[elff]

If you look at the manual, It states 1.25" 

[miller11386]

I apologize on that. Thanks for the clarification Kenny


Btw elff, contact dave. My synapse came with the recirc fitting. so I would imagine yours did as well.

[elff]

DDM is a little tied up this week.
I'll give him a call next week when they are back from Nationals.

the fitting for the BOV isn't the issue.  It's getting a 1.25" port on my intake system.

[miller11386]

You have the dejon intake... so you would need to weld a fitting into the pipe...

So much for the virgin white pipes.

Maybe try to find another intake to practice it on?

[elff]

It doesn't necessarily have to go on the Intake.
I have a metal elbow after the intake that then connects to the compressor inlet on the turbo.
Here is the stock one compared to the Dejon Metal one.  [Stolen w/out permission from Steve's Review thread]

That might be a better option and I could ask Dave at Dejon to create one for me and have it powder coated so no loss of Engine Bay Bling.
I would have to install a single NPT fitting for the OCC line and that's all

[kennysabarese]

He'll just have to repaint it.

I wouldn't just assume this will solve all the problems. I have the same codes as you guys with a stock turbo which recirculates.

[elff]

This isn't for the code.

This is for the stumble at stops so the MAF doesn't go WTF.