[LYEGUY]

Hello,

After installing my catless downpipes and switching to an MHD Stage 2+ Tune, I began noticing a very faint fluttering sound during acceleration. I can hear this sound under a moderate and heavy acceleration. At first the turbo spool sounds normal but as the RPM climbs that flutter sound starts

Max boost on this Tune is right under 17psi, from what I understand people run up to 19-20psi and don't experience problems so I'm really stumped as to why this is happening. There are no codes or jolting or anything like that just a fluttering sound when accelerating.

Here is a list of my currents Mods:

MHD Stage 2+ Tune
Catless Downpipes
AA Race Intercooler
VRSF Chargepipe
Forge DV's

Short Log I Took Yesterday: https://datazap.me/u/lyeguy/march-22...og=0&data=3-21

This only happens under acceleration so I'm pretty sure it isn't diverted valve related. Any help would be greatly appreciated. Thanks

[T1M]

Logs please. Hard to say what is happening without them it's just guessing.

[LYEGUY]

Originally Posted by T1M

Logs please. Hard to say what is happening without them it's just guessing.

I'll post some logs after I get out of work. Should I be looking for anything specific in my logs?

[LYEGUY]

Originally Posted by T1M

Logs please. Hard to say what is happening without them it's just guessing.

Added Log

[dcafs]

What colour springs are installed on the forge?

[CarAbuser]

Logs look good. No problems other than some timing corrections.

[LYEGUY]

Originally Posted by dcafs

What colour springs are installed on the forge?

Yellows but they are old (Yellow Paint is starting to chip) Do you think that would make a difference? I didn't think it was a DV problem because I was hearing the flutter sound on acceleration and the DV's are closed anyway

[Chris@VargasTurboTech]

We have had some issues in the past with the Forge getting "sticky" and/or slow to respond. Suggest a rebuild and make sure that you have a dedicated nice big thick line directly from your manifold to them.

Flutter on acceleration (if real) is not good for turbo longevity at all. Def take some logs and see what's going on.

Chris

[LYEGUY]

Originally Posted by Chris@VargasTurboTech

We have had some issues in the past with the Forge getting "sticky" and/or slow to respond. Suggest a rebuild and make sure that you have a dedicated nice big thick line directly from your manifold to them.

Flutter on acceleration (if real) is not good for turbo longevity at all. Def take some logs and see what's going on.

Chris

I posted a log up top I don't know if you can tell anything from that. What should I be looking for in my logs to determine compressor surge?

Also, from what I understand, The DV's would only be causing compressor surge problems on deceleration. Since I'm hearing this sound on acceleration am I safe to assume the DV's aren't the problem or no?

[Chris@VargasTurboTech]

Nothing screams out to me about on-throttle surging, you do have a throttle closure -small- that could possibly be causing you a little grief and if your ears are sensitive might be what you hear. With no disrespect to the MHD tunes at all, ultimately it's always best to have a pro-tune for your specific car/altitude/fuel/etc. Try putting on a more conservative map and seeing if the issue repeats.

As to directly answer your question about on throttle.... if you get a partial throttle closure, once the pressure differential between your manifold and the charge pipe reaches some X value (depends on BOV/BPV/Springs used), the valve(s) are supposed to quickly bleed off excess boost. With a lighter spring and a better line, even with that quick throttle closure you have it might be enough to get rid of what you're hearing. I don't have enough information here to promise you one way or the other, but it's always good practice to make sure the mechanical components are functioning properly.

All the above said.... remember you have to hold the keyboard close to my ears so I can hear what you're hearing, lol.

Chris

[LYEGUY]

Originally Posted by Chris@VargasTurboTech

Nothing screams out to me about on-throttle surging, you do have a throttle closure -small- that could possibly be causing you a little grief and if your ears are sensitive might be what you hear. With no disrespect to the MHD tunes at all, ultimately it's always best to have a pro-tune for your specific car/altitude/fuel/etc. Try putting on a more conservative map and seeing if the issue repeats.

As to directly answer your question about on throttle.... if you get a partial throttle closure, once the pressure differential between your manifold and the charge pipe reaches some X value (depends on BOV/BPV/Springs used), the valve(s) are supposed to quickly bleed off excess boost. With a lighter spring and a better line, even with that quick throttle closure you have it might be enough to get rid of what you're hearing. I don't have enough information here to promise you one way or the other, but it's always good practice to make sure the mechanical components are functioning properly.

All the above said.... remember you have to hold the keyboard close to my ears so I can hear what you're hearing, lol.

Chris

Thanks again for getting back to me so soon.

It could just be me I am very finicky about sounds and I can only hear it with the windows down at lower speeds. Also I've been paying more attention and it only seems to be happening at lower RPM's with partial throttle openings.

With that being said I have ordered a rebuild kit as well as a spring kit for my forge DV's and I'm gonna message Wedge about getting a custom tune.

How do I go about getting thicker lines to my DV's?

Thanks again and I look forward to your response

[Chris@VargasTurboTech]

Originally Posted by LYEGUY

Thanks again for getting back to me so soon.

It could just be me I am very finicky about sounds and I can only hear it with the windows down at lower speeds. Also I've been paying more attention and it only seems to be happening at lower RPM's with partial throttle openings.

With that being said I have ordered a rebuild kit as well as a spring kit for my forge DV's and I'm gonna message Wedge about getting a custom tune.

How do I go about getting thicker lines to my DV's?

Thanks again and I look forward to your response

IIRC the forge each have their own line, the normal way to go about this is to drill and tap the intake manifold.

That said, recently a different vendor came up with a solution to avoid drilling and tapping the manifold. I haven't tested it to ensure it works as advertised but it looks promising. I sent you a PM with more details about the Tmap BOV Line Adapter.

Chris

[dcafs]

Originally Posted by LYEGUY

Thanks again for getting back to me so soon.

It could just be me I am very finicky about sounds and I can only hear it with the windows down at lower speeds. Also I've been paying more attention and it only seems to be happening at lower RPM's with partial throttle openings.

With that being said I have ordered a rebuild kit as well as a spring kit for my forge DV's and I'm gonna message Wedge about getting a custom tune.

How do I go about getting thicker lines to my DV's?

Thanks again and I look forward to your response

Key point - "partial throttle openings"......therefore you have a differential between the boost pressure in your charge pipe and the boost pressure in the intake manifold.
The diverter valves crack open with about a 4 psi differential and you should hear a hissing sound as the valves bleed off the pressure difference.

Is that what you are referring to a surging?

I experienced turbo flutter on my GTI and it sounded like chirping - not hissing.

When I go part throttle on my 135i, the forge valves hiss quite a bit until I fully open the throttle. It's just boost pressure in the charge pipe getting ahead of the pressure in the manifold because the throttle plate is partially restricting full flow and this triggers the DV's to crack

[LYEGUY]

Originally Posted by dcafs

Key point - "partial throttle openings"......therefore you have a differential between the boost pressure in your charge pipe and the boost pressure in the intake manifold.
The diverter valves crack open with about a 4 psi differential and you should hear a hissing sound as the valves bleed off the pressure difference.

Is that what you are referring to a surging?

I experienced turbo flutter on my GTI and it sounded like chirping - not hissing.

When I go part throttle on my 135i, the forge valves hiss quite a bit until I fully open the throttle. It's just boost pressure in the charge pipe getting ahead of the pressure in the manifold because the throttle plate is partially restricting full flow and this triggers the DV's to crack

I would describe the sound as someone trying to make a machine gun sound with there mouth (Hope that makes sense) Definately not a chirping though

[FireBlaze]

Originally Posted by LYEGUY

Thanks again for getting back to me so soon.

It could just be me I am very finicky about sounds and I can only hear it with the windows down at lower speeds. Also I've been paying more attention and it only seems to be happening at lower RPM's with partial throttle openings.

With that being said I have ordered a rebuild kit as well as a spring kit for my forge DV's and I'm gonna message Wedge about getting a custom tune.

How do I go about getting thicker lines to my DV's?

Thanks again and I look forward to your response

Are you sure you're not just hearing the raspy exhaust due to being cat-less now? My exhaust sounded more raspy and a little wheezy at low rpm city driving. I'm pretty sure its normal.

[dcafs]

Originally Posted by LYEGUY

I would describe the sound as someone trying to make a machine gun sound with there mouth (Hope that makes sense) Definately not a chirping though

That sounds like the DV's fluttering to me....maybe oscillating on the very edge of cracking pressure back and forth.

If it happens on part throttle only then I would get new springs or you can add the shims that came with the kit to stiffen up your existing ones.

I guess over time the springs lose their stiffness (kind of like me getting older....lol)

In fact, I am going to shim mine next time I open up the DV's.

[Faredo]

Look at his throttle position at 4085.

[LYEGUY]

Originally Posted by Faredo

Look at his throttle position at 4085.

Care to elaborate?

[Faredo]

Originally Posted by LYEGUY

Care to elaborate?

your throttle is closing a bit during your pull. looks like you where easing into it by pedal position. There was a slight overboost about 1k beforehand that might have caused your throttle to back off a moment. You might have heard flutter near the top of your roll in, 4085.

[GEOS07335i]

Originally Posted by Chris@VargasTurboTech

IIRC the forge each have their own line, the normal way to go about this is to drill and tap the intake manifold.

That said, recently a different vendor came up with a solution to avoid drilling and tapping the manifold. I haven't tested it to ensure it works as advertised but it looks promising. I sent you a PM with more details about the Tmap BOV Line Adapter.

Chris

Are there other vendors other than Vader solutions? I'm pretty upset about the customer service so far.

[Chris@VargasTurboTech]

I'm not aware -shoot me an email with your info and I'll beat on him a little for you (he actually lives pretty close to me).

Chris

[GEOS07335i]

Originally Posted by Chris@VargasTurboTech

I'm not aware -shoot me an email with your info and I'll beat on him a little for you (he actually lives pretty close to me).

Chris

Chris,
Thanks for the offer I just checked and it looks like the shipment is now in Transit. Expected delivery on Saturday.