Blow off valve and compressor surge between tunes

W

Wojomojo

New member
So since I added methanol and updated my tune, I've gotten compressor surge instead of blow off valve noise (vented to atmosphere). If I switch back to my tune before methanol, my blow off valves work every time. With my methanol tune I get compressor surge and don't get the blow off noise. Every once in a while I'll get the surge and then right at the end the smallest little bit of blow off valve noise.

I'm tuned with Torrie at Unleashed. I emailed him and he said he did nothing but add boost. Don't get why it would work with one tune and not another if he didn't change anything else.

Any ideas as to what's up? Just don't want to wreck my turbos as apparently surge is bad.
 
How much boost are you seeing now with the methanol tune?  You could always have the boost backed down to see if that is contributing to the compressor surge.  Any smoke from the tailpipe?
 
See what bugs me is that if I just Rev it lightly in park, the bovs don't work with my meth tune. I'd only be making like 4 psi under a Rev. If I switch to the tune before, light revs will work with the bov. So the bovs do work. I don't see why the increased boost would cause them to not work when making the lower boost. Like I could see at 23 psi they could possibly not open up, but they should open under a Rev or when making low boost.
 
Make sure you don't have a boost leak, I'd check all piping to the turbos visually first. If you don't see anything you can build a boost leak tester and that to rule out a leak in the system. Might be leaking at the higher PSI.
 
I've been doing research all night and I guess I'm just still confused. Why would I be able to switch a tune and the blow off valve works flawlessly every time, then switch to a another tune and it never works. A boost leak doesn't seem to explain that. If I make 8 psi in either tune, one will open bov and one won't. I'll check all the piping/hoses and wires, but still doesn't make sense to me. It's like one tune doesn't create negative vacuum somehow to open the bov. I can do some testing on that today too.
 
The bov's on these cars are electronically opened and are located in the tube coming from the turbos to the intercooler. The waste gate's are inside the turbo's allowing exhaust to bypass the turbo.

Your issue from what I understand Is you do not hear boost blowing off when you let off the gas correct?

Or are you saying your boost pressure is surging in large increments under a load?  If you upload a data log of the issue it would help.
 
Under boost and throttle let off, I don't hear the psshh, the bovs aren't opening. I hear a whine/whistle, the sound of air going back through the turbos. If I switch to my previous tune the blown off valves work all the time. I realize they're electronic because there's no line going directly to the bovs. As I'm typing this I just checked all my lines and they looked good. I just switched back to my old tune again and the bovs work fine. Gonna go for a cruise and see if they keep working under high boost.
 
Wojomojo said:
Under boost and throttle let off, I don't hear the psshh, the bovs aren't opening. I hear a whine/whistle, the sound of air going back through the turbos. If I switch to my previous tune the blown off valves work all the time. I realize they're electronic because there's no line going directly to the bovs. As I'm typing this I just checked all my lines and they looked good. I just switched back to my old tune again and the bovs work fine. Gonna go for a cruise and see if they keep working under high boost.
Click to expand...
All you can do then is try to log the pressure surge and show Torrie the issue.   
 
I probably should make a note that this behavior can change with tunes.  For example, with some of LME's tunes, it is common to hear a honking sound (like a duck call?), while with others it's a normal BOV sound.  May not be anything amiss with the tune at all.
 
SHOdded said:
I probably should make a note that this behavior can change with tunes.  For example, with some of LME's tunes, it is common to hear a honking sound (like a duck call?), while with others it's a normal BOV sound.  May not be anything amiss with the tune at all.
Click to expand...
Quack Quack lol SHOdded.
 
Holy christ. Look at your charge pipes flexing. You may be experiencing a problem as there is in influx of pressure heading into your inner cooler tubes.... but due to the expansion of the rubber, it is not making it into the manifold. This absolutely would cause surginess and with the map sensor not reading the proper pressures, it doesn't know when to open the waste gate and a multitude of things. I vote that is your problem right there.

 
Stupid questions here -- you SURE that you have a 3 bar map sensor? Can you verify your part number is CX-2231 -aa5z-9f479-b?

Can you get the BOV noise under low charge? SO small boost increments? That would rule out the pipe flexing issue (which I think you will still want to address...

I tend to agree that your BOV is not working at all with the meth tune.

 
Yeah its the 3 bar, purchased from ecopowerparts. In the correct spot as well. The video shown with the bovs working is a 3 bar tune, and yes my bovs work in that tune under extremely low boost. Barely applying throttle while driving will still create the psshh noise.

The new meth tune under any amount of boost, both low and heavy boost will have no blow off noise, just the screech/squeal
 
I remember seeing my OEM (rubber) bends blowing up like the huge, football sized steak burrito's I've been known to scarf down every now & then.

One of the thankful reasons I upgraded to the hard charge/hot pipes.

No more worries about that, or potential ruptures/boost leaks.
 
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