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Discussion Starter #1
Hey guys. Ive been searching around for the best way to check for a boost leak. I have taken my car into two shops and both said they couldnt find a leak. I thought it was DP or Exhaust related but it ended up not being. Car runs strong. No misfires or anything. Pulls to redline and such. Its on an E54 Tune with the Aux rail (for reference). When looking through the logs and speaking with Adam, it looks like the car is making about 13-14 psi. Last tune on 91 the car was making 25. Said the tune is requesting the same amount of boost as the 91 so I must have a leak somewhere.

As for things Ive tried:

Checked hose clamps on Hardpipes.
Check Turbosmart WGA (I have the old two hose version on the NX2). Both are seated and secured. The line that goes to the BRA seems fine. Cant hear any crazy wooshing from anywhere particular.
Checked the Intake.
Checked the TB Clamps

Honestly... I dont know. Its odd that it makes the 13 psi and doesnt tail off anywhere. Just pegs and stays.

I have a few logs if anyone is interested. Or if there is anything I can buy to test this myself....
 

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Back in my fast and furious days, I made a boost leak tester out of some pvc pipes and some compressed air fittings. Basically pressurizing the compressor side of the system close to your boost pressure and feeling/listening for leaks. I'm sure you'll find some diys on YouTube.

That said, if your car is behaving normally and pulls hard and you've checked for leaks, I have a feeling there is no issue. The way I understand how our cars control boost, you only get as much boost as you need to hit a certain torque target. Perhaps with the better fuel, you are not needing as much boost as on 91?
 

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Hey guys. Ive been searching around for the best way to check for a boost leak. I have taken my car into two shops and both said they couldnt find a leak. I thought it was DP or Exhaust related but it ended up not being. Car runs strong. No misfires or anything. Pulls to redline and such. Its on an E54 Tune with the Aux rail (for reference). When looking through the logs and speaking with Adam, it looks like the car is making about 13-14 psi. Last tune on 91 the car was making 25. Said the tune is requesting the same amount of boost as the 91 so I must have a leak somewhere.

As for things Ive tried:

Checked hose clamps on Hardpipes.
Check Turbosmart WGA (I have the old two hose version on the NX2). Both are seated and secured. The line that goes to the BRA seems fine. Cant hear any crazy wooshing from anywhere particular.
Checked the Intake.
Checked the TB Clamps

Honestly... I dont know. Its odd that it makes the 13 psi and doesnt tail off anywhere. Just pegs and stays.

I have a few logs if anyone is interested. Or if there is anything I can buy to test this myself....
If all the clamps are tight and the pipeware isn't cracked then a boost leak wont be the problem. Is there a reason it wouldn't more likely be a faulty boost solenoid stuck open and bleeding off boost pressure and therefor relying on waste gate actuator spring pressure only to hold boost?
Seems to me the main pipes and IC are the most reliable parts of the pressure system. More so than the control side.

Ciao
 

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Discussion Starter #6
Thanks for all the input. Gonna do a pressure check Tuesday with a pressure tester and see it there are any obvious leaks. The car has a full type b motor. Cpe charge pipes. Turbosmart bov etc. It started doing the low boost thing after some hard launches so I'm thinking it's not a software problem. Hopefully it's gonna be simple but maybe it is a stuck selonoid. How do I check that?
 

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Thanks for all the input. Gonna do a pressure check Tuesday with a pressure tester and see it there are any obvious leaks. The car has a full type b motor. Cpe charge pipes. Turbosmart bov etc. It started doing the low boost thing after some hard launches so I'm thinking it's not a software problem. Hopefully it's gonna be simple but maybe it is a stuck selonoid. How do I check that?
Well its ab simple device, an electromagnetic solenoid operating a normally closed valve. If you suck or blow through the line to the it should hold pressure if not its leaking.
Got it all pressurized. At 12 psi the bottom of the wga does this...

Not sure what I'm looking at here in the video but it looks to me like a sense line insnt properly installed on the upper end in the image.

Ciao
 

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It's pissing air from the actual bottom of the wga where the rod is.
OK, bit hard to see air in a video,lol. I'd check that sense line though,looks like the clamp isn't actually seated over the base of the spigot but further down the hose. This isn't whats really leaking is it?

Ciao
 

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Discussion Starter #11
Sorry! Yeah it's the only thing that's leaking. The rest is tight. No leaks. You can hear it and when you put your finger up there the air is blowing across the rod that is connected to the turbo.
 

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Sorry! Yeah it's the only thing that's leaking. The rest is tight. No leaks. You can hear it and when you put your finger up there the air is blowing across the rod that is connected to the turbo.
Ok cool, at least you found the issue. It been relying solely on the spring pressure for boost control hence the low boost pressure. Thats a Turbosmart unit isn't it?

Ciao
 

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Discussion Starter #13
Yeah. That's what's confusing. Adam just said that it's normal for that to do it to self regulate pressure? And yeah it's a twin port iwg75
 

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Yeah. That's what's confusing. Adam just said that it's normal for that to do it to self regulate pressure? And yeah it's a twin port iwg75
If you lose boost sense pressure to the valve then you will have low boost pressure controlled by the spring only. The valve uses the boost pressure to assist the spring keeping the valve closed and bleeds that pressure off as a means of reducing boost by virtue of the fact that now the pressure on the bypass valve from the exhaust can overpower the spring and the reduced sense pressure in the bypass valve actuator.
Ciao
 

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Discussion Starter #15
If you lose boost sense pressure to the valve then you will have low boost pressure controlled by the spring only. The valve uses the boost pressure to assist the spring keeping the valve closed and bleeds that pressure off as a means of reducing boost by virtue of the fact that now the pressure on the bypass valve from the exhaust can overpower the spring and the reduced sense pressure in the bypass valve actuator.
Ciao
These things confuse the hell out of me. I'm actually not normally this dumb about motors but this is my first turbo car.

I'm assuming from what I'm reading is that right now it's simply the spring that is allowing the system to get to 13 psi. But it's not functioning correctly to allow for any higher levels of pressure. I know on some setups the bottom port on them vent to atmosphere but on ours that's not the case. So if it's leaking from the actual housing itself that it might be a torn diaphragm.

Am I close? Lol sorry and thank you a ton for the education!
 

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If it's leaking from around the rod coming out of the dome section of the actuator, that leads to the wastegate flapper, something is not right, 100%
 

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Discussion Starter #17
If it's leaking from around the rod coming out of the dome section of the actuator, that leads to the wastegate flapper, something is not right, 100%
Yes that's 100% where it's just pissing air out. You can hear the air in the video but if you reach up there but if you reach up there with your hand you can feel it coming directly from the bottom of the wga
 

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Yes that's 100% where it's just pissing air out. You can hear the air in the video but if you reach up there but if you reach up there with your hand you can feel it coming directly from the bottom of the wga
Yes thats not right. Very unusual for a Turbosmart unit to leak I think. However beware, and without being critical of your troubleshooting air leaks can be very hard to pinpoint sometimes. I've had this happen to me many times over the years in your situation trying to locate air leaks in confined locations with lots of other potential leak source around as the air can shoot out of the actual leak location and then deflect off other things giving you a false impression. I only mention it because its so unusual for a turbosmart unit to fail. Best way is to mix up a soap and water solution( without it getting sudsy) and apply it to the suspect area then increase the pressure as you look for bubbles. We used to use a dedicated solution called "snoop" but the home made stuff is just as good.

Ciao
 

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Discussion Starter #19
Yes thats not right. Very unusual for a Turbosmart unit to leak I think. However beware, and without being critical of your troubleshooting air leaks can be very hard to pinpoint sometimes. I've had this happen to me many times over the years in your situation trying to locate air leaks in confined locations with lots of other potential leak source around as the air can shoot out of the actual leak location and then deflect off other things giving you a false impression. I only mention it because its so unusual for a turbosmart unit to fail. Best way is to mix up a soap and water solution( without it getting sudsy) and apply it to the suspect area then increase the pressure as you look for bubbles. We used to use a dedicated solution called "snoop" but the home made stuff is just as good.

Ciao
Yeah I understand. It is rare from what I read but we checked the other lines around it and it was coming directly from the bottom. Also can you please give me some education on how a twin port wga works vs the standard single? I know one goes to the BRA and the second goes to the selonoid but how does the pressure from the bra play a role assuming you don't use it when you have a typical single port?
 

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Yeah I understand. It is rare from what I read but we checked the other lines around it and it was coming directly from the bottom. Also can you please give me some education on how a twin port wga works vs the standard single? I know one goes to the BRA and the second goes to the selonoid but how does the pressure from the bra play a role assuming you don't use it when you have a typical single port?
So my understanding is that you use pressure to both sides of the diaphragm and one side has spring pressure as well and you bleed pressure or allow pressure to the spring side of the actuator via the boost control solenoid to control boost pressure. It means you get better control and can achieve high boost outputs with a light spring.

Ciao
 
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