is this compressor surge?
- Thread starter isnms
- Start date
wha is lots and lots of surge? is that wha it sounds like? cuz if it does, then im in trouble too. guess i need to adjust my HKS SSQ, I get that sound if I only boost a lil bit (like normal driving)
With the way the HKS bov works, you need to set it to the softest setting. That way, even with only 1-2 psi of boost, it will open when you let off the throttle. That way you won't have any surge. 
i dont think you can adjust the hks ssq bov anymore. the one i recently got has no screw in the back so you can adjust ittubbie said:With the way the HKS bov works, you need to set it to the softest setting. That way, even with only 1-2 psi of boost, it will open when you let off the throttle. That way you won't have any surge.
tubbie said:With the way the HKS bov works, you need to set it to the softest setting. That way, even with only 1-2 psi of boost, it will open when you let off the throttle. That way you won't have any surge.
You will get compressor surge at high boost then, no?
my requirc value was making noised kind up like that. I took a few of the washers out and it got a bit better.
How old is that Bosch? Did the 103 make any difference?
Dan
How old is that Bosch? Did the 103 make any difference?
Dan
Mine is adjustable. I only get that sound if I barely boost (1-2 psi) and then shift. If I boost any higher, Im cool. So, should I adjust it a lil softer or not worry about it?
Yeah that definitely sounds like compressor surge, but we need to know the answer to a few questions first. Such as how much are you boosting? If you are at low boost some race valves will cause compressor surge simply because they arent designed for low boost applications (ie the stock 6-7psi), you may need to reduce the number of washers that you have in the valve to reduce the spring rate. Either that or increase the boost and make full use of that valve. Whether or not you are recirculating the valve does not matter, it should be a clean clear pshhh if the valve is adjusted correctly. If you are shifting and only boosting 1-2psi and it makes that sound dont worry about it, like I said before its only because the valve was designed for high boost and getting surge at low boost is pretty much normal when using an upgraded BOV or bypass valve.
Same thing. I did not change.
It started when I installed the 50trim and the 110. Now I've ruled out the bosch.
Is 8psi on a 50trim more than on a stock ct? Just can't understand why it's doing it on the new turbo and not the stock. I didn't think I was jumping into more pressure than the bosch was rated to handle. I'd like to keep the over rich from happening. If I do plumb in an atmosphere bov and it continues to surge then what. Did I get a bad rebuild on my turbo?
So no one else upgrading to the 60trims or 57 or other, using a recirc cbv is getting these sounds?
sorry i'm just rambling now.
It started when I installed the 50trim and the 110. Now I've ruled out the bosch.
Is 8psi on a 50trim more than on a stock ct? Just can't understand why it's doing it on the new turbo and not the stock. I didn't think I was jumping into more pressure than the bosch was rated to handle. I'd like to keep the over rich from happening. If I do plumb in an atmosphere bov and it continues to surge then what. Did I get a bad rebuild on my turbo?
So no one else upgrading to the 60trims or 57 or other, using a recirc cbv is getting these sounds?
sorry i'm just rambling now.
no, 8psi is 8psi is 8psi, the only reason you get a performance increase when upgrading to a larger turbo is due to the increase in efficiency and lower intake temps, so that should not matter. If your rebuild was done incorrectly it would have little effect on the bov as well, since you would more than likely suffer from a bearing failure or something similar and your turbo would start singing its death song. To me it simply sounds like your not running enough boost to make full use of that BOV, if you cant adjust it to make the spring rate lower than you should turn the boost up. Id suggest getting a BC and upping the boost to around 11-12 psi, whatever amount so that you are not experiencing boost cut (it will still be safe up to that point, that is why the fuel cut is there) and see if the sound changes. From my experience with dsms, a buddy of mine with an ssqv on his gst sounded completely different at 12psi and 25psi. But his also used to make somewhat similar sounds, but that was due to the valve being dual chambered and the two chambers venting at different times. So the car was not making this noise before the turbo upgrade? If your running the same boost and all the mods on the car are the same before the turbo upgrade that is strange indeed. are you sure that you put all the vaccum hoses back properly?
edit: I just re-read your post, your problem is the bosch 110. If you cant reduce the spring rate anymore than you simply arent pushing enough boost through it to make full use of it. Since you are still at stock pressure id either put the stock bov on, or up the boost and see if that helps. But if it is a race valve, I doubt 11-12psi will make it sound off properly. You should try another valve or deal with it until you can get a lex afm and 550s. If you do get a boost controller just remember to get an aftermarket boost gauge, DO NOT rely on the stock gauge to give accurate measurements
edit: I just re-read your post, your problem is the bosch 110. If you cant reduce the spring rate anymore than you simply arent pushing enough boost through it to make full use of it. Since you are still at stock pressure id either put the stock bov on, or up the boost and see if that helps. But if it is a race valve, I doubt 11-12psi will make it sound off properly. You should try another valve or deal with it until you can get a lex afm and 550s. If you do get a boost controller just remember to get an aftermarket boost gauge, DO NOT rely on the stock gauge to give accurate measurements
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Not looking to argue.
With that said, 8psi isn’t 8psi.
My reasoning is that with a larger turbo you make more HP with 8psi than with a smaller turbo.
I tend to agree with the efficiency statement but only after you move the smaller turbo out of its efficiency range or don’t run the large turbo high enough to reach its E range.
I am not sure what boost ranges cars that run the Bosch work at but I find it hard to believe it would not work at 8psi since the effective pressure on the valve should be momentarily much greater once the TB is closed. Hence the reason for the value in the first place.
I am wondering if maybe the initial closing of the TB is opening the value and then the value is shutting again one it has released the pressure then reopening once the pressure increases.
I never noticed it before since I usually only do hard shifts at WOT, at the track, with the cut-out open and the windows closed.
I made a few passes today at work going from 2nd to 3rd probably at around 12psi after reading Charles’ post and noticed the same type of sounds.
I really don’t want a loud atmospheric BOV but don’t want to damage my turbo with surge either.
I will be interested to hear the consensus on this one.
Dan
With that said, 8psi isn’t 8psi.
My reasoning is that with a larger turbo you make more HP with 8psi than with a smaller turbo.
I tend to agree with the efficiency statement but only after you move the smaller turbo out of its efficiency range or don’t run the large turbo high enough to reach its E range.
I am not sure what boost ranges cars that run the Bosch work at but I find it hard to believe it would not work at 8psi since the effective pressure on the valve should be momentarily much greater once the TB is closed. Hence the reason for the value in the first place.
I am wondering if maybe the initial closing of the TB is opening the value and then the value is shutting again one it has released the pressure then reopening once the pressure increases.
I never noticed it before since I usually only do hard shifts at WOT, at the track, with the cut-out open and the windows closed.
I made a few passes today at work going from 2nd to 3rd probably at around 12psi after reading Charles’ post and noticed the same type of sounds.
I really don’t want a loud atmospheric BOV but don’t want to damage my turbo with surge either.
I will be interested to hear the consensus on this one.
Dan
When you changed to the 50 trim, your still only boosting 8 psi, but the amount of air has increased. So, since your bov can only blow off X amount of air, when you increase the amount of air, it still only blows off X amount of air. Soooo, the remaining air has to go back out the compressor. Hence the surge. What you need is an adjustable bov spring. You need to set it as soft as possible without the bov opening at max boost. That way at part throttle and 1-2 psi, the bov will open when the throttle closes, so you will not get surge.
1. the bosch, 110 or 103, is not adjustable
2. more boost makes the noise louder. on my boost controller, 8psi is my low setting and 12 psi is my high setting. these readings are registered on my zt-2 head unit.
3. a smoke test revealed only one leak in the intake manifold gasket that has been fixed now. all hoses are routed properly. vacuum at idle is ~20inHG and holds boost pressure fine.
4. it was not making that noise, that i remember, with the 103, that i have back on there now, and stock turbo
5. it to do not look for the "sound" a bov makes. i just don't care about sound. i care about function. i want my bov to function to save the life of my turbo. i didn't think that the amount of pressure i am running was beyond what the bosch was designed to handle.
thanks Dan for letting me know you heard it on yours too.
2. more boost makes the noise louder. on my boost controller, 8psi is my low setting and 12 psi is my high setting. these readings are registered on my zt-2 head unit.
3. a smoke test revealed only one leak in the intake manifold gasket that has been fixed now. all hoses are routed properly. vacuum at idle is ~20inHG and holds boost pressure fine.
4. it was not making that noise, that i remember, with the 103, that i have back on there now, and stock turbo
5. it to do not look for the "sound" a bov makes. i just don't care about sound. i care about function. i want my bov to function to save the life of my turbo. i didn't think that the amount of pressure i am running was beyond what the bosch was designed to handle.
thanks Dan for letting me know you heard it on yours too.
Blue87T(Dan) said:
Not trying to argue either, just trying to make conversation. But we had a huge topic about this over in the dsm forums, and the conclusion was that 8psi is in fact 8psi. Yes a larger turbo at 8psi is not in its efficiency range, but since that larger turbo isnt in its efficiency range it is pushing out 8psi at a much lower temp than the smaller ct which IS in its efficiency range. Of course colder air means more oxygen molecules which in turn means more power per lb of boost. I might be wrong, but that was the general consensus
Try disconnecting/reconnecting the vac line on the valve and see if you can hear it actuating. Better yet, look into the discharge port while you do that. You either have a leak in that vac line or the valve isn't responding. It doesn't have anything to do with your turbo or how much boost you're running. The valve just isn't opening when the throttle is closed. Plain and simple.