Maximum boost v. external wastegate spring
09-19-2012, 11:56 PM
#1
Maximum boost v. external wastegate spring
Alright well i have a bit of an issue.
I leave for the GRM $2012 Challenge a week from today. Well... 6 days from the time you read this, probably.
I ordered a 10psi spring for my Turbosmart 38mm EWG. Unfortunately, i done fucked up and didn't notice that it was for the new style smaller wastegate, and i have the older style that requires bigger springs.
SO.
I'm stuck with my 7psi spring for the time being.
The internet would have me believe that you should never exceed 200% of your wastegate spring. Or 300%, depending on which forums you read.
300% is ok.
200% is not.
In the event that strange things start to happen much past 200%, i need some guidance on how to overcome this limit in a safe-ish and controllable manner. Ordering another spring is not a possibility, as the spring would not arrive in time without paying an inordinate amount in shipping charges. (Which, i'm NOT doing for a $26 part.)
How boost is currently being controlled:
Single port hookup. (Bottom portion to MBC, top portion vented.)
Ball/spring MBC
Using reference port on compressor. (Yes, i've read the threads that tell me to use "Port B" instead. I'll do so when i start to see drop.)
Sooo...
1) Is the 200% rule a myth?
2) If it's NOT, are there other ways to increase boost past it safely? I've seen references to a dual-port hookup like so:
Target boost is in the 20-25psi range. Higher if i have the fuel.
I leave for the GRM $2012 Challenge a week from today. Well... 6 days from the time you read this, probably.
I ordered a 10psi spring for my Turbosmart 38mm EWG. Unfortunately, i done fucked up and didn't notice that it was for the new style smaller wastegate, and i have the older style that requires bigger springs.
SO.
I'm stuck with my 7psi spring for the time being.
The internet would have me believe that you should never exceed 200% of your wastegate spring. Or 300%, depending on which forums you read.
300% is ok.
200% is not.
In the event that strange things start to happen much past 200%, i need some guidance on how to overcome this limit in a safe-ish and controllable manner. Ordering another spring is not a possibility, as the spring would not arrive in time without paying an inordinate amount in shipping charges. (Which, i'm NOT doing for a $26 part.)
How boost is currently being controlled:
Single port hookup. (Bottom portion to MBC, top portion vented.)
Ball/spring MBC
Using reference port on compressor. (Yes, i've read the threads that tell me to use "Port B" instead. I'll do so when i start to see drop.)
Sooo...
1) Is the 200% rule a myth?
2) If it's NOT, are there other ways to increase boost past it safely? I've seen references to a dual-port hookup like so:
Target boost is in the 20-25psi range. Higher if i have the fuel.
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09-20-2012, 07:36 AM
#2
The issue with it is normally once you get to such high pressures the back pressure in the exhaust is enough to overcome the force of the boost pressure pushing on the diaphragm and the spring. If this was an IWG I'd say just go to the hardware store and buy a pull spring to use as a helper spring, but since its an external You could just shim it, or you could see if a spring from the hardware store would work.
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09-20-2012, 08:51 AM
#4
mkturbo.com
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I was running 17psi with a 6psi spring in my external Tial wastegate and it was fine. I am planning on upping that to about 24psi on the 6psi spring once I get the car running again.
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09-20-2012, 09:24 AM
#5
Characteristics of this motor tell me that it's rather unlikely that i'll be able to sustain 300% spring rating.
Of COURSE i'm going to try it anyways. This thread is about ways to "stretch" farther than you should be able to. I don't care about the percentage, i'm just trying to milk your brains for ways to combat the wastegate blowing open if that starts to happen.
This may all be a moot point. The Sales Executive at Turbosmart responded to an email concerning the part numbers of these springs and says she should be able to get me a 14psi spring in time. They have AWESOME service over there.
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09-20-2012, 09:25 AM
#6
The issue with it is normally once you get to such high pressures the back pressure in the exhaust is enough to overcome the force of the boost pressure pushing on the diaphragm and the spring. If this was an IWG I'd say just go to the hardware store and buy a pull spring to use as a helper spring, but since its an external You could just shim it, or you could see if a spring from the hardware store would work.
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09-20-2012, 09:30 AM
#7
If the 10psi spring isn't for your specific ewg then its not a 10psi spring. Meaning it could be a 4psi spring for all you know.
And when it blows open it doesn't blow all the way open and drop boost more than when it was on a lower spring within its range of operation, dunno wtf you're talking about there.
But if they get you the right spring, cool beans.
And when it blows open it doesn't blow all the way open and drop boost more than when it was on a lower spring within its range of operation, dunno wtf you're talking about there.
But if they get you the right spring, cool beans.
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09-20-2012, 09:41 AM
#8
If the 10psi spring isn't for your specific ewg then its not a 10psi spring. Meaning it could be a 4psi spring for all you know.
And when it blows open it doesn't blow all the way open and drop boost more than when it was on a lower spring within its range of operation, dunno wtf you're talking about there.
But if they get you the right spring, cool beans.
And when it blows open it doesn't blow all the way open and drop boost more than when it was on a lower spring within its range of operation, dunno wtf you're talking about there.
But if they get you the right spring, cool beans.
Either way... at the worst case scenario at this point, the 7psi spring goes back in. And i'm just trying to figure out how to get another couple psi out of it before running into weirder/slow spool. Best case scenario, i get the 14psi spring and i have no issues at all.
Just so we're on the same page, this isn't a BP.
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09-20-2012, 09:45 AM
#9
I realize this... I'm saying that even if i were to be able to push 20psi on the "10psi" spring for example, it would be slower than 14psi on the 7psi spring. The spool up gets REALLY bad, and this car doesn't "hit" until boost has stabilized at the target. (Probably due to some other weirdness, it's something i've tried to figure out for years.) That may be for a different thread, though.
Either way... at the worst case scenario at this point, the 7psi spring goes back in. And i'm just trying to figure out how to get another couple psi out of it before running into weirder/slow spool. Best case scenario, i get the 14psi spring and i have no issues at all.
Just so we're on the same page, this isn't a BP.
Either way... at the worst case scenario at this point, the 7psi spring goes back in. And i'm just trying to figure out how to get another couple psi out of it before running into weirder/slow spool. Best case scenario, i get the 14psi spring and i have no issues at all.
Just so we're on the same page, this isn't a BP.
No.
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09-20-2012, 10:14 AM
#14
Ummmmm.... Yes.
It's not all about max boost. 20psi isn't helpful if it takes 3-4 seconds to reach that point on a weak spring vs. the 14psi i can reach in literally less than half a second on the "correct" spring. I realize the 10psi spring isn't really a 10psi spring, hence the quotes.
Like i said in that very post that you quoted, the car doesn't actually really MOVE until a split second AFTER it hits target boost. It's not fast until it finishes slamming up to maximum. I don't care about your experiences with your Miata, or turbo cars you've had, or any of that ****. This doesn't even mirror my experiences with my other turbo cars.
It's just what this car does, and i have no idea why. I have to work with it, and this is why i'm asking my questions.
Why is this relevant? Because if spool goes out the ******* window @ 20-24psi on the 7psi spring, the car will probably be faster at a lower boost amount with proper control.
So yet again, let's keep it simple and go back to the very first questions i asked in the original post instead of arguing about what MY car does.
SIMPLY PUT: Is the "dual port" method of hookup effective in giving another couple psi of headroom?
It's not all about max boost. 20psi isn't helpful if it takes 3-4 seconds to reach that point on a weak spring vs. the 14psi i can reach in literally less than half a second on the "correct" spring. I realize the 10psi spring isn't really a 10psi spring, hence the quotes.
Like i said in that very post that you quoted, the car doesn't actually really MOVE until a split second AFTER it hits target boost. It's not fast until it finishes slamming up to maximum. I don't care about your experiences with your Miata, or turbo cars you've had, or any of that ****. This doesn't even mirror my experiences with my other turbo cars.
It's just what this car does, and i have no idea why. I have to work with it, and this is why i'm asking my questions.
Why is this relevant? Because if spool goes out the ******* window @ 20-24psi on the 7psi spring, the car will probably be faster at a lower boost amount with proper control.
So yet again, let's keep it simple and go back to the very first questions i asked in the original post instead of arguing about what MY car does.
SIMPLY PUT: Is the "dual port" method of hookup effective in giving another couple psi of headroom?
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09-20-2012, 10:19 AM
#17
Ummmmm.... Yes.
It's not all about max boost. 20psi isn't helpful if it takes 3-4 seconds to reach that point on a weak spring vs. the 14psi i can reach in literally less than half a second on the "correct" spring. I realize the 10psi spring isn't really a 10psi spring, hence the quotes.
Like i said in that very post that you quoted, the car doesn't actually really MOVE until a split second AFTER it hits target boost. It's not fast until it finishes slamming up to maximum. I don't care about your experiences with your Miata, or turbo cars you've had, or any of that ****. This doesn't even mirror my experiences with my other turbo cars.
It's just what this car does, and i have no idea why. I have to work with it, and this is why i'm asking my questions.
Why is this relevant? Because if spool goes out the ******* window @ 20-24psi on the 7psi spring, the car will probably be faster at a lower boost amount with proper control.
So yet again, let's keep it simple and go back to the very first questions i asked in the original post instead of arguing about what MY car does.
SIMPLY PUT: Is the "dual port" method of hookup effective in giving another couple psi of headroom?
It's not all about max boost. 20psi isn't helpful if it takes 3-4 seconds to reach that point on a weak spring vs. the 14psi i can reach in literally less than half a second on the "correct" spring. I realize the 10psi spring isn't really a 10psi spring, hence the quotes.
Like i said in that very post that you quoted, the car doesn't actually really MOVE until a split second AFTER it hits target boost. It's not fast until it finishes slamming up to maximum. I don't care about your experiences with your Miata, or turbo cars you've had, or any of that ****. This doesn't even mirror my experiences with my other turbo cars.
It's just what this car does, and i have no idea why. I have to work with it, and this is why i'm asking my questions.
Why is this relevant? Because if spool goes out the ******* window @ 20-24psi on the 7psi spring, the car will probably be faster at a lower boost amount with proper control.
So yet again, let's keep it simple and go back to the very first questions i asked in the original post instead of arguing about what MY car does.
SIMPLY PUT: Is the "dual port" method of hookup effective in giving another couple psi of headroom?
Dual port increases response not increases pressure. The spring increases pressure.
And Its not my opinion with my cars, its a ******* FACT.
All the bullshit you spouted off about onset, yadda yadda yadda is pretty ******* retarded since we're comparing a 7psi spring to a ???psi spring.
Bottom line, throwing away all the full on retard bullshit, either wait for the new spring or crank it up with the 7psi "correct" spring, or go to a hardware store and pick out a secondary spring and try to crank it up that way til your new one comes.
I'm actually trying to help you here, not just mouthing off. Holy ****
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09-20-2012, 10:24 AM
#20
Simply put: NO..
Dual port increases response not increases pressure. The spring increases pressure.
And Its not my opinion with my cars, its a ******* FACT.
All the bullshit you spouted off about onset, yadda yadda yadda is pretty ******* retarded since we're comparing a 7psi spring to a ???psi spring.
Bottom line, throwing away all the full on retard bullshit, either wait for the new spring or crank it up with the 7psi "correct" spring, or go to a hardware store and pick out a secondary spring and try to crank it up that way til your new one comes.
I'm actually trying to help you here, not just mouthing off. Holy ****
Dual port increases response not increases pressure. The spring increases pressure.
And Its not my opinion with my cars, its a ******* FACT.
All the bullshit you spouted off about onset, yadda yadda yadda is pretty ******* retarded since we're comparing a 7psi spring to a ???psi spring.
Bottom line, throwing away all the full on retard bullshit, either wait for the new spring or crank it up with the 7psi "correct" spring, or go to a hardware store and pick out a secondary spring and try to crank it up that way til your new one comes.
I'm actually trying to help you here, not just mouthing off. Holy ****
For the lasttime, i'm not comparing a 7psi spring to a ???psi spring. I was using the example of the ???psi spring being pushed past what it can actually handle to show what i'm trying to avoid.
As i said, with MY car, and i don't give a **** about what your cars do (Or my Miata), once i exceed what the spring can handle, it's slow as ****. As stated, it's NOT all about max PSI. I really don't know how to make that any more clear. Feel free to get mad about it.
I appreciate the bolded portion.
Now you and Leafy can fight to the death over who is right, since you're disagreeing.
Anyways, now for a question about the dual port... I'm afraid i don't understand how it works if it has no bearing on max boost you can possibly run. When you hook up the top port, it works WITH the spring to keep the diaphragm compressed. Asking purely because i don't know: How would this NOT help to increase max boost?
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