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Over boosting

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TWOpointFORliter

10+ Year Contributor
644
120
Jul 31, 2009
Crown Point, Indiana
I’m trying to get my car ready to be tuned and I’m having a issue with boosting past spring pressure. My mods list is up to date but the basic run down is a 6062 divided T4, 38mm tial WG’s with the 24# springs, 3 port IR boost solenoid with both the top and bottom wastegate ports hooked up and boost sourced from the compressor cover. The turbo and hot parts are brand new this year with just a little cruise time on them. The gates and pretty much everything else in the engine bay are a few years old with 3,500 miles on them. Everything worked perfect the last time it was on the road in late 2020 and the HX35 and the old hot parts were still on the car. Currently car is spiking to 32ish psi and maybe beyond but I haven’t stayed in it long enough to find out. The wastegates are opening I can hear them and see exhaust soot inside the brand new dump tubes. I have boost leak tested it to 40psi. I have eliminated the boost solenoid and hooked the lines directly to the compressor cover. I have replaced the wastegate diaphrams even though the old ones looked perfect and had no signs of a tear or being pinched. I switched to 5mm vacuum line with this new setup to have a tighter fit on the barbs but just today switched it back to 6mm thinking the wastegates might now be getting enough volume of air to work properly. I have verified the vacuum line routing is correct countless times. None of this has helped with my over boosting issue. Next on the list is to take the WG’s back off and bench test them and possibly lower the spring pressure. I figured I would see if anyone else here had some input on possible causes or something I’m missing before I do that. Could the 38mm WG’s just not be big enough for a 60mm turbo? I wouldn’t think so but I’m not counting it out. Any help is appreciated. I want to have some fun with this thing this year.
 
So your controlling boost with the ecu i assume, what have you done on that to control / setup this?
 
So your controlling boost with the ecu i assume, what have you done on that to control / setup this?
Boost table is zeroed out currently so nothing. It should be just running spring pressure with the table zeroed but it’s still over boosting even when I take the solenoid out of the equation.
 
Boost table is zeroed out currently so nothing. It should be just running spring pressure with the table zeroed but it’s still over boosting even when I take the solenoid out of the equation.
So it is activated and in the misc tab right for bcs to be used?

If its activated and zerod and still nothing then its not seeing it and working with it.
 
If its activated and zerod and still nothing then its not seeing it and working with it.
Yes it is activated and clicks like it should when activated so it is being recognized by the ecu. Like I said though it is still over boosting when I run the waste gates directly to the boost source and don’t even have the solenoid in the system. So even if there is a communication issue between the solenoid it wouldn’t matter with the wastegates hooked directly to the boost source. That’s why I’m lost on where else to turn. I got no problem buying new wastegates if need be I just don’t want to drop another $700 and have the problem still be there.
 
Yes it is activated and clicks like it should when activated so it is being recognized by the ecu. Like I said though it is still over boosting when I run the waste gates directly to the boost source and don’t even have the solenoid in the system. So even if there is a communication issue between the solenoid it wouldn’t matter with the wastegates hooked directly to the boost source. That’s why I’m lost on where else to turn. I got no problem buying new wastegates if need be I just don’t want to drop another $700 and have the problem still be there.
Arh, i overlooked the removal part and problem still stands. As you mentioned trial a softer lower psi spring, this will confirm you have control mechanically. Also i dont know what #24 springs relates to in PSI terms and google is not helping here. Whats that setup hold to spring rating wise?

i think this is the first ideal step to confirming you have control. Then work from that.

what I do know is if your target is say 25 psi and you use 24 psi spring(s) then the solenlid wont do much as its too close to the end goal and will spike and over power it. While it still happens on a slightly softer spring so its able to be controlled more.

also in your ecmlink settings for wgs whats your lock set to? We had another chap recently have an issue on setting up and working not right and we got him going again. So hopefully we can get you rolling soon to.
 
I have eliminated the boost solenoid and hooked the lines directly to the compressor cover.

When you have it like this, the upper WG ports are open to atmosphere, right?

38mm - since you have 2 of them, it seems like that should be enough.

0.84 a/r, don't know what that is "equivalent" to in a single scroll. But it might be a question.

The "24 psi" springs, that is the stiffest spring setup Tial offers as far as I know. Once you hit 24 psi of boost, things are happening awful fast.
When English Racing was putting my setup together, I tried to talk them into putting the 19psi wastegate spring(s) into the single V44 we used. They weren't interested. The spring in it was and is the standard ~13 psi spring that those units came with. Instead, they set the "crack pressure" to ~19 psi in the boost controller, which is not the one in DSMlink although that one should be fine with the IR solenoid.
ER never ran the car higher than 34psi but that only needed ~70% duty cycle on the boost controller.
 
When you have it like this, the upper WG ports are open to atmosphere, right?

38mm - since you have 2 of them, it seems like that should be enough.

0.84 a/r, don't know what that is "equivalent" to in a single scroll. But it might be a question.

The "24 psi" springs, that is the stiffest spring setup Tial offers as far as I know. Once you hit 24 psi of boost, things are happening awful fast.
When English Racing was putting my setup together, I tried to talk them into putting the 19psi wastegate spring(s) into the single V44 we used. They weren't interested. The spring in it was and is the standard ~13 psi spring that those units came with. Instead, they set the "crack pressure" to ~19 psi in the boost controller, which is not the one in DSMlink although that one should be fine with the IR solenoid.
ER never ran the car higher than 34psi but that only needed ~70% duty cycle on the boost controller.
Yes the top ports were VTA and the lower ports were hooked directly to the compressor cover. The boost was exactly the same as it was with the solenoid hooked up.

The 24 psi setup are all three of the heaviest springs in the wastegate. If I lose the small spring it will bring it down to 19psi. I’m gonna give it a try maybe tomorrow if I have time but this spring combo when I had my hx35 on the car held wastegate pressure right at 24psi just like it was supposed to with no spike on spool up. I planned on running all the boost until I either ran out of fuel or turbo whichever came first that’s why I had the stiffest spring combo.

The more I think about it the more I think it’s a bad wastegate but what could be bad on the wastegate especially if I just replaced the diaphragms. I can’t imagine one or both of them would fail in such a short time. I don’t run coolant to the wastegates but they aren’t discolored from heat like I’ve seen some of them after alot of use. They still look brand new.
 
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Pulled the wastegates off the car and bench tested them. With the 24psi spring combo that was in there the WG wasn’t opening till 30+psi. Switched it out to a 9psi spring and it was opening at 12psi. Then I tried the 17psi combo and it is opening around 23psi. I think it’s weird it pushes past the spring pressure but both gates acted identical with all the different spring combos I tested. I’m about to install them back on the car with the 17psi springs and see what happens.

On a side note I noticed I have 2 different model tial wastegates. One was bough new in 2009ish and never used and the other one was bought in 2019. They both have different serial numbers on them and have very subtle differences in the housing. The older one was bought from Jnz and the newer one was from extreme so I know they are both legit. Just didn’t know that tial redesigned them at one point in between when I purchased them.
 
I've never looked into how you would bench test a wastegate, but what puzzles me about it is, how do you account for the pressure that is in the exhaust manifold and collector that would also be trying to push the valve open if it was on the car? Right?
For example, let's say you had it in the car with the 17psi springs in it, and sure enough, it starts to open at 17psi. That would mean that 17psi of air in the lower wg chamber, plus whatever force is on the valve from the exhaust pressure that's in the manifold, all that together is equal to the force you get with it on the bench and 23psi of air in the lower chamber. That could make some sense. Right? But in your case, with the 24psi springs, it didn't open when it was in the car until I guess quite a bit higher. Or else it was opening but not enough to keep the boost down. That could be, because when you have more spring in there, it's not just the closing force that's higher, it's also got a higher *spring rate* as you open it.

Anyway, trying it on the car with the 17psi combo sounds like a good idea to me!
 
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I've never looked into how you would bench test a wastegate, but what puzzles me about it is, how do you account for the pressure that is in the exhaust manifold and collector that would also be trying to push the valve open if it was on the car? Right?
For example, let's say you had it in the car with the 17psi springs in it, and sure enough, it starts to open at 17psi. That would mean that 17psi of air in the lower wg chamber, plus whatever force is on the valve from the exhaust pressure that's in the manifold, all that together is equal to the force you get with it on the bench and 23psi of air in the lower chamber. That could make some sense. Right? But in your case, with the 24psi springs, it didn't open when it was in the car until I guess quite a bit higher. Or else it was opening but not enough to keep the boost down.

Anyway, trying it on the car with the 17psi combo sounds like a good idea to me!
I followed the directions in the video that tial put out on how to bench test their wastegates. Just had to put together a tester which I did with stuff I had laying around the garage.
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They didn’t mention anything about trying to account for the exhaust pressure so it didn’t concern myself with it. It does make sense that it would affect when the valves open. However my bench test did reflect what the gates where doing on the car. It’s all back together gonna take it for a drive after dinner and see where the boost is at.
 
Just took it for a drive and boost held at 22psi with the new spring combo. I’m happy with that so I’m gonna send it.
 
Just took it for a drive and boost held at 22psi with the new spring combo. I’m happy with that so I’m gonna send it.

Yeah that sounds good!

Thanks BTW for all the info in PMs that we did in 2020, about the Quarter Master 8-leg twin disk clutch. I've had mine now for over a year and it's doing real nice. Wait, nice might not be the exact right word LOL but it's doing what I wanted it to do!
 
Yeah that sounds good!

Thanks BTW for all the info in PMs that we did in 2020, about the Quarter Master 8-leg twin disk clutch. I've had mine now for over a year and it's doing real nice. Wait, nice might not be the exact right word LOL but it's doing what I wanted it to do!
Always glad to help that’s what this site and our community as a whole has always been about. Glad it’s working out for you so far.
 
If your wanting to use the solenoid then you might consider the spring where it works at gate pressure under 20psi so you got some room for the ecu to work something, 2-3 psi is very tight for the solenoid to work perfectly well.

This is of couse just an opinion but does mean if it fails your not able to use full activated pressure from the spring anymore
 
If your wanting to use the solenoid then you might consider the spring where it works at gate pressure under 20psi so you got some room for the ecu to work something, 2-3 psi is very tight for the solenoid to work perfectly well.

This is of couse just an opinion but does mean if it fails your not able to use full activated pressure from the spring anymore
It held the 22psi with the solenoid hooked up and all the tables zeroed out. I’m happy with that being my minimum wastegate pressure since the only time it will see that low of boost is when 93 is in the tank for winterizing and cruising to the shootout. Once the 93 tune is finalized I’m running the 93 out and filling it back up with e85. I’m guessing at that point boost will be 35-40psi but maybe even higher if my fuel pump can keep up. That’s why I put the 24psi springs in there to start because I was worried about the exhaust pressure pushing the gates open at high boost. I had a hard time holding boost with the holset due to what I’m guessing was very high back pressure with the divided t3 manifold it used to have.
 
It held the 22psi with the solenoid hooked up and all the tables zeroed out. I’m happy with that being my minimum wastegate pressure since the only time it will see that low of boost is when 93 is in the tank for winterized and cruising to the shootout. Once the 93 tune is finalized I’m running the 93 out and filling it back up with e85. I’m guessing at that point boost will be 35-40psi but maybe even higher if my fuel pump can keep up. That’s why I put the 24psi springs in there to start because I was worried about the exhaust pressure pushing the gates open at high boost. I had a hard time holding boost with the holset due to what I’m guessing was very high back pressure with the divided t3 manifold it used to have.
Arh ok thats alright then. Seems like the solenoid for now is redundant but could bebuseful later for you then.

When its on zero across the board was you getting the kangaroo effect on spring pressure? This is what i got when i had mine all zero'd. Weird thing but once it got holding actually pressure itself it went away. Dont know why i had that and you not said about it so interested to know what your settings are.
On the lock section what you got that all set as? 0% below and 100% below? What are your ones set to here.

More i know on this the better as i read about different setups here but its also not a hugely talked about part of ecmlink for some reason
 
Arh ok thats alright then. Seems like the solenoid for now is redundant but could bebuseful later for you then.

When its on zero across the board was you getting the kangaroo effect on spring pressure? This is what i got when i had mine all zero'd. Weird thing but once it got holding actually pressure itself it went away. Dont know why i had that and you not said about it so interested to know what your settings are.
On the lock section what you got that all set as? 0% below and 100% below? What are your ones set to here.

More i know on this the better as i read about different setups here but its also not a hugely talked about part of ecmlink for some reason
It wasn’t jumping up and down if thats what you mean by the kangaroo effect. It hit 22psi saw a slight spike to 22.8 and then settled back down to 22. I only ran it out to 5500 though since I’m doing tuning pulls with my remote tuner. The new file I was sent this morning is good to 7500 so I’ll report back to you if the boost jumps around or just holds steady when I do another pull. I’m not sure what the lock section is currently set to but I believe it is still at the factory settings since we haven’t gotten to the point of adjusting the table yet.

I agree with keep with the tradition of getting as much info out there about our cars as possible to help everyone keep them going and make good power with.
 
It wasn’t jumping up and down if thats what you mean by the kangaroo effect. It hit 22psi saw a slight spike to 22.8 and then settled back down to 22. I only ran it out to 5500 though since I’m doing tuning pulls with my remote tuner. The new file I was sent this morning is good to 7500 so I’ll report back to you if the boost jumps around or just holds steady when I do another pull. I’m not sure what the lock section is currently set to but I believe it is still at the factory settings since we haven’t gotten to the point of adjusting the table yet.

I agree with keep with the tradition of getting as much info out there about our cars as possible to help everyone keep them going and make good power with.
This pic (at the bottom) is what the lock is, i read its the cycle from and to. But others go - and some like myself go slightly + in 0%. This is where I would like to know more on as i wonder if it was doing a huge cycle and causing my 0-19psi kangaroo effect as it sweeps from both figured when all set to Zero.

Can you pictures yours. I might also ask ecmtuning on a more detailed setup for this as its very vague at best
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This setting which you showed set to 19psi is, as far as I know, the same thing as "crack pressure" in AEM boost controllers, which is what I have.
It's just a way of keeping the valve slammed shut until you hit 19psi or whatever number you put in there.
It will stay slammed shut because you are giving it 100% ( or the max it is capable of) until you hit 19psi.
Then when you hit 19psi it switches over to the tables that you have filled out with whatever numbers you want.

The other field there that is labeled "Lock at 0% below" is just there so that the solenoid can take a rest all the while you are running in vacuum (no boost). Usually you set that to somewhere near 0psi or just a little above, like 1 or 2 psi, at which point the solenoid starts getting 100% signal so it wakes up and keeps the valve slammed shut.

In my car, 19psi is a tad bit high for pulls from low rpm in 3rd gear if I'm going uphill. I will get bucking as the revs climb past that point. What happens there is, as soon as 19psi is reached, my duty cycle drops from ~100% to my setting which was only 46% the last time I fiddled with crack pressure. At that low rpm the boost won't stay up to 19psi with only 46% duty cycle so the boost drops all of a sudden. Then the controller puts duty cycle back to 100% so boost comes back up. It might cycle back and forth like this a couple times before revs come up to the point where 46% is enough to hold it above 19psi. In 2nd gear, the revs come up so fast that I don't have this problem, so 19psi would be ok in 2nd gear. But for the sake of 3rd gear (and 4th) I set my crack pressure to 17psi.

Now I have my duty cycle set to 55% so I could probably have my crack pressure set a little higher.
The AEM boost controller is kind of simple-minded. It doesn't have the tables like ECMlink has. All it has is, you tell it what duty cycle you want, and what "crack pressure" you want. And that's about it.
 
Run a boost source directly to the lower ports and leave the top ports open. If you still overboost it’s a mechanical issue with your setup.
I’ve already done that. I’ve also benched tested both of my wastegates and found that with 3 different spring combos in them both wastegates don’t open till after the rated spring pressure. Both wastegates react exactly the same as each other with all 3 different spring combos when bench tested and with them installed on my car reflect exactly what I saw on the bench. Just don’t understand why they don’t open at the rated spring pressure any insight as to why that might be?
 
Maybe your compressor gauge is wrong?
I was using my old 30psi autometer gauge for the bench test. There is a picture above of what I put together to bench test the WG’s. Plus both my Omni map sensor and the gauge currently in my car reflected exactly what the results were on the bench. So idk it’s just strange that every spring combo I’ve tried holds more than it should by the exact same amount on both gates.
 
I’ve already done that. I’ve also benched tested both of my wastegates and found that with 3 different spring combos in them both wastegates don’t open till after the rated spring pressure. Both wastegates react exactly the same as each other with all 3 different spring combos when bench tested and with them installed on my car reflect exactly what I saw on the bench. Just don’t understand why they don’t open at the rated spring pressure any insight as to why that might be?
The only thing I read had a direct line to both ports. The top port has to be left open to atmosphere. I must have missed one of your posts.
 
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