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:

https://www.miataturbo.net/attachmen...ine=1348113364



Target boost is in the 20-25psi range. Higher if i have the fuel.

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.

Who cares what percentage you're at? Worst case it gets blown open, which will do nothing more than make boost drop. Keep raising it til it wont go higher. Leave it there.

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.

Right, but once i reach the point that it gets blown open, the car is faster at the point on the boost controller BEFORE it starts blowing shit open. I can run 14psi on this wrong 10psi spring that's in the car right now, but it's WAY slower than 14psi on the correct 7psi spring, because i'm blowing the fucking thing open like crazy.

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. :)

I'm not looking for unlimited control at 40psi on a 7psi spring... just something to stretch another 2-3psi if i need to. Is the method i posted something that might do such a thing?

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.

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.

ummmmm, WAT

No.

Yes because your spring is too short and even with the boost reference un plugged or plugged into the wrong hole there is nothing keeping the flapper closed at rest.

How is a 10psi spring holding down the flapper worse than a 7psi spring?

Are you guys high?

omfg

Because the 10psi spring is for a different waste gate and is shorter than the 7psi spring.

If its for a different wastegate ITS NOT A 10PSI SPRING.
Therefore it has nothing to do with this discussion unless both of you think its still a 10psi spring.

apple =/= banana

Ok. Stepping out of this thread. Its going full retard.

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 shit. 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 fucking 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?

Ok, stop with the "10psi" spring. It's not relevant other than to show what happens with my car with a spring that's too weak. I thought i made that pretty clear earlier, but apparently not.

No. Just run the standard config. Its not going to effect spool, it'll just effect the max boost you can run and spool if you're trying to push past the cracking limit of your current wastegate spring setup.

Simply put: NO..
Dual port increases response not increases pressure. The spring increases pressure.

And Its not my opinion with my cars, its a fucking FACT.

All the bullshit you spouted off about onset, yadda yadda yadda is pretty fucking 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 shit

..... WHAT THE FUCK.


That's exactly what i'm asking. IS IT EFFECTIVE IN HELPING TO PUSH PAST THE LIMIT OF MY WASTEGATE SPRING SETUP.

Jesus fucking christ.


I mean, i guess i got my answer out of that, but holy shit my forehead is bruised right now.

It is a FACT that leafy is a fucking retard and pulls complete and utter bullshit out of his ass with every one of his posts.

I would quote all the retardation but that would take a day or two.

LOL, nice edit. I'll tone it down, too, then. :)

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. :idea:

As i said, with MY car, and i don't give a fuck about what your cars do (Or my Miata), once i exceed what the spring can handle, it's slow as fuck. 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. :bowrofl:

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?

:bowrofl:

Fair enough. I'll just throw that out then.

Hugs? :makeout:

Not sure why we're fighting we're saying the same thing.

what does your boost gauge actually read with the 2 different springs?

EDIT: without the mbc

Clearly not.

14psi. With a boost controller of course.

But i believe you might be missing the issue. I'm simply trying to stretch a little past theoretical limits while avoiding a shitty spool. It's really that simple. And i probably should have just kept it that simple.

I was talking about the spring and he was talking about the dual port. I'm half paying attention to a meeting so I may have left out a sentence for clarity.

im asking because if you take the mbc out and run the 2 springs w/o control it will let you know which spring has the higher rating.
will one spring fit inside the other? if so put em both in

Ugh. So half your attention is even worse than normal? I wasn't asking about what to do about the spring. That's already set in stone. If i get the 14psi spring from Turbosmart in time (50/50 chance), then i'll run that. If i don't, i'm running the 7psi spring, and just needed to know if there were any valid options to keep it happier at higher pressures. That's all.


This thread is a fuckin' trainwreck. I'm thinking about posting the same thing on ClubFagster just to see what sort of bullshit comes out for the lulz.

The 7psi spring is stronger than the "10psi" spring that isn't actually for my wastegate. I don't really need to remove the MBC to figure that out. Even with a ball/spring, the wastegate is getting blown wide open by my crazy awesome motor at like 8psi.

I thought about stacking them, but they're too similar in OD. :facepalm:

The GOOD news is that i will be able to stack the 14psi and 7psi springs if i end up having enough fuel to want to crack 30psi.

Ok, say you dont put the vac line on the wastegate at all. It will stay closed until the exhaust backpressure pushing on the diaphragm is greater than the spring pressure then it will start to crack open. It will spool like a normal car with a boost controller up to this point. After that point it will spool like a car without a mbc that is getting wastegate cracking. Now if you connect it like normal then the car will spool like normal until the the exhaust pressure + the boost pressure (coming through the mbc) is high enough to overcome the spring pressure. If the requested boost (from the mbc) is higher than that cracking exhaust pressure I mentioned earlier then it wont spool as hard. Eventually you'll make enough gas pressure that no matter what you set the mbc to the wastegate will be all the way open and you wont be able to make more boost.

So right now if it spools perfectly fine to 14 psi if you then set the mbc to like 24 psi then at the very least it would spool like normal to 14 psi and then get as high as 24 psi or till the exhaust pressure forces the wastegate all the way open.

:facepalm: so you just described how an ewg operates. Did you google it or something? WTF does it have anything to do with what he's asking.

Just stop posting..



OP,


Can't you also shim the original spring? I know it has to "seat" but doubt it would go anywhere if it didn't. The possible downside is boost creeping to death if current setup requires full range of motion on the valve.

Ehhh... i could maybe look into shimming.

Stupid question: Shim goes under or on top of spring? I might be a little worried about seating, since i'm paranoid like that, but fueling would be more the issue than strength of motor if i DO run into creep issues.


To maybe hopefully illustrate what i'm talking about in terms of how the car responds... (and hopefully not to further confuse)

When i first hammer it in 2nd, you'll see the boost gauge hit 14psi pretty much immediately. You might be able to hear it, maybe not, but the car doesn't really "hit its stride" until maybe 1/4-1/2 a second after it's already achieved max pressure. It's not dependent on RPM, does it all the time. It'll kinda start moving as it spools up, but it just feels weird. Starts to move, hits full boost, wait for it.... SLAM. My Miata doesn't do this. (But of course, it's a baby dick motor with a baby dick turbo on the Miata.)

IF it looks anything like a Tial on the inside, you'd put the shim on top not bottom
I'm pretty sure spring wouldn't go anywhere even if it shifted, since its pretty wide relative to the housing, and would still be seated on the bottom.

I'm honestly not sure if it even seats on the cap anyways... i'd have to look at it again. Thanks!

Well this all ended up as a clusterfuck.

Got the new spring. Didn't put it in. Clutch is toasted.

Currently looking at a clutch rated for 505ftlbs. Because i probably need it.

yuk. that's going to suck if you daily it

Ehhhh.... maybe? If i go with the South Bend, i've driven that one and it's not a ton more pedal effort.

On the flip side, my clutch already never felt stock, but i have no idea what was in it. PO said it was stock, but i don't believe him.

But i've got the shit here to boot 25-30psi through this thing now, and there's no way i'm NOT doing that.

what clutch?
I have ACT ZM2-XTG6 and it spent it's whole life in fast turbo cars.

Spoken like a boss.
I fully support this statement :)

Looking at:
Souf Bend SS-DXD "Stage 3" and the SS-X "Stage 4."
ACT HDG6 (6 puck sprung, rated for 422ftlbs, might be a little low)
Spec Stage 3 or 3+

My daily driver is fun.

So is mine.
Its just as fast but actually hooks up:giggle:

we're talking about miatas here, right?
HDG6 is a 6 puck with "heavy duty" pressure plate. You want the "xtreme" pressure plate. for miata heavy duty pp is 300ft/lbs and xtreme is 400ft/lbs.

Personally if I need to upgrade my clutch I'll be getting a 949 twin disk because racecar.

No not a Miata. MX6.

Ideally i "need" something that will hold 500ftlbs.

Ran the xtg6 on my previous miata.
Will never do that again.