Tial f41 1 bar spring. opens @ 10 psi?

[SleeperG]

I'm having a strange issue.

i have a brand new authentic tial f41.
I just opened it while on the car to verify spring color, and it is in fact the large blue spring, which the tial reference chart says is the 1 ar spring.... which is what i want.

The reason i checked it is cause after months of not having my boost gauge hooked up i plumbed it the other day.
My wastegate opens at 10 psi and stays flat all the way to redline.
I have a 50 trim turbo.
I thought my boost gauge was off,
so i checked the map reading on my logger (MMSD for my DS-MAP speed density ecu)
My logger shows my MAP sensor is reading 10 psi as well.


My question is this: With my boost gauge, my MAP sensor and my wastegate..... all sourced at the plenum(Obviously all the same source)
Why is my wastegate opening @ only 10 psi.

I considered for a moment that perhaps my turbo was blown, or i had a massive boost leak.
But even if i had a massive boost leak, and all my turbo could force into the engine despite the leak.... was 10 psi. why would the wastegate still open.
I have an external dump from the manifold... so its obviod when the wastegate is open.


Any ideas?

 

[T9S1i]

so you arent running any kind of boost controller? Just pressure source directly to the WG?

 

[SleeperG]

My ds-map has a built in electronic boost controller,

but at the moment, its just a single line from the plenum to the wastegate. no boost controller.

 

[T9S1i]

wow, it doesnt seem like anything obvious... im going to have to put more thought into this one.

the wg is set up properly right? Pressure line going to the bottom port on the wg and the top port is open to atmosphere?


have you done any boost leak tests?

 

[SleeperG]

I haven't yet done a boost leak test.

my gate is sourced properly. vented on top, boost line goes to the bottom port.


It just doesn't make sense.

If the boost gauge was off. then my MAP sensor would show it.

The MAP and the boost gauge read the same....
but the wastegate opens at 10 psi.
I don't get it.

The ONLY thing i could think of would be the spring was painted the wrong color......
it just doesn't make sense.


I mean i'm pretty sure i have a boost leak because i'm not spooling till 5k rpms. Wheras a month ago i was at full spool by 4100.

but that doesn't( in my mind) explain how my wastegate can open and hold perfectly 10 psi till redline without so much as a twitch out of the needle.

when it shoudln't be opening at all until 14.** psi.

 

[tkelly27]

Stop bumping your thread. If I'm not mistaken, 14psi refers to the static condition. If you have back pressure in your manifold, this number will go down. Try doing a boost leak test and see when it opens, if that's not 14, then that would indicate to me that you have problems.

 

[SleeperG]

from my understanding. a 10 psi wastegate will open and hold 10psi
a 20 psi wastegate will open and hold 20 psi.
provided its appointed to an appropriate sized turbo and the turbo cna keep up with the engine.

I'll do my boost leak test today if i get the time.
Perhaps it will reveal the source of the issue, although i don't know why it would, given that the wastegate, boost gauge, and my MAP are all sourced at the plenum.

 

[Defiant]

I'd say your first suspect should be that Tial may not have their springs calibrated to lab-instrument specs.
I would never expect the rating of a BOV spring to be within 20% of "spec", nor would I depend on one to be my source of boost control. Hook up a ball-and-spring MBC to live by.
Don't run a modified DSM without a working boost gauge. The second gauge, when no mechanical gauge is run, is the color of the bent, broken, or burned parts found in the dead engine.

 

[SleeperG]

I haven't had my oost gauge hooked up simply because my previous 94 galant was totaled.
When I swapped everything over to my new 94 galant GS, I just didn't get around to plumbing it right away.
Mainly because I already had a precise and dependable digital reading through my ECU.

Back on topic:
I spoke with one of the guys from Tial (Jake), and he said that their wastegate spring pressure ratings assume a 1:1 backpressure ratio


He said what i'm describing usually happens when there is too much backpressure.
My mods list hasn't been updated in a while.

I run a SBR g50 50 trim. 2.5" tubular o2 with wastegate blockoff, 2.5" up to the flex, then 3" mandrel bent from the flex back to the muffler. Its a VRS exhaust.
My manifold is a tubular SBR manifold with a tial f41 mounted off the collector.


Is that really going to sequester my turbo into 10 psi ?

If backpressure(and nothing else) is whats causing my base spring pressure to remain always @ 10 psi, i'll accept it.
My DS-MAP has the provision for its own built in electronic boost controller using a GM boost control solenoid.
I've been wanting to start tuning the boost curve with it, but have been hesitant to start cranking up the boost if my base pressure isn't going to be a constant.
I mean i have the fuel and the tune to run 25 lbs with zero knock(because i was before i switched manifold and wastegate setup)

Are there any other concievable situations where I would e having the symptoms that I am?

 

[T9S1i]

have you checked for boost leaks yet?
maybe you could have too much backpressure but i dont know about that.

 

[SleeperG]

I'm going to do a boost leak check tonight or tomorrow now that the weekend is here, i'll post my results

 

[SleeperG]

Dude at Tial said they have never had a defective spring.... but have had ones that were painted the wrong color.
He suggested I send the spring in and he can veriy exactly what spring it is, and send me the correct one if in fact it is incorrect.

So i'll boost leak check tonight or in the morning, barring any revelations... i'll send that spring out to tial.

 

[T9S1i]

check your boost source line to the wastgate for any small tears or holes... i guess you would find em during a boost leak test

 

[SleeperG]

check your boost source line to the wastgate for any small tears or holes... i guess you would find em during a boost leak test

I'll check that today..... but seems to me any leaks in THAT line would raise the boost above the spring pressure, as opposed to lower it.

 

[NewTurboTuner]

My Tial has the .9BAR spring too. When my car was base tuned, we did it at spring pressure and it only gave 10psi.