External wastegate guys....lets talk springs

[MmmBoost]

Gentlemen,

I'm finally joining the club of External Wastegaters after a long and hard fought battle with my IWG. so......I'll be installing this bad boy soon and had a few questions...





I have an Electronic Boost Controller than I plan to try out with this unit for a while and I'm curious about your setups

What spring are you running?
How are you controlling boost?
What is your maximum boost level?
Any comments or impressions....or perhaps why you chose which spring?

[kneel]

Chris I'm running the TIAL 38mm waste gate with the Big Yellow Spring and the Small Green. think it is total 17.5lbs spring.
Couldnt get the car to go past 22-23psi so with the help of John EErieB6 i added the Small Green. Car makes around 30psi. My Podi only reads to 25psi so not sure on actually boost it has made. I let off when it hit PODI in the Gauge......not reconmended. Running a Forge MBC to control boost.
Guessing around 28-30psi.
(new podi VEI) gauge soon to arrive

[nein-reis]

I also have a Tial 38mm WG, have the whatever springs came in it. I use a Hallman MBC and have no problems setting 30+ psi I ran it off the spring once and saw it peak 40.

[ricekikr]

I think rule of thumb is boost should only be up to double spring rate. But I've seen cars with 7psi spring running more than triple boost.

Precision 39mm (15psi spring) = Steady 30psi boost, haven't tried higher than 30psi.

Fwiw, Precision 39mm ships with several springs, for slightly less $$ than tial 38mm with one spring.

[dougyfresh]

TiAL MVS 38mm

The unit originally was a 1.3bar unit but when my car was tuned the springs were taken out and it was tuned at 0.4bar which is where it currently resides.

N75 controlled boost

28psi is the highest I'm running currently.

[Dan[FN]6262]

I'm also running the PTE 39mm WG. Whenever I run spring pressure, I see 16psi on the gauge, so I'm guessing I have a 15psi spring in the unit. I've ran up to 34psi with my PTE6262, but the turbine housing wouldn't flow anymore after that. also ran 42psi with the Comp, on the same spring. but that was an accident. got a new MBC and it was cranked down A LOT farther than what I thought.

My advice, just put the biggest baddest mother effer in there. it'll help spool and boost profile won't be wavy. You don't want that thing cracking open before you reach your desired boost level. but I think you know that

[dougyfresh]

larger spring you loose part throttle adaptability

[Dan[FN]6262]

yeah, if you're running the N75, but Chris uses a EBC.

[dougyfresh]

should use the N75

[Dan[FN]6262]

I ran the N75 for a while, but then it started to die, so I just swapped back in a MBC. not like it really matters in my car though.


IIRC, there was a reason for Chris running the EBC, instead of the N75, but I can't remember.

whatevah, I honestly don't care what he runs, just as long as he keeps taking those sweet ass photos

[Turbavanttro]

My advice, just put the biggest baddest mother effer in there. it'll help spool and boost profile won't be wavy. You don't want that thing cracking open before you reach your desired boost level. but I think you know that

I disagree. He won't have any cracking issues using an EBC or N75. Why doesnt everyone just toss in a heavy spring and be done with it? Because it generally leads to increased wear and tear on the turbo, etc., and not better performance.

Rule of thumb previously stated is correct, run a spring that is approximately 50% of minimum desired boost level (so if you are going to run two files, a 25psi file and a 35psi file, you're probably safe with a spring around 17psi). If cracking open prematurely is an issue, try the dual port setup. Using that second port helps keep it shut.

[Dan[FN]6262]

depends on the quality of the EBC and it's controller. and how can you say it causes more wear and tear on the turbo? they're designed to spin hundreds of thousands of rpms and with stand insane temperatures. running a heavier spring will just mean that you have to run a lower boost duty cycle with the EBC/N75.

When I was running the N75, I only had to run a 30% duty cycle to make 24-25psi. so really, if you run a heavier spring, and can run a lower boost duty cycle with a EBC/N75, wouldn't that mean that the EBC/N75 would last longer?

but yes, I also agree with running a spring around half of your desired boost level. That's not a new concept though.

[dougyfresh]

IIRC, there was a reason for Chris running the EBC, instead of the N75, but I can't remember.

Had trouble getting the PID tables set properly if I recall correctly. Might have been because of the internal gate issues he resolving by going to an external gate.

[drjonez]

I think rule of thumb is boost should only be up to double spring rate...

This is the generally accepted methodology.

Back in my Supra days, I ran a Tial 38mm with an 8 PSI spring and used an EBC to control boost up to 24 PSI with zero problems.

[Dan[FN]6262]

Back in my Supra days, I ran a Tial 38mm with an 8 PSI spring and used an EBC to control boost up to 24 PSI with zero problems.

what size turbo were you running?

[drjonez]

what size turbo were you running?

T4
60-1
p-trim

[Dan[FN]6262]

Nice! bet it had no problem getting out of its own way haha

/end thread jack

[SleeperAvant]

I'm running the Tial F38 with both large blue and small blue spring.

[Turbavanttro]

and how can you say it causes more wear and tear on the turbo? they're designed to spin hundreds of thousands of rpms and with stand insane temperatures. running a heavier spring will just mean that you have to run a lower boost duty cycle with the EBC/N75.

Using a spring pressure that is far too large is likely* to lead to more wear on the turbo because pressure may not be dumped when it should if adequate pressures are not available to overcome the spring pressure, which leads to higher temps, more internal stress/wear, and reduced life. I wasn't getting into the details of how to run a larger spring since there is no reason to run a larger spring than necessary.

but yes, I also agree with running a spring around half of your desired boost level. That's not a new concept though.

My advice, just put the biggest baddest mother effer in there. it'll help spool and boost profile won't be wavy.

[Dan[FN]6262]

lol yeah, I know I contradicted myself between posts, but I still think bigger is better

pressure will still be dumped when it should, otherwise you'd experience a high boost spike when running a heavier spring.

but this is all unnecessary rhetoric. I honestly don't want to argue about it.

both are just different methods to achieve the same goal.

[Antoinebourdeau]

I'm running the TIAL 38mm waste gate with 10psi spring (Big Yellow Spring and the Small Brown IIRC).
had no problem running 25psi with the n75 and a hta3076r, I now switched to a MBC set @20psi with no problems.

[MmmBoost]

Wow.....this blew up this morning.......

IIRC, there was a reason for Chris running the EBC, instead of the N75, but I can't remember.

Had trouble getting the PID tables set properly if I recall correctly. Might have been because of the internal gate issues he resolving by going to an external gate.

Incorrect. I changed from running an N75 for pretty much the very same season that I am moving to and external wastegate. When trying to run high boost ===> large boost spike ===> boost drops to 24-ish ===> boost tapers down as RPMs increase.

I had maxed out the N75 and I have maxed out the EBC......same bullshit. The wastegate is the problem, not my tuning or my method of control. The same thing even happens when running a MBC.


I have plans to run two control circuits. On circuit running the N75 and tuned for around 21-22 PSI. The other circuit will be controlled by my EBC which I have independent control over 6 different boost curves......they will be selectable by a toggle.


I have my reasons on why I am controlling the boost the way I am......so lets try and keep the thread on topic, please.

[M-Hood]

I'm also running the PTE 39mm WG. Whenever I run spring pressure, I see 16psi on the gauge, so I'm guessing I have a 15psi spring in the unit. I've ran up to 34psi with my PTE6262, but the turbine housing wouldn't flow anymore after that. also ran 42psi with the Comp, on the same spring. but that was an accident. got a new MBC and it was cranked down A LOT farther than what I thought.

My advice, just put the biggest baddest mother effer in there. it'll help spool and boost profile won't be wavy. You don't want that thing cracking open before you reach your desired boost level. but I think you know that

Dan I think you need to actually look at how the External WG works. The valve goes up to open so it is not even possible for it to "Crack" open under high exhaust pressure on the turbo side. That is an issue that happens with internal WG setups because the flap opens outward. For the EWG to open the pressure is applied to the bottom of the diaphram inside the housing to force it and the valve upward, pressure is put to the top to keep it closed when using it as a dual port.

I run a little 10 lbs spring in my old 2 bolt Tial 38mm and I have no issues pushing 37psi.

[spindoctor]

My advice, just put the biggest baddest mother effer in there. it'll help spool and boost profile won't be wavy. You don't want that thing cracking open before you reach your desired boost level. but I think you know that

Few years back, I remember reading a thread at MR2oc about a 631whp 3S-GTE MR2 that's got a GT35R and 60mm HKS external gate setup. The dyno sheet shows the power curve dipped when the external gate opened, as its dumping exhaust gases way too much instead of it spinning the turbine wheel.

FYI, John Shepherd(quickest/fastest DSM @ 7.7sec) runs a Tial 44mm external gate on his custom FP GT42R. Runs about 60psi boost. :D

[M-Hood]

Few years back, I remember reading a thread at MR2oc about a 631whp 3S-GTE MR2 that's got a GT35R and 60mm HKS external gate setup. The dyno sheet shows the power curve dipped when the external gate opened, as its dumping exhaust gases way too much instead of it spinning the turbine wheel.

FYI, John Shepherd(quickest/fastest DSM @ 7.7sec) runs a Tial 44mm external gate on his custom FP GT42R. Runs about 60psi boost. :D

The more boost you run the smaller the WG can be. A 38mm WG is big enough for a A4 1.8t when running more then 20psi which just about every single A4 owner does. A larger WG is only needed when running really low boost like you would find on a NA car that puts a turbo on. It just helps to control boost creep in the higher rpm's.


Just look at the boost curve, just shows you that a 38mm valve and 10psi spring can have a sharp curve when using a EBC.

[Dan[FN]6262]

Mike, I know how it works, but you're talking about using both the ports, I only use the bottom port.


like I said before, there are so many ways to set it up to achieve the same result.

[MmmBoost]

Mike,

Pressure from the manifold is trying to force the valve open..... It isn't holding the valve down.




The wastegate inlet is on the bottom.......the valve is the on the bottom.....the valve moves up, therefore manifold pressure is trying to work against spring force.

[M-Hood]

Damn that is right and its too early in the morning. LOL

Odd thing is that my friend with the 2.3 liter EVO can run 35+psi on his HTA35r .63 a/r and he runs it as a single port with MBC. If it is cracking open then the pressure in the manifold is way too high. IN that case then a higher rate spring will need to be use. But not needed when running it with a EBC and dual port setup. Not sure why people still want to use the N75 valve since it reacts so slow compared to a EBC.

[MmmBoost]

Not sure why people still want to use the N75 valve since it reacts so slow compared to a EBC.

Because I don't want to spill my Starbucks all over my lap in the morning when I'm merging into traffic.


which is exactly the reason I want to run two boost control circuits. On for mild manners.......the other for any boost level I want.

[dougyfresh]

/\
haha. I was not going to comment on Mike's N75 sentence but you did.



Go tell the B5 S4 guys that sentence, Mike. You'll probably also ask them why they are using a MAF too like people like Chris and I are on our B6s. The factory Motronic software works great when operating correctly. A few of us (EPL, ASP, Jeff Lee/Austin@GIAC, a few Maestro users, etc..) have figured out how to do that and still make significant more power with factory resolution than the cars did from the factory.

[M-Hood]

Because I don't want to spill my Starbucks all over my lap in the morning when I'm merging into traffic.


which is exactly the reason I want to run two boost control circuits. On for mild manners.......the other for any boost level I want.

EBC vs N75 valve shouldn't be an issue with that size turbo. I ran my EBC with my T28 and had no issues with boost control on the street. Also ran it with my GT35r when my only car and my 100% daily driver for work. Been running that EBC for 10 years now with 5 years of that on the street as my daily driver. Boost control was never an issue.

Go tell the B5 S4 guys that sentence, Mike. You'll probably also ask them why they are using a MAF too like people like Chris and I are on our B6s. The factory Motronic software works great when operating correctly. A few of us (EPL, ASP, Jeff Lee/Austin@GIAC, a few Maestro users, etc..) have figured out how to do that and still make significant more power with factory resolution than the cars did from the factory.

Doug your talking about a K03 and K04 which is too small for a EBC. This is not an issue once running a GT28r or larger turbo since boost onset is not as quick.


Nearly all of the N75 valve boost curves I have seen over the 11 years I have been around all show the EBC having a really soft/slow boost curve.

[dougyfresh]

Doug your talking about a K03 and K04 which is too small for a EBC. This is not an issue once running a GT28r or larger turbo since boost onset is not as quick.

No, I am talking about 770/GT28 on the 2.7 motor and GT30R or bigger on the 1.8/2.0 motor.

[nein-reis]

If I dont want to spill my coffee all lover my lap, I stay away from 4K RPM.... lol. Merging is another story, better have that coffee 1/2 way gone by then. I agree with Doug on this subject though, any time OEM Controlled systems can be utilized the better, my N75 always caused major issues and that is why I do not currently run one... and I am about to go to a MAF setup before I even start my 2.0L.

[M-Hood]

No, I am talking about 770/GT28 on the 2.7 motor and GT30R or bigger on the 1.8/2.0 motor.

Then those people run a N75 valve because they are too scared to run a EBC or they are told to run the N75 valve by their tuner.

BTW the 2.7 owners with the larger turbo setups still tend to run internal wg turbos which is why most of them still use the N75 valve. Those people don't have the option for dual port control which is a big advantage for using the EBC.

[ZimbutheMonkey]

I run a big 'ol ugly Turbonetics Deltagate II 35mm with what I think is a 12 PSI spring. Handles the exhaust volume from a 60-1 with a .48 A/R housing just fine. At 55% duty cycle with my AEM controller I can hit 25 PSI no problem, so there's a lot more there if I wanted to. Never had any creep with it. 38mm is plenty for your 2871r, even a 35mm would handle whatever you can throw at it with that size turbo.

PS: e-boost controller is the way to go, screw the N75.

[M-Hood]

If I dont want to spill my coffee all lover my lap, I stay away from 4K RPM.... lol. Merging is another story, better have that coffee 1/2 way gone by then. I agree with Doug on this subject though, any time OEM Controlled systems can be utilized the better, my N75 always caused major issues and that is why I do not currently run one... and I am about to go to a MAF setup before I even start my 2.0L.

The N75 just has its limits. To me its like using a 5 year old computer vs buying something that is newer and quicker.

[Turbavanttro]

Mike, Pressure from the manifold is trying to force the valve open..... It isn't holding the valve down.

The dual port setup uses the top port on the EWG to help the EBC keep it closed. That's what I think Mike's statement referred to.

[Dan[FN]6262]

FYI, John Shepherd(quickest/fastest DSM @ 7.7sec) runs a Tial 44mm external gate on his custom FP GT42R. Runs about 60psi boost. :D

haha yeah, John Shepherd was the reason I use to own a DSM. his car is nuts

[M-Hood]

The dual port setup uses the top port on the EWG to help the EBC keep it closed. That's what I think Mike's statement referred to.

No he was right. I just keep forgetting that the EWG gets installed with the bottom of the valve going into the exhaust manifold. Just seems that it would work better the other way when using it as a single port to control boost and pushing the valve up and allowing the exhaust inside of that part of the valve body out past the valve.

[MmmBoost]

Just because someone says their using the N75 it doesn't necessarily mean that it's the actual N75 valve. I am using a PWM solenoid instead because my N75 was leaking. It is no different than an EBC solenoid and infact it is the same solenoid used by a number of EBC manufacturers.

Slow or fast spool depends on programming, not the valve itself. They both serve the same purpose....to regulator pressure to the wastegate. It's all about how you tune. The advantage the ECU control over boost has is that perhaps you're only 1/3 on the pedal and the ECU requests 13 PSI.....it will try and achieve that and hold it there vs. the EBC just always trying to skyrocket boost to the moon as soon as possible. There is no operator input in the EBC and trying to get anything less than 100% boost is very difficult.


We don't all drive race cars and want to extract every last ounce of performance out of our cars every time we give the car more than 8% pedal.