External Wastegate Info

[TJCTalon]

Hey guys, another question.

I just got my hands on a TiAL 38mm wastegate. I dont know what model. In fact I dont know much about external wastegates and how they work. There are no good threads on this site explaining them. Do you guys know what model this is?

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This is what I understand from what research ive gathered.

We all know wastegates divert exhaust gases around the turbine wheel to help control boost. Same thing goes for internal to external gates. You can run a wastegate off the exhaust manifold ( some say this is the better way to divert gases) or off the o2 housing.

Second and for most my main question is the spring rates for external wastegates. I understand that if you get a 1bar spring (14.5psi), with a boost controler you can basically double that to about 30ish psi. But you cant lower the boost below the spring rate of 14.5 psi. Ive also read that some people have trouble controling boost after X1.5 the boost spring rate. That the wastegate blows open when trying to control more then 1.5 the spring rate. Im trying to find out what spring is correct for me.

So my questions are, Which way is the best place for the wastegate? (o2 housing or mani). And can some one please elaborate on the spring combination and rates for me?

Thank you guys,
TJCtalon

Edit: So anyone who has information, pictures or links about wastegates put them in here.

 

[SpawnedX]

The best way is off the manifold collector, next is off the O2, and the least of the options on a single runner, cracking will happen.

How much boost do you wish to run? The springs are only like 30.00 if you ever need to upgrade, and there is a chart that you can use to see how to get where you want to be.

Oh yeah, that is the 38 mm (F38) model.

BTW 1 BAR = 14.7 PSI, that's just for your science edification.

 

[SpawnedX]

EXTREME PSI : Your #1 Source for In Stock Performance Parts

 

[TJCTalon]

On extremepsi's website it says the 1bar spring is 14.5:EXTREME PSI : Your #1 Source for In Stock Performance Parts

 

[SpawnedX]

I will make sure to shoot them for that.

Another problem with running it off a single runner is that it can only bypass exhaust every other pulse, so you will reduce boost creep, but not entirely.

 

[TJCTalon]

Cool good to know. I am still wanting some info on spring rates, and if anyone has issues controling boost after 1.5x the spring rate. Anyone have anything to add to that?

 

[Absit]

1 BAR is 14.5 PSI
1 ATM is 14.7 PSI

They're nearly interchangeable.

 

[99gst_racer]

Cool good to know. I am still wanting some info on spring rates, and if anyone has issues controling boost after 1.5x the spring rate. Anyone have anything to add to that?

You can usually run double the rate of the the spring before you have to worry about any inconsistencies in target boost.

So, how much boost do you plan to run?

Also, here's the Tial spring chart: http://www.dsmtuners.com/forums/fre...te-spring-chart-bar-psi-conversion-table.html

 

[TJCTalon]

Well I would like to run 16-18 daily on pump gas. But when I switch over to e85 It would be nice to not have to switch springs.

 

[99gst_racer]

So run a large RED and small RED combo to have 17-18 psi, and then add a MBC down the road to efficiently bump up to 30-35 psi. Good adjustability range with no need to ever mess with the springs.

 

[TJCTalon]

Okay thank you,

Is there anything special when taking this thing apart? I know it will want to shoot open, so leave a couple bolts on so it doesnt shoot apart?

Also Idk if you guys can tell in the pic, but the valve isnt closed all the way. Im guessing it should be? Could there be something wrong with it?

 

[JusMX141]

Sounds like it's missing the valve seat to me.

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[gofer]

Sounds like it's missing the valve seat to me.

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The valve seat goes on the flange thats not showing in that picture, isn't it?

 

[99gst_racer]

Yeah, we need to see the other flange to see if the seat is present or not.


As far as taking it apart to change springs; chuck the gate up in a bench vice. That way you can take all of the screws out without having to deal with the force of the springs trying to tear the threads out of the last bolt hole or two. Using a bench vice is particularly beneficial when trying to put the top back on.

 

[TJCTalon]

Okay here are the valve pictures:

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Also do you guys know where I can find an affordable mitsu style manifold set up for external wastegate? It seems not alot of people make them, I even had a hard time finding ebay special manifolds for mitsu style turbo.

 

[gofer]

Damn, Justin was right, you are missing the valve seat... How in the hell did he guess that?! You can get one for cheap here ---> Amazon.com: Tial SS F38 Valve Seat

Where do you want to run the wastegate, off of the o2 housing or exhaust manifold?

 

[TJCTalon]

The 20g I just picked up has the wastegate flapper welded shut, so I was wanting a manifold. I dont have alot of money either, I would even settle for ebay quality. If I did have the money I would go with dn performance mani, that one looks really good.

 

[gofer]

The problem with trying to settle for something cheaper, as far as exhaust parts goes, means you'll be replacing it A LOT sooner and spending the money twice.

Heres a cheaper alternative than the DNP $1k tubular, its the SBR manifold. I've never ran one personally but its flanged for a Mitsu housing so the 20g you have will bolt right up. Just be sure to select to have the wastegate hole pre-tapped/drilled when you order it, it doesn't cost any extra and that Tial you have will bolt right up.

SBR Cast Exhaust Manifold

 

[JusMX141]

Damn, Justin was right, you are missing the valve seat... How in the hell did he guess that?!

I'm f*ckin GOOD, that's how.




Seriously, I've seen such an issue more than once...it was the first thing that came to mind.

 

[DSM_ThuNDeR]

Okay here are the valve pictures:

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NOT TO HYJACK or anything! but my MSV TIAL looks the same way (I think). maybe thats why my turbo isnt spooling and boosting where it should?

 

[TJCTalon]

Yes that could be why its not building boost, go to the link gofer posted and pick one up for 13 bucks!

 

[DSM_ThuNDeR]

Yes that could be why its not building boost, go to the link gofer posted and pick one up for 13 bucks!

I am building boost, but its EXTREMELY LAGGY for the turbo I have (HX35). Im going to take the sucker off right now and see if I was right. Last time I did remember seeing something like that. Lets just hope I'm right!

JUSTIN you give miracle advice!

 

[TJCTalon]

Okay so I opened her up today and found what I think is the large blue spring. Is this correct?

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[GRAVEDIGGER]

Okay so I opened her up today and found what I think is the large blue spring. Is this correct?

According to the wastegate spring list that 99gst_racer posted that should be a 14.5psi spring and should be what you want.

 

[TJCTalon]

Yes its perfect I was just confirming whether that was a large or small spring. Im pretty sure its a large.
I got lucky, no need to buy a new spring