2yan

Hey,

I've had the car with a CX racing kit for a while and now recently have been facing issues with a stuck closed waste gate.
That's right, I have all the boost. I have an event coming up in a few weeks that is more than the usual autox event so I can't just expect that I won't over boost during the event.

So now I need to open up the waste gate actuator anyway and have been wanting to use a boost controller + a much lighter spring (2-3PSI) so that I can pick my boost levels better and actually use the MegaSquirts boost controlling abilities.

1. I'm having trouble figuring out how best to do that, where does one buy new springs, how does one pick the right spring? Does anyone have any experience swapping the actuator itself?

2. Would it be better to just swap the turbo? If so I've been having trouble finding literature understanding sizes of wheels etc. Unfortunately googling "Turbo miataturbo.net" or anything related really doesn't help given that we use the word "Turbo" a lot.

Dr.Sep

Sheesh, first figure out why its not opening... is the actuator arm binding from not aligning? Are you not getting vacuum to the wastegate canister?

What kind of wastegate actuator do you have, most are not able to be opened up -- generally just aftermarket ones like ones offered from Turbosmart

you can really only go slightly less than double your spring pressure; so if your spring is 7psi you can generally only raise that to about 13psi with a boost controller. Beyond that you need to go to something like a 4 port electronic actuator, and I am 100% not going to go into depth on to why or how as that info is readily available.

First thing is first, figure out why your current one is not working -- I am betting your turbo is clocked in a way that doesn't quite line up and is binding the rod

2yan

I'm already checking in on why that isn't working.

My goals are to be able to electronically pick between 3-9ish PSI depending on conditions and the current actuator not working was just the tipping point of "ok, time to get into it and make the upgrades while I'm at it""

borka

iTrader: (1)

I doubt you can get 3psi with any spring or actuator. Especially on a China charger with their small port.

Do an experiment, disconnect the wastegate arm from the actuator, tie it open with a string and go drive and floor it in 3rd gear all the way to redline and see how much boost you get.

This will tell you that no matter what actuator you have, you can't be under that value without opening up the hole bigger..

What psi are you currently getting when the wastegate was actually working properly and what are you getting right nright stuck actuator can goto 25psi and make your engine go boom

jt@namiata.com

Yes, all that, and put a vacuum pump on it to prove/disprove that the actuator is actually working. Then, when you reconnect or replace it, test again to be sure that the trubo is clocked properly so that the actuation isn't bound up.

A vac pump is good for all sorts of things:

2yan

When the wastegate was working properly it was sitting around 7-8 PSI.
I see, so the turbo is going to spool up to a certain amount due to the constriction from an open wastegate port no matter what. I'll need to do that experiment later to figure out my lower limit, that makes a lot of sense though. I do want to be able to get as low as I can.

Additionally, I still need to figure out if anyone here has experience swapping out this specific actuator, failing that, a recommendation for a smaller turbo that'l plug in. I imagine this is the sort of recommendation that would come from someone who has done either with this specific kit.

I'm currently using the Megasquirt to cut fuel/spark if the car hits a predefined boost limit for temporary and jarring safety.

jt@namiata.com

Looks like this guy?
https://www.cxracing.com/TRB-T3-48-V-8PSI

borka

iTrader: (1)

You actually need to blow 5-10psi of compressed air into the actuator. Pulling vacuum on it will do absolutely nothing.

jt@namiata.com

Correct. Thus why you'd reverse it. The shitty broken link I posted should be going to this:
It does both vac and pressure. Great tool.

2yan

Yes, that's the one.

I'll get that vac pump, testing it with some pissies makes sense.

2yan

The vac pump helped me diagnose my issue, It was just really rusty. I still want to be able to electronically lower boost so I still need to figure that part out.
Other than that this turbo desperately either needs to be swapped or rebuilt.

Dr.Sep

Lower boost beyond wastegate electronically? Can’t, can only use EBC to raise unless you have a dual port wastegate and a 4 port solenoid

2yan

So the turbo finally blew up. I'm trying to avoid purchasing another manifold and now stuck trying to figure out a smaller t3 turbo.

Dyladjent

Lars (@shuiend)from MKturbo seems to have figured out the best cheap t3 turbo. The ones he uses in his kits seem to hold up decently. You might want to look into those.

Xaendeau

I'd also recommend reaching out to MKTurbo. I've seen their kits hold up really well, so he found a really good supplier.