Mazdaspeed turbo on a 1,6 '93: I need more boost
#1
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Hello
I own a old pre FM Ihi turbo kit. The turbo is cracking inside near the wastevalve, so I got a new mazdaspeed turbo from ebay. It's on the car and runs fine. But I can't get 12 psi boost with this kit. So I got a manual boost controller. Now I can get more boost, but the boost is not stable. It's 10 - 11 12 - 11,5 - 11 - 11,5 - 12 ... in seconds or less. Really boring and you can hear it too.
I was thinking about replacing the actuator. I want it to be adjustable, +- 12 psi is my goal.
The old actuator could do the trick but the mounts are cracking too and I guess it won't hurt to replace it. It is 10 years old.
What actuator (type, brand) should I buy for my project? It would be nice if it would just bolt on but I guess that's not gonna happen. The FM parts are max 9 psi and I blame the manual boost controller for the unstable boost, so I won't to lose it.
Thx
I own a old pre FM Ihi turbo kit. The turbo is cracking inside near the wastevalve, so I got a new mazdaspeed turbo from ebay. It's on the car and runs fine. But I can't get 12 psi boost with this kit. So I got a manual boost controller. Now I can get more boost, but the boost is not stable. It's 10 - 11 12 - 11,5 - 11 - 11,5 - 12 ... in seconds or less. Really boring and you can hear it too.
I was thinking about replacing the actuator. I want it to be adjustable, +- 12 psi is my goal.
The old actuator could do the trick but the mounts are cracking too and I guess it won't hurt to replace it. It is 10 years old.
What actuator (type, brand) should I buy for my project? It would be nice if it would just bolt on but I guess that's not gonna happen. The FM parts are max 9 psi and I blame the manual boost controller for the unstable boost, so I won't to lose it.
Thx
#2
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It sounds like you need more pre-load on that actuator. If it does not have enough then you can get situations with an internal wastegate/wastevalve where it is opening a bit before the desired boost. So you will rocket up to 5, then slowly creep to 12. A adjustable actuator rod might be the ticket.
The real solution is an external wastegate, which can be run on a setup with an internal gate turbo by integrating it into the downpipe. But thats a big of an investment you might not have to make.
The real solution is an external wastegate, which can be run on a setup with an internal gate turbo by integrating it into the downpipe. But thats a big of an investment you might not have to make.
#4
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
My turbo has a wastegate that goes to the downpipe. The old turbo was almost the same type (just one character is different on this turbo n°) , it just had a stronger actuator.
I guess mazda wanted to have max 8 psi for the mazdaspeed turbo.
Anyway, I can shorten the actuator rod, then I can make 9 psi. If I connect the actuator to the inlet (after the IC, instead of the turbo) I get +- 10,5 psi for a moment that goes to 10 psi, stable. Still not 12 psi![](https://www.miataturbo.net/images/smilies/smile.gif)
I'm a bit scared to shorten the rod: the spring is always compressed and maybe it keeps my wastegate from opening enough.
The MBC is this one:
http://imgs.inkfrog.com/pix/gtschris/mbc2a.jpg
It is a ball spring, but it has got a vent, once is opens. I was thinking of blocking the vent to see what it does. Superglue![](https://www.miataturbo.net/images/smilies/smile.gif)
You want pics, don't you?
Old setup:
http://www.flickr.com/photos/43043415@N04/4584871296/
New turbo:
http://www.flickr.com/photos/43043415@N04/4584242797/
I guess mazda wanted to have max 8 psi for the mazdaspeed turbo.
Anyway, I can shorten the actuator rod, then I can make 9 psi. If I connect the actuator to the inlet (after the IC, instead of the turbo) I get +- 10,5 psi for a moment that goes to 10 psi, stable. Still not 12 psi
![](https://www.miataturbo.net/images/smilies/smile.gif)
I'm a bit scared to shorten the rod: the spring is always compressed and maybe it keeps my wastegate from opening enough.
The MBC is this one:
http://imgs.inkfrog.com/pix/gtschris/mbc2a.jpg
It is a ball spring, but it has got a vent, once is opens. I was thinking of blocking the vent to see what it does. Superglue
![](https://www.miataturbo.net/images/smilies/smile.gif)
You want pics, don't you?
Old setup:
http://www.flickr.com/photos/43043415@N04/4584871296/
New turbo:
http://www.flickr.com/photos/43043415@N04/4584242797/
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