Boost isn't Steady

[low_psi]

For Spud:

Boosted 9.5 steadily for a week or so and then it started to leak off after peaking at 9.5psi. Reset the ECU, got rid of the hesitation issue. Still peaking and then leaking off after hitting 9.5psi.

Why did the car all the sudden start leaking boost? Is anyone holding higher boost steadily? We will be checking all the vaccum lines tomorrow, so is there anything else to do?

I know he posted this already, but I'm looking for other suggestions.

[SuperSpud]

I know Im not... oh wait... lol

[unwrittenLaw]

i'll bump this because i'm curious too...

[perfworks]

Originally posted by mx3ownzj00
For Spud:

Boosted 9.5 steadily for a week or so and then it started to leak off after peaking at 9.5psi. Reset the ECU, got rid of the hesitation issue. Still peaking and then leaking off after hitting 9.5psi.

Why did the car all the sudden start leaking boost? Is anyone holding higher boost steadily? We will be checking all the vaccum lines tomorrow, so is there anything else to do?

I know he posted this already, but I'm looking for other suggestions.
How do you know its leaking boost?? Do you hear it??
It could be just spiking. Boost pressure will equal out in the manifold sometimes depending on throttle position, load and atmospheric changes. Also pressure drop in the system. The turbo may not be able to hold the boost. Sometimes also with internal wastegates the spring pressure tightens up after the flapper has opened.
There are many things it could be. You need to get a reference from the boost gauge in different spots after the turbo to see what is going on for sure. And are you using a stock recirculating valve??
i suggested to many on this board already that have the MSP to get the bosch recirculating valve to upgrade because sometimes the spring tension in the stock unit will flutter

[SuperSpud]

Originally posted by perfworks

How do you know its leaking boost?? Do you hear it??
It could be just spiking. Boost pressure will equal out in the manifold sometimes depending on throttle position, load and atmospheric changes. Also pressure drop in the system. The turbo may not be able to hold the boost. Sometimes also with internal wastegates the spring pressure tightens up after the flapper has opened.
There are many things it could be. You need to get a reference from the boost gauge in different spots after the turbo to see what is going on for sure. And are you using a stock recirculating valve??
i suggested to many on this board already that have the MSP to get the bosch recirculating valve to upgrade because sometimes the spring tension in the stock unit will flutter yes, he means spiking.. (Its my car)... it goes to 9.5psi up until around 4500, then drops down to 7'ish....
when I downshift from 5th to 3rd, it goes way down to like, 5-6psi, which is lower than it registered when I got my car.... and boost holds right at 9.5 in 5th, no spiking...

[boostisgood]

With a manual boost controller, you will find boost to be higher in the higher gears, If its 7.5 in 3rd gear, you will see, and hold the 9.5 in a higher gear. I truly cannot remember the explanation, Ill try to find it today, in my SCC mag that referenced it.

[perfworks]

Originally posted by SuperSpud
yes, he means spiking.. (Its my car)... it goes to 9.5psi up until around 4500, then drops down to 7'ish....
when I downshift from 5th to 3rd, it goes way down to like, 5-6psi, which is lower than it registered when I got my car.... and boost holds right at 9.5 in 5th, no spiking...

Ive seen this happen first hand when you downshift. There really isnt a load and the high rpm allows the air to flow so measured boost will be less. Untill you floor it again but then it really wont pin to a higher psi anyway till you hit 4rth

[SuperSpud]

so if I want to set it at 9.5 psi,, I should let it spike higher? and then let it come down to 9.5???

so it would spike at like 12, then stay at 9.5?? is that what your saying?

[perfworks]

Originally posted by SuperSpud
so if I want to set it at 9.5 psi,, I should let it spike higher? and then let it come down to 9.5???

so it would spike at like 12, then stay at 9.5?? is that what your saying?
Again spud there are alot of different reasons why you are spiking. It is evident when you initially go into WOT. The process includes how well the engine can process the air it is given.
Then other factors take place like pressure loss and spring tension in the control devises. The MSP has a very small turbo to begin with that can only pump so much efficiently at the higher RPM levels without the stock induction " bypassing" it

[unwrittenLaw]

I'm just a bit worried about spiking to 12-13 on a constant basis...

[yashooa]

Mine hits 12 for about 2 secs then drops to 11 and then stays on 10 until shift. I had to play with the MBC fot a few days but for the last couple weeks it has ran great not one bit of boost loss.

[SuperSpud]

Originally posted by unwrittenLaw
I'm just a bit worried about spiking to 12-13 on a constant basis... as am I

[kwiktsi]

Originally posted by SuperSpud
so if I want to set it at 9.5 psi,, I should let it spike higher? and then let it come down to 9.5???

so it would spike at like 12, then stay at 9.5?? is that what your saying?


Dude- you are not spiking- a spike is right to xx psi than instantly falling to whatever. These cars go to a higher psi and hold it there for a while, then drop as RPM's increase. If I have to explain to anyone else that it is caused by a shitty turbo combined with a weak WG spring and a 4 banger revving to 7k, I will lose it :).

You have IM'ed me several times about this and I told you it is the nature of the car. If you don't want the boost to ever drop or fluctuate, get a bigger turbo, extrenal gate and an electronic controller. It is not a boost leak with the car, we have been through this :).

My car has a damn $500 Blitz controller and it always drops around 2-3 psi from peak (and I tightened my wastegate!!) and is as much as 4-5 psi higher if I roll on it in the higher gears until the load lessens.

I don't know the reason it didn't do it at first and does now- could be the wastegate spring loosening up a bit, air density, etc. We have gone through this :).. There are times where mine will hold solid and times it will drop also- again, there are a lot of variables to be considered.

Joe

[kwiktsi]

Originally posted by boostisgood
With a manual boost controller, you will find boost to be higher in the higher gears, If its 7.5 in 3rd gear, you will see, and hold the 9.5 in a higher gear. I truly cannot remember the explanation, Ill try to find it today, in my SCC mag that referenced it.

It is due to engine load being greater and longer duration in the higher gears. It is not just MBC's a lot of EBC's do it too- my Blitz DSBC does it too.
Joe

[SuperSpud]

Originally posted by kwiktsi



Dude- you are not spiking- a spike is right to xx psi than instantly falling to whatever. These cars go to a higher psi and hold it there for a while, then drop as RPM's increase. If I have to explain to anyone else that it is caused by a shitty turbo combined with a weak WG spring and a 4 banger revving to 7k, I will lose it :).

You have IM'ed me several times about this and I told you it is the nature of the car. If you don't want the boost to ever drop or fluctuate, get a bigger turbo, extrenal gate and an electronic controller. It is not a boost leak with the car, we have been through this :).

My car has a damn $500 Blitz controller and it always drops around 2-3 psi from peak (and I tightened my wastegate!!) and is as much as 4-5 psi higher if I roll on it in the higher gears until the load lessens.

I don't know the reason it didn't do it at first and does now- could be the wastegate spring loosening up a bit, air density, etc. We have gone through this :).. There are times where mine will hold solid and times it will drop also- again, there are a lot of variables to be considered.

Joe I done got told lol

[Brian MP5T]

Hey, I read the whole thread and about your boost drop...

Are you running a stock Mazdaspeed or have you tweaked it. The reason I ask is that if you use the stock intergrated wastegate at higher than intended pressures you will encounter a " Skate " problem. That is to say the wastegate will have a higher chance for inconsistent max boost ( The Boost Needle Might Skate ). If this is the case and you want better control I have two solutions.

1. Expensive, Swap to a Garrett T-25 without a wastegate and weld a Proper wastegate like Tial 35mm to the manifold.

2. Less Expensive Lock the stock wategate Actuator and then ... like above... get a proper wastegate.

When playing with Pistons under boost, the more loose your boost pressure is , the harder it will be for your fuel management system to maintain Stoych Balance. Hope it helped./members/Brian MP5T/mazda mp5t - zoom zoom - (1).jpg

[kwiktsi]

Originally posted by SuperSpud
I done got told lol
lol...
Joe

[kwiktsi]

Originally posted by Brian MP5T
Hey, I read the whole thread and about your boost drop...

Are you running a stock Mazdaspeed or have you tweaked it. The reason I ask is that if you use the stock intergrated wastegate at higher than intended pressures you will encounter a " Skate " problem. That is to say the wastegate will have a higher chance for inconsistent max boost ( The Boost Needle Might Skate ). If this is the case and you want better control I have two solutions.

1. Expensive, Swap to a Garrett T-25 without a wastegate and weld a Proper wastegate like Tial 35mm to the manifold.

2. Less Expensive Lock the stock wategate Actuator and then ... like above... get a proper wastegate.

When playing with Pistons under boost, the more loose your boost pressure is , the harder it will be for your fuel management system to maintain Stoych Balance. Hope it helped./members/Brian MP5T/mazda mp5t - zoom zoom - (1).jpg

Well said..

Nice car BTW. How's it run :)? Any #'s on it?
Joe

[Tex]

Hey Perfworks,

Where does one buy this Bosch recirculating valve? I went to the Bosch web site, and could find no such animal.

Thanks.

[low_psi]

are there no options regarding the replacement of the stock WG's spring, to a stiffer one? i'm not familar with which turbos use the same wastegates.

[kwiktsi]

Originally posted by mx3ownzj00
are there no options regarding the replacement of the stock WG's spring, to a stiffer one? i'm not familar with which turbos use the same wastegates.

You can possibly get a heavier one- my turbo guy said he could probably match one up, but he needs either a PN or my stock one to look at and I don't have a PN and I can't take my car apart, I need it :).

the stock gate is adjustable, just a bitch to get off and do it. You will still have variations on boost though, just not quite as bad.
Joe

[low_psi]

Originally posted by kwiktsi


You can possibly get a heavier one- my turbo guy said he could probably match one up, but he needs either a PN or my stock one to look at and I don't have a PN and I can't take my car apart, I need it :).

the stock gate is adjustable, just a bitch to get off and do it. You will still have variations on boost though, just not quite as bad.
Joe

yes, those options kind of kill the idea for me, spud needs his car running everyday... i'm sure he doesn't want to leave it with me for the night to tinker with :)

what would you change in the stock WG though? there a way to make the spring tighter(stiffer), i'm guessing?

[kwiktsi]

Originally posted by mx3ownzj00


yes, those options kind of kill the idea for me, spud needs his car running everyday... i'm sure he doesn't want to leave it with me for the night to tinker with :)

what would you change in the stock WG though? there a way to make the spring tighter(stiffer), i'm guessing?

The stock rod is adjustable (threaded), so you just tighten/shorten it. The thing is if you do that, it will increase boost and if you bring it in for any type of work where they check for psi, you will get nailed for tampering with it.
Joe

[Brian MP5T]

Originally posted by kwiktsi


Well said..

Nice car BTW. How's it run :)? Any #'s on it?
Joe

I Just got it together a week ago. The Turbo is brand new and I wanted to give it a rest and fine tune the fuel management system before seeing what it will do under " Adverse Throttle Position " I'll keep you posted. Later

[brennan]

Ok, for people who have the mbc, how many threads do you guys have left on your knob? to sit at 9.5psi, I'm just wondering, Also how high does this joep mbc boost to? 20psi or 30psi? again just wonderin

[perfworks]

Originally posted by Tex
Hey Perfworks,

Where does one buy this Bosch recirculating valve? I went to the Bosch web site, and could find no such animal.

Thanks.

We are a direct distributor for them. You can contact me thru email and we can send it to you. I believe they are $58 + shipping. They are a great upgrade. I use it now and i run well over 13-14 psi on a T3T4 right now. We use them all the time for up to 20psi on much larger turbos with no leak. You should really look into it. At our last meet here in NJ A new member bought one and is very satisfied.

[low_psi]

Originally posted by brennan
Ok, for people who have the mbc, how many threads do you guys have left on your knob? to sit at 9.5psi, I'm just wondering, Also how high does this joep mbc boost to? 20psi or 30psi? again just wonderin

joe- the spring adjusts exactly how i thought. since its adjustable, you can always just re-adjust it back down to stock ;)

brennan- when spud gets back, i'll look at his for you. my suggestion is that you keep it threaded OUT, and slowy thread it in after checking the boost. when we installed it on my friend's gst, we hit 2bar the first run :eek: we shat ourselves...

[unwrittenLaw]

I wanted to bump this, because I'm interested to see if anyone else has adjusted their wastegate spring...

[t3ase]

I've been thinking about trying it but Joe told me it was a total pain in the ass to do.

[unwrittenLaw]

Yeah, well I'm curious because I think since I took mine into the dealer about a cel, they did something to the wastegate, because I put my mbc back in a week later and can not get past stock boost, no matter how much I turn the screw in on the mbc...They didnt tell me they did anything, but I dont trust them...its pissin me off..

[t3ase]

Here's some info from our PMs.. (read from bottom up)

quote:
--------------------------------------------------------------------------------
kwiktsi wrote:
Under the exhaust manifold. Adjusting it is the right way to do it (although Mazda won't like either ), but bending it is how I did it after I got pissed trying to adjust it. If you look at the wastegate actuator, you will see that the rod coming off it is adjustable- loosen the lock nut and thread it in (clockwise about 2 full turns to start. I don't know if you can get it better from underneath the car or not, I know it looked like I had to pull the damn turbo to do it right .
Joe


quote:
--------------------------------------------------------------------------------
t3ase wrote:
What, bending it or adjusting it? I should be fine adjusting it.. So, I'd want to look at the intake manifold (from under the car?) and find a lock nut. Loosen the nut and what exactly do I tighten once that's loose?


quote:
--------------------------------------------------------------------------------
kwiktsi wrote:
The rod on it is adjustable- it is a BITCH to do though. If you look down under the manifold, you will see a lock nut on it, you need to loosen this and tighten the rod. If you can't get it, you can get pissed off and bend it like I did . But that will end the warranty since it will be kind of noticeable .
Joe

quote:
--------------------------------------------------------------------------------
t3ase wrote:
How'd you tighten the wastegate? I thought the discussion was that we had an internal wastegate which was not adjustable.

[t3ase]

Hope that helps ya

[unwrittenLaw]

Thanks for the info...see I dont want to mess with the wastegate if its something that the dealer is going to be able to notice... I mean if they gonna bitch about me removing the weatherstripping and putting a K&N filter on...I can only imagine what they'd do if they saw the wastegate being messed around with...man this blows...I put in colder plugs so I could run higher boost, and now I'm stuck at stock boost...:(

[t3ase]

Did you check all of the connections and stuff?

[unwrittenLaw]

Yeah, everything looks normal...but I cant see the wastegate very well and wouldnt really know what to look for down around there..but all the vacuum lines look normal from what i can tell. The line from the T down to the wastegate is that hard plastic crap and its starting to crack, but the cracks arent deep enough to be leaking I dont think..I hold steady boost, it just wont increase with the mbc in there...

[t3ase]

If you really can't figure it out, I'd drop another $45 to Joe or email him and see if he can send you one out for free just to try and make sure it's not the MBC.

Edit: I wouldn't think that there was something physically that the dealership could change so it ONLY handles up to 6.9psi of boost or whatever you said you were pushin'

[unwrittenLaw]

Yeah I was thinking that, but it worked fine before when I was using it and I blew through it before I put it on and checked it, seemed good...I dunno, its just strange how it runs fine and holds stock boost very well...better than before I took it in...
It seems that since the dealer thought the cel was from a "boost concern" as they put in the invoice, that they adjusted the wastegate to where it wont take more than normal boost...wish they would've told me what the heck they were doing to my car, instead of trying to be all secretive on me like I did something wrong...I guess I'll take out the mbc and check it....