Boosting Problems

Hey guys, I'm having a bit of trouble boosting as of this afternoon. I was coming home from school and a buddy of mine was behind me, so I decided to give it a little WOT in 2nd gear :smokin: . Anyways, I noticed that it didnt feel quite as strong at all as it usually does. I did a 3rd gear pull immediately after to see where my boost was, cause I had just installed a MBC (bleeder-type) the previous evening. To my surprise, the gauge shot up to around 22+ psi! :eek7: It was only there for a maybe a quarter of a second, so no damage was done (at least I think). I pulled over to the side of the road and turned the MBC ALL the way out, so that the boost would/should drop to around 9 psi (I think that's what the actuator is set to). Then I went out and tested it again, and results showed it was still boosting insanely high, ~22 psi.

This kind of worries me, because I had been boosting earlier in the day today with no problems and boost stayed at ~15 psi. I'm thinking maybe the wastegate is just stuck closed. I don't know why this would be, but it's the only thing I can think of right now. I tried pulling on the actuator arm to see if it would move, and it didn't (not sure if it's supposed to or not). Is there any way to test if the wastegate is staying closed shut? What if I just disconnected my MBC and tried it out?

Any help would be appreciated!

Matt

If you are using a bleeder type MBC teed into the WG line, turning it out (opening it up) will raise boost, not lower it. Close it all the way if this is what you are indeed using, and see if it drops. Bypassing it will certainly tell you if its the MBC or something in the WG system that is malfunctioning. When people have boost issues, I always recomend to first run a line stright from the manifold to the WGA. That will show you what the WGA and WG are trying to do, without interference from added boost control devices.

Nope. I shut it all the way and it still didn't drop. :(

Bypass it and let us know what happens.

I ran the line teed into the bov line straight to the actuator. The results are a LITTLE better, but its still at about 19-20 psi, as opposed to 22+ like it was when the boost controller was there.

Should I be able to move the WG arm back and forth? Cause mine won't budge at all.

Thats normal, the spring is pretty strong. You really have to put some nut into it before it moves. On the car, its almost impossible.

Is it spiking to 20 psi then coming back down, or is it acting normal at first then creeping to 20 psi? What turbo is this?

Edit> Just saw some mods in your sig. Dont see a turbo there. If this is the T25 its definitely a spike, nt creep. Its hard to get rid of spike on a turbo that spools as fast as a t25 does.

Yes, I forgot to mention that i'm still on the t25. It's definitely not just a spike. It seems to be staying at high boost for good (until it inevitably drops off, of course). I haven't tested this thoroughly though, because I don't want to blow 20+ psi of hot air into my almost stock car for any type of prolonged period of time. It stays up there for a least a second or two, since that's the only amount of time I've exposed it to. I've never seen/heard of a spike that holds for over two or so seconds.


EDIT>>> I don't know if this is relevant or not, but I still have the BCS plugged in. The hoses have all been removed, but it's still plugged into the electircal port thingy. And both the source on the compressor housing and intake pipe have been capped.

HAve you tried using the stock BCS again? I wonder if that will change anything... At any rate, the spike is at low to mid rpm, where fuel supply is still adequate. At high rpm where fuel supply is an issue, it drops off. So I dont think it will hurt anything. I did it for a long time. Its not very efficient though, as you know.

The best way to get rid of spike is to make the WG open faster. That means a MBC that is fast (bleeder type is the exact opposite of what you want), rigid lines that wont flex (reinforced high pressure fuel injection hose works for me), and a good source. Sharing with the BOV may not be best. Disconnect the WGA arm at the flapper, I Think its the same setup as mitsu turbos, held on with a cotter pin or similar. MAke sure that the flapper arm moves freely! You cant really lubricate it since it gets so hot, so hopefully its good. Thats just about it for factors affecting spike.

maybe the MBC is faulty....i know mine took a lot of tuning to get right...the turning of the knob and the boost i ran was not a linear function...5 clockwise turns got me up from 10-12 psi only, and the one more turn wormholed me straight up to 16. isnt that crazy? so myabe its your mbc...i know that u can spiked as high as 22 if you dont run an MBC, as what was happening to me a while ago...?

Well, I'm just going to keep off the throttle (it's tough) until tuesday or wednesday, which is when my joep mbc should arrive. I'll let you know if it helps! :)

Please do! I'm quite curious.

Well I got the JoeP installed today, and I must say it is a very nice piece! However, it did not help in solving my boosting problem. I'm still hitting 22+ psi. I started in 3rd gear at about 2k even and let it go. I watched my boost gauge closely, and it went straight past 15 psi and kept going, I let off at 20 or so, cause I didn't care to see how high it got. I'm going to try a few things this weekend with the wastegate to make sure it's working properly. I'll keep you updated! :)

Thats normal, the spring is pretty strong. You really have to put some nut into it before it moves. On the car, its almost impossible.

Mine is somewhat stiff but I can still move it without puttin some nut into it... ?????Good or Bad????

Are you getting excessive lag? If not its probably fine and you are just too strong for your own good. :icon16: If you have a T25 it may be lighter than the mitsu actuators. Cant remember the last time I tugged on one of those...

SOmething is wrong if its shooting straight up to 22+ psi and not falling back. Are you sure its not rising to set boost THEN creeping up to 22 psi? I cant even remember what turbo you have :banghead: Oh yeah, T25 it looks like. I would put a line from an air compressor on the actuator and see if you can make it move. Or remove the cotter pin, slip the arm off, and make sure the flapper arm swings freely. If the T25 spring is lighter and 96 spyder can move his, maybe your did get porked somehow. Slide that arm off the flapper and see if both move freely. Let me know.

with it connected that arm is pretty stiff. i was tugging on mine after i got it back from RRE [out of the car] and it took a bit of nut to budge the thing at all...

Alright, I've got another update for you guys, and I think I have found the problem. After taking off the entire exhaust mani/turbo/o2 housing out as one, I noticed that the new gasket we put on last weekend that connects the turbine outlet and o2 housing was a bit... off. I don't know if it's because I'm using an evo3 o2 housing, but the gasket was covering up a good 1/4 inch of the wastegate hole in the turbine housing!!! The worst part was that it was covering the side that the flapper opens up to, so the exhaust gases were shooting straight into a wall, basically. Well when we pulled off the gasket and looked at the underside, you could easily see what I was talking about. about 3/4 around the wastegate hole was black, about a ~1/4 inch big! This was obviously not going to work, so we busted out the dremel and carbide bit and went to town on the gasket! It was easy to see how much needed to be taken out, since the black created from the exhaust pummeling into the gasket made a nice line that showed exactly were it was. After 45 minutes of grinding, we got it to the size of the wastegate hole, perfect.

It was amazing how much the gasket was covering up the hole, and the fact that it was covering the part of the hole where the flapper opened up made it even worse. I'm really surprised we didn't notice this when we put it together last weekend :screwy: .

Now, we haven't been able to put everything together and see if it's fixed because we have a broken exhaust mani-to-head stud that needs removing :banghead: and a new exhaust mani-to-head gasket to put in. However, that's tomorrow's job and we should be finished by early evening tomorrow! I'll let you know how it goes! :)

That will do it! Lesson learned, always check that the gasket fits, especially on ported parts. I'll bet it fixes your problem.

Sometimes you just have to put down the keyboard and take the car apart. ;) Pay attention girls...

Well I have yet another update for you women :wink: . After fixing the manifold stud, replacing the manifold gasket, and putting it all back together, the car was STILL boosting 20psi+ with the mbc all the way out. After being a little pissed off about this, I decided to test the actuator (should have done this in the first place, but you live and you learn). Turns out I found 2 HUGE holes in the actuator itself. It was venting off so much pressure that the arm doesn't even move, no matter how much pressure you put in it. Of course this is undoubtebly this cause of my problem!

The question is, do I have to buy a new actuator (~$90 new at machv), or can I just JBweld them bitches up. It seems like one of the leaks is coming from the inside of the actuator side that connects to the arm, so I don't think I could weld that one up unless it would be ok to JBweld the outter edge of the arm to the actuator. Any suggestions on which way to go? Should I just pick up a 14b and screw this POS turbo? I can get a good-running 14b locally for $50, and the hacker/tweaker install kit from RRE for like $120 I believe. Would this be a better way to go, seeing as how I really don't want to spend any money trying to fix the t-25 when I can upgrade for just a few dollars more? Thanks! :)

There should be enough blown T25s around to pick up a free actuator from someone local, if there is someone local. I have several. I certainly wouldnt dissuade you from upgrading to a 14b though, its a great upgrade for a 2g.

Its still very good that you found that gasket problem. You would not have had good control over boost with that gasket in the way like that, even on a good actuator.

Alright I found a good t25 actuator. My question is, do I have to take the turbo and/or entire wastegate arm to replace the actuator? Or is there a way to replace it while it's still on the arm?

I had a quick question and didnt want to make a new thread. I just put in my Greddy boost guage a few days ago. It looks like it works fine, at idle its at about 500. When i speed up it rapidly picks up to around 8 or 9 and then stops increasing. Is it normal for it to just hold at 8 or 9. The car is bone stock, just wanted to know if this is normal.

Alright I found a good t25 actuator. My question is, do I have to take the turbo and/or entire wastegate arm to replace the actuator? Or is there a way to replace it while it's still on the arm?


Turbo stays in the car. Slide the acutator arm off the flapper arm, and remove the 2 (?) bolts holding the canister to the compressor housing. Thats it. It can be a pain to get to the bolts sometimes, so plan on it being a 10-15 minute job.

So how again is the actuator arm supposed to slide off the flapper arm? There seems to be a little "fitting" on top of where the two arms connect, and I don't konw how to get it off, or if I even have to.

<crowd chanting in the backround>

14B!! 14B!! 14B!! 14B!!

<crowd chanting in the backround>

14B!! 14B!! 14B!! 14B!!


:grinno: Haha, I would if I didn't have to get an install kit for the SOB. Even the hacker/tweaker/DIY kits are like $195! Although, the 14b would hold me over much better than this piece of shit t25 will! :lol:


EDIT >>> I WOULD get a 14b if it would be at all possible to do it without buying the install kit. I realize that I will surely need a new SS oil feed line and turbo-to-manifold gasket, there's no two ways about it. But will that be all I really need to have if I just tweak everything else? Thanks! :)

The actuator arm just slides over the pin on the flapper arm. There is usually a cotter pin that keeps it from falling off. All mitsu turbos use the cotter pin, cant for the life of me remember if the t25 uses a cotter pin or some other fastener.