Jrbar89

ok i started having this problem with my car a while back after i replaced my exhaust mani and t25 gasket since they blew out. I have been trying to figure this out since then but no luck so far. The motor is Completely stock. so when i cruise its drives fine but when i give it a lil to much gas it sputters and losses power from where ever i gas it to 4k. After 4k it builds boost and goes but still doesn't seem like what it use to. At the top end it drops about 2-3psi of boost.
right now its running at 13\14 psi. Before it was Running at 12 psi. i tried to lower the boost but i max out the waste-gate actuator and its still at 13 before it messed with it was at 15. No clue what would have cause my boost to go up. I went through all my piping and re tighten everything down. I checked my turbo and it had some shaft play fyi not sure if that would be it. i unplugged my maf and it seems to be fine since it runs like complete shit when i did. any suggestions on what my problem is. and just to make sure if i lengthen the waste-gate actuator it lowers boost correct. I'm a newbie to 240s and sr20.
Oh just replace spark plugs and fuel filter just so you know thought that was my problem at first.

sil80dude

Check your timing and ecu codes, tps voltage and clean your MAF. Check your maf out to make sure the sensors arnt broken. Its hard to tell but clean them with a qtip and iso 99%. If one of the little sensor springs that senses air is broken your car will act really weird. I hit a pothole one time and the car started acting really weird bogging on and off and it turnedout one of the little springs was busted off and barely touching the connection giving weird airflow readings. You can find the info to do everything with a search on here. With replacing the gaskets their is more exhaust pressure and more boost. The actuator needs to have a little bit of pre load keeping it tight. Dont loosen the wastegate arm your car will not build boost.

Jrbar89

Ok kol i willd do everything you listed ran out of time today. will post tomorrow about the results. And my cluster doesn't show any check engine but i will check anyways.

Jrbar89

oh and the actuator is pretty much all the way extended and still building 13 psi.
i want to get it back to stock which is what 8 psi.

Jrbar89

DUDE it was just my MAF sensor i took it out didnt even look that dirty but bought some iso 91% dont think they make 99% anymore; since lil kids started drinking that stuff and germx. but cleaned it off real quick slapped it back in and boom instance results pulls hard. I cant believe it was just the MAF I didnt even check to see if i was still leaking boost as soon and i hit it didnt break up had the biggest smile on my face did a doughnut and came back home.

Jrbar89

went and test drove runs great but im still at 13 psi but i want to lower it back to stock i think its just to much for a bone stock motor.Plus this thing has put in some work and have around 85000 miles. But like i said before the wastgate actuator bar doohickey is pretty much extended as far as it can go. i thought lengthening the bar lowers boost but its the same. what do i need to do to lower it?

sil80dude

It will lower boost pressure but not how you want too. You need the wastegate shut too build boost in the first place. If you leave it open a bit it will be laggy and barely even spool. What you need buddy is a cheap external boost controller. You can find a decent one for around 25$ to your door. Put it inline AFTER the intercooler for the best response. It will bleed off some of the pressure to the actuator and you can lower the boost like that.

Here this is what I have on my SR. Works perfect!
http://m.ebay.ca/itm/380858368315?nav=SEARCH

I ran 20+ psi on a gt2871r with stock motor for 2 years and no problems. Then I did the headwork as a winter project and did my HG too. You will blow your stock t25 at 14psi because it will get too hot. 10 psi is more then safe on stock setup.

Jrbar89

Thanks man i went ahead and bought the controller car is going to sit for awhile untill i get it.

steve shadows

Don't waste your money on a boost controller that isn't dual solenoid for an internal wastgate. Get the upgraded HKS actuator arm/and unit it's around 100$ and you can set your base boost as high at 12-13 psi with NO drop off or very little drop off (from the diaphragm not collapsing). Then when you're ready for a bigger turbo or need a boost controller get the Blitze Dual SBDC - I have tried all of them. I love haltech and apexi for all kinds of things. But when it comes to a boost controller nothing beats that thing. It's insanely efficient at holding boost. thanks

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sil80dude

Dunno about some of these statements. A bleed style manual boost controller is the most cost effective and most common way people adjust boost levels. Sure you could spend 100+ on a different actuator but I don't see the point. Also you could spend 300+ on an electronic one but I bet you wouldn't notice the difference. Maybe if you have a built car and your looking for a perfect boost curve then maybe it's worth it but just spend the money somewhere elese. If a bleed style MBC is good enough for 500hp SRs and other hi hp cars it's perfect for you.

Kingtal0n

the ONLY problem with manual boost controllers is,

ok well two problems,

1. You have to open the hood to adjust it (which means no high/low setting)
2. Sometimes it takes many tries to get the adjustment proper (so drive, pop hood, drive, pop hood, drive, pop hood, drive, hood latch breaks)

Other than that, rock solid performance if you build it right. Don't buy one

Nah steve, I've tried most electronics and I have to say, the greddy profec B Spec-II is the king of $220 boost controllers, all day. And if your one of those single turbo RB26 or 2jZ guys, you can't beat the boost per gear feature (boost vs speed) of the AVC-R for elminating tire spin.

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steve shadows

Have you tried the dual SBC dual solenoid? It will literally hold any spike flat. I have used all of them too...been doing this and build consulting for 11 years.

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inopsey

so this means your word is the end all of knowledge on the subject? i have a blitz dual solenoid boost controller and it did not keep the internal actuator from spiking even with the gain at <5%. went external wg, not an issue. dont waste your money on an 'upgraded' internal wg, they dont exist.

Jrbar89

Ok well i had already bought the Manuel boost controller before you posted about the blitze.
Right now dont have that kinda money to spend on the car i have other stuff i want to put my money into suspension mostly. Just wanted something cheap for the moment will take your advice tho and when i ready for a EBC i will look up the blitze. but right now cheap ebay is the way i have to go. Ok so i got the controller in and im trying to install of course no instructions and i tried an educated guess and yeah didnt work shit boosted 20+ quickly let off and parked. Maybe just the way my boost gauge is hooked up but i kinda had to do it that way since there is like a nipple that came off my piping from the turbo. my boost gauge was hooked up at the T by the bov and the wastgate connected to the nipple off the piping from the turbo. I have at the moment a line from intake to a T that splits to Bov then to the controller to the waste gate but i had that nipple off the piping still so i put my boost gauge there. Im new to the 240 game and sr20det this is my first turbo car and everything i have been doing myself by looking up stuff online.

Jrbar89

here is a pic might not have made sense the way i explained. And on the wastegate there is another nipple that has a cap on it fyi dont know what that is for.

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sil80dude

hey dude! your close. check this pic out

http://homepage.ntlworld.com/dub.se7en/TGTT/MBC_1.JPG

you want the arrow on the "T" to point towards the wastegate . run the boost pressure line that runs into the back of the arrow onto the "T" and connect it to your intake mani or a boost source AFTER the intercooler. This will avoid boost spikes. Your going to have to blow through the line that goes to the furthest port from the adjustment knob on the contoller and adjust it so there is just a small ammount of air coming out of the hole closest to the adjustment knob. This should give you a good baseline. The more air coming out the lower the boost. Your going to have to start some where and adjust it from there. Start with 1 rotation and fine tune it till you get the level you want.

Jrbar89

ok i re ran the lines like on the picture and im still boosting way to much no matter how i turn the knob its the same. and im getting spikes to i have no clue what im doing man LOL and im scurrd ima blow my motor. I have the intake pressure line ran to the T from there front of arrow ran to the wastegate and the other port on the t ran to the arrow on the controller. no line to bov and port closest to knob is open. If you can post a pic how its ran on yours that would be helpfull.

sil80dude

Hmm seems like your wastegate is acting up and sticking. If you turn the boost contoller knob all the way down until it stops it wont bleed any air and should give you natural wastegate spring pressure which SHOULD be 7-8 psi not 12. I would take the wastegate off and check it out. You can hookup a air hose with a regulator on it if you have one too test. You run pressure into the wastegate and see how much psi it takes to open it. A manual boost controller can only raise boost not lower it.

sil80dude

I local turbo shop might have a wastegate for you that would be 7-8 psi. 12 psi is prettymuch the max on a stock t28 before you do damage, any more and your motor can handle it but your turbo wont and you will cook the internals

Jrbar89

Kol will try and pick one up from tays automotive tomorrow let you know if it works. i was thinking my wastegate was messed up somehow but didnt how to check or anything. Let you know if it fixes it thanks.