manual boost controller

[GreddySpyder]

I just received my manual boost controller and I was wondering if anybody had any good pictures or advice about hooking it up. I know from the illustration that it says to t off from the BOV line and connect to the wastegate line, but at what point in the waste gate line should i connect, and do i need a t-fitting for this as well. Also the line from the BOV is larger than the one going to the wastegate, where do you get such an adapter to hook it up? Once installed i'm assuming i should start with the screw mostly open and tighten it down until i am at the given boost level. I'm already at 15psi, what is the highest efficient boost level for the T25? Feedback will be appreciated, thanks!

 

[97GSTURBO]

You don't actually tap the wastegate line, you replace it. Tap the BOV line and run it to your MBC, and replace the wastegate line with the one coming off of your MBC (Clamp it on there!), and cap off your turbo nipple (Clamp it on there!) and the factory wastegate actuator silinoid. The most boost you want to push out of your T-25 is 16-17PSI anything more than that is just hot air

 

[mikeydsm]

ok well here is how i have my MBC hooked up. Go to a hardware store and buy a t fitting that will fit the hoses. They have choices between brass and plastic it doesnt matter which u get as long as it fits. Then you see the thinner of the two lines that runs from the bov. the one that goes to the intake manifold. Cut that anywhere i did mine in the middle but anywhere is fine. put the t fitting in and plug the vacuum hose that will go to the mbc in. Once that is dont you have to look at the wastegate. you should see two hoses comming off of it. remove them and cap the one off and put the other hose from the mbc on there. then ur set. (im not sure which one is the one u hook the hose to on the wastegate tho.)

 

[GreddySpyder]

Originally posted by mikeydsm
ok well here is how i have my MBC hooked up. Go to a hardware store and buy a t fitting that will fit the hoses. They have choices between brass and plastic it doesnt matter which u get as long as it fits. Then you see the thinner of the two lines that runs from the bov. the one that goes to the intake manifold. Cut that anywhere i did mine in the middle but anywhere is fine. put the t fitting in and plug the vacuum hose that will go to the mbc in. Once that is dont you have to look at the wastegate. you should see two hoses comming off of it. remove them and cap the one off and put the other hose from the mbc on there. then ur set. (im not sure which one is the one u hook the hose to on the wastegate tho.)

i only saw one line coming out of the wastegate, maybe i just need to look again. anyway, all of those areas that the hose on the wastegate runs to currently aren't important? i should just pull the line and hook it straight up to the mbc? does anybody know which line it is that i need to use on the wastegate?

 

[wishihadatalon]

1/4 inch vacume hose. to install it is easy. the easiest way to explain it is all you will need in the end is a line running from the waste gate acuator to the t fitting in the bov line. all the lines hooked up to the waste gate acuator get tossed and everywhere you took a line off cap it. this is the important part

 

[GreddySpyder]

that is the illustration i was looking at earlier, what i didn't understand is what happens to the rest of the line from the wastegate whenever you put that end on the mbc. also, the line coming off of my wastegate is way to skinny to fit the end on the mbc.

 

[Gtalon]

Then how do you hook it with a external westgate with 2 nipples instead of 1?

 

[wishihadatalon]

go get new vac hose to install. all the other lines like the bcs and the nipple on the turbo elbow(the one right above the waste gate) and do what that pic says and thats it. for my caps i used a piece of vac hose and put a sheet metal screw into the end of the hose.

I have never seen a external wastegate before so i wouldn't know. sorry but i can't help you there.

 

[GreddySpyder]

Thanks for the help everybody, I installed it today. I was running 15psi before, now it is at 17psi. Amazing how much faster it felt to my butt dyno. About how much horsepower do you get with each psi on the stock turbo?

 

[GreddySpyder]

actually, i was just driving, and realized that it spikes to 17psi, but then returns to 15. So i tightened the screw a little more, now it spikes to about 20psi then levels out at 17. Just a guess here, but that can't be good for my turbo/motor can it? What level is it safe for it to spike to? if i can only set it to spike to 17 then return to 15, i am no better off than i started without the mbc.

 

[wishihadatalon]

each pound of boost it like 7-10 hp at the wheels. if it spikes in low rpms its fine from what i hear but its not great for the car higher up. if you want to minimize spike shorten the vac hoses to the mbc. the shorter the better. i have no spike and my vac lines are pretty tight hardly any room to pull it.

 

[GreddySpyder]

As it is set right now, it spikes to about 19psi in the mid rpm range, around 4k rpms, then almost instantly it drops to 17psi. I hope this isn't hurting anything, I will try what you said about shortening the line and see what that does for me. What mbc are you using? I am using one that i got from a guy on ebay for $20 shipped, i was kinda weary about it at first but he didn't have any negative feedback about it. What is suprising me is that it doesn't seem to be pulling timing or anything and I am running the stock fuel system unless the guy that had this car before me upgraded something.

 

[GreddySpyder]

I looked again and found that the screw i had used to plug the line that i took off the wastegate had popped out. So i put a larger screw in and put the hose clamp around it, and that seemed the spiking for the most part. Now the only prob i notice is that i am getting boost creep starting around 5500 rpm. It goes from 17psi down to about 10psi from 5500rpm on. I'm guessing i just need to play with the screw on the BOV to hold pressure better. From what i have read the stock turbo doesn't hold full boost at high rpms anyway, but to what rpm should it hold what amount of boost? I know it shouldn't drop to 10psi...

 

[doug]

Originally posted by GreddySpyder
Now the only prob i notice is that i am getting boost creep starting around 5500 rpm. It goes from 17psi down to about 10psi from 5500rpm on. I'm guessing i just need to play with the screw on the BOV to hold pressure better. From what i have read the stock turbo doesn't hold full boost at high rpms anyway, but to what rpm should it hold what amount of boost? I know it shouldn't drop to 10psi...

For a T-25, this is normal. Yes, you're right, the stock turbo can't hold boost to redline. And that's not boost creep-- boost creep is when the boost gradually goes up because of a restriction in the wastegate exhaust path, usually an O2 sensor housing that doesn't flow well enough.

And you're starting to push your luck running 17 PSI all the time. Most people don't recommend anything over 15 on the stock turbo because the intake air temp is just too high at any psi much over that.

For an MBC install, I prefer just running a hose from the turbo compressor nipple to the MBC, and then a hose back to the wastegate. No teeing into the BOV hose or anything.

 

[GreddySpyder]

Originally posted by doug


For a T-25, this is normal. Yes, you're right, the stock turbo can't hold boost to redline. And that's not boost creep-- boost creep is when the boost gradually goes up because of a restriction in the wastegate exhaust path, usually an O2 sensor housing that doesn't flow well enough.

And you're starting to push your luck running 17 PSI all the time. Most people don't recommend anything over 15 on the stock turbo because the intake air temp is just too high at any psi much over that.

For an MBC install, I prefer just running a hose from the turbo compressor nipple to the MBC, and then a hose back to the wastegate. No teeing into the BOV hose or anything.

So basically there is no point in using the mbc until i get a larger turbo? I was running 15 psi BEFORE i put on the mbc due to my Greddy intercooler piping and BOV. I definitely don't want to hurt my engine or turbo so maybe i should just take the mbc off and put things back how they were until i get the T28 killer i plan on getting. I just ordered a palm pilot and will be ordering the pocketlogger ASAP, it is supposed to read intake temperature, so maybe i should just keep the mbc on there set at 15 psi until i get the pocketlogger and see what the intake temperature difference is at 17 psi. I realized after leaving that last post that i misused the term "boost creep", to what level and at what rpm should the boost fall off with the stock turbo? I need to know this info to know if i have my BOV adjusted properly.

 

[doug]

The MBC isn't hurting anything if set at 15 PSI, so if it were me, I'd leave it in. It may even help spool times some. Then you also don't have to worry about putting it back in when the time comes, and you get used to playing with it. Plus, if you ever put in some race gas, you can run higher boost, like at the track or whatever. Besides, 17 PSI won't kill you, it'll just shorten the life of the turbo most likely. So if a new turbo is in your near future anyway, it may not be that big of a deal.

I can't give you hard numbers on PSI vs. RPM with the T-25-- your numbers just sounded about right compared to mine and some others I've seen. I'm pretty sure your BOV adjustment is fine.

 

[AdoreGSX]

what psi does the stock turbo run normally?

 

[IMMORTALSPYDER]

Anywher from 7-15psi depending on the car.

 

[blcknspo0ln]

15 psi stock?

i thought the stock spring for the WGA was set to 11 psi.. and it varied +- 2 psi.. i know i ran 10 psi without an MBC