boosting prob????

i have a 95 tsi i dont have many mods. the car was running 14-15psi after i took the bcs piece out, so i have no mbc to controll boost. well i took my turbo off and ported the manifold and o2 housing and put a 2.5 downpipe on now the car is only running 9-10psi i know this is what stock is suppost to do by why did it change? i also had the battery disconnected if that has anything to do with it.

I really am guessing here, but i think its because when you ported the exhaust manifold and the o2 housing, your PSIs go down becuase...wait... nevermind i almost hand it....i think it has to do with backpressure or with the wastegate....damn wait till kevin or jake gets on they will tell you...sorry...it might be helpful to list all the other mods you have so they know what you are dealing with.

boost gauge, dump tube hack just free mods besides the downpipe and porting

i think what metalhedskater was trying to say is that when you ported the wastgate and O2 housing, more air is allowed to exit out of the waste gate than it's suppose to thus decreasing the turbine spinning speed. normally for a turbo larger than a stock T-25 will have no problem. but since you're still on the stock T-25 without a MBC, the air flow is not high enough (provided that a lot of it is being drawn out of the wastegate) to generate the sufficient amount of air pressure to maintain the boost. get a boost controller will give you the ability to control the wastegate actuater to hold the boost.

i think that was what he's trying to say. correct me if i messed up.

Nope that was it! thank you RiceRocket! Yea normally people do what you have done in order to reduce boost creep, Riff.

I knew it had to do with something with the wastegate

its because you dont have a boost controller anymore. you had to have hooked a hose strait from the turbo compressor housing to the wastegate cause the spring is only like 8-9lbs. hook it back up to the BCS or buy a MBC and you will be fine. either that or your wastegate flapper came off of the wastegate arm. check it out!

i never had a boost controller just the stock one. and the hoses are hooked up to the bcs. maybe there back words what would it do if they were backwords??

you said~
the car was running 14-15psi after i took the bcs piece out, so i have no mbc to controll boost.

right there you said you didnt have a boost controller! now you put it back in? you didnt say that at first... if you have the hoses hooked up wrong it could have an effect on the wastegate! not positive on the BCS.

more flow out of the turbine might be sucking the WG flapper open. just a thought...

make sure you pluged the electrical part of the BCS back in... :)

i have the bcs on the car, what i was tryin to say was i did the bcs mod, the lil restriting plastice piece.

If you have an MBC then you don't want the BCS hooked up. If you don't have an MBC then you do want the BCS hooked up. By the way, did you remember to plug the BCS back in??? That will do it every time.

yea its pluged in, well why would the car run 14- 15 psi stock anyway did the bcs mod change it that much?