turbo problems

[Nomore78]

hello, if i do leak test and i get no psi can the air be going through the turbo?? lately my car wont go to full boost, looses pressure at 5000-5500 rpm, looses arf and jerks, once i get off boost its normal. the car works great but no high rpm or full boost. doing the leak test get no psi, dont even hear hissing, the air feels going in but i cant find were its going out. so i capped at the TB and i got a little more air in but still no psi, then i capped the turbo outlet and i got a little more air but still no psi. my cars doesnt smoke or anything like that and the turbo shaft has minimal play. when i hit boost the turbo sound fluttering.the car came with an obx racing turbo (i know they are bad) i had it rebuild a 1000 miles ago so maybe it wasnt a great rebuild. i live in Colombia and turbo cars are pritty rare, i have no shops or places to buy parts, so i have to order them from us. so there is no easy way for me to get a turbo and see if thats my problem. i was thinking of ordering cx racing turbo so i can see if that is my problem so i can save for good turbo later down the raod. any help on budget turbo or on the leak down test would be verry appritiated. i love that car but its been 4 months of non stop gueesing, got new fuel pump, regulator and some vacum lines and the problem continues.it has to be the turbo in my mind. thanks
norman

 

[tektic]

It sounds like you need to find the large leak in your intake track before you buy anything. Start spraying soapy water during your test. If it is the turbo it will be a rubber seal around the compressor housing with could be had for only a few dollars. No one here will recommend a cx turbo.

 

[Nomore78]

thanks for the feedback. i will take the turbo out and have it checked. i sprayed soapy water on everything. i dont even hear the air go out, just go in. i went to gas station and used a big compressor,didnt even hear a hiss. i am pretty sure that the leak isnt in the piping because i capped the turbo outlet (coldside) and barely got a hiss and some bubbles putting compressed air at the inlet. also capped at the TB with the same result. in the tutorials ive seen peolple put their air pressure regulators to desired psi and with in a few seconds the system is presurized. i made the compressor turn on a couple of time with the same results. when i drive the car it goes into boost 10psi and when i hit 5000 rpm if i stay on it it bucks and goes lean. once i am of the throttle the car goes normal.
i know cx racing is not the way to go, but on ebay used turbo is more expensive than the cx one, and the setup i want (precision turbo) requires a extra parts and dont want to spend more than i have to right now, until i have all these issues fixen and the car can go to redline.
anyone selling a good cheap used turbo that i can try?
thanks

 

[Nomore78]

to have my crappy obx turbo rebuild is like 330 dollars, buying used oem turbo seems to be more than that or buy the cx td05 (or another china turbo). those are my options.
i will take the turbo off and inspect it before i make a purchase (maybe its a seal like tektic said)
my setup for refernce is 5000 miles ago, graveyard block 2.3, manley piston and rods, eagle crankshaft(as far as i know) arp headstudds, got a fresh cylinder head, walbro 255, evo 560 injectors, fuel lab fpr and a haltech p1000. i cant go past 5000 rpm /ubbthreads/images/graemlins/banghead.gif

 

[Nomore78]

i am not looking for big boost just that the would handle 16 psi and act normal. so i can start palnning the next mods
thanks

 

[kumfasa]

Am I reading your post correctly? You capped/Sealed the turbo outlet where it goes from the j-pipe to the inter-cooler piping and then pressurized the inlet. Was that the turbo inlet or the air filter/maf inlet. IF it was the turbo inlet then you were only pressurizing the compressor housing!
Can you post a couple of hi res pics of your engine bay so we might spot something amiss?

Could be a failed blowoff/Bypass valve. Leaks air into the intake tract when boost leak testing and pushes open at low boost causing the car to fall on it face when boosting.

Another way to test for leaks is with a smoke machine. Plenty of youtube examples, then you can see where the leak is.

 

[Nomore78]

Just took those, kumfasa yes pressurized the system from turbo inlet (everything connected),then capped TB and then at turbo outlet and barely any air pushing my hand. And I mean a compressor on big tank started twice. I could hear the aid just go in and that compressor is at the gas station is pretty big.
Any help is very welcomed

 

[Nomore78]

 

[Nomore78]

i am thinking of getting the fp green dsm turbo, it seems the easiest fit with the least amount of extra hot side parts. the web page says that i have to buy a oil feed line that goes from the filter housing and its like 110 bucks. its totally ruining my budget, is it absolutely a must? or can i keep the feed line were i have it? almost all the cheap turbos that fit have that oem weard shape for the bolts for the j pipe, sisnce i dont have any of that this looks much easier. just have to save twice as much /ubbthreads/images/graemlins/bawling.gif
i am going to take the turbo off and inspect it properly before any purchase.
is the 110 oil feed line from the filter housing really nesesarry?
thanks

 

[AllanL]

do you need the green urgently?

if i were you, i'd spend the money fixing the other issues first.