As the title says, i'm barely building any boost (no matter what i do with the MBC) with my 92 that has an ebay turbo with an internal wastegate. I've searched high and low for boost leaks and cant find any, although there is a slight hiss near the intake manifold. i can't remember if that hiss was always there or if it started around the same time as the boost drop. also it doesnt seem like a boost leak to me since it hits the same 18 in/hg of vacuum as before. i also haven't been able to spot any exhaust leaks before the turbo. i even changed the manifold to turbo gasket just to be safe, to no avail. there is no smoke from the tailpipe so i wonder... is my ebay turbo finally blown but the oil seals are ok? or is that not even possible?

EDIT: forgot to mention that the wastegate has two nipples on it. the upper one I can't blow into, the other blows right out by the rod with hardly any resistance. i can switch the vacuum line with my MBC on it from one to the other and it makes no difference whatsoever.

 

what turbo is it?

for the wastegate, you use the top nipple, leave the bottom open.

 

Do you have a leaking BOV or recirc valve?
Stationary checks wont work as you can not build boost without driving the car. (Or using anti-lag.)

 

its a t04e turbo. a/r 60

i've tried tightening the BOV already, no luck :(

wouldnt vacuum reading be different though? i guess i'll have to build a boost leak tester... I was trying to avoid that.

 

well it's not going to build boost on a 1.6L untill like 4.5K or above.

 

it hit full boost well before 5.5 before, now i barely hit 1-2 psi in first at redline and maybe 3 psi in second at redline.

 

Is your vacuum measurement after the throttle? If yes, it will not be affected. MAF Idle would be affected though.

 

bad coupler? bad turbo gasket?


what's full boost?

 

ahh good point!

i've checked all the couplers, none have any tears/holes, and all of the pipes are in their couplers fully. and i tried changing the manifold to turbo gasket just to be safe even though it didnt seem to be leaking.

full boost is about 7 psi.

 

Disconnect the MBC and run just WG.

 

lol wut?

 

probably should have, but I haven't tried this yet. i'll give it a shot after work on the way to lowes to get stuff for a boost leak tester. best case scenario is i dont end up having to make one.

 

What is the waste gate set as? Why are you using a MBC?

 

wastegate is 7 psi, i had bumped it up to 9 at one point but realized it was probably a bad idea and turned it down. it would have made more sense to just remove the MBC i know, but i wanted to have the option to turn it back up.

 

While you're still chasing ---- bypass it completely... Less parts, less stuff to narrow down.

 

i'll give it a shot. it wont make it any worse, that's for sure.

 

Are you sure that the waste gate is closed?

Did you have to clock the turbo to fit your car?

Have you moved the wastegate actuator?

 

So there are no unusual hissing noises when you try to build boost in higher gears? When my CHRA failed, there was no oil smoke, just a light metallic noise and no boost...but that's with a dual bb turbo, not a chinkacharger.

 

i havn't pulled the downpipe off to check, but I have moved the flapper with the rod disconnected and it moves freely. also i can pull the rod and it has plenty of resistance.

EDIT: now that i think about it, the rod was pulled out a little bit with the flapper as closed as it would go. i figured that was supposed to be like that for more tension on the flapper making sure it was closed. was i right with my assumption or is my wastegate most likely not closing all the way?

 

not that i can hear.