14b/7cm hotside boost problem

[chris00326]

So heres the deal. i have a 14b that i put a 7cm exhaust houseing on because the 6cm was cracked at the flapper. at ide the vacuume reads 15-16hg. I can hear the turbo spool and i can feel it. heres my problem. the gauge says i dont hit 15lbs until 7k rpms in 1rst. 6k in 2nd and 5-5500 in 3rd. it also says i dont start spool until about 4k. i have no data logging tools and no fuel management. i was thinking maybe the wga isnt holding the flapper down all the way but before i tear it back apart was wanting some feedback. also i do have a pre turbo exhast leak at manifold to turbo due to missing bolt. all 3 others are there and bolted down tight. any help is appreciated. thanks.

 

[Ghost_92TSi]

Fix the bolt.

 

[chris00326]

I should have mentioned that before i put the 7cm houseing on the bolt was missing too and i hit 15lbs at 3000rpms before it creeped up to 20.

 

[kchaazz]

Sounds like you may have a severe boost leak and the missing exhaust bolt isnt helping either. Sure it may have seemed ok before but youve since disturbed the gasket and it may no longer be sealing on three bolts. Also you messed with some boost piping to do the swap unless you left the turbo in place and just changed the housing in which case i would still check for boost leaks, get that missing bolt replaced and also check to be sure that the center section is squarely and properly secured to the turbine housing but either way you need to stop and fix the issue or the turbo is going to die.

 

[Kyle_T]

I had the same problem with my 14b & 7cm housing. Wasnt hitting full boost until like 5500rpm. Turns out the wastegate flapper wasnt fully closing. I had to shim the actuator out a little and now it hits 15psi at 2500.

 

[chris00326]

I didnt even think about a possible boost leak. i guess im going to have to tear into it. i was hoping for something simple stupid . ill check it out as soon as i find the time and ill leave an update when im done. thanks.

I have one other question. would the exhaust turbine wheel have anything to do with it considering the housing is bigger and letting to much exhaust escape without using it causeing extreemly slow boost?

 

[Joethefallen23]

All TD05 turbines are the same size, be it a 14b or Evo 3 16g. So no, the housing isn't going to cause a 3000+ rpm spool increase time.

I'm betting on WGA not holding the wastegate shut. If you had a boost leak large enough to hit boost @ 6000 rpm, your car would be running like shit, if at all. Shim it with some flat washers. Fix your exhaust leak while you're at it....

 

[chris00326]

Alright cool. thanks.

 

[Dsmkauai]

Your best bet is to upgrade to a holset actuator, it is by far the best way to fix this problem. I had my 16g holding 19.5-20psi totally solid in my gst and that never happen before the holset acuator. I even had hahn's aftermarket adjustable actuator but was only like 7-10psi adjustable I think. I think my holset is 14-18 I think adjustable and when using my 2-step boost control I could zero out the setting and get a solid 15psi to launch with!! sounds like either a major boost leak or your wastegate is junk!

 

[Dsmkauai]

All TD05 turbines are the same size, be it a 14b or Evo 3 16g. So no, the housing isn't going to cause a 3000+ rpm spool increase time.

And I'm sorry to tell you but your wrong bro!! 14b's can come with 6cm turbine housing or 7cm (which is a upgrade and gives alittle more mid-top end power), there's also a 10cm turbine housing like on my hrc 16g which can easily work on any tdo5 turbo!! They didn't come stock on 1g's that way but there are different housings easily available! And yes a larger turbine housing (like the o.P. has 7cm) on the same wheel will be alittle lagger, which you probably won't notice anyways (and wouldnt be 3k lag) even on my 10cm full spool around 3800rpm. The larger 10cm housing is said to help with boost creep and seemed to work good for me getting 37lb/min out of a 35lb/min turbo and at only 20psi, of cousre was only possible due to the holset acuator!

 

[Joethefallen23]

And I'm sorry to tell you but your wrong bro!! 14b's can come with 6cm turbine housing or 7cm (which is a upgrade and gives alittle more mid-top end power), there's also a 10cm turbine housing like on my hrc 16g which can easily work on any tdo5 turbo!! They didn't come stock on 1g's that way but there are different housings easily available! And yes a larger turbine housing (like the o.P. has 7cm) on the same wheel will be alittle lagger, which you probably won't notice anyways (and wouldnt be 3k lag) even on my 10cm full spool around 3800rpm. The larger 10cm housing is said to help with boost creep and seemed to work good for me getting 37lb/min out of a 35lb/min turbo and at only 20psi, of cousre was only possible due to the holset acuator!

And I'm sorry to say, but you're wrong in a sense... I said turbine, not housing. Do me a favor and compare the inducer and exducer sizes of a 14b and 16g turbine.

 

[chris00326]

Well i know my wga is fine. checked it before i put everything back together by hooking up an air hose to it and it didnt leak. i was in a bit of a hurry though and didnt even check to see if the flapper was seated. I also didnt think the spring size really matteres considering im running off a mbc which should bypass the wga spring. im not trying to hit 20lbs right now without at least a bigger fuel pump.

 

[SBstar]

You more then likely have one of these four issues.

1. During installation the new 7cm housing did not properly seat and seal to the chra.

2. Waste gate flapper is not sealing.

3. Giant boost and/or exhaust leak. Fix that turbine housing bolt!

4. The turbo itself has some issue, blown, bent/broken fins, etc

 

[Joethefallen23]

You say that your WGA is fine and then proceed to say you never checked if the flapper is seated...The whole point of this revolves around the flapper. If it can't stay closed long enough to start spooling, you won't build boost until way in the upper band when the load is able to overcome the mass of exhaust escaping through the flapper. You need to make sure the WGA is fully seating the flapper and holding it closed. If not, you need to shim it and that should solve your problems.

I also didnt think the spring size really matteres considering im running off a mbc which should bypass the wga spring.

You would be correct, the whole purpose of the MBC is to delay the stock WGA from seeing its' "opening pressure." Unless the spring is just so catastrophically worn that it's budging open at any sign of boost(read 1-3 psi), it has no effect on why you're seeing 15 psi by 7000rpm.

 

[chris00326]

Like i said before i was in a hurry to get the turbo back on the car . it wasnt the only mistake i made not checking the seat of the flapper haha.

I dont think the turbo is effed. it all actually looked really good when i took the housing off. the fins were in supprisingly good condition with none broke or bent and no shaft play and they spun freely. so i believe the turbo is fine. i do apreciate the help.

 

[Dsmkauai]

And I'm sorry to say, but you're wrong in a sense... I said turbine, not housing. Do me a favor and compare the inducer and exducer sizes of a 14b and 16g turbine.

Ok ok well you didn't say wheel in that statement and then jump to saying housing but I guess ill read your mind and say ok your right, yes all tdo5's use the same turbine wheel!!

 

[Dsmkauai]

A mbc can only do so much, if you have a 7psi wastegate acuator. You will only be able to control up to about 14psi basically double spring psi, that being said at 14psi its pushing the spring way past were its supposed to be and therefore makes it hard to control boost, which is why the holset acuator becomes so key to solid boost over 15psi on these turbos unless of course you go external. And o.p. until you fix the major leak from the missing bolt, you will just fight trying to make boost and are really making your tubro work extra hard! Fix the bolt asap or no more help from anyone!! hahaha

 

[chris00326]

Hahaha fine ill fix damn exhaust leak .

So i shimmed the WGA. now its pretty much fixed i just have to fix the exhuast leak still. in third i hit full boost at about 3500 so its still a little laggy but i think once the leak is fixed itll be alright.