about 0.96 exhaust housings . too big for 7M?

[supramaze]

Okay so now I have edited my ignition map, with a bit more advance. In fact I have downloaded five different AEM ignition maps for comparison. So I am quite sure its all good for making boost and power.


so I got out and tested... and WTF ! still no power and no boost. All the advanced timing did (as expected) was making the spooling maybe 1000 rpm earlier according to datalogs. it got more responsive, which is a improvement... but there is no godamn power ! it still feels like dragging something very heavy behind, totally useless. maximum boost was about 10 psi. and I can clearly hear that wastegate is not open, as I have a open dumppipe. wastegate is shut , no doubt.

I am quite sure the fuelling and timing is good enough for making a hell of a lot more power than this. ridiculous. last year with stock ecu and piggyback i was over 22 psi and it felt like rocket.


i think i am going to break out the f*cking sledgehammer and smash the pos turbo

 

[dbsupra90]

still no power and no boost.. maximum boost was about 10 psi.

yeah 10psi it isnt going to do much. glad you got it to spool a little better tho.

still sounds like you have an issue w/ the gate. either vac lines, vac source, hookup, or gate itself.

 

[Doward]

Where is your wastegate pressure feed line coming from in the system?

1000 rpm faster spooling from the timing is nice What wastegate spring are you running?

Remove the filter, grab the compressor wheel by hand, and spin it - does it spin freely? Minimal radial and axial play?

 

[supramaze]

Where is your wastegate pressure feed line coming from in the system?

1000 rpm faster spooling from the timing is nice What wastegate spring are you running?

Remove the filter, grab the compressor wheel by hand, and spin it - does it spin freely? Minimal radial and axial play?

the feedline is coming direcly from compressor housing thru a 6 mm connector. the waste spring is a 11 psi. boost is normally regulated by a boost solenoid. solenoid is pressure tested, and have also tested with all hoses disconnected to see what boost the spring alone gives. even tested with a 1 bar airpressure on the top port to force the gate closed, expecting the boost to rise , but no luck there. if i operate the gate with compressed air from garage i can hear the sound change dramatically as the gate opens and closes. the valve has markings from the flange with sealing lip.

manifold was pressure tested, welds checked over and over again.

have now checked the compressor by hand. it does spin quite freely, but not as free as my other turbo which was a 61mm full ballbearing. it does have play both radial and axial. i can feel axial play, hard to measure but im guessing about 0.5mm. radial play is little worse, i can actually get the blades hit the housing very lightly if the axle is pushed to side and rotated.



it almost feels like that this turbo is more a restriction than helping up. bad turbine design? it just doesnt go up in speed. to finaly close the wastegate issue , i plan to remove the wastegate completely och bolt a plate to close the wastegate port on manifold. desperate , i know

thanks for all help, any advices are welcomed.

 

[Doward]

Any evidence that the compressor wheel has already been in contact with the housing?

Further, try picking up your wastegate signal from the intake manifold itself, see if that helps (the pressure you get directly from the compressor housing, vs the pressure you get from the manifold, could indicate intercooler problems)

 

[7MGTEsup]

Sounds like the turbo is junk if it has any axial play, and enough radial play to touch the housing.

 

[supramaze]

Any evidence that the compressor wheel has already been in contact with the housing?

Further, try picking up your wastegate signal from the intake manifold itself, see if that helps (the pressure you get directly from the compressor housing, vs the pressure you get from the manifold, could indicate intercooler problems)

yeah im pretty sure, as it has some light scratch and markings from the blades. its very light though. have tried taking the pressure from manifold vs compressor , it was no difference in behavior.

 

[supramaze]

have done some more testings today. with two port wastegate control and temporary raised the rev limit to 7000 rpm (i know, high for a 7M) things finaly starts to happen . (with the improved timing map) boost still doesnt come alive when i need it , it build quite slow as usual with 8-10 psi up to 5000 rpm. then it starts to raise and after 6200 rpm the boost really starts to build very rapidly. by 6800 i saw 22 psi . anyways, it gives a bad powerband and this finaly proves one thing . 0.96 housing is not good on street for a 7M. to big and need more revs than a 7M is good for. Doward; does this makes sense?

i dont wont to rev more then perhaps 6500 , and this leaves me with getting another turbo. I going for Dowards advice here, a PTE 67 DBB 0.68 AR.

 

[Doward]

Yeah, you've got way too much exhaust wheel for your application.

Find a .68 and put on there

BTW, how did it feel up around 7000rpm? :rofl:

 

[supramaze]

Yeah, you've got way too much exhaust wheel for your application.

Find a .68 and put on there

BTW, how did it feel up around 7000rpm? :rofl:

:evil2: :biglaugh: well, atleast I can say that the car really took off for a change :naughty:


does anyone have a dyno chart with a PT67DBB 0.68 turbo? would be great to see

 

[Doward]

Nate's running a PT67 with a .81, IIRC. Well, a GT4067 with a .81, but it's basically the same thing

 

[a_sesshoumaru]

How would the .96 ar work with 180psi compression per cylinder? would it boost faster?

 

[a_sesshoumaru]

hm it should not be one of those. in fact its a "OBX racing" T4 turbo, manufactured,assembled and balanced in USA. so its says anyways. price tag about 550 USD

but, maybe i got ripped off damn feels like so


my other smaller 61mm turbo was a Turbonetics

I guess i got ripped off too, cuase my turbo is OBX 55mm compressor wheel and 60mm turbine wheel. But it may be a good thing. Maybe it will spool faster