Injured turbo blades- symptoms?

[RyleyMA61]

Okay guys, all may remember my lovely damaged CT26:





Now, it doesn;t blow smoke under boost, and still delivers the power smoothly and rapidly, and runs the appropriate 6psi boost. There is maybe 1mm of vertical shaft play and 0mm of horizontal. There is a slight drop of oil as you can see in the pictures:

However, just as the 7M is kicking into stride, there is a slight pause and flat spot before the turbo does its thing and sends me off down the road.

Since installing a bigger i/c and 2.5" piping, this slight delay has increased....

But it doesn't seem like lag, like the turbo is taking ages to build up, just like its about to hit full stride, pauses, then goes for it.

Could this be the effect of the damaged fins?

Also, a noise I previously thought to be my alternator/alternator belt (metallic scraping, slipping noise, kind of squealing) happens at random- but more often after spirited driving. The noise fades in and out also at random, of varying intensity...

However, the metallic aspect of the sound made me think it could be the turbo blades...

Could the damaged fins be scraping on the inside of the housing without causing dramatic effects to power and not blowing smoke etc?

So, to summarise:

a) Could the damaged fins cause the pause in power, or is it just lag?
b) Could they be making the metallic scraping/slipping noise, or is it most likely my alternator, as suspected?

[kingmick]

Yes it would be a combination of the bigger cooler and piping and the broken impeller that is making it more noticable now!
The turbo will prob kill itself reasonable qiuck being that much out of balance!
Yes it can cause the scraping noise because it is out of balance, but you will see it if the impeller is touching the housing.

did i miss anything else?

[Aust162]

^ what he said. look really,really carefully at the comp housing around the impeller blades. if you can see scraping, than thats obviously from the damaged blades and it spinning unbalanced.this can give the noise too, my friends rs liberty did this.

[RyleyMA61]

thats the thing though- it spins smoothly and doesn't appear to have hit the housing- and i've been booting it around for months now.....

ill do a double check, but thanks for the help guys

[mullett]

you'll see if you take the housing off, if the blades are scraped on the outside edge...Just being out of balance like that might be enough to cause the scraping noise...I guess...

RM.

[Yian]

I think your car is telling you something Ryley.

*whispers*".....GT35R..... GT35R...."

[Draven]

yeah, 'cause that'll make useable power in an ma61

[JustCallMeOrlando]

Of course it will, you just need to redefine your definition of useable.

[Draven]

to "above 150km/hr"

[JustCallMeOrlando]

It's a 7M baby. Big stroke it up Would make an awesome burnout machine.

[myne]

Was talking to a pair of guys at mallala with GT35 paired 3SGTE's.
They said they had full boost (?16psi?) by 2800rpm.

Sounds usable to me

[Draven]

a 7m with a gt35 can make 350+rwkw... that's not usable in an ma61

That would also have to be with the smallest a/r... for the 7m, you'd want the 0.9 or 1.06

[Yian]

a 7m with a gt35 can make 350+rwkw... that's not usable in an ma61

Ahhhh... meh. It'll still be fun heh heh.

[JustCallMeOrlando]

Was talking to a pair of guys at mallala with GT35 paired 3SGTE's.
They said they had full boost (?16psi?) by 2800rpm.

I call bullshit on that. Even with a tiny A/R. If it were that effective everyone would be using one.

[Draven]

for reference, p00jay hits 22psi@~3500rpm on the h00j a/r