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alex687 wrote:what does clipping the turbine involve? cutting a bit off each turbine blade?
I think I need a new turbine wheel before I look at that option!
... Google 5 to 8 degree clip off turbine .. supras have been doing this for years for better flow 
.. it does work 
- it's a band aid at best and not really done any more. Due to the nature of the modification, it cannot be done on ceramic turbines.mr2magic wrote:Due to the nature of the modification, it cannot be done on ceramic turbines.
It helps compensate for a turbine/compressor mismatch where the compressor is to large thus causing more exhaust gasses to be pushed through the turbine than it can swallow (turbine swallowing capacity = phi). To aid the gasses in their quest to get out of the housing the tips of the turbine are clipped to present less of an obstruction. 
without sacrificing the turbine efficiency??. nice job ... proper flowing turbine is best alex687 wrote:so wouldn't porting the wastegate have the same effect by allowing the gases in their quest
... can post picks .. made my wastegate ports massive 2mad wrote:Thats what i did
how far back into the housing did you have to enlarge them?alex687 wrote:2mad wrote:Thats what i did
Go for it.
Not sure I have the patience to do something like that!alex687 wrote:Wow nice job.
.. found it kinda therapeutic .. i could theorise but the car went like stink after doing this ... with no creep The wastegate has the job of divertung the exhaust gasses before they've imparted their energy on the turbine and has no impart on the capacity of the turbine. Increasing the wastegate area by too much will hurt transient respons and top end because more of the fixed amount of exhaust gas available from combustion will go through the wastegate if it opens.mr2magic wrote:Re porting the wastegate and thereby improving flow:
In a word no.
.. exhaust gases have to get out through the turbine or wastegate ... seemed to help me 
mr2magic wrote:Was it a standard ct26?
.. my mods worked real well .. wish i had concentrate data 
We know the ct20b has the perfect exhaust housing, turbine and compressor combo. Porting the wastegate would mean, that more gas bypasses the turbine from the moment the flapper cracks open........less gas at the turbine means less power. But as with any theory, the real world numbers will tell the whole story.mr2magic wrote:Hmmm I really believe that your being mislead.
... but i had creep ... so the power was not usable .. after porting no creep 
Basically the wastegate cannot divert enough exhaust gas to stop the increase in turbine speed - ergo the wastegate is to small. mr2magic wrote:Boost creep or boost spike points to a mismatch aswell
So you're not really making more power, you're making the correct amount
.. sounds plausible bud .. creep fc-uks things up proper 
