Opening up the hotside on the FPgreen
Opening up the hotside on the FPgreen
I was curious what others thought about extrude honing the hotside on the green? I feel it is the only thing that really holds this turbo back.
What is the nozzle area (cm2) taken from anyway?
All I can think of is the area in the throat of each scroll for example: 6.1 cm diameter for outboard scroll, 6.4 cm for inboard scroll, and 1 cm between them. These are the dimensions I got on an old 9.8 turbine housing I have and the math calculated to 9.81 cm2 so this might be it, anyone?
With careful dremel work I brought it up to 11.28cm2 but still hesitant to install it at this time
All I can think of is the area in the throat of each scroll for example: 6.1 cm diameter for outboard scroll, 6.4 cm for inboard scroll, and 1 cm between them. These are the dimensions I got on an old 9.8 turbine housing I have and the math calculated to 9.81 cm2 so this might be it, anyone?
With careful dremel work I brought it up to 11.28cm2 but still hesitant to install it at this time
The outlet/exducer area needs to be done with a die grinder as well. This is where most of the material needs to be removed anyway as it shrouds the turbine exducer, creating excessive backpressure.
You don't even want to think about having it extrude honed. This would be pretty lame in my opinion. You wouldn't want to do anything that lame. As COVR4 mentioned, take a look at 9sec9's pics or send the housing out to WOT or RevMoto for porting.
Last edited by sparky; Mar 18, 2008 at 05:50 AM.
What type of grinder, and what bits are you using for porting the housing? You can deep port the inlet scrolls with a straight type, long reach(long head chuck) die grinder and some long shanked carbide burs.
The outlet/exducer area needs to be done with a die grinder as well. This is where most of the material needs to be removed anyway as it shrouds the turbine exducer, creating excessive backpressure.
You don't even want to think about having it extrude honed. This would be pretty lame in my opinion. You wouldn't want to do anything that lame. As COVR4 mentioned, take a look at 9sec9's pics or send the housing out to WOT or RevMoto for porting.
The outlet/exducer area needs to be done with a die grinder as well. This is where most of the material needs to be removed anyway as it shrouds the turbine exducer, creating excessive backpressure.
You don't even want to think about having it extrude honed. This would be pretty lame in my opinion. You wouldn't want to do anything that lame. As COVR4 mentioned, take a look at 9sec9's pics or send the housing out to WOT or RevMoto for porting.
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It seems that many are already maxing out the Green's compressor with the current housing, so I'm not sure how much more help opening up the turbine housing would lend.
If the compressor truly is already maxed out, then you will just be introducing more lag and loss at the low end.
If the compressor truly is already maxed out, then you will just be introducing more lag and loss at the low end.
The 'nozzle area' measurement (cm) is taken from the cross-section of the housing at the tongue. Basically, the first radial section that has an unobstructed gas path to the turbine wheel.
Extrude honing is generally a beneficial process, particularly on turbine housings. The benefit is in improving the surface finish, which improves turbine efficiency. Flow can come up a hair too, due to the reduced boundary layer. It is $$$ though and will take a lot of EHing to remove enough material to increase the a/r.
The only hand porting I'd recommend is a gasket match at the inlet / discharge, and smoothing out any cast lumps and bumps in the entrance section. Abitrarily hogging out the inlet won't help, and will likely hurt.
Extrude honing is generally a beneficial process, particularly on turbine housings. The benefit is in improving the surface finish, which improves turbine efficiency. Flow can come up a hair too, due to the reduced boundary layer. It is $$$ though and will take a lot of EHing to remove enough material to increase the a/r.
The only hand porting I'd recommend is a gasket match at the inlet / discharge, and smoothing out any cast lumps and bumps in the entrance section. Abitrarily hogging out the inlet won't help, and will likely hurt.
Maybe you should call Robert at Forced Performance to find out whether the ExtrudeHone abrasive process might have a negative impact on the critical machined radial tolerances between turbine blade tips and the housing. The inducer and midsection turbine tip clearances are especially critical and effect turbine wheel performance. What is it that you are trying to achieve anyway? Maybe another route would be to send the turbo into FP ad have them clip the turbine.
It seems that many are already maxing out the Green's compressor with the current housing, so I'm not sure how much more help opening up the turbine housing would lend.If the compressor truly is already maxed out, then you will just be introducing more lag and loss at the low end.
Extrude honing does not touch any of the machined features of the housing. Unless the process goes horribly wrong, it has no effect whatsoever on tip-to-housing clearances.
And yes, extrude hone the housing long enough and its a/r will certainly increase.
And yes, extrude hone the housing long enough and its a/r will certainly increase.
JKav: Thanks for clearing up my misconception with regard to Extrude Honing as it pertains to turbocharger housings.
I still want to talk about the A/R vs. porting issue a bit more with you but work calls! So,let's leave it for later.
Ultimately, these technologies have to be weighed on a power gained per dollar spent basis. Are there any dynocharts or before and after pressure tests showing significant gains from this process as it applies to turbine housings?
There is a lot of self serving hype that accompanies these "hitech" methods. When it gets down to surface microfinishes and such I am reminded of the tuning shop in Texas which specializes in Italian and German turbocharged exotics.
Anyway, they advertise a process whereby they micropolish the turbocharger wheel blades to a mirror finish, this supposedly, according to them improves airflow across the turbine blades, etc. It is however a rather expensive process and only they claim improvements in turbocharger performance on their inhouse dyno.
Similarly, Precision Turbo and Engine will do a polish job on your compressor housing, but even they will tell you that it doesn't do a whole lot for increasing power.
I still want to talk about the A/R vs. porting issue a bit more with you but work calls! So,let's leave it for later.
Ultimately, these technologies have to be weighed on a power gained per dollar spent basis. Are there any dynocharts or before and after pressure tests showing significant gains from this process as it applies to turbine housings?
There is a lot of self serving hype that accompanies these "hitech" methods. When it gets down to surface microfinishes and such I am reminded of the tuning shop in Texas which specializes in Italian and German turbocharged exotics.
Anyway, they advertise a process whereby they micropolish the turbocharger wheel blades to a mirror finish, this supposedly, according to them improves airflow across the turbine blades, etc. It is however a rather expensive process and only they claim improvements in turbocharger performance on their inhouse dyno.
Similarly, Precision Turbo and Engine will do a polish job on your compressor housing, but even they will tell you that it doesn't do a whole lot for increasing power.
Last edited by sparky; Mar 18, 2008 at 09:52 AM.
I agree with JKav that ExtrudeHoning will provide an improvement over the stock casting finish, but I would guess that extrudehoning alone would provide less of an improvement than porting alone. Extrudehoning is also a somewhat pricey process, and you'd have to balance the cost versus the incremental gains that might be obtained...