JBH

The car has lots of potential beyond stock. For track, here are my modifications. The car has neutral handling and is very predictable. I do not use ducting to the brakes and I have never experienced a soft pedal - must mean I am not going fast enough.
Moton Club Sports
Springs: 570lb front / 800lb rear
25mm adj. front sway bar
22 mm adj. rear sway bar
Camber plates
RS Strut Tower Brace
993 TT brakes front and 964T fronts moved to rear
SS brake lines
RS clutch/pressure plate/flywheel
Close Ratio Gear Set (2-5):
Steel Synchros
Motorsport LS Differential
7200 HF turbo
GHL Headers
B&B Muffler
SC Cams
1 bar spring
Remove air pump
Front mounted auxillary oil cooler
Recaro SPGs
6pt Harnesses
Roll Bar
Align and Cornerbalance

Staffan

Basically, do you claim that the HF spools faster than the stock K27?

Vince5

Nice list of mods
Who did the custom gearing for you ?
BTW I still have your email where you gave me your gear ratios a while ago thanks !

Kevin

The K27 Hyflow uses the same turbine wheel and turbine housing as the 7200.. With a more efficient compressor wheel one should be making more boost sooner vs later.. Unless, your turbine wheel becomes less efficient. One can have this happen if the turbine wheel is clipped (by accident) by metal or gasket material or and other FOD.. As a result it will require more exhaust energy to turn the wheel vs in a non-damaged turbine wheel.

Staffan, I am saying this because you have a high probablilty of turbine wheel clipping.

Staffan

So you are saying that the HF turbo spools faster than the stock K27, if not damaged of course?

Kevin

The Hyflow should build boost sooner=faster.. Now if your wastegate is weak and blow-off alot of boost pressure before reaching the target boost setting you will in effect slow down the turbine wheel giving you a sluggish response.. Again if your wastegate valve guide (worn from wear) isn't doing it's job, the valve is not seating 100% the result is premature bleed off of the turbine wheel. The Hyflow can generate alot of air.. Up to 1.8-1.9bars, of course this is not recommended.

As a side note, I will be posting some recent pictures of K27 shafts from rebuilds that owners have not known that they have had issues with there turbochargers. I probably have received 5 K27's in the last 2-3 weeks that have had wiped out turbine wheels.. Two of the five were from pre-detonation, the other 3 were from welded headers or headers that have cracked, and lastly gasket material that has broken down..

Staffan

The data collected on the two occasions for the graph are less than a week apart.
I wanted "before and after" data two compare the two turbos.
The data for the HF turbo was collected the day after installation.
The wastegate is the same, nothing differet between the tests.

I am now going to remove my catalytic converter and check the turbine wheel for damage.
This is going to take me a few hours to do....

Kevin

Why do you have to run your stock cat while taking the car to the track? You have considerable back pressure if you are running the stock pieces. It's going to be tough to check for FOD, you will need to view the portion of the wheel that is in the volute. I usually shine a light from the inlet side of the turbine housing.

eyue

JBH, why do you change to SC cam ? And what is Steel Synchros ?

Staffan

It's an empty cat.

I will check the turbine wheel carefully.

Kevin, do you have any data or graph showing the difference between the K27 and HF turbo? At what rpm should I expect 0.9 bars of boost from the HF turbo with stock ROW headers and an empty cat ?

Kevin

Steffan are you running the stock wastegate spring?

Staffan

Yes I am running the stock WG with a stock spring, but together with an Blitz dual selenoid EBC.

I believe it was set to apx. 0.85-0.9 bar running K27, set slightly higher (apx. 0.9-0.95 bar) when running the tests with HF.

Staffan

I have checked my turbine wheel, used a 500W lamp directed into the turbo exhaust intake.
Inspected the turbine wheel from the turbo exhaust out side.
Looked like there was two layers of wheels, was more could be wrong there, but I looked at each wheel from the side and I found no damage what so ever. I will say that it's not possible to see everything without taking it apart, but for now I see no reason to do that.

I will do the exact same test again and compare the logs when we have less snow overhere to see if the result is the same. Also recieved emails from 3 HF turbo owners saying the same thing that the HF spools slower but has more top-end power, one of them had a dyno test with the same result but I haven't got the data, the other two was based on seat of the pants feeling.

Would be interesting if anyone could share their data who's done the same test.

Anyway, I am happy with the HF turbo, makes me faster on the track so no problem there, but still haven't seen any data showing it spools faster that the stock K27.