So there have been a few threads recently on Hybrids, good and bad results have been had, inconsistencies in production to name a few.
What was a good hybrid 2/3 years ago before the High flow tubular manifold, "welly" cooler, mapping improvements now it seems it's quite cutting, part of the issue is that the gap between a stock K04 and Hybrid is getting smaller. Your stock K04 can get upto 300bhp while the Hybrid K04 still has yet to be surpassed at 344bhp and somewhere in between there are supposed to be a stage 2 and stage 3 version...
So can the 344bhp be beaten? and can 344bhp be beaten without WMI? is it really worth trying to do it when a GT28 or GT30 will do it without issue? and is there now still a market for it?
Where am I going with this , well I have no intention of going BT so thought I might have ago at beating 344bhp and aim to develop a bigger and better hybrid.. Question is though , when is a hybrid not a hybrid, well I think that as long it can fit in exactly the same place a stock K04 can fit then it can be classed as a hybrid.
At present we are limited by the compressor housing and turbine housing, but with making these bigger we introduce new issues such as lag, which is one of the Hybrids benefits, in so much lag is kept to a minimum compared to say a Gt30 turbo, making it more drivable ( open to debate )
My aim is to build a more powerful turbo, in a K04 frame.
So there is the first version and please bare in mind this is development item, it is fully functional and is going to fitted to an Audi TT for testing. I am open to all and any comments and don't expect it to make mega BHP from the off but be a start to a finished item even if it is concluded the current hybrids are the best option.
Billet GT35 compressor wheel on a K04 bearing housing with RS6 turbine
Fitted inside a heavily modified K04 compressor housing
GT35 compressor next to a stock K04
Mocked up on the Relentless manifold
GT35 compressor V Billet 2283 compressor wheel
Now this first version was to see if a Garret compressor wheel could be sucessfully mated to RS6 turbine wheel and installed on the CHRA of the K04.
The compressor wheel was machine so that a sleeve could be installed inside the compressor so that it could be put onto the original turbine shaft. as the compressor wheel is held in place in part by the fitting over the shaft but mainly by the clamping force of the nut on the top and the thrustwasher washer. As you can see it doesn't look pretty but it fits, it was send off and fully balanced, twice, to ensure that it would survive spinning at high speeds. Although the compressor wheel is considerably larger that the stock wheel the billet wheel means that it is light and weighs only slightly more than the original stock cast k04 wheel.
In order to get this wheel to fit the compressor housing the original inlet was completely machined out and a new billet inlet was machined. This was then Tig welded up to ensure that it was secure for when the inside was machined and also to allow the radius of the exducer to remain.
Now my intention with this version is to prove the GT compressor wheel can be used, I'm not chasing the numbers here but would like to get over 300bhp at relatively low boost. I am aware that balance needs to be found between compressor and turbine specs. That just because it's big doesn't mean it'll work...
I have also heavily modified the turbine housing to aid flow, I will post some pictures .
Any comments welcome.