discopotato03

Hi all , been reading for ever about CBRD and FP std 9 frame turbo upgrades and the only thing I'm finding hard to get feedback on is the possibility of FP's 84mm inlet port shrouded compressor housings for the std 9 and BBK turbos .

FPs site shows this housing for the BBK turbos but not the std 9s compressor wheel .

Has anyone tried this housing on the BBK Full that can post results over the std 9 housing ?

Also do you think that this housing profiled for an otherwise std Evo 9 turbo would be the way to get every last pony and pound out of it and with no losses over the std housing ?
I guess it also begs the question what happens if you fit the 18G RR compressor and the FP 84mm housing profiled to suit it , simple and effective ?
That would make the cartridge all Mitsy components and easily rebuildable locally in Australia . I'm not criticising FPs and CBRDs unique wheels but cost savings passed on to the customer is a win for everyone - provided the unit works properly .

Cheers Adrian in Oz .

sparky

iTrader: (1)

The FP 84mm comp hsg. is an anti-surge solution. With the stock IX turbo, or the BBK-Full, surge is not usually an issue. Whereas, if you were to configure the cartridge with the larger Black, or Red comp and turbine wheels then surge may become an issue that would need to be addressed.

discopotato03

Yes that's true but it would be interesting to try the FP84mm one to see if it gained anything anywhere .

I was only pondering the Mitsy 18G RR compressor because its such a simple change over (same OD as 16G) and it wouldn't be any harder to profile the 84mm housing and locate the radial slot to suit . FP could virtually sell the wheel and housing as a kit and anyone that can re balance the rotating group could fit it - if it was workable . Something tells me that Robert would have tried that before going down the 68HTA White road but you never know .
Possibly the FP White was intended to be an affordable upgrade and the 84mm housing would have added to its price .

Cheers A .

sparky

iTrader: (1)

Not trying to be nosey, Disco, but I get the feeling that either the BBK-Full, or the FP HTA Green would be suitable to your application. I read on another recent thread that FP now has a licenced Aussie distributor. Or am I wrong?

CO_VR4

iTrader: (83)

Adrian,

I'd suggest you check with FP directly. You might be happy with the answer.

discopotato03

I think they are available here in limited numbers but cheaper I think to buy direct from a US dealer .
The reason I initially asked about the port shrouded housing on a BBK full was that FP mentioned it on their site .

I find the port shrouded comp housing idea interesting because it has been claimed that they allow the compressor to run in a semi unloaded state at low engine airflow rates and another air source for the full height blades to draw a high airflow rates .
I also figure that it couldn't hurt to have 84mm plumbing right to the inlet boss given that all any turbocharger has is atmospheric pressure to feed it with .
The notion that turbos "suck" air in is at best an urban myth .

Yes for the detectives I am contemplating a 9 based turbo and S1 cams for an Evo 6 GSR .
With turbos there are just so many options for 4G63's , OE9/9RS/FP White/BBK Full/or even a TD05HR18G with 84mm housing .

I'm a little wary of the HTA Green because I think its a bit over the top for an engine that doesn't need high revs . I want brutal torque in the mid range and the turbo has to be responsive . It if falls over at 7 thats fine .

Steep learning curve ATM , cheers A .

sparky

iTrader: (1)

Did you post up a link to the 84mm antisurge cover for the CBRD BBK....hint, hint? There was a thread that touched on this topic of installing this cover on the BBK once before a while back.

If I recall, Chad Block chimed in that the cover was not needed on his turbos, etc. However, if you want to fit that compressor cover to any of the IX based turbos you could just purchase one from FP and install it onto whatever you wish, couldn't you?

This is gonna seem like a dumb question, but I have never messed much with compressor sides. Does the compressor cover need to be cut internally to fit each different comp wheel. I imagine that a stock IX comp wheel, a BBK comp wheel and an HTA Green comp wheel all have different major diameters and inducer diameters?

So, if you just purchase a blank 84mm cover from FP would you then need to have it internally machined in your home country depending on whichever comp wheel you finally decide to employ?

discopotato03

Sparky yes the compressor housing has to have the same profile as the wheel itself so that the blades are as close as is practical without touching at high speeds .
Really the compressor housing is sort of like a turbine housing in reverse with the air being drawn in at the "eye" and centrifuged out at the wheels exducer tips/major diameter .
With trim its the inducer (at the eye) that increases in diameter as the trim size increases , trim is the ratio of the inducer area compared to the exducer/major diameters area .
The reason I'm mildly interested in the Reverse rotation (RR) 18G compressor it that its major diameter is the same as the std 16G one but it is larger at the inducer so a bolt on for the std cartridge . Naturally the 18G's blade profile is different so the compressor housing needs to be "re profiled" inside to match the cross sectional form of the larger trim compressor wheel .
The advantage of the same major diameter but larger trim wheel is that its mass or inertia is 3/5s of 5/8s of FA greater but its pumping capacity increases . I'm not sure with Mitsubishi turbos but with Garrett often its the middle of three trim sizes in a wheel family that makes the nicest maps from a thermal efficiency point of view .
Now as we've seem the aftermarket has catered to custom CNC'd compressor wheels and obviously at times compressor surge creeps in because the effort to get the turbine side "responsive" means the compressor zips up quickly but the engine can't swallow all the air its attempting to pump .
If you look at compressor maps of turbos using port shrouded housings they tend to rise quickly up the LHS of the map meaning the surge line is higher as its rises up the LHS of the map .
What that basically says is that the wheels upper or full height blades are free to cycle air out of the surge slot and mainly the lower height or "splitter" blades are doing the pumping .
The compressor wheel is free to spin a little faster because the mass of the air being pumped is less so the turbine isn't working as hard and the rotating assembly can idle a bit faster in this phase .
As the engine revs rise the "increasing volume" of the engine is better able to swallow the incoming air , the pressure difference between the full height and splitter blades drops away and both sets of blades are free to pump into the inlet system .
It is critical where that radial surge slot is in a compressor housing and it must be located just in front of the splitter blades leading edges if its to work properly . This is why a wheel and housing are a matching set and while you can usually re machine a given housing out for a larger wheel you can't move the surge slot easily .

History has shown us that the RR 20G conversion on Evo turbos was not all that successful and I reckon the speed match was out between the compressor and turbine enough to make the turbine struggle to drive the wheels extra air pumping capacity .
The $64 question is that if you could partially remove (effectively reduce temporarily) the wheels drive power requirements the turbine - actually the whole rotating groups speed could rise - and it may allow better response/without surge/the compressor to give its all once the engine was beyond the speed at which the compressor wanted to surge .

When you can use a turbo manufacturers std components the bits can be much cheaper than custom ones and available in volume .
Like I said IF say an 18G RR wheel in a port shrouded compressor housing could be made to work all that's non std parts wise is the housing itself .
Even the std one could possibly be faced off and a new machined boss made to fit it . HKS does something like this on their T04Z comp housing .

Anyway food for thought , cheers A .

Just for the record I'm not saying that what Chad and Robert have done is wrong or have any interest in building turbochargers , other than for myself , but I like to consider cost effecting bang for buck options at times .

Evolution is a revolution IMO . Love that car !

BLKCarbonEVO

iTrader: (2)

If you are not planning to be a regular autox or road course guy then you should just get the Red or Black. The Red only spools a few hundred rpms slower than the BBK and will make more power and is a great match for the stock block.

If you are looking to really tear the streets up then the Black is where I would look. The Black is an absolutely amazing turbo and I couldn't be happier. I have never ran any of Chad's turbos but I have had a Red and the Black spools almost the same as the Red but makes are good 30-40hp more at the same boost level.

Mikey