Julian
Oh ok, how do you find it @Rob ? I am keen to go 19T but have been hesitant up until now because of the boost spiking etc.
Some people say it's a serious problem with the standard 19T, others say that with the larger housing, freer flowing exhaust, use of high octane fuel etc that it isn't really a big issue.
@Ex850R , I reckon this housing was an alright deal for $200 or whatever I paid for it, so if you've got yours apart some time I think it could be a good investment. The casting and finishing looked really good to me, with nice thick flanges etc. Treat yourself!
Just back to the original question also, is billet always the best choice if you can afford the bit extra cash, or is there any reason someone would want the cast wheel version?
Vee_Que
Billet is more about blade design. They can make them a longer tip which will increase flow. The issues with spool is not as big a deal as long as you use bugger injectors with it.
deleted_user_160
I'll do my best to find the billet v's cast thread from a while back.
Though in a nutshell, one does not offer performance gains over the other in flow if they are of then same spec. Where the billet do offer gains is in the heat cycling. Full boost, no boost, full boost, no boost. In short periods of time. The billet wheels handle the constant cycling better than the cast. It a why you see them on a large portion of real truck/bus turbo.
The other pro of the billet wheels is small production and prototype runs you can do.
Frontline the design of the wheel? Make a small change on the next one. And so on.
The other thing you should consider, which is severely overlooked. Turbine wheels.
Inconel wheels are far superior in handling the extreme heat.
And again unless your on the gas 24/7 it's not really of much use.
deleted_user_160
Oh and dont forget you can anodise billet wheels all kinds of pretty colors.
Here's the thread.
https://www.enginebasics.com/Advanced%20Engine%20Tuning/Billet%20vs%20Cast%20Wheels.html
Julian
Ok thanks for the info guys. I suppose for the little bit extra cash I might as well go with one of the billet wheels. Before reading about turbos i didn't even think they'd really cast something as thin as a turbine blade.
Sorry if it's hijacking a cast vs billet thread, but just with that boost spiking of the 19t that some people report, is there any reason not to go an 18T instead? Like, unless i plan to go nuts in the future with running big boost, would the 18T do anything I'd want it to without this boost spike issue?
Just bought some second hand green injectors too, so they'll be going in!
deleted_user_160
Probably where your going to notice the biggest gains other than wank factor. (Which is entirely a good reason to go ahead and do something)
The choice of your blades.
The amount of single blade design and the combination of the X+x wheels make a huge difference in how the boost will come on and perform for your desired application
Vee_Que
Stick with the 19t, especially with the bigger rear housing. I don't see boost spiking as am issue with a good intercooler and a tune though.
Julian
Yeah in the near future I'll be getting a tune (actually i might put up a wanted ad for the m4.4 ecu now whilst i think of it) but not currently planning to do an intercooler upgrade for a while. I guess as long as the car can be driven without risk of having a hand grenade go off in my engine bay before i get the tune sorted it's ok.
Philia_Bear
I near alwaus go with a billet 19t as the cost of having the turbo rebuilt is the same for me if using a stock 16t wheel or using a billet 19t wheel
Julian
Ok, I am probably going to get a whole new kinugawa rather than rebuild my current one and put a new wheel into it, as I wouldn't mind having new wastegate actuator and cbv whilst I'm in there, and would otherwise have to get the whole thing rebalanced.
deleted_user_160
Philia_Bear;106022 wroteI near alwaus go with a billet 19t as the cost of having the turbo rebuilt is the same for me if using a stock 16t wheel or using a billet 19t wheel
Though the OP was cast vs billet
Philia_Bear
Julian;106027 wroteOk, I am probably going to get a whole new kinugawa rather than rebuild my current one and put a new wheel into it, as I wouldn't mind having new wastegate actuator and cbv whilst I'm in there, and would otherwise have to get the whole thing rebalanced.
The cost being the same for getting a new kinagawa one vs rebuilt with a kts wheel and kinagawa housing and mitsubishi bearings
Id go down the path of rebuilt any day of the week
deleted_user_160
I would like tackle the kinugawa unit my self.
Keep your existing unit, as spare or sell off get some money back and spend it on an intercooler or tune. That your holding off on.
Vee_Que
Having just been in a 850r with a 20t and larger rear housing . The compressor surge does not appear to be an issue.
Julian
Hey @Vee_Que , interesting to hear. I guess I don't really understand how the larger housing prevents that surge- I would have thought having a more freely flowing housing would make boost spiking even worse? I have also only really heard people talk about it happening with the 19T for some reason.
I am also interested to know why companies like ipd list the 18T as the standard turbo for their "stage 3" upgrades, rather than the 19T?
I'm on the cusp of getting one or the other, but am wondering if predominantly driving around Newcastle the 18T would be better suited. There's additional pressure for me to get this job done now since the car is sitting in pieces taking up half the room in my dad's garage where his 850 should be haha
Vee_Que
Just go for the slightly bigger one. The surge is not happening as additional flow is not overspeeding the turbo near the top, unlike the smaller housing.
Julian
Ok, when you say "near the top" you mean T higher rpm? I was thinking surge tended to be low rpm problem with this turbo, hence people saying not to go full throttle at low rpm without a tune? Sorry for all the questions, it's just good to know what's going on and there seems to be a bunch of different opinions out there around this topic. Cheers
Vee_Que
It's life blowing through a thick straw vs a thin straw onto a wheel, both spin it. One takes a tad longer/spin it slower. Which is fine for the bigger wheel
Julian
Ok, thanks. Regardless of whether I go with an 18 or 19, is it possible to just buy the turbine wheel and have fitted to my existing chra with whatever balancing may be required? Or get the whole cartridge and use my existing compressor and turbine housings? Just trying to figure out whether buying a whole new turbo is required or whether I could build it from some of my existing parts.
Vee_Que
Need a machined compressor housing, a chra would be simpler and not much more considering balancing costs.
