To billet or not to billet?
 

Greetings fellow slowbaru owners!

I purchased a standard Blouch TD05 8cm 18g that is going to be installed on my WRX within the next few weeks and just found out Blouch is now offering a billet compressor wheel for the 18g. To upgrade an existing 18g it would be $250.

My question to anyone who knows, would it really be worth the extra $250 and effort to upgrade to a billet wheel? Does it actually flow much more? If I'm going to do it I'd rather do it now while the turbo is out of the car.

Any advice would be greatly apreciated!

The billet is lighter, stronger and has better flow in the upper RPM range. So it will spool faster at a lower RPM and still have big turbo high RPM spool. $250 more is not that much to step up to a better turbo. If your only looking to boot to 20psi or so the standard 18g will do, but if you are looking to wined the car out to maximum potential 24-25-26 psi the Billet is the way to go.....lot more to spend then just $250 to get there though. It really depends on you-budget-HP goals.

yea agreed, depends on your budget and HP goals, but I don't think that this $250 upgrade is gonna make all that difference if you don't have/change some other components of the car. like if you are gonna boosting in the 25-26 psi range, you might want to also consider getting a meth kit as well... what have you done to the car already?

It's currently down at Area1320 having the following installed:

Blouch TD05 8cm 18g PNP'd & ceramic coated
Modded WRX 830cc injectors
Grimmspeed uppipe + 44mm EWG
Hallman RX pro MBC
Walbro fuel pump
MAF & Turbo inlet
ACT streetlite clutch
ACT Streetlite flywheel
Perrin crank pulley
Turbo XS FMIC
TGV deletes
Phenolic intake spacers
TurboXS UTEC

As for my HP goals, I'd be happy with anything over 300whp atm but my end game goal is 350-400whp. I'm in no hurry to get there but would rather not do the same thing twice. So if it's a huge improvement going to a billet wheel....I'd rather do it now then install the turbo and six months down the line realize I should do the compressor wheel upgrade.

As for going 25-26 psi....yea I wont be doing that soon since I'm on the stock block. I'm guessing I'll be staying at 20-21 PSI.

The billet wheels are designed more efficiently and make more power everywhere on the map... they spool sooner and flow better up top. I'd definitely think about doing it. I know my next turbo will be billet for sure.

looking at your hp goals, with what you have now you should definitely break 300whp easy. I had broken 300whp with a VF34 and a huge APS topmount. However, getting into the 400whp range with that turbo won't be as easy. I would reccomened a bigger turbo like an FP Green. Also TGV deletes and intake spacers why? the TD 05 18g should fit, you'll definitely need to do that for a bigger turbo like an FP Green, but not what you have now. Also lighter flywheel is most likely gonna give you false misfire codes if you care, and i highly reccomend against changing your crank pully, and just so you know on a stock 2.5 block with a meth kit you can definitely boost safely up till 24-25 psi.

TGV deletes and spacers because its cheaper to do everything and get tuned once instead of multiple times, plus it can be crossed off the list for the future. He bought the 12lb flywheel which does not cause problems (The 8lb on the other hand does. :wink:).

350-400whp isnt going to happen with this turbo on his 2.0. Khellen is looking for a nice fat powerband, and this should certainly do the trick. :)

Why would you highly recommend against a lightened crank pully? I would say just the opposite. i have had a perrin light weight crank pully on my car for almost 6 years and i would never go back. it is a good mod for not alot of money. it allows you to shift gears much smoother and add a tiny bit of hp.

Definitely going to take all of the advice in this thread into consideration. I'm also gonna talk to Ryan down at area1320 tomorrow when we pick up Ben's car. So far the major benefit to me would be the somewhat better spool, but a PNP'd TD05 8cm 18g is still going to spool perfectly fine for my needs without the billet wheel. I think if I've got some spare time I'll run it down and have the blouch guys do it, but its dosent seem like a MUST for what I'm shooting for.

Also, to address the other things brought up:

I'm not planning on hitting 400whp with the 18g (I'd probably go 30R and a 2.5L when I'm ready for that), what I meant was that is my end goal for the car. Then again, that's just a number right now, 300-350whp might be good enough, we'll have to see! Right now anywhere between 300-350whp would make me ecstatic.

I'm not installing TGV deletes and phenolic spacers for fitment, they are for better air flow (TGV) and slightly lower intake temps (Spacer). Does either really make a difference? I don't really know but if I've got everything apart...I'd rather get it on the car so I don't have to get the car retuned 4 months from now.

Not sure what the regular 18g does on a 2 liter, but you'd hit that whp goal on the 2.5L fairly easily.

On the 2.5L, TGV deletes were worth 7whp throughout the rpm band IIRC. They're a good mod to do since the motors fail/the butterfly valves get stuck over time.

well this has been a long debate, and i'm still not convinced its safe. To quote some previous people on this debate basically,"regardless of the engine configuration (inline, boxer), the crank of a four-stroke motor is going to have torsional vibration. I really don't understand why anyone would think that the boxer motor is magically exempt from torsional vibration. The WRX/STI stock pulley (two metal pieces with rubber squished in between) is a harmonic damper not to be confused with harmonic balance as even SOA techs have said that the stock cranks do not act as balancers. It is used to damp the torsional vibrations. Since our crank is so short (a flat 4 has the shortest crank of any car engine configuration) the torsional vibrations are greatly minimized compared to any other type of engine. But replacing the stock pulley might harm your engine ( especially if you're way above stock turbo power levels) in the long run because it eliminates this damper." Both lighter crank and lighter flywheel I think will end up causing more issues than what is worth, I'm not expert I could be wrong, but I'm an everyday driver, I like to play it safe and besides there are much safer ways to make an extra 5 whp. Just my two cents, again I'm not claiming to be an expert this is just what I've come across during my research since 2002 for my car....

^^ the above points are very valid. But the only flaw is Subaru's aren't revving to 9000 rpms. At stock rev limits aftermarket crank pulleys show no sign of being causes to engine failures.

I will always run a lightened crank pulley on ALL of my cars..

Dave- 18g's on 2.0's with the right tune can see around 330-340whp

After much thinking.....I drove down to blouch today after work....had 5 minutes to spare before they closed. Couldn't find the shop from the address given on their site, but after coming home I think I have a better idea of where this place is. Guess I'm headed back after work again tomorrow!

well, if you're going to get a lighter crank pulley AND lighter flywheel, apparantly kartboy claims that their lighter pulley (not the lightest of your options but still way lighter than stock) will not cause any weird CELs for your subbie, i dunno, I've had my car since 2002 and I kept stock flywheel and stock pulley, but if you're gonna do it, might as well go with a company that claims that their lighter pulley with a lighter flywheel will not cause any weird CELs. Gimmick makes one too (good price), it doesn't look as cool/fancy as the AP, COBB, or Perrin, but let's be honest its not about looks right its about functionality right? or both? But to answer your original question, I would only do the compressor wheel if you're planning on holding on to the turbo for a while, but if you're planning on upgrading your turbo soon, then save your $250. Unless you think the billet compressor wheel will add value and when u go to sell your turbo you might be able to get some of the $250 back?

Yea, going to get the billet wheel since I plan on staying with the 18g for a while. I think they have a ball bearing upgrade too, but I'm not about to spend 900 for that.

As for the flywheel and crank pulley, if its just misfire codes, can't they be tuned out with a UTEC? Dunno, I understand the risks of running lightened flywheels and crank pulleys but I've had heard from a few people now running the same exact setups they have absolutely no problems. If it does cause problems, it wont be in 5 miles, it'll be in something like 30k-50k miles.....I think I can live with that risk.

I'm not sure its something that can be "tuned" out because it has something to do with crank speeds being unusually faster than what the ECU thinks it should which somehow causes false misfire codes, i know that you can "tune" the ECU to make it less "sensitive" for lack of a better word, but i dunno, it seems like a bunch of other people have no issues so i'm sure you'll be fine too, anyway post up your numbers when you get everything done, i think you'll easily be in the 330whp range

I'm assuming when I was told they could be "tuned out" they were referring to the codes being cleared. I'm not completely sure though.

I'll definitely post up my numbers once everything is said and done. I think I've got everything I need to complete the build now and all that is left is having blouch do the compression wheel upgrade. Hopefully I'll be heading over there today!