BW s475, 476, 480 users come in :)
This is garrets testing of a cast VS a billet wheel of the same dimensions. The billet wheel was heavier, the cast lighter. Yes the cast wheel did outperform it. But so marginally you would never notice it in a real world application. Just like the mentioned smaller hubs of PTE won't be able to shave off enough weight to make a seat of the pants difference. It's all media hype BS put out there to sell turbos IMHO.
You can't just run the left side exh. manifold to one side of the scroll and the right side manifold to the other. For a proper twin scroll system to work you need to divide the exhaust pulses correctly. You'd need 1764 going into one side and 3258 going into the other. Otherwise you defeat the whole purpose.
it! You can't just run the left side exh. manifold to one side of the scroll and the right side manifold to the other. For a proper twin scroll system to work you need to divide the exhaust pulses correctly. You'd need 1764 going into one side and 3258 going into the other. Otherwise you defeat the whole purpose.
it!There are many write ups on this on yb and many other forums I suggest you try it for yourself instead of using Google.

Anyways this is off topic of what advice he was looking for start another thread billet vs cast if you would like
Thanks. It's the older V2 billet 76/92 thru forced inductions. Turbine is same 92/81 they have been using for awhile now. 1.25 AR with some porting.
The Best V8 Stories One Small Block at Time
There are many write ups on this on yb and many other forums I suggest you try it for yourself instead of using Google.

Anyways this is off topic of what advice he was looking for start another thread billet vs cast if you would like
What ever you need to tell yourself to sleep at night man. Thats not a "twin scroll" setup and if your still running the 2.5" pipes they are way over sized. A 2.125" to 2.5 open collector will spool better than a 2.5" divided setup at your power levels. Thats been done too.
Last edited by Forcefed86; Jan 8, 2014 at 07:10 AM.
What ever you need to tell yourself to sleep at night man. Thats not a "twin scroll" setup and if your still running the 2.5" pipes they are way over sized. A 2.125" to 2.5 open collector will spool better than a 2.5" divided setup at your power levels. Thats been done too.
All I did was point out false information given to people that don’t know any better.
Don’t tell someone a billet wheel performs better than a cast wheel it doesn't.
Don’t claim how well your twin scroll setup works, when you don’t have a twin scroll setup.
Don’t claim your system will out spool another with no data to back it up.
These statements confuse people trying to learn. 90% of the turbo crowd doesn’t understand how a twin scroll setup works and thinks billet turbos massively outspool cast units because they are lighter weight. Let’s get past the “Monkey-see” “Monkey-do” BS and explain why things work. Then let people decide for themselves. We all gain from it.
All I did was point out false information given to people that don’t know any better.
Don’t tell someone a billet wheel performs better than a cast wheel it doesn't.
Don’t claim how well your twin scroll setup works, when you don’t have a twin scroll setup.
Don’t claim your system will out spool another with no data to back it up.
These statements confuse people trying to learn. 90% of the turbo crowd doesn’t understand how a twin scroll setup works and thinks billet turbos massively outspool cast units because they are lighter weight. Let’s get past the “Monkey-see” “Monkey-do” BS and explain why things work. Then let people decide for themselves. We all gain from it.

Side note....Have you tried a billet wheel just for the hell of it? lol
Last edited by Camaro9969; Jan 8, 2014 at 09:45 AM.
Side note....Have you tried a billet wheel just for the hell of it? lol
What cast wheel? What bullseye billet wheel? Were they the same dimensions? I can tell you they weren’t without waiting for your answer. If you understand the physics behind the wheels and what makes them perform better or worse you would agree. Yes, the bullseye design may have performed better, the fact that it’s billet means nothing.
I also have direct experience with the 60mm bullseye billet batmowheel drop in replacement for the HX40. Dyno runs were made back to back with nothing but a wheel swap @ 30psi. The cast 60mm wheel made more power overall, the batmowheel made a tiny but more power in the midrange. Difference in spool times were negligible. As you can see even the “drop-in” replacements are a totally different design. It’s totally different dimensions! I also tested the 60mm 6 blade billet wheel from Holset VS the Cast wheel. There was no notable difference in performance! I'm telling you a cast replica of the batmowheel would perform the same (if not marginally better) as a billet wheel.
As far as the divided housing goes you can’t compare someone else’s setup to yours. You would have to compare a properly sized hotside non-divided, VS your divided setup. If you were local I'd put money on a 1.125" non divided hotside out spooling your current one. Hell I'd help you build it.
This is garrets testing of a cast VS a billet wheel of the same dimensions. The billet wheel was heavier, the cast lighter. Yes the cast wheel did outperform it. But so marginally you would never notice it in a real world application. Just like the mentioned smaller hubs of PTE won't be able to shave off enough weight to make a seat of the pants difference. It's all media hype BS put out there to sell turbos IMHO.
The fact is the billet wheels that are making more power on these cars are DIFFERENT (sometimes substantially) than their similar cast counterparts. The designs they are using in many instances you simply can not get away with in a weaker cast wheel without risking it coming apart any time you near max shaft RPM.
As far as the divided housing goes you can’t compare someone else’s setup to yours. You would have to compare a properly sized hotside non-divided, VS your divided setup. If you were local I'd put money on a 1.125" non divided hotside out spooling your current one. Hell I'd help you build it.

)Divided turbines work so well on V8s that BMW blew several million dollars trying to make it work on their new V8-let alone EVERY auto manufacturer with a turbo on an OE car is using divided set ups to gain spool-transient response-and efficiency.

http://www.autozine.org/technical_sc...duction_4.html
Lets forget that every Semi (hell, even every diesel passenger truck) for the last 20 years have had divided hot sides for the same reason. But hey-its probably all BS anyways
Last edited by coltboostin; Jan 8, 2014 at 11:39 AM.

The fact is the billet wheels that are making more power on these cars are DIFFERENT (sometimes substantially) than their similar cast counterparts. The designs they are using in many instances you simply can not get away with in a weaker cast wheel without risking it coming apart any time you near max shaft RPM.
Show me one aftermarket wheel that has a design that could not be made in a cast process. When have you ever seen a cast wheel pull itself apart the hub in a drag race application? I've never seen or heard of it. Not that a casting couldnt be bad, but it's not common place. Sure in drag race applications turbos will fail in lots of ways, but it's not due to the wheels casting failing.
)Divided turbines work so well on V8s that BMW blew several million dollars trying to make it work on their new V8-let alone EVERY auto manufacturer with a turbo on an OE car is using divided set ups to gain spool-transient response-and efficiency.
Lets forget that every Semi (hell, even every diesel passenger truck) for the last 20 years have had divided hot sides for the same reason. But hey-its probably all BS anyways
Your confused again.... I never debated a true twin scroll system won't outperform a non divided setup. If you don't have the cylinders paired properly into each side of the scroll your defeating the purpose of a twin scroll system. The above 2 members I'm chatting with do not have the cylinder paired properly.










