blouch 8cm vs 10cm hotside comparisons
 

So their is always alot of arguement about the effects of the 10cm exhaust houseing vs the 8cm exhaust houseing with no one able to provide solid evidence to support anything.

For any sort of comparison to be accurate it really needs to be done on the same car with the same fuel and zero other supporting mods.

Through abit of resesearch i have found one exact comparison and thought it would be good to share. If people come across similar comparison could they please post them up and i will add them to this post. Just to be clear the peak numbers could mean anything so dont take them as gospel, just use the plots as a tool to compare the difference between the 8cm and 10cm houseing

[B]Blouch 1.5xtr TWINSCROLL 8cm vs 10cm[/B]
Fuel u93
No change in supporting mods
8cm blue
10cm red

[URL=http://s1152.photobucket.com/user/tonydavies1/media/Mobile%20Uploads/graph_zpsl9frtexs.jpeg.html][IMG]http://i1152.photobucket.com/albums/p498/tonydavies1/Mobile%20Uploads/graph_zpsl9frtexs.jpeg[/IMG][/URL]

with the 1.5xtr its probs a good bet to get the 10cm. The 1.5xtr has the same front wheel as a 2.5xtr, but slightly smaller turbine wheel.

With the 2.5xtr 8 or 10cm work. Its just shifting the spool vs high rpm characterisics.

with the 3.0xtr, id probs still go a 10cm. The 3 has the same turbine as the 2.5, but has a bigger comp wheel. I think the 10cm would compliment it well. I very nearly got the dom3-10cm.

it all comes down to how you want it to perform. And like everything, everyone has thier own idea of whats best.


One thing that benefits all these turbos is the 3inch inlet. If you dont have a silicon inlet, then you may aswell specify the 3inch option, and get an inlet to suit. Stock location Subaru has a very convoluted intake track and when these turbos really get sucking, they can empty the inlet very easily due to the restrictions of the inlet track. Having the 3 inch inlet helps in that it kind of has a buffer by way of larger volume of ait infront of the turbo. And makes it just that little bit easier for air to enter the turbo. It wont really flow any more air, but it will allow them to spool a bit quicker.

[QUOTE=Bram;829268]with the 1.5xtr its probs a good bet to get the 10cm. The 1.5xtr has the same front wheel as a 2.5xtr, but slightly smaller turbine wheel.

With the 2.5xtr 8 or 10cm work. Its just shifting the spool vs high rpm characterisics.

with the 3.0xtr, id probs still go a 10cm. The 3 has the same turbine as the 2.5, but has a bigger comp wheel. I think the 10cm would compliment it well. I very nearly got the dom3-10cm.

it all comes down to how you want it to perform. And like everything, everyone has thier own idea of whats best.


One thing that benefits all these turbos is the 3inch inlet. If you dont have a silicon inlet, then you may aswell specify the 3inch option, and get an inlet to suit. Stock location Subaru has a very convoluted intake track and when these turbos really get sucking, they can empty the inlet very easily due to the restrictions of the inlet track. Having the 3 inch inlet helps in that it kind of has a buffer by way of larger volume of ait infront of the turbo. And makes it just that little bit easier for air to enter the turbo. It wont really flow any more air, but it will allow them to spool a bit quicker.[/QUOTE]

Good infomation Bram. Though i think you may have missed the point of the thread alittle bit. Im trying to compile a list of dyno plots that shows the exact real world differences between the houesings on the exact same turbos when nothing other than the houesing has been changed. As seen in the first dyno i have posted. Not trying to compsre the 2.5 to 3 etc etc.

yeah. I got that. I was just guving a quick run down on how i would choose them.

What your looking for is going to be very difficult to find. I dont think many people would go to the trouble of removing the turbo, changing just a turbine housing and then re installing it and retuneing it. People tend to do a lot of mods at once, so a back to back comparison is gonna be a rare thing.

blouch 8cm vs 10cm hotside comparisons
 

The starting thread is useful but it is not just a case of saying bigger is better when it comes to a turbine housing. Each size compressor will have a sweet spot range so what works well for a GT35 may make a GT30 a lag monster.

Check out this Perrin link and also part 1 for some extra controlled comparison between GT and billet GTX wheels and also different sized back housings.

[url]http://blog.perrinperformance.com/garrett-gtx-turbo-comparo-part-2/[/url]

Blouch do seem to get great results though from small compressors and big back houses.

I guess that Cobb has also moved in this direction by combining a TD05 compressor housing but high flow H wheel but with a 20G turbine and 8cm back housing. A couple of years back and a 20G seemed to be a more common pairing with a TD06.

Yep 100% agree, never said it was going to be easy

Agree. It seems to be an art rather than a science.