A local club member is running a half-bridge 13B in a FC.
The turbo is a Holset XH35 but he does not know what variant it is or its specs.
In 2nd or 3rd gears, it reaches max boost around 4000 rpm, and by 6400 rpm the boost drops down to 11psi.

The DP feeds into a 3" silencer then splits into the stock rear "Y" exhaust with straight through silencers.

Which or both do you think is causing the high back pressure.
Personally, I do not like either the exhaust or turbo.

 

The stock y pipes are skinny as hell. I really have no idea.

He could have a 22cm housing or larger which could be causing the later spool. I dunno. It's not enough info....

 

if it's the HX35W from a Ram (commonly used on a lot of 4 cylinders) they're like a 14cm^2 housing with a T3 inlet. That may hold him back.

 

+1...I'm running the HX40 which is MUCH larger with the 19cm^2 hotside and I see full (14 psi atm) boost by 3500rpm and it stays that way all the way to 8k.

 

HX-35 is wayyy to small for what hes going for. A stock port motor will be pushing that turbo let alone a bridge. Tell him to try the turbo exchange in concord nc. They will be able to tell you all the housings available for that turbo and order them for you. Im on a 26cm internal wastegate housing with the gate welded up. With a streetport i get 20 pounds right before 4 grand.

 

Also his exhaust needs to go, got to let that bridge breathe.

 

What size turbine wheel is a HX35 then?

Compressor, especially if its a 7 blade, is better than a GT35R one, so thats not the issue.

Is the turbine wheel much smaller than a GT35R one then? As people have no issue with them it seems.

Be good to get some real facts rather than heresay before making any big changes.

Although I cant remember the 35 turbine wheel size, it sounds like the rear section of the exhaust would be causing more issues.

A bridge sounds overkill for that spec too in my eyes, but thats a different story.