Running at 20psi as low boost is no prob .( which is where I leave it anyway) But have removed the divider and will see very soon if it sits at base boost which is around 17 psi any way due to my bigger actuators. .
Here is the pic of UAS ones. We made a jig to match the long US version split dumps and no longer made in house. They are now made for us out of stainless steel by www.qualityperformanceexhaust.com.au here in Sydney, who made this set in the pic. They make dump pipes for some big name performance workshops in Sydney. Not cheap though, Aussie labour. We make 10% margin at full retail.
Maybe John has got some back to back results if he has a jig for long version splits Care to share the results ??
We haven't done any testing by changing dump pipes only on 300ZX's. We have on a Skyline that had a HKS turbo and bell mouth dump pipe made around 8rwkw more than a very nicely designed split dump pipe.
Thought you told me that the split wasn't match ported to the turbine housing like mine so doesn't make it a valid test .(pipe slightly smaller than the turbine wheel) Also did you didn't compare the spool up differences or just peak power . Bell mouths won't make anymore peak power on my car but Would like to see the difference in spool .thats the main purpose of splits . .
I could probably dig and find dyno readings from the dyno. The bell mouth was definitely not worse anywhere on the graph, only better. I was surprised myself, Andrew and Ben weren't. These split dumps were far more expensive and very well made stainless and Tig welded. Although match ported properly? Maybe not and more critical on Splits.
These are the 4 bolt bell mouths that rollin got made for me. Cost about $500-$600 from memory. The position of the O2 sensors makes changing them a breeze. Compared to stock is quite amusing:
thats a good pic in comparison to stock adam, there are quite a few zeds floating around now with these dumps, never did any before and after testing, but even on a stock turbod car they seem to really help