nealnanoHX

So I have a Blox/Drag/GoAutoworks style cast turbo manifold for my B series turbo build that is still a long ways from being complete. Here is the mani I have and I know many other out there are using it as well. The GoAutoworks kit I will be getting comes with this manifold so instead of using the supplied one I will use this one and sell the other one, or keep it as a backup. I will of coarse do the same work it it though.
http://www.ebay.com/itm/HONDA-B16-B1...#ht_3269wt_968
Anyways I go bored today at work so I decide to do some improvements to the poor casting. I spent a good 2-3 hours removing large amounts of material from the inside of the mani that would hurt flow and turbo spool. There are some very large humps of cast iron inside that are I think meant to help direct exhaust flow to the turbo and wastegate. However these are major restrictions in the mani and in IMO are what is making these mani flow so poorly and only be good fr 400whp tops.
These pics of it suck by here tare some before shots.


painted it black but removed the paint. You can kind of see in the second pic in the turbo flange/collector there is a very large hump that restricts flow and there are also 2 around the wastegate that restrict flow to both the the turbo and the wastegate and is most likely the cause of boost creep with these manis under higher boost. I will post up pics on the after tomorrow once I take some so stay tuned.

Spawne32

iTrader: (3)

i could have swore i saw a thread just like this one a while back

nealnanoHX

Dont know, I did not start it. This is not your average port match and smooth things out. I took out large amounts of material from the inside of the collector area in the mani. Looking threw the runners now if all flows right to the collector.

nealnanoHX

Ok so here are the pics of the finished port work.

This is where the most work and material was removed.

boosted_D

iTrader: (1)

looks good man! I also have a cheapie cast mani. I am going to do the same thing before it goes on. Mine doesn't look as restrictive as yours did to start off though, just be a little less porting for me I think.

No reason a well ported cast mani won't flow like a log. It will just last a lot longer cuz it wont crack and break, and it's a hell of a lot cheaper!

This porting should help solve a lot of the contamination issues that cast mani's have, again, nice work!

nealnanoHX

Thanks. It took me about 2 hours just to remove all the material from inside the collector, there was a large hump there. It is hard to see in the before pics because I did not take them to show the inside of the mani but you can kind of see it in the second pic from the top.
Yeah I feel this mani will flow well for 400whp no issues and maybe even do 500whp but it will be a bit restrictive that high.

rusty90crx

Did this on my old sohc but didn't notice a difference

nealnanoHX

I dont think this will make more power overall. However it will help the mani flow much better, decreasing back pressure and increasing boost threshold and preventing boost creep.

rusty90crx

never thought of it that way good info thanks

nealnanoHX

Here is a side by side of the collector before and after so you can see the work done a little better.
before

after

can you see the large hump of material right under the top of the inside of the collector in the before pic?? I pretty much totally reworked the inside of the collector and the wastegate area.