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Custom turbo
OM616 Offline
10mm MW
****


Posts: 564
Joined: Jul 2009
Location: Michigan
#1
Custom turbo
I have been going back and forth on turbo choices and setups for my 617a with a super pump and really want to stay away from twins of any configuration. I want to be able to have 5lbs as close to right off idle as I can and be able to make 30 to 35lbs of boost quickly and up to 5000 ish RPM. Target power range with the engine mods is high 300 to low 400HP.

I know a compound or sequential set up would be able to do that, but it is just a lot of extra stuff to deal with and to fail. A VNT turbine would allow me to be able to adjust when boost starts to come in, but they can be restrictive. The issue is the VNT turbo compressors "generally" do not want to make 30+Lbs of boost the 50lbs/min range without being way out of their maps. 

I was thinking of a S200 turbo with a 12 cm twin scroll turbine housing and a quick spool valve, but I don't think choking off the turbine to 6cm will get me the boost as soon as say a GT25 VNT turbine will, so I am thinking about taking a GT25V turbine and center section and mating a S200 compressor to it. I most likely will have to bleed off some air on the bottom end to keep the compressor with in the lower end surge limit but it will definitely generate the boost at the volume I am looking for and the VNT turbine should get me the boost curve I want.

In a perfect world I would make a new header that had an external waste gate to help control the EMP and boost levels in conjunction with the VNT pod, but I think there is enough room for an adapter manifold (between the stock manifold and the turbine flange) with an oval port for a waste gate. 

I don't want to get into the " a S200 compressor will not fit on a GT25V turbine shaft", yada yada. I would like some feed back as to how crazy such a set up would be in operation. I know I will need to do some bottom end by-pass/bleed most likely to keep the compressor happy, but I have seen a few of those set ups and they work well. 

A twin scroll is simpler and would flow better, but I really like the adjust ability of a VNT. I have put them on other MBs and was able to control how responsive the turbo is very easy. They just max out at 20 lbs lol.

Thoughts?
07-29-2020, 01:46 PM
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Austincarnut Offline
Holset
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Posts: 286
Joined: Jun 2012
Location: USA
#2
RE: Custom turbo
(07-29-2020, 01:46 PM)OM616 Wrote: I have been going back and forth on turbo choices and setups for my 617a with a super pump and really want to stay away from twins of any configuration. I want to be able to have 5lbs as close to right off idle as I can and be able to make 30 to 35lbs of boost quickly and up to 5000 ish RPM. Target power range with the engine mods is high 300 to low 400HP.

I know a compound or sequential set up would be able to do that, but it is just a lot of extra stuff to deal with and to fail. A VNT turbine would allow me to be able to adjust when boost starts to come in, but they can be restrictive. The issue is the VNT turbo compressors "generally" do not want to make 30+Lbs of boost the 50lbs/min range without being way out of their maps. 

I was thinking of a S200 turbo with a 12 cm twin scroll turbine housing and a quick spool valve, but I don't think choking off the turbine to 6cm will get me the boost as soon as say a GT25 VNT turbine will, so I am thinking about taking a GT25V turbine and center section and mating a S200 compressor to it. I most likely will have to bleed off some air on the bottom end to keep the compressor with in the lower end surge limit but it will definitely generate the boost at the volume I am looking for and the VNT turbine should get me the boost curve I want.

In a perfect world I would make a new header that had an external waste gate to help control the EMP and boost levels in conjunction with the VNT pod, but I think there is enough room for an adapter manifold (between the stock manifold and the turbine flange) with an oval port for a waste gate. 

I don't want to get into the " a S200 compressor will not fit on a GT25V turbine shaft", yada yada. I would like some feed back as to how crazy such a set up would be in operation. I know I will need to do some bottom end by-pass/bleed most likely to keep the compressor happy, but I have seen a few of those set ups and they work well. 

A twin scroll is simpler and would flow better, but I really like the adjust ability of a VNT. I have put them on other MBs and was able to control how responsive the turbo is very easy. They just max out at 20 lbs lol.

Thoughts?
Not to get off subject I'm curious, what is the redline on a 616? Will you be doing anything to beef up the valve train and doing anything to lower compression?  I had an unfortunate failure last month with my 617...
07-29-2020, 10:07 PM
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OM616 Offline
10mm MW
****


Posts: 564
Joined: Jul 2009
Location: Michigan
#3
RE: Custom turbo
what happened?
07-30-2020, 01:27 PM
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