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Rb20 High Flows

s213b

By s213b,
in Engines & Forced Induction

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s213b Rising Star

s213b

Posted
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I've just been told the rb25 highflow I thought I had is actually an rb20 highflow :/

does anyone know how much the tiny rear housing will flow on a rb25?

I know it's going to choke power, but can anyone shed some light on roughly how much it'll make on a rb25 with all supporting mods + 256/264 cams and e85?

I'm wondering if I should try get a op6 rear housing or just leave it as it is and get a hypergear in the coming months...

Cheers

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hypergear Grand Master

hypergear

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Technically the Rb20 and Rb25 's turbine housing end are the same. It depending on what the configuration is when the high flow was done, usually the RB20det's wheel sizes are smaller for better response. If that is the case it will chock the Rb25det in upper rev range.

I can still high flow your stock Rb25det turbocharger and produce a responsive 260rwkws mark, while the OP6 usually make 30kws more. That is also about at the limitation of factory exhaust manifold with internal wastegate assembly. Once setup on a high mount with a proper external gate, there will be another 30kws of gain.

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Blackkers Experienced

Blackkers

Posted
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If you've got the turbo handy could you show us a photo of the front and rear? might be able to gauge how 'hi flowing' it may be by judging the size of the turbine/comp wheels

these pictures are of the current profile 21u highflow. i guess you can compare them to yours

n9L3NvG.jpgymEnwxa.jpg

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s213b Rising Star

s213b

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Technically the Rb20 and Rb25 's turbine housing end are the same. It depending on what the configuration is when the high flow was done, usually the RB20det's wheel sizes are smaller for better response. If that is the case it will chock the Rb25det in upper rev range.

I can still high flow your stock Rb25det turbocharger and produce a responsive 260rwkws mark, while the OP6 usually make 30kws more. That is also about at the limitation of factory exhaust manifold with internal wastegate assembly. Once setup on a high mount with a proper external gate, there will be another 30kws of gain.

Hi Stao, I don't have a rb25det turbo, how big a job is swapping over a turbo housing? Could I just put an op6 rear housing on it to free up some power in the upper rev range? Lol am I going to have some 190kw idle spooling turbo if I leave it how it is? :/

Im just going to use this turbo to run the new motor in, eventually ill get an internal gate ss2 off you. No more highflows for me

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s213b Rising Star

s213b

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If you've got the turbo handy could you show us a photo of the front and rear? might be able to gauge how 'hi flowing' it may be by judging the size of the turbine/comp wheels

these pictures are of the current profile 21u highflow. i guess you can compare them to yours

n9L3NvG.jpgymEnwxa.jpg

The turbos on the car now, it's going to be tuned this week, but I had a good look at it before it went back on, and it looked identical to that photo. Same size & style wheel

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s213b Rising Star

s213b

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Will not bolt on. And you rather use the high flow you have then that configuration.

I know it won't bolt on, was just curious if it would physically fit in the stock location. I'm not keen on a .63 anyway, just saw one come up cheap

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