TURBO COMPRESSOR OUTLET

[NCred02]

Does anyone know if the RB20 and RB25 are the same? MyRB20 pipe is just a bit smaller than the turbo out let. Bolts dont line up and opening is different size.

My turbo is "direct fit" aftermarket and theres been a few snags.

Any ideas on how to get this done or where to find one would be appreciated.

Can I bore out the old one? widen the hole spread? 

[NCred02]

Hole spacing is 54mm. I need 58mm

[NCred02]

This is the spacing I need . Bolts are 58mm apart. Is this standard RB25 dimensions? 

[TurboTapin]

RB20 and RB25 turbo inlets are not interchangeable. I've never heard of someone modifying one to fit but everything is possible. 

[GTSBoy]

Anything metal can have holes filled up, redrilled elsewhere, etc etc. Even if you have to add metal around the outside to make space.

Or, cut off existing flange and weld on new one to desired dimensions.

[NCred02]

On 12/3/2021 at 9:33 PM, TurboTapin said:

RB20 and RB25 turbo inlets are not interchangeable. I've never heard of someone modifying one to fit but everything is possible. 

So if I understand. A RB20 turbo compressor outlet and a RB25 are not the same size?

Excuse my lack of knowledge. never had a turbo and my first Japanese vehicle as well. I have searched for outlet specs and cant find any information on bolt pattern or spacing    

[NCred02]

On 12/3/2021 at 7:20 PM, NCred02 said:

This is the spacing I need . Bolts are 58mm apart. Is this standard RB25 dimensions? 

Edited from above post

[TurboTapin]

On 12/4/2021 at 5:08 AM, NCred02 said:

So if I understand. A RB20 turbo compressor outlet and a RB25 are not the same size?

Excuse my lack of knowledge. never had a turbo and my first Japanese vehicle as well. I have searched for outlet specs and cant find any information on bolt pattern or spacing    

Correct, they are not the same. An RB20 compressor outlet does not bolt onto an RB25 turbo. 

Edited December 4, 2021 by TurboTapin

[TurboTapin]

See this thread. It explains it perfectly. 

Exhaust Mainfold | Skyline Owners Forum

 

Picture of RB25 elbow gasket on RB20 turbo elbow for comparison. Both the size and flange are different. As @GTSBoy has already mentioned though, it can be made to fit. I would just open up the flange with a die grinder and drill out the bolt holes so they match up. 

 

 

Edited December 4, 2021 by TurboTapin