Porting the wastegate hole.. How much is too much??

[tonys87]

Hi guys! I read a thread a while ago where bison suggested you don't over port the waste gate hole. It even had his recommended limit. I can't seem to find that thread. So I hope you see this Bison
I just installed a RJC down pipe that fit great but the puck doesnt cover the hole completely. My waste gate hole now is 1 3/8

I think I just might buy a new exhaust housing and port it again maybe a Lil smaller. I wanna be able to turn down the boost down to at least 16psi for the streets. Thanks everyone!

 

[bison]

Hi guys! I read a thread a while ago where bison suggested you don't over port the waste gate hole. It even had his recommended limit. I can't seem to find that thread. So I hope you see this Bison
I just installed a RJC down pipe that fit great but the puck doesnt cover the hole completely. My waste gate hole now is 1 3/8

I think I just might buy a new exhaust housing and port it again maybe a Lil smaller. I wanna be able to turn down the boost down to at least 16psi for the streets. Thanks everyone!

Depending on the turbo used and the mass flow potential of the engine you may need a larger hole than what I would use on an application. An example would be a my black car. With a .950 or so hole I have no issue running the 25-29psi the compressor needs to make on the engine it's on to use 100% of what it can support. If I wanted to turn the boost down to 16psi on that engine it would need a much larger hole. It would only be about 500hp at 16psi. Probably a 1.250" would be required. The problem with that is when I wanted to run 29psi and make 800+hp the backpressure has a lot more surface on the puck area to press on and may cause the boost to drop as rpm climbs and the mass flow increases. If the hole isn't covered completely then it will have less than optimium spoolup. RJC had a plate that can be sandwiched on between the dp and housing and you can open it up to any size hole you want.

 

[tonys87]

Thanks a lot for the info Bison. I'm running a 6765 dbb turbo and it dynoed at 515rwhp at 16psi. I recently swapped down pipe and don't know wether this issue with the puck was there with the other DP. I will check with rjc and see if they still have that plate. If not I guess I'll just buy another housing and port it correctly to align with the puck.

 

[bison]

Thanks a lot for the info Bison. I'm running a 6765 dbb turbo and it dynoed at 515rwhp at 16psi. I recently swapped down pipe and don't know wether this issue with the puck was there with the other DP. I will check with rjc and see if they still have that plate. If not I guess I'll just buy another housing and port it correctly to align with the puck.

You would need a very large hole to be able to run that turbo at only 515whp. They have the plates in stock.

 

[Sweet6]

Like Bison said Just get the place from RJC and then cut a new hole. My buddy did the same thing. It worked perfect.