I've done searches and have come up with some posts that talk about modifying a HKS downpipe by adding another pipe to let the wastegate breathe better. I know this, but is there anyone out that has a picture of how this is done or can give me some detailed instructions i.e. piping size etc. That would be great.

Thanks,
Raymond

 

I'm doing the same. I'd like to get 1-1/4" pipe to do it but I haven't been able to find it yet (1-1/2" mandrel bends are readily available but might be just a little too large).

Here's the bosal dp:
http://www.subarureview.com/images/1055.jpg

I believe it uses 1-1/4" for the wastegate side and 2-1/2" for the main part.

 

you need a plasma cutter because that metal doesnt cut very easily its kinda thick. i have one was gonna do taht but just put it on

 

Also, instead of a twin dump design you can take it to a machine shop with this picture

and have them make it into a bell mouth type. I did something similar with a downpipe for my MR-2 and it cost me about $60 to do.

 

Thanks for the help guys, I'll take that pic to the mechanic at my work to see if he can do that, cause if he can he'll do it for free.

Thanks again,
Raymond