Wastegate hole size question.......

[Rayk]

I have my TA49 on the way to John Craig for a rebuild and upgrade to a TA60 and I'm wondering if I should increase the wastegate hole in the exhaust housing while it's there.

The hole on the TA49 is currently .9" and I have installed an RJC puck into my old BGC 3" downpipe and it is centered well around the .9" hole. The RJC puck is 1.375"

So, should I have the hole increased? And, if so, how much? I haven't had boost creep problems yet but I may want to turn up boost later on. My set-up is below.

Performance with the TA49 has been 11.70 to 12.20 & 115-118 MPH with about 22 lb boost on 93 with alchy.

 

[slimtastic]

it couldnt hurt as your gonna be putting a bigger compressor on. take the hole to around 1.20"....

also keep in mind that the less boost you run, the more wastegate you need. the more boost run the less wastegate you need

 

[bison]

Leave it alone. The ex backpressure will be the same or more and you still have the small 31. Trim ex wheel. Enlarging it will give the backpressure more surface area to push on which will lead to boost loss st high rpm. Don't expect anything out of the larger compressor wheel at your current power level.

 

[Rayk]

Leave it alone. The ex backpressure will be the same or more and you still have the small 31. Trim ex wheel. Enlarging it will give the backpressure more surface area to push on which will lead to boost loss st high rpm. Don't expect anything out of the larger compressor wheel at your current power level.

Thanks, Bison. I really didn't expect a lot more power going from the 49 to the 60 but felt I would get a few more ponies if I raised the boost to 25 or so. Won't the TA60 give me a little more at higher boost than the 49?