Downpipe Wastegate flange & puck, enough room?

[Gnx6]

I needed to upgrade my downpipe puck size to go with the 6262 bb Turbo. I currently have a TE-60 and a Terry Houson pipe from 05 I think. I have seen and read about people modifying the downpipe with the larger puck. Here is a picture of my pipe with the new puck overtop in roughly the right position. I will have about 5mm of contact left on the flange where the dowpipe flange and turbo meet. Is this enough room for good contact, no leaks and warping or do I need to get a new downpipe with the different shaped flange that has the larger puck? Thanks for your input.

 

[jasjamz]

ATR SS pipe with a RJC Mega Puck installed by TurboBuRick on the left. Stock THDP 3" on the right. I ported a Precision 6262 Cea/Cea to match the THDP puck and it holds 18 psi steady during some short testing on a stock long block. I will get real track results when the track opens. The boost will set for 25 all the time so as long as it can keep that steady he won't need to change out his puck. Now when we add the new top end....???

 

[Evaddave 87gn]

Once I get my rollbar installed I will also be making changes to my THDP puck. I had major boost spike issues last year. I had to restrict my boost last season so I do not intend to have another summer like that.

I'll be following your progress.

 

[jasjamz]

Once I get my rollbar installed I will also be making changes to my THDP puck. I had major boost spike issues last year. I had to restrict my boost last season so I do not intend to have another summer like that.

I'll be following your progress.

Sometimes I see that the boost spike is cause by the wastegate not opening fast enough. Not be cause it need a bigge hole or puck.

 

[Evaddave 87gn]

Yes, agreed been down that road.

 

[bison]

Sometimes I see that the boost spike is cause by the wastegate not opening fast enough. Not be cause it need a bigge hole or puck.

Yup. This is what I see most of the time. Opening the hole excessively leads to boost fall off if you start working the turbine hard. Bigger is not better unless you can put a controlled source of pressure against an external gate type setup. If the turbo is sized properly I have yet to see the need for more than 1.100" on the wastage hole. The 6265 I ran back in december had an untouched as cast and machined hole. I didn't measure but it's .950 or smaller.

 

[Evaddave 87gn]

Yup. This is what I see most of the time. Opening the hole excessively leads to boost fall off if you start working the turbine hard. Bigger is not better unless you can put a controlled source of pressure against an external gate type setup. If the turbo is sized properly I have yet to see the need for more than 1.100" on the wastage hole. The 6265 I ran back in december had an untouched as cast and machined hole. I didn't measure but it's .950 or smaller.

Maybe boost creep would be a better term than spike....

My 6776 DBB was creeping to 25-27 but after some changes I was able to control the boost to hold at 23-24lbs when I set my boost control to 18 or lower. When I put a regulator on the actuator with an air hose I found the gate was cracking around 20lbs. This is with no pressure on the puck. This is what is leading me to increase my puck size.

 

[bison]

Maybe boost creep would be a better term than spike....

My 6776 DBB was creeping to 25-27 but after some changes I was able to control the boost to hold at 23-24lbs when I set my boost control to 18 or lower. When I put a regulator on the actuator with an air hose I found the gate was cracking around 20lbs. This is with no pressure on the puck. This is what is leading me to increase my puck size.

Boost creep and spike are totally different. If youre getting boost creep then the turbo is likely to large for your application. The 67 compressor wheel will flow enough air to support 9 sec power. You have to keep in mind the ex pressure is pushing on the puck also. So in reality the gate is opening before you get 20psi in the actuator and you were still getting creep. The 67 compressor is not too happy being at WOT flowing less than 55lbs/min. Chances are you were flowing a lot less than 55lbs/min if you are having creep issues. If you were flowing that mass flow you would probably not need to do anything to the wastegate since the exhaust volume and pressure would be much greater and the gate would open further quicker even though the manifold pressure would be the same or less. If you open too much and you run the compressor wheel for all its worth the opposite of creep occurs and sometimes looks like spike. I ran a T72 compressor up to about 800hp (678hwp) last week with a 76 p trim turbine which is in reality a big mismatch of wheels. The wastegate hole was 1.050 and it was a Precision .85 3 bolt housing with a heavy actuator spring. I just ran it from 70-140mph in 3rd today and it stayed rock steady at 27psi in 3rd till it hit 5700 then it slowly tapered off about 1psi by the time it was at 6000rpm. It did spike a little to 28psi on ramp in but settled in a few frames. I didnt log backpressure but that combo is just dying for a GTQ/HPQ turbine. Id expect it to pick up about 40whp with no increase in manifold pressure. I might and probably would have a creep issue if i did nothing but switch to the GTQ turbine and kept the T72 compressor and tried to run it around 22-23 psi.

 

[Gnx6]

So..... Do you think it will clear?

 

[jasjamz]

Not without a lot of grinding. I would port the housing try it with the stock puck first.