THDP on stock turbo?

[BAD87GN]

I have a very lightly modified GN, and am in need of an exhaust. I was thinking of putting on a stainless Terry Houston from the turbo back - will I need to modify anything on the turbo to do this? I know there is some talk of modifying the puck, but is that a must? Thanks in advance.

 

[turbosam6]

I have done it, as have many others. The only thing you might do is port the wastegate hole in the turbo housing a little larger to prevent boost creep. I had no problems.

 

[87GNcospg]

if the THDP is installed on a stock turbo and you do not port the wastegate hole in the turbo housing, is boost creep for sure going to happen?

 

[kh440]

Other than modify or remove the heat shield it's a pretty easy bolt-in

 

[UNGN]

Originally posted by 87GNcospg
if the THDP is installed on a stock turbo and you do not port the wastegate hole in the turbo housing, is boost creep for sure going to happen?

Boost creep probably will Not happen. No porting is required. If you want more boost control, you can improve the shape of the hole without increasing the diameter.

Some people confuse the overboost situation caused by chips like thrashers with boost creep. The wastegate hole could be the size of a sewer pipe and it still won't solve this overboost. The Chip is allowing the turbo to overboost by holding the solenoid open. Creep happens when the solenoid is closed and the boost is still climbing.

My feelings are mixed with putting a THDP with a stock turbo. I picked up 4 mph and dropped .4 when I switched from a stock elbow/downpipe/gutted cat/crappy exhaust to an uncapped THDP with a Dump. A HUGE difference.

But I have also run a THDP vs. a ported stock elbow/2.5" DP thru a good exhaust Back to Back and the difference was only .05 seconds and 1.5 mph running high 11's.

The biggest bang for the buck is the cat and cat back. If you are going to buy a THDP anyway, get one with a dump and you can put off the exhaust for another year or so. If you are going to buy a THDP and put a Cat on it, save your money and buy a Cat back instead.

 

[RobV6]

Thanks

To UNGN.....You answered a question I was about to post.

Sometimes timing is just right.

 

[strikeeagle]

The puck in the THDP is significantly larger than that in the OEM elbow. This allows you to port the wastegate hole in the turbine cover to a larger size, but you're not obligated to.

In short, a SS THDP is a nice upgrade, and you are under no obligation to modify the turbine cover when the THDP is added. However, porting the turbine cover will reduce boost creep to the extent that the hole in the turbine cover is too small to handle flows resulting from even minimal hotrodding of a TR...