F
forester sti
Guest
I just did a big detailed write up comparing the two, but then the laptop crashed and lost all! 
So the brief version is!
GT Spec headers 4 into 1 collecter finishes at 57mm where it meets the up-pipe!
The GT spec up-pipe starts at 57mm, so any bit either way when bolting together, the bolts aren't tight in the holes, so movement is possible, so this can create a small restriction!
The Harvey one is 60mm so there is room for error!
There is a threaded hole near the outlet of the up-pipe (I assume for a sensor)
The GT Spec has this fitting protruding into the pipe maybe 4mm, so createing a small restriction,
The Harvey one has this bit machined away!
The turbine inlet of the turbo is 50mm diameter, Both up pipes finish at 50mm
The GT Spec reduces from the 57mm pipe down to the 50mm at the flange that bolts to the turbo, so that makes a sizable sudden ledge all the way around the enterence to the turbo, (that seems very silly)
The Harvey one reduces from 60mm down to 50mm over about 50mm half way up the up-pipe, and it seems to incorperate an expansion joint there! and so the pipe that leads to the 50mm turbine inlet is 50mm and smooth!
I'm looking forward to Ciaran RS/RA re-enforcing the headers and fitting them withe the heatwrapping, then I'll get JGM to map her to make the most of it!
I'll let you's know how I get on!
Dan
So the brief version is!
GT Spec headers 4 into 1 collecter finishes at 57mm where it meets the up-pipe!
The GT spec up-pipe starts at 57mm, so any bit either way when bolting together, the bolts aren't tight in the holes, so movement is possible, so this can create a small restriction!
The Harvey one is 60mm so there is room for error!
There is a threaded hole near the outlet of the up-pipe (I assume for a sensor)
The GT Spec has this fitting protruding into the pipe maybe 4mm, so createing a small restriction,
The Harvey one has this bit machined away!
The turbine inlet of the turbo is 50mm diameter, Both up pipes finish at 50mm
The GT Spec reduces from the 57mm pipe down to the 50mm at the flange that bolts to the turbo, so that makes a sizable sudden ledge all the way around the enterence to the turbo, (that seems very silly)
The Harvey one reduces from 60mm down to 50mm over about 50mm half way up the up-pipe, and it seems to incorperate an expansion joint there! and so the pipe that leads to the 50mm turbine inlet is 50mm and smooth!
I'm looking forward to Ciaran RS/RA re-enforcing the headers and fitting them withe the heatwrapping, then I'll get JGM to map her to make the most of it!
I'll let you's know how I get on!
Dan
