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4" true downpipe

Maiden69

Go Kart Newbie
Location
Texas
Car(s)
2020 GTI
You better get those welds fixed before using that part. Uneven bead and misaligned, especially at the starts and stops plus the hot spots. Look inside and see if the weld permeated the seam like it should have. From those pics, it doesn't look like it will have.

I'm not trying to rain on your parade because I'm sure that you're excited for a new part, but that's just unsafe. Plenty of people have had fires due to broken welds that weren't done properly.
I am a welder, and there is nothing wrong with those welds. Fitment is poor, but that's what you get for using pie-cuts from a straight piece of tubing against a cut in a mandrel bed radius. As long as he back purged or used Solar Flux the welds will be solid. The area doesn't look over heated, which is a plus. Most welders tend to overheat stainless trying to fill in gaps like those, so looks like the guy know what he is doing.

Uneven bead and misaligned... seriously? Can I see your welds? Those welds are decent, unless you are TFS Justin, Jodi, Kanekid, or Aaron-6160, then they are definitely subpar. Another good welder from this website would be @GTI Jake

Look inside and see if the weld permeated - penetrated, welds don't permeate, unless you are referring to soldering. Which in this case, working on 16,14 or 11ga stainless, penetration is a given with the color of the welds. The concern here would be back purging or flux use to prevent sugaring... which will definitely result in cracking in a down pipe with those tight bends .

If you look at the welds, there is barely any deep purple, mostly silver to straw color, some pink-light blue, which is ok. Silver to straw is preferred, pink to purple is fine. Dark purple to any dull color is overheated, from those pics I only see 3 spots, and they are about 3-4 dabs long... for me there is no concern at all. A lot of companies would go over those welds with no filler on a decent pulse setting to cover them up, you will never know and you will pay them $$KK for their pretty colors. Or they will clean it up with Surfox or pickling paste, and run the tubing through Scotch-brite pads and remove all the color leaving a baby smooth surface.
 

The Dude

Autocross Champion
Location
PNW
Car(s)
MK7 GTI S
I am a welder, and there is nothing wrong with those welds. Fitment is poor, but that's what you get for using pie-cuts from a straight piece of tubing against a cut in a mandrel bed radius. As long as he back purged or used Solar Flux the welds will be solid. The area doesn't look over heated, which is a plus. Most welders tend to overheat stainless trying to fill in gaps like those, so looks like the guy know what he is doing.

Uneven bead and misaligned... seriously? Can I see your welds? Those welds are decent, unless you are TFS Justin, Jodi, Kanekid, or Aaron-6160, then they are definitely subpar. Another good welder from this website would be @GTI Jake

Look inside and see if the weld permeated - penetrated, welds don't permeate, unless you are referring to soldering. Which in this case, working on 16,14 or 11ga stainless, penetration is a given with the color of the welds. The concern here would be back purging or flux use to prevent sugaring... which will definitely result in cracking in a down pipe with those tight bends .

If you look at the welds, there is barely any deep purple, mostly silver to straw color, some pink-light blue, which is ok. Silver to straw is preferred, pink to purple is fine. Dark purple to any dull color is overheated, from those pics I only see 3 spots, and they are about 3-4 dabs long... for me there is no concern at all. A lot of companies would go over those welds with no filler on a decent pulse setting to cover them up, you will never know and you will pay them $$KK for their pretty colors. Or they will clean it up with Surfox or pickling paste, and run the tubing through Scotch-brite pads and remove all the color leaving a baby smooth surface.

Maybe these are a little better?
 

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Maiden69

Go Kart Newbie
Location
Texas
Car(s)
2020 GTI
They're pretty rad. Good place to work too
I bet, I have a small shop at home, just moved so everything is still in boxes or piled up in my garage. But I wish I had the money and space for all the toys they have. I'm buying a small press for sure. My last addition was a Strong Hands tube notcher and a floor mounted metal bender. My Eastwood TIG200 gave up after 9 years and I bought an Everlast PowerTIG 200-DV, used it once so I need to play with the pulse setting to get used to it. I used to "pulse" with the pedal as needed.
 

MSH

Go Kart Champion
Location
Denver
… trackslags DP effectiveness (with real world results to back that up) don’t just have to do with this perceived volume of flow from being bigger. the results (spool/power) you are gaining are due to the reduced egts and the scavenging effect that are results of the large internal section directly off the turbo as well and the gradual reductions in size....

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Recent post on the MK7/MQB Big Turbo FB page. Only change here is going from AWE catted to Trackslag catless. AWE has the cat further up in OEM location...similar to the IE catted I have on my R. Car is Vortex XL/MPI/UM Tuned. Black line = AWE/Orange = Trackslag
"Tom" = APT owner. "20 deg hotter" refers to Trackslag dyno day ambient vs when car was dyno'd w/ AWE
For me at high elevation in Colorado it's the quicker spool that has me intrigued with these things. My std Vortex hits peak boost at same rpm as sea level XLs (~3350)

EDIT - The Trackslag DP was the catted version. NOT catless as I stated in my original post
 
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daconchslop

Autocross Champion
Location
South Carolina
The spool is very noticeable in my car. Went from 3” catted to Catless TS. Best way I can describe it, spool feels like going from 93 to e85.
 

Maiden69

Go Kart Newbie
Location
Texas
Car(s)
2020 GTI
Going from a 3" catted (especially with the cat in the OEM location) to any cat-less will help spooling. Going from 3" to a 4"-3" tapered is optimal. Having the extra volume right after the turbine lessen the backpressure which helps moving the gasses out. If there were more space running a longer taper would benefit those running big turbos (anything bigger than the 45/47 size of the IS38), I don't think it would make much difference from IS20/IS38.
 

FB-GTI

New member
Location
MO
Car(s)
VW GTI -> Golf R
View attachment 217329
View attachment 217330

Recent post on the MK7/MQB Big Turbo FB page. Only change here is going from AWE catted to Trackslag catless. AWE has the cat further up in OEM location...similar to the IE catted I have on my R. Car is Vortex XL/MPI/UM Tuned. Black line = AWE/Orange = Trackslag
"Tom" = APT owner. "20 deg hotter" refers to Trackslag dyno day ambient vs when car was dyno'd w/ AWE
For me at high elevation in Colorado it's the quicker spool that has me intrigued with these things. My std Vortex hits peak boost at same rpm as sea level XLs (~3350)
Re: AWE has the cat further up in OEM location...

I've seen both of these DPs, the TS has a larger diameter cat and it is shorter. I suspect the dimensions of the cat plays a larger role in the differences noted than the location along the exhaust.
 

Maiden69

Go Kart Newbie
Location
Texas
Car(s)
2020 GTI
Recent post on the MK7/MQB Big Turbo FB page. Only change here is going from AWE catted to Trackslag catless. AWE has the cat further up in OEM location...similar to the IE catted I have on my R. Car is Vortex XL/MPI/UM Tuned. Black line = AWE/Orange = Trackslag
"Tom" = APT owner. "20 deg hotter" refers to Trackslag dyno day ambient vs when car was dyno'd w/ AWE
For me at high elevation in Colorado it's the quicker spool that has me intrigued with these things. My std Vortex hits peak boost at same rpm as sea level XLs (~3350)

Re: AWE has the cat further up in OEM location...

I've seen both of these DPs, the TS has a larger diameter cat and it is shorter. I suspect the dimensions of the cat plays a larger role in the differences noted than the location along the exhaust.
The TS downpipe used is catless..
 
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mk6'12gti

Drag Racing Champion
Location
Cleveland
The 4" dp is on and feels amazing my butt dyno feels a difference but it could just be placebo. Either way car feels better and spools quicker as well. Needless to say a 4" dp doesnt disappoint.
 

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FB-GTI

New member
Location
MO
Car(s)
VW GTI -> Golf R
The TS downpipe used is catless..
Not according to the post the owner made in the big turbo FB group.

"Shoutout to Tom, APTuning United Motorsport for taking great care of my car and getting it dialed in. At the start of May, APT installed Iroz MPI and LPFP, Vortex XL, ethanol sensor, APT 4 bar sensor kit, and custom fuel lines on my car. The black line from the dyno is with an AWE catted downpipe. The orange line is from this week switching to a Trackslag catted downpipe. The temps were in the 90s this week. APT also installed an AFR Autoworks HPFP cap to get rid of the barb fitting."
 
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