Downpipe What's the best brand ?

[Reggie Enchilada]

is that the one you're running? Pics?

I had one one my 2016 and I'll be getting one for my 19 shortly. This is a comparison of the old version vs.the stock DP. There's a couple of differences for the new version that include a longer cast section which goes to the flex section, different bend geometry for fitment on the MK7.5 with the larger ABS pump heat shield, and a bracket that bolts to the block. The cast section on the old and new is 3.5" in diameter which tapers to 3" for the rest of it. Every weld on it was flawless, I really can't say enough about how nice they are. The catless ones go for about $650. Emmanuele Design used to stock the catless ones, but I had to special order the new one since they don't sell many catless ones. Going to be a bit of a wait since it has to come from Germany during this pandemic.

 

[El_bigote_AJ]

Bumping this...

So I switched out a 3” with high flow cat for the beefy trackslag (catless) unit and couldn’t be happier! The fit is great especially considering it’s size, it sounds much deeper and aggressive with my XR1 mufflers - and it really helped my hybrid spool up and hit the set point much much sooner. I’m sure some of that can be contributed to being catless...

These shots from the logs for comparison also have very close ambient and IATs... zero tune adjustments and same fueling at e48ish also in the upper RPM range the wastegate duty’s down about 8-10% across the board. Having that extra spool also makes the car feel (and tires cry) much quicker.

Btw Old dp the boost was at 18-20psi when at 3600

Top 2 are the old DP bottom is from 2 nights ago.

 

[jimlloyd40]

The thing I don't understand about this DP is since it still reduces to 3" at the exhaust connection how it makes it spool sooner? The simplest example I can use is if it's a waterline that's bigger in the beginning but it tapers down in size it will still come out the end of the pipe at the same flow rate. Based on the quicker spool I want to order it but I can't understand it. I guess based @El_bigote_AJ log above I believe it I just don't understand it.

 

[El_bigote_AJ]

The thing I don't understand about this DP is since it still reduces to 3" at the exhaust connection how it makes it spool sooner? The simplest example I can use is if it's a waterline that's bigger in the beginning but it tapers down in size it will still come out the end of the pipe at the same flow rate. Based on the quicker spool I want to order it but I can't understand it. I guess based @El_bigote_AJ log above I believe it I just don't understand it.

yeah, i don't know if its really related to flow for making it spool sooner, cause not only is it tapering to 3" but at the vband we even taper it to 2.5" and my hybrid38 is still getting to 28 at 3600 with a potentially restrictive FMIC also.

its my understanding that the larger section right off the turbo having so much volume right away is allowing the exhaust gas to expand and lower the egts which is helping the spool.

my results could also be extreme cause i went from catted to catless also - but i do have a friend from catless 3" to catless trackslag and he gained 300-400 rpms on spool of his UM tuned vortex xl car.

 

[jimlloyd40]

yeah, i don't know if its really related to flow for making it spool sooner, cause not only is it tapering to 3" but at the vband we even taper it to 2.5" and my hybrid38 is still getting to 28 at 3600 with a potentially restrictive FMIC also.

its my understanding that the larger section right off the turbo having so much volume right away is allowing the exhaust gas to expand and lower the egts which is helping the spool.

my results could also be extreme cause i went from catted to catless also - but i do have a friend from catless 3" to catless trackslag and he gained 300-400 rpms on spool of his UM tuned vortex xl car.

Thanks for that. I'm getting closer to ordering it. The one thing my TPC20 needs is to be able to spool sooner.
I kind of wanted to get the Cat version because I'm tired of smelling my catless DP but that might negate the earlier spool.

 

[GTI Jake]

Thanks for that. I'm getting closer to ordering it. The one thing my TPC20 needs is to be able to spool sooner.
I kind of wanted to get the Cat version because I'm tired of smelling my catless DP but that might negate the earlier spool.

Not all cats are created equally, so it depends on what you get.

 

[JerseyDrew77]

Thanks for that. I'm getting closer to ordering it. The one thing my TPC20 needs is to be able to spool sooner.
I kind of wanted to get the Cat version because I'm tired of smelling my catless DP but that might negate the earlier spool.

As El_bigote_AJ pointed out, the bigger open area that is created in that 4 inch 180 turn is what helps the turbo spool faster because it's now able to push out the exhaust gas faster.

 

[jimlloyd40]

As El_bigote_AJ pointed out, the bigger open area that is created in that 4 inch 180 turn is what helps the turbo spool faster because it's now able to push out the exhaust gas faster.

I'll take your word for it. And his.

 

[PowerDemon]

Not all cats are created equally, so it depends on what you get.

Is GESI the way to go or do you have another preference for premo cats? 1-200 cell?

 

[daconchslop]

its my understanding that the larger section right off the turbo having so much volume right away is allowing the exhaust gas to expand and lower the egts which is helping the spool.

This.

 

[GTI Jake]

Is GESI the way to go or do you have another preference for premo cats? 1-200 cell?

GESI actually has Gen1 300 & Gen2 400 cell cats, different rating and pricing to fit any budget and flow appropriate for 350-550hp as well as models for 550-850hp (larger OD body).

100-200 cell cats are generally so cheaply made that actually flow significantly worse than 300-400 cell good quality cats. Those 100-200 cell are more “fake it” than actually controlled emissions/smell.

Nothing I’d use for Mk7, but GESI makes Gen2 cats rated for 1,200hp per cat so don’t kid yourself about headroom there’s plenty to be had for any application.

HJS makes great quality, but far less common in the USA. The guys in Europe get most of ‘em

 

[Subliminal]

$400 for a cat tho

 

[GTI Jake]

$400 for a cat tho

Good isn’t cheap, and cheap isn’t good.

 

[El_bigote_AJ]

Good isn’t cheap, and cheap isn’t good.

Yup.

The one trackslag offers is a $520 upcharge, so at that point I figured I would just wait and get a gen2 GESI welded in when available.

 

[riceburner]

im selling an awe catted dp if anyones looking