4” Downpipe 'bigboy' - Volkswagen Golf R MK7, MK7.5 / Audi S3 8V

Kobe Motorsport down-pipe (big-boy') offers a perfect base for serious Stage 3 hybrid turbos. Made from high temperature corrosion resistant 304 stainless steel not like some who claim high-grade SS but it's only lower grade of 201.
 
Our Down pipes features mandrel bends piping and TIG Welded and fully purge welded for a stronger weld. Most aftermarket down pipes are only 3” in size but the Kobe Motorsport features 4” reduced down to 3" after flex joint. All other 4" Down pipes on the market DO NOT feature upper bracket support which in turn adds load to other sections of the system and turbo, our DP features a support brace which has easy access for install.
 
Going 4" in diameter has been proven to increase RPM spool time to be 300-500rpm and thats based on 3.5 & 3" catted down-pipes -"check pictures for graph". It is important to note that ECU tuning is required to ensure that the engine runs and performs efficiently and to ensure that the CEL does not come on. We designed, developed and weld our first prototype of this system in house, like almost all of our products - Check them out.
 
Why not 4" the whole system?
Most Hybrid direct bolt on turbos (TTV5, EQT Vortex, Kobe G76) have a Turbine Flow rate of 20-25lbs/min. Those who run larger frame turbos like G35-1050 turbo could flow (35lbs/min turbine Flow) - Read On
 
Turbine Flow rates
Based on Garretts info - (Not to be confused with compressor flow)
EQT, TTV5, Kobe G76 (Approx.) - 20-25lbs/min = 300-350cfm
i.e G35-1050 - 35lbs/min =510cfm
 
Now according to mygolfmk7.com and their data on flow testing the Trackslag 4" Cat-less down pipe will flow 573CFM. But that does not include the rest of the exhaust. Their testing with a Trackslag DP Catted with stock cat-back (MK7 GTI) and the whole system only flows 222CFM....Thats right...!!! They also completed another flow test on a straight through cat-back exhaust with Y-pipe w/ Trackslag Catted and it flowed 388CFM.
Now unless you get your own cat-back flow tested you will never know what it flows. But we could assume ("hate using that word") that most aftermarket cat-backs for the MK7 Golf R would be probably somewhere in between these flow rates (222→388CFM) Lets say = 305CFM - Divide the difference
 
Approx. 305CFM - Aftermarket cat-back exhaust systems w/ Trackslag DP Catted
 
Now you can add approx. +144CFM due to our down-pipe being cat-less and similar design to other 4" down pipes (570CFM). So 300CFM + 144CFM = 444CFM.
 
Now...with all that data, as stated before most hybrid turbos for the MQB with turbine flow 300-330CFM so 444CFM is more than adequate for our 4" Cat-less Down pipe w/ our cat-back. So using a full 4" system unless G35 turbo or more is absolutely useless and by then you have to go custom made down-pipe and exhaust.
 
*Please remember that this data is based off 3rd party data, so please do your own research and findings.
 
https://mygolfmk7.com/2021/12/mk7-gti-stock-exhaust-flow-test/
https://mygolfmk7.com/mk7-gti-downpipe-testing/#4-1-test-environment
 
Thank you to mygolfmk7.com for the available data.
 
Why not go 3.5" for the lower section?
We want our customers to be able to option their exhaust with what they want. Going 3.5" doesn't allow alot of room/space for a high-flow 100cell cat which we offer as an added option. Most aftermarket 4" do not offer the option of hi-flow cat.
 
Fitment:
 
MK7 Volkswagen Golf R
MK7.5 Volkswagen Golf R
Audi S3 8V 2014-2020
 
Features:
 
304 Stainless Steel
4”→ 3” Exhaust System
Mandrel Bends
Increased Spool Time 300-500rpm
TIG Welded and Back Purged
Fits stock cat-back and most aftermarket cat-backs
1.6mm Wall Thickness
Billet CnC'd Stainless V-Band
High Quality exhaust clamps
Right side support bracket - Most aftermarket DP do not have this
Optional - 100 Cell Cat $350
 
 
** Please note - Going cat-less causes higher emissions to the environment. This product should be only used for off-road use and not for road legal use. Please check your local laws regarding this. By purchasing this product you are also agreeing to these conditions and hold no liability for your actions.