How to retro-fit the front brake air guides from the Audi RS3 (2017->)

[golfdave]

Disclaimer:- This info is for community usage. I am NOT affiliated to, or sponsored by, any company/individual to promote them or their products. Companies/individuals may NOT use my name, photos, or threads/technical guides, for financial or personal gain (fraudulent misrepresentation).

Part 1 of 3
Vehicle used in this guide
UK spec, 2014yr model, Mk7 Golf Estate (GSW), GT (Highline) trim, 1.4lt TSI (140PS) CHPA petrol engine, MQ250 6speed manual gearbox, multilink rear suspension, & with retro-fitted 312mm front brake discs as per the DCC option for this car, & as per the GTI/GTD/GTE.

Vehicles that this guide is applicable to
Any VAG (Audi/Seat/Skoda/VW) "MQB" platform cars with the pressed steel lower front wishbones.

Introduction
There are “air deflectors” fitted to many small VAG cars to increase air flow to the front discs. In these cases the wheel rims & wheel arches are small that they virtually encase the brakes & restrict the air flow to them. So VAG fit air deflectors/guides to the fronts of the wishbones. However, on the bigger cars there is supposed to be enough room to allow the air flow to naturally cool the brakes down. Unfortunately, I & many others have found that on long (enthusiastic) drives over twisty roads, or track use that the cooling is not adequate!

Research
Originally, I used the items from the older PQ35 (A5) platform, Audi TT-RS (2010-2014yr) & Audi RS3 (2011-2013yr) & did a “How to guide”. These items were made to work with the Audi cast alloy wishbones & bigger brakes (370x32mm discs with 4 pot calipers). However, these items interfered with my smaller (312mm disc) brake callipers when you turned the wheel inwards as my callipers are closer to the wishbone & pivot point due to the smaller brake disc diameter. Also as the VW Mk7 Golf has pressed sheet steel wishbones, serious modifications to these air guide/flaps were required to solve both issues & different fixings were needed instead of the original Audi fixings!

I also noticed that they created more aero drag due to them hanging below the wishbone. There is a long steep 70mph limit hill near me which I used to have to ride the brakes on, before I fitted the Audi TT-RS air guides. With those air guides fitted I noticed that I no longer had to do this & the car would sit at a steady indicated 70-75mph, as more aero drag is created! So I was always on the lookout for a more aerodynamic solution to the problem!

In November 2017 I noticed a post by forum member "Wide" from Sweden here:-
Movie: *Testing* Brake cooling on the GTI Facelift (same on the MK7) | GOLFMK7 - VW GTI MKVII Forum / VW Golf R Forum / VW Golf MKVII Forum
In which he states,
QUOTE:-
“tested a set of brake cooling from Stertman Motorsport. These are for most of MQB cars”. – “Stertman has only webbpage in Swedish unfortunately..I don´t know were the part is from, it is a little secret...”.
END QUOTE

So no info, nothing about “made by Audi for RS3” etc! With the nice smaller NACA style duct I considered this a possible solution, but with the three cable ties used as attachments I thought it was not “official”.

It was not until I saw those same items appear in this thread here:-
RS3 Brake Deflectors | GOLFMK7 - VW GTI MKVII Forum / VW Golf R Forum / VW Golf MKVII Forum
started by forum member “drrck” that I took note, as now they had correct info including genuine Audi part numbers!

Parts required
VAG ETKA illustration for Audi RS3/2017/Front Axle, Steering/No.407-000

Parts list & approx. costs in UK £
Item No.20:- 8V0 407 811, Air Duct left side, £11.58 (x1)
Item No.20:- 8V0 407 812, Air Duct right side, £11.58 (x1)

Each item above includes three cable ties which are also listed as spares separately below.

Item No. 21:- N108 219 01, cable tie, 7.6mm x 375mm.
These are Hellermann Tyton T120ROS, "outside serrated" series, actual size is 7.6mm x 385mm. Made from PA66HS (Heat stabilised Polyamide 6.6) temp range of -40C to +105C, breaking strength of 535N (54.53kg).

However, I did NOT use these OEM cable ties, instead I used 9mm wide versions as they fit better (see "Further considerations on fitting").

Misc. info:-
Unsprung weights:-
These MQB platform Audi RS3 air guides:- total weight of 0.25kg for both sides inc. all cable ties
Previous PQ35 (A5) platform Audi TT-RS/ Audi RS3 air guides:- total weight of 0.48kg for both sides as modified with stainless steel bolts/washers & plastic spacers.

 

[golfdave]

Part 2 of 3
Fitting
Firstly, it is best to be able to jack up & have the whole front end of the car in the air & supported by either axle stands, or in my case two 3ton professional trolley jacks! however, it can be done using one jack & doing one wheel at a time! Slacken off the respective wheel bolts whilst the car is on the ground, then jack up & fully remove the wheel bolts & wheel. This will give you better access for fitting of the air guide. Clean the wishbone so not to trap dirt etc between the mounting surfaces.

Now in the linked to threads above, the OP has just cable tied the items in place & has not thoroughly looked at the fitment as they DO NOT fit perfectly 100%!!

Modifications to Duct/Flap to allow for the pressed sheet metal wishbone/arm:-
Because this is made for the MQB platform Audi RS3, which has a slightly different pressed steel wishbone/arm, there is a difference in the spacing of the locating lugs on the air guide/flap. You have to completely remove the rear leg nearest the engine & shave flat the bit on the plate & shave the rear middle leg down & put a concave (curved inwards) shape with a half round file, to the inside instead of a straight cut. You can't just remove the rear middle leg as it needs the guides for the cable ties, & then wet & dry fine sandpaper smooth the cut edges for a factory finish. I noticed that after initially fitting them without any modification, that I had already stress cracked the plastic legs & that was after only 10 days!!

The Clubsport (CS/CCS), TCR, Mk7.5 R, & various other late top model (2017yr->) Mk7.5 Golf's all appear to be fitted with this newer "Audi" arm from the RS3. The main reason being it has an almost solid (stiffer) rear bush with no voids, therefore NO trimming is required of the Audi RS3 air duct to fit it to the wishbone. However.....

Modifications to Duct/Flap to allow for the calipers being closer when on full lock due to smaller disc size:-
These items are designed to work with the 370mm x 34mm big discs & 8 piston monoblock callipers for the 2017-> (FL), Audi RS3. People have said they fit their cars ok, but those people have the bigger 340mm R/PP/CSS brakes which move the calliper further away from the pivot point (I also doubt on full lock with full suspension extension that they won't hit the duct, just they haven't looked properly). However, these items interfered with my smaller brake callipers when you turn the wheel inwards as these callipers are closer to the wishbone & pivot point due to the smaller disc diameter. I have the GTI/GTD 312mm brakes & found that on 2/3 lock each side with the wheels off the ground that the brake calliper hits the duct! So, I had to trim the top section as shown. With the wheels on the ground the ducts as purchased (unmodified) only interfered with between 3/4 & full steering lock. However, I prefer to have no restriction throughout the full range of suspension & steering movements.!!

If you have different callipers you will have to modify to suit! But they are NOT a 100% perfect fit for all Mk7 Golfs as some sellers are stating!!

Position the duct flat plate section which is on the wishbone, so it just touches the outer ring of a dimple in the wishbone for the ball joint plate. When you fit the duct, fit the cables ties loosely, & you will find there is a sweet spot with about 5mm of variation in which the duct fits perfectly on the wishbone. I placed mine to get the middle cable tie on the thicker section of the wishbone.

Modifications to Duct/Flap to allow for the SuperPro aluminum wishbone/arm:-
If you have fitted the SuperPro aluminium arms, the ducts need to be modified slightly differently. Forum member "tigeo" has written a "how to " guide here:-
https://www.golfmk7.com/forums/inde...e-ducts-to-fit-superpro-aluminum-lcas.406335/

Further considerations on fitting
I used black 9mm wide cable ties (Nylon 66, -35C to +85C, 79.37kg breaking strength) which fully fill the channels & are stronger!! The temperature range is not as high (+85C vs +105C) as the OEM cable ties, but even with my brakes very hot I doubt that even the closest cable tie will feel a temperature greater than 85C!!

Place the cable tie head at the front, on the underside facing the road & the tail should exit the head pointing straight down at the road. This makes cutting the surplus off easier as the duct is not in the way if you fit as per Audi with the head & tail facing towards the front of the car, & then tighten up. Basically, you do not want to over tighten & crack the plastic. Cut the surplus off FLUSH with the head, as per the standards & manufacturers of cable ties state!

 

[golfdave]

Part 3 of 3
Results
Does it work? Yes It does!! My alloys are dirtier now where the brakes vent out from their leading edge, but the brake discs are much cooler! Compared to the previous older Audi TT-RS versions these have a smaller frontal area, so less aero drag, with an actual duct shape to trap & guide a smaller amount of air efficiently to the inner part of the rear face of the brake disc where the internal disc vanes are. I have also noticed the car carries on a lot further when you lift off the throttle at say 60mph!

EDIT:- September 2018
In August 2018 forum member "Chillout" posted in this very thread:-
How to retro-fit the front brake air guides from the Audi RS3 (2017->) | Page 3 | GOLFMK7 - VW GTI MKVII Forum / VW Golf R Forum / VW Golf MKVII Forum
Linking to a post dated 13th August 2018 on the "drive2.com" Russian forum here:-
Дефлекторы тормозов — SEAT Leon FR, 1.8 liter, 2013 year on DRIVE2
This post by a Seat owner "Vivacuba" who fitted these same newer Audi RS3 (2017->) items, & included a photo of brake discs taken with a thermal imaging camera with temperature readouts, as a before & after fitment of the air guides, & showing a reduction of 12 to 24% in pad/disc temperatures with the air guides!

However that thermal imaging picture of the before & after heat measurements is not "Vivacuba"'s, & is not of the Audi RS3 air guides! Instead it is of a similarly designed homemade 3D printed solution from a thread dated 25th August 2017 posted by forum member "Phenyl85" on the Audi-Sport.net forum here:-
Solution for RS3 brake problems | Audi-Sport.net

QUOTE:-
Dear fellow RS drivers,
A lot of you unfortunately experience problems with the brakes on your RS (especially the RS3 8V).
Despite Audi’s efforts to fix this problem they haven’t managed to do so. For that reason Luc and I started developing a solution ourselves. And we are happy to tell you the agony is finally over! After a period of extensive testing, fitting, reshaping and optimization there finally is a solution for the (thermal) brake problems.

Fitment
The developed set is available for the Audi RS3 (8V, 8V.2, 8P) and the TTRS (8S and 8J).

Development
We have been testing for a year in real life with multiple prototypes. Last week the finished air deflectors were tested on a dyno with road wind simulation to thermally validate this kit on a real RS. The results were above any expectations. A difference of 24-28% in disc temperature has been measured for multiple times.

Test procedure
We have been heating the brakes up for multiple times to peak temperatures: 290- 400C. Then the brakes were left to cool with road wind simulation for 30sec @ 100km/h (1 side with air deflector, and the other side without any cooling; such as the RS3 8V and 8V.2, they have no air deflector whatsoever). Did some more testing today on the grossglockner in Austria together with an Audi RS3 8V. With cooling the discs were 41C and the RS3 8V without cooling were 119C. After 20km's of downhill from the Grossglockner the temperature with cooling was 143C and without cooling >250C.

Specifications
The deflectors are 3 dimensionally aero optimized in AutoCAD. They are being 3D printed out of PETG which is heat-, water-, salt- and road grime resistant. The set is tested up to >300km/h.
END QUOTE

It appears that Audi saw the above parts that "Phenyl85" was making & then decided to make their own version which came out on the newer facelift RS3 (2017->) versions later that same year!

EDIT September 2023yr:-
Apex Nurburg (Misha Charoudin). This video (dated February 2023yr) on preparing their VW MK7 Golf GTI-PP, at the 4:19 mark they talk about using these same RS3 parts & have noticed an improvement in brake cooling!!

Conclusions
At least this time Audi actually designed a proper part compared to the previous items for the TT-RS! The strange part is why they designed it with wide channels for the cable ties & used narrower cable ties?! Maybe the engineers designed it for the wider cable ties, but when the bean counters had to sign it off they told the engineers to use narrower cable ties to save money??!!

 

[Chillout]

Great tutorial!

 

[TecklenburgVW]

Thank you; still waiting on my order to be sourced. The online retailer indicated that Audi was a bit hesitant releasing the part for purchase.

Sent from my SM-G920V using Tapatalk

 

[drrck]

Much better pics than I managed. Excellent write-up! I'll check mine for rubbing when I do my brake fluid bleeding this weekend.

 

[golfdave]

Much better pics than I managed. Excellent write-up! I'll check mine for rubbing when I do my brake fluid bleeding this weekend.

I recon they will rub at full lock & full suspension drop/extension as even with your "PP" brakes at 340mm they are smaller than the 370mm so push the calliper closer to the brake duct. Then you also have the fact that our callipers are single piston, so the majority of the calliper is on the rear side of the disc, so closer to the duct compared to the monoblocks. Then you have the steel arm which is wider across the top for the middle & innermost cable tie points.

Quite a bit of modification to get the ducts to fit to our cars as well as the item fits in its original place on an Audi RS3!

Too much bad info out there & sellers saying "fits MQB Golf, easy cable /zip ties included". Also a few people who have fitting the part & not noticed any of the bad fitment issues as they are not as thorough like I am!

I am more concerned because if you have an inspection etc. (in UK we have MOT each year for cars over 3yrs old) & they see a cable tied part to the wishbones (alarm bells may ring) with the car in the air on a two post lift (so wheels at full drop), & that the brake callipers hit the this duct which stops you from getting full steering lock....FAIL!!

 

[Whackamac]

Nice write-up. I just ordered a set! Can't wait until they get here!

 

[7umberjackZac]

I recon they will rub at full lock & full suspension drop/extension as even with your "PP" brakes at 340mm they are smaller than the 370mm so push the calliper closer to the brake duct. Then you also have the fact that our callipers are single piston, so the majority of the calliper is on the rear side of the disc, so closer to the duct compared to the monoblocks. Then you have the steel arm which is wider across the top for the middle & innermost cable tie points.

Quite a bit of modification to get the ducts to fit to our cars as well as the item fits in its original place on an Audi RS3!

Too much bad info out there & sellers saying "fits MQB Golf, easy cable /zip ties included". Also a few people who have fitting the part & not noticed any of the bad fitment issues as they are not as thorough like I am!

I am more concerned because if you have an inspection etc. (in UK we have MOT each year for cars over 3yrs old) & they see a cable tied part to the wishbones (alarm bells may ring) with the car in the air on a two post lift (so wheels at full drop), & that the brake callipers hit the this duct which stops you from getting full steering lock....FAIL!!

Sounds like a personal problem. Ordered for way less than the dealer. Good god. $52 each. E-acca!

Sent from my SM-G935V using Tapatalk

 

[golfdave]

Sounds like a personal problem. Ordered for way less than the dealer. Good god. $52 each. E-acca!

Sent from my SM-G935V using Tapatalk

you have to modify for the pressed steel wishbone as they were not made for them...they just fit without modification, but you end up with a stress fracture in the plastic base...I know that's what I did...

Then you have to modify if necessary because of the brake caliper size & disc spacing...I have GTi 312mm discs & standard VW sports suspension -15mm...so had to modify again for that..

& my Audi Dealer charged £23.16 for the pair...standard price.

 

[White18]

Modified as shown, will these ducts fit a Mk7.5 GTI Autobahn with the DCC levers that attach to the wishbone?

 

[golfdave]

Modified as shown, will these ducts fit a Mk7.5 GTI Autobahn with the DCC levers that attach to the wishbone?

Should do as there are cut out in the plate for the DCC levers...as the Audi has these also...

What size brake are you running? 312mm or 340mm?

 

[White18]

Should do as there are cut out in the plate for the DCC levers...as the Audi has these also...

What size brake are you running? 312mm or 340mm?

I'm new to all this VW stuff. It is a 2018 GTI Autobahn w/DSG. Does that narrow it down? I think 312mm.

 

[DAS_STIG]

I'm new to all this VW stuff. It is a 2018 GTI Autobahn w/DSG. Does that narrow it down? I think 312mm.

I thought the newer ones (including 7.5) automatically had the PP brakes with the SE and Autobahn models? Do your front brake calipers have "GTI" in white letters on them? If so you have the 340 mm brakes and most likely will not have to modify the air guides as OP described.

 

[White18]

I thought the newer ones (including 7.5) automatically had the PP brakes with the SE and Autobahn models? Do your front brake calipers have "GTI" in white letters on them? If so you have the 340 mm brakes and most likely will not have to modify the air guides as OP described.

The red calipers have "GTI" in silver edged in a darker color. does this photo with my 18" wheels help?