A4 Tubular Front Subframe

[b55240]

For the last few months I have been trying to source a front subframe for my car from VW and Audi and everything seems to be on international backorder with no availability. I tried to place 3 different orders and looked on Etka for cross part number availability and tried to order a few of those. I have been able to track down one part number which "may" work, but at this time, I am just frustrated with this entire thing and the stock subframe still has 3 issues that concern me.

1. Ground clearance. I am not driving that low, but I am tired of my subframe scraping over speed bumps.

2. Stock subframe suffers from poor welds and have several problems where they like to "shift" and cause a popping sound, especially in reverse. This can be addressed by seam welding, but this could lead to the subframe deforming since it is only stamped steel.

3. Stock subframe likes to rust. For me this isn't a huge issues since I live in Florida for the time being, but up north this is a major concern.

With all this in mind, I started researching and looking into the different options I had and the more I thought about it, the more I realized that a custom solution may be required. It would also work between platforms, so B5/6 A4, B5 S4, B5 and B5.5 Passat.

I have finally found a fabricator who is willing to make a tubular subframe for me. I dropped off the tubing for him this morning. He told me he is going to start fabricating the jig today and should be able to start bending all the piping this week. Stay tuned because there will be many more pictures to come!

In the meantime, this is the tubing I dropped off to him:



And if everything goes according to plans, this is what I will end up installing in the car:

Bottom:



Top:



I am actually going to set up the subframe to use the factory mounts just in case there is too much NHV with the 034 Motorsports solid inserts.

If you have any questions, please feel free to ask. I am bringing home the jig with me as well so if I would need to make a few more in the future, I can.

[Davdraco1]

How much did it cost for everything?

[Rodgman15]

That. Is. Awesome.

In for cost lol

[MarcRogers]

For the last few months I have been trying to source a front subframe for my car from VW and Audi and everything seems to be on international backorder with no availability. I tried to place 3 different orders and looked on Etka for cross part number availability and tried to order a few of those. I have been able to track down one part number which "may" work, but at this time, I am just frustrated with this entire thing and the stock subframe still has 3 issues that concern me.

1. Ground clearance. I am not driving that low, but I am tired of my subframe scraping over speed bumps.

2. Stock subframe suffers from poor welds and have several problems where they like to "shift" and cause a popping sound, especially in reverse. This can be addressed by seam welding, but this could lead to the subframe deforming since it is only stamped steel.

3. Stock subframe likes to rust. For me this isn't a huge issues since I live in Florida for the time being, but up north this is a major concern.

With all this in mind, I started researching and looking into the different options I had and the more I thought about it, the more I realized that a custom solution may be required. It would also work between platforms, so B5/6 A4, B5 S4, B5 and B5.5 Passat.

I have finally found a fabricator who is willing to make a tubular subframe for me. I dropped off the tubing for him this morning. He told me he is going to start fabricating the jig today and should be able to start bending all the piping this week. Stay tuned because there will be many more pictures to come!

In the meantime, this is the tubing I dropped off to him:



And if everything goes according to plans, this is what I will end up installing in the car:

Bottom:



Top:



I am actually going to set up the subframe to use the factory mounts just in case there is too much NHV with the 034 Motorsports solid inserts.

If you have any questions, please feel free to ask. I am bringing home the jig with me as well so if I would need to make a few more in the future, I can.

Oh man. This is just more reason to keep my b5. How much was this? What type of tubing did u use? I want one of these like yesterday!


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[b55240]

I have actually been thinking of getting a small batch made since I will already have the jig. I have a feeling total cost will be around 1200-1600 once everything is powder coated. I have been keeping track of the costs so far.

The tubing is 1.75" x .120 DOM tubing which is the same tubing dimensions as they use in roll cages. I will be using .5" steel for the suspension pickup points. In the end, it should be significantly stronger than stock, resist rust, and just about break even as far as weight goes. I will be weighing it once it is completed to get an exact weight.

I am actually extremely excited because I never thought my car would be getting this much attention. I have quite a bit more done on my build thread and if anyone has any ideas that I have overlooked, I would love to hear them!

[Turbo_B5]

Make sure you make it have enough room for a v8.


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[Bordom]

Make sure you make it have enough room for a v8.


Sent from my Jailbroken iPhone 6s iOS9.3.3 using Tapashit

What he said x99999999

Everything graciously mispelled by Android

[mysman]

You should add camber/castor adjustment for the LCAs.

[walky_talky20]

How about the ability to easily drop the oil pan for oil pickup tube clean-out service?

Sidenote: I understand the "want" for one of these. It looks pretty awesome. But, especially in Florida, there should be no reason to approach a dealer for a subframe. These are highly available in junkyards across the country. The ones on the East coast (south of Maryland or so) should be cherry. They are not very specific - just 2 types: 1.8T 5-speed, and...the rest of them. I'm not trying to rain on your parade here, just want to point out to the forum readership that clean replacement subframe availability really is non-issue for the most part. Do carry on, though.

[b55240]

I have been toying with the idea to make adjustable lowers arms, but for the time being, I am thinking of using the concept that the RS6 uses with two bolt hole locations to widen the front track. The mounting points will definitely be strong enough and I could simply make a spacer for the front axles. This tubular subframe would open a few options and space on the underside of the vehicle. Once I get the car back, I will be looking at the clearance for the oil pan as well since that front tube wouldn't be hard to notch or create a bit more clearance.

I have searched a few junkyards in Orlando and Jacksonville and 90% of cars are automatic which use different mounting locations for the transmission. Seeing as I have a B5.5 Passat which is FWD and manual, it quickly becomes very hard to find a subframe. You then run into the issue that it can be scraped and rusted since the subframe does sit so low. I would also not have to weld the subframe to prevent the "shifting" issue that some cars experience.

This just seems like a cost effective solution since a new subframe is about 1k and this will run me about 1200-1600 once I have it all powder coated and installed back in the car. Check out my build thread in my signature to see the other little things I have done to the car in the meantime and this solution will start making much more sense.

[Turbo_B5]

I have been toying with the idea to make adjustable lowers arms, but for the time being, I am thinking of using the concept that the RS6 uses with two bolt hole locations to widen the front track. The mounting points will definitely be strong enough and I could simply make a spacer for the front axles. This tubular subframe would open a few options and space on the underside of the vehicle. Once I get the car back, I will be looking at the clearance for the oil pan as well since that front tube wouldn't be hard to notch or create a bit more clearance.

I have searched a few junkyards in Orlando and Jacksonville and 90% of cars are automatic which use different mounting locations for the transmission. Seeing as I have a B5.5 Passat which is FWD and manual, it quickly becomes very hard to find a subframe. You then run into the issue that it can be scraped and rusted since the subframe does sit so low. I would also not have to weld the subframe to prevent the "shifting" issue that some cars experience.

This just seems like a cost effective solution since a new subframe is about 1k and this will run me about 1200-1600 once I have it all powder coated and installed back in the car. Check out my build thread in my signature to see the other little things I have done to the car in the meantime and this solution will start making much more sense.

just make sure its made with room for a v8.

[A1 A2 German]

California Jay is making these too, already placed an order or we'd be talking. Sub'd for results.

[Turbo_B5]

California Jay is making these too, already placed an order or we'd be talking. Sub'd for results.

I hope it fits a v8.

[tar]

Make sure you make it have enough room for a v8.


Sent from my Jailbroken iPhone 6s iOS9.3.3 using Tapashit

just make sure its made with room for a v8.

I hope it fits a v8.

Just stop

[mysman]

You should also add a brace to box off the "C".

[DoesntCare]

The completed subframe he pictured was actually built with a V8 swap in mind.

Here is the build thread for that subframe

[b55240]

I couldn't find anyone else that was producing a solution for this. That's why I took on the project to begin with. Adding a removable brace would be a good idea, but I have to wait and make sure I have room to fit it without clearance issues from the transmission.

[A1 A2 German]

Funny, those pictures looked familiar.

I'd been contacting TinyTim (the designer and the first known maker of a tumblr subframe I know of) since ~2014 to produce me one. Unfortunately he become very tied up with real life and was unable to make me one.

If you're going to make these you should incorporate tabs/bungs for a skid plate, and if going to sell them have all models with atleast the tabs/bungs for a skid plate to be added.

You should make plates that go up to an oem bumper...
With an additional "clip on" piece to fill the void for the people using the Rs4 bumper...almost like a large shim for $25 more that fills the air void created by an Rs4 bumper sitting more forward then an oem. If you're into B5's, you're either oem or Rs4 so it's a given.

It would be very easy to add a NACA duct like this http://secure.chassisshop.com/partlist/6016/ to each side of the skid plate on the underside facing up.

Now that allows the user to run dryer tube to the disks, or even run the line up 2' to feed fresh air (however best suited for cooling off the disks).

Do it, do it!

And definitely do a lower brace ( bolt on and off to remove trans, etc) that's adjustable 100% exactly like a strut tower brace. The brace would run from rear subframe bushing to other rear subframe bushing and have a center threaded stud with jam nuts to tighten/losen. And in this case, would possibly want to consider using flat/boxed tube as not to impede ground clearance.

I mean shit, 1 or 2 extra days of monkeying around, you can have an epic subframe. Make the rear brace and skidplate "add on features" but really would be nice that all come with it.

[A1 A2 German]

I just weighted by subframe.

Completely stripped of all hardware and fastners, however with subframe bushings pressed in:

33 pounds

A couple bushings fell apart once removed from the car, but mostly intact so within ~1/2 pound at most (weights 33.5lbs at most).

[b55240]

I have actually been thinking of making a skid plate, but I have to get the subframe first. I was thinking of drilling in holes and inserting a rivnut or something along those lines on the first one to see where I could place mounts. The problem comes in that I have a B5.5 Passat, so I would need to figure out how to come up with a solution that could work. I have actually thought about getting a OEM belly pan and using that as a starting point for the skid plate on the A4, S4, and then possibly the RS4. Once I get the subframe back, I will be looking into this since it is an excellent idea! Protects our motors since they are already pretty exposed to begin with.

There are two other projects I am planning in starting as well, but all that comes down to is time and I want to see the ability my welder has. I want to make a tubular front structure to get rid of the heavy stock plastic and bumper bar. This way I can actually use a universal radiator since there really are no options to go to an aluminum core. The next is a rear diffuser which I am going to probably mould out of alumilite to begin with and then produce from abs plastic or something along those lines.

I spoke to my welder today and he told me he was finishing gathering a few more materials and has started working on the jig. So hopefully I will have progress pictures slowly start coming in from him.

[RENOxDECEPTION]

sub'd