Home / Product Reviews / B7 Audi S4 Carbon Fiber Hood (Vented) by Aerofunction

 

Audi S4 - Carbon Fiber Hood

This is a review of the Aerofunction B7 AF-1 Hood in carbon fiber which can be found & purchased from Aerofunction directly. Email them at info@aerofunction.com to place an order…alternatively, it’s available on Amazon here for $879 plus shipping.

I had been looking for a carbon fiber hood for my Audi S4 (and my A4 before it) for quite some time until I found a link to this hood posted on Audizine when I was up browsing late one night. Previously, the only manufacturer who made a vented hood for the B7 Audi platform (2005.5-2008 A4s, S4s, and RS4s) was Vorsteiner, and that hood had been discontinued well over a year ago. When I heard about this hood I was thrilled, and I contacted Aerofunction immediately. Aerofunction explained to me their fitment guarantee and three year warranty on all parts, and assured me if I wasn’t happy I could ship it back and get a full refund. The price seemed very fair, so I went ahead and made the purchase. I couldn’t find any firsthand reviews of the hood before buying it, so I took a ton of pictures (and even a video!) to show just how nice it looks. I’m really excited to be one of the first people to buy this hood and share pictures of it, and I have a feeling a lot more Audi owners will be buying this soon as it’s a really good product at a really fair price, and offers both performance & aesthetic benefits…

Audi S4 Carbon Fiber Hood by Aerofunction

The hood offers great looks, OEM-like fitment, and the vents can be drilled/cut-out to be functional. When you order the hood, you can choose either fiberglass or carbon fiber. The carbon fiber doesn’t offer a ton of weight savings over fiberglass (which is also very light), but I thought it was well worth the extra price for the carbon fiber version to match my other carbon accents (like my interior trim and B & C pillars). The hood comes from Aerofunction without the vents cut-out so that if you do not wish to have them functional you don’t have to (some people worry that water may get into the engine bay). I indeed wanted the vents cutout, but luckily I have a great body shop, Phoenix Collision & Custom Paint, to help me with that. My hood came within a few days of me placing the order and I had it shipped directly to my body shop so they could paint it.

Audi S4 Carbon Fiber Hood

The only downside to the hood is that if you want to cut-out the vents to make them functional, it will take your body shop some extra time and expense to do so. My shop told me it took about 10-15 hours to complete the hood, which included time to paint and install it as well, although most of that time was spent cutting & filing each vent to make sure they were cut-out perfectly. It was time well spent, and I’m really happy with the paint scheme we chose that exposes some carbon fiber but not too much and blends nicely with the rest of the car’s carbon fiber accents. My body shop said that the hood fit very well and didn’t need any major adjustments or anything like that – they reused the stock hood latch and used a small shim underneath the latch to make it fit absolutely perfect. You can see the fitment really well in the video below – I am very impressed with how it lines up with the body lines, I have seen a lot of carbon fiber hoods in my days and very few fit this well:

The Aerofunction website advises you to use hoodpins. When we first installed the hood, I was seeing the hood lift and move at high speeds (80 mph) more than I liked. We had cut out all of the vents to be functional, and our theory was that the top layer and bottom layer of the hood was separating at high speeds due to the air pressure. We decided to take the hood off and fill any gaps between the top & bottom layers by injecting an expanding foam into it. The foam may have also added 2-3 lbs, but the hood felt a lot more solid and best of all, no lifting or movement at high speeds (I’ve tested it up to 100 mph so far). I feel pretty confident without hoodpins, so the plan is to run without them permanently. Here is a picture of the underside of the hood after we injected foam and painted the underside black:

2012-12-11 15.39.49

The only other modification we made was to remove the factory hood strut, as I worry it is too strong and may crack the hood. It is pretty common advice to do this on carbon fiber hoods as the OEM hood struts are intended to raise something that weighs 5x as much and therefore may be exerting too much force for such a lightweight object. To replace it, you can either buy an RS4 hood strut (the RS4 has an aluminum hood so the strut is softer) or buy an aftermarket hood prop like this one I ordered on Amazon. While I’m waiting for the hood prop to come in, I’ve found that a Swiffer broom/stick does a pretty good job as a temporary measure.

Carbon Fiber Hood Vents - B7 Audi S4

I originally meant to try to do some data logging and find the before & after of the intake temperatures with the hood installed. I never got around to that prior to having this installed, but you can feel hot air venting out of the engine bay from the two side vents, and given the placement of the middle “scoop” I would imagine that is also helping keep things cool. I think it definitely offers performance advantages in terms of airflow, and weighs about 50 lbs less than a stock hood (the stock hood weighs in around 70 lbs for reference, and this hood is about 15 lbs) so the weight savings is very nice, especially in a front heavy car like the V8 powered S4. The hood is designed to have a cover underneath the vents to collect any rain or condensation which is great so that you don’t have to worry about taking your car through a car wash or rain storm and having too much water come in contact with the engine through those vents – it’s already taken care of…

B7 Audi S4 - Top View

I have quite a few more  pictures that I’ve taken, and I’ve got to say I’m very pleased with the hood from every angle. It did exactly what I wanted it to from an aesthetic standpoint – wake it up, give it a little contrast, and make it appear more aggressive without being too over the top – and the functional benefits of it are great too. I’d definitely recommend both the hood and Aerofunction if you’re in the market!

B7 Audi S4 with BBS Wheels and Carbon Fiber Hood

You can check out the rest of the pictures below:

 

About the author: Nick Roshon

 

Nick Roshon is a blogger who is passionate about Audis and European cars in general. He owns a 2006 S4 and before that had a 2006 A4. His driving experience includes numerous track days throughout California, Nevada and Arizona. In his day job, Nick is a digital marketer and lives in San Diego, CA, USA.

 

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13 Comments

  1. Great looking hood! any pics from under the hood?

  2. Thanks! I have one picture of the underside here – it’s not the best photo, but you get the idea: http://nickscarblog.com/wp-content/uploads/2012/12/2012-12-04-13.26.59.jpg

  3. Hey Nick,

    FYI – your Flickr button/link under the “Follow Me” section of your page is a dead link.

  4. Thanks, I’ll fix that now! I appreciate it!

  5. What did you inject in between the two layers? Something automotive specific or something like Greatstuff minimal expanding foam?

  6. Debating between this and euroGEAR CF hood, what would you say be the major differences between the two nick?

  7. Great question – I’ve had both, so I feel pretty well equipped to answer.

    Obviously the biggest difference is that one has vents, the other doesn’t. When I had the Eurogear hood, it lifted at high speeds and definitely needed hoodpins. IMO it felt flimsy – it was didn’t have much reinforcement along the underside of the hood, so the air getting underneath the hood was lifting it quite a bit. The Eurogear is also a bit lighter, which I think is also due to less reinforcement under the hood. Price wise, the hoods are about the same. The Aerofunction hood will take more work to get fitted as you need to cut out the vents, so you’ll probably end up spending more on this hood. Both hoods fit pretty well I thought. I’m very happy with the Aerofunction hood in the end, as I love the look & functional benefits of the vents. The Eurogear hood I was never very pleased with, and then I had an accident in my A4 and decided to just go back to a stock hood after it was destroyed.

  8. hey nick I been following your blog for a wile now and I am a fan I just recently got an audi s4 b7 dolphin grey to be exact, I have the same type of rims you have and I am curious what size of tires are you using in yours since I like the way it looks if you could send me an email I would appreciate it. thanks a lot.

  9. I’m running 235/35/19 tires on my 19×8.5 ET35 BBS wheels. Thanks for the kind words!

  10. Fernando Wilkins

    Hi Nick, I’m considering ordering the same hood. The body shop told me carbon fiber hoods have the characteristic of being wavy. It seems from your close up shot that this is the case. Is it just a shadow or was that a true statement by the body shop?

  11. Hi Fernando – yeah, I think the close up shot is a fair representation – I wouldn’t say it’s super wavy by any means, but it won’t be nearly as straight/flawless as steel or aluminum will be. It’s really only noticeable when you’re polishing or really looking for it.

  12. Hi Nick, I’m considering buying the same aerofunction AF-1 vented carbon fiber hood that you have for my ’08 S4 cabriolet. However, my car is black and I would like to retain the full carbon fiber appearance instead of painting it. Do you have any pictures of the hood prior to you painting it red? Is the full hood the same carbon fiber that appears around the vents/scoop? Also, how well does the carbon fiber texture and pattern match oem interior carbon fiber trim as that is what is in my car? Many thanks for your input, Tony

  13. Hi Tony – I don’t have any pictures, but yes the carbon fiber weave is uniform throughout and matches what you can see on my hood in the vents, so you should be able to get a pretty good idea from that. The weave matches the interior pretty well, I think the interior is maybe a slightly smaller weave but not too far off. I think it will work well, although I really like having the hood painted minus the vents so it’s more subtle.

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