The B7 RS4 platform and how supercharger kits make it even better.

The TTS supercharger in my engine bay complete with a “revolution” carbon fibre induction kit.

Having owned a B7 RS4 previously in saloon form, it’s safe to say I know my way around the architecture pretty well. I think it’s important to note a b7 RS4 is not by any means a slow car, pretty sure the factory figures were 0-60 in around 4.9 seconds and limited to 155mph. Back in late 2005, 14 years ago Audi thought it was acceptable to blow the outgoing e46 m3 out of the water with the b7 RS4. A 4.2 litre naturally aspirated v8 producing 414bhp and 317lb-ft with a mighty for a v8 redline of 8250 rpm. The cars natural dynamic is one of confidence with subtle hints of understeer when you push the limit , but push a little further and the 60-40 rear bias can and will send you sideways if you’re not careful. ( I may have had an unfortunate moment in the wet ) The RS4 was developed at a perfect time, just a couple of years behind the Lamborghini Gallardo. Why would I mention that? It may have something to do with the flat bottom steering wheel the European cars could be specced with. (Sorry America) and the monstrous 8 piston front brake callipers with their 365mm drilled Brembo discs. Add a set of simply gorgeous “wingback” bucket seats that clench around you when sport mode is engaged. With blistered wide arches and 19” concave alloys you really have a spec list worthy of any petrol heads attention. So by the sounds of it a pretty special recipe right? … well not quite as the b7 became a pioneer for some pretty unique issues. Mention the word “carbon” to any RS4 owner it’s not the carbon clad interior that springs to mind, more the inlet ports that become coated in the stuff. Effectively choking itself the b7 coats it’s ports with a hard treacle like carbon deposit which can only be removed manually or with a walnut blast. (Around £500 every 40k Miles ) This results in many RS4s making anything from 350-380bhp a massive loss from manufacturers claimed figures. With leaking Dynamic Ride Control (DRC) Audi’s advanced suspension which self levels itself at high pressure through hard cornering, and you’re starting to see a pattern emerge.

The “wingback” bucket seats offered to European specced cars.

This being said the B7 has an incredibly capable chassis which when enhanced correctly can become one of the best saloon/estate cars on the market. Audi’s DRC suspension became a bit of a PR disaster with so many sets replaced under warranty that most second hand buyers chose to fit coil-over suspension once out of warranty (myself included). This will save you a fortune over time and can always stiffen things up nicely. So we have a great chassis a manual gearbox , bucket seats and a smattering of Lamborghini parts so what’s missing? … tune-ability the second hand market is flooded with lightly modified b7’s but nothing to blow your skirt up as it’s widely known naturally aspirated engines are hard to make power from. So I guess that leaves … forced induction. My car was fortunate enough to be owned by the right guy at the right time. In 2011 and 85k miles TTS (a UK based performance company) decided to rectify the b7s power issues by developing a supercharger kit for the platform alongside MRC Tuning. A well known Audi tuner from Banbury. My car was used as one of the test platforms with it running various exhaust set ups including standard whilst the charger was fitted. (At a cost of around £18k )Performance figures ranged from 592ps with de-catted standard downpipes to 622ps with 100 cel downpipes and a Milltek cat-back. Typically to supercharge a b7 rs4 you will need to , have a full carbon clean, replace your injectors , fit de-catted down pipes a Milltek cat-back (or other after market upgrade) fit a cold air feed which involves removing the right hand side auxiliary radiator , upgraded fuel pumps and use a higher octane fuel at all times , an upgraded clutch won’t go a miss if you intend on launching the car. Budget £20,000 for this work as there may be the odd teething problem during fitting.

Lamborghini sourced flat-bottom wheel fitted to my b7 rs4

Back to the chassis then, how does it feel with what can only be described as 270ps more than stock? Well with the correct tyre and coilover set up (H&R and Pirelli in my case) you would swear this car was oem which is the biggest complement I can pay it. The power surge is epic the torque genuinely throws you back into those sumptuous buckets and you surge forward at a ludicrous speed. 0-60 has now been decreased to 3.4 seconds and top speed of 190mph is now within your reach. Back to that “sport mode” left hand side of the wheel the top button does a few neat tricks on a standard car , it sharpens up throttle response the buckets grip you tight and it opens your exhaust valves on oem or valved after market systems. This really lets the v8 sing all the way to 8500rpm when mapped and tweaked you may notice a slightly increased appetite for oil. The b7 has always liked somewhere between 500ml- 1l per 1000-1500 miles so anything around the top end is nothing to worry about. Shorter service intervals are also recommended as intake and oil temps are higher than standard. I think to summarise the b7 RS4 in any guise is a very special car and the last of its kind. With a supercharger the performance side of things is certainly up to more modern standards. So if you love a manual gearbox and a high revving v8 this is the perfect combination. Audi have dominated the small fast estate car market, is this the ultimate dad wagon?

Published by sjfbusby

a big nosed bearded idiot who likes to write about cars. Lucky enough to have owned a few quick ones too.

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