Audi never released an RS4 B5-sedan, not counting two secret factory prototypes. Sad, Fredrik Almquist thought, who took matters into his own hands and composed his own, tuned version with bells and whistles. 630 hp of Nogaro Blue perfection at its finest!
When it comes to his custom specification RS4 Sedan build, Mr. Almquist has really done his homework. Since the project start in 2001, a whole 14 years ago, it has been a constant development process. Every winter being invested into further build progressions to enable full driving recoupment during the short Swedish summers.
The build is now optimized at all corners to get close to some kind of factory perfection. Fully loaded with solid bushings, cross braces, frame reinforcements, together with a precision engine build. A potent '90s dream with up-to-date performance, including character that cannot be found with newer cars. The '98-'99 cars being the last ones without ESP or DCS from the factory on the S4.
The exterior hides more development than meets the eye. With a sedan version of the RS4 front bumper not being available from the factory, the estate version has been sectioned and carefully stitched together to fit the short body type. This, together with donor car OEM RS4-fenders all around, gives a massive factory impression. All covered with Audi's very appreciated option color Nogaro Blue, which Fredrik's car sported even from the beginning.
"I have a lot to thank my friend Fredrik Bergase at Paint IT AB for. He was irreplaceable when it came to the body- and paintwork," Fredrik explains. "We have together put in many hours to reach this level of finish."
The interior continues in the Nogaro Blue theme with matching Recaro Pole Position racing seats—an expensive factory option for the RS4 back in the day.
Tuned twin turbo V-6
Fredrik calls the engine specification for his beast RS4+, built to handle all of 1,000 ethanol horsepower with enough boost. 2.7L, acoustically pleasing V-6 BiTurbo—constructed from atoms and massaged in all corners. Forged, modified, and balanced with cunning consulting and performance from Stertman Motorsport in Sweden. Everything from MIRA-machined, flow-optimized AZR-heads to fully forged interiors. Boost pressure is made by twin TIAL R605 snails starting at 3,300 revs with 630 hp at 2 bars at the top.
The main objective being all encompassing reliability and cooling, a goal that has been fruitful.
"Since I thoroughly enjoy track days, I'd like to enjoy them to the limit. Running up a whole tank of E85 fuel without having to go into the pits to cool off. And now I can do that," Fredrik says.
By the same reasoning, the exhaust noises have had a focus—where 95dB sound levels are faithfully held. A 3-inch 034 Motorsport exhaust system ends in a single 3.5-inch silencer in the rear, delivering sonic nirvana at sane levels.
In total, the car has been lightened more than 200 pounds. And a verified corner weight of 3,350 fully loaded up brings the total in at around 330 pounds below the current RS4. With 630 hp and 800 Nm in the rear pocket, there is—to put it mildly—some performance reserves in stock. "I have been able to keep up the pace with the 997 GT3 RS and similar cars on track days," Fredrik humblebrags. "It is truly amazing for me to say! A lot of the driveability has come with my optimizations of the differentials and chassis."
Optimized four-wheel performance
Hence the driveline has been an important cause, effectively helped by a Stasis Engineering center diff together with an LSD-rear diff. Bolted with solid aluminum bushings; a great deal of understeer has been handled. Furthermore, Fredrik has focused on the suspension, with great result following. Currently, a custom PSI Raceline coilover kit is mounted, based on the hypercar quality, Swedish pride, and Öhlins TTX36-kit. This after throwing everything from lowering springs to modified PSS9 in the garbage during the development phase.
"Now I have a chassis that performs on track and is surprisingly comfortable on the road. A lot of chassis optimization has gone into this, and now a great deal of camber to get the Michelin Pilot Sport Cup tires to perform at their maximum," Fredrik says.
And perform it does! It brought in 1.23.30 at the Bilsport Superstage track battle in Sweden, well under Porsche GT3 RS times! But more is apparently to come.
"I have now gone up three width increments on the OZ wheels and am now running Cup tires with 265 width compared to the former 235. So more cornering grip is to be expected for improved times."
The long time prototyping of this unique S/RS sedan continues, with more track time and development in the garage. Reliability combined with power, chassis, and methodic detail orientation—truly a winning combination!
Modified H&R PSS9s weren't good enough for Mr. Almquist and got rejected to the scrap heap.
The Swedish Öhlins, hypercar-worthy, TTX36 coilovers were the select and expensive choice for Fredrik's build.
Donor parts from a written-off RS4 estate. A flashback to attest the bodywork that has been invested in this build.
A great deal of fitment work went in to create the unique RS4 sedan rear bumper.
The luxurious Nogaro Blue color begins with a solid layer of straight-up character.
A key component to the performance of the project is the solid hardware within the drive line.
The forged journal holders are tightened to specification by Fredrik himself.
High voltage through Audi R8 V-10 ignition coils.
The mythical 1,525 kg fully loaded corner weight of this beast, surprisingly light.
Brand-spanking-new Michelin Pilot Sport brings some grip to the well-constructed chassis.
The car sees a lot of track driving, something that Fredrik set out to achieve from the start.
Fire reigns from the exhaust when Fredrik puts down the hammer. Photo captions