This unique “858 CSL” is a breathtaking BMW 8 Series with 630 hp and a V10 engine

A Southern California company has given BMW’s classic 8 Series a gentle, subtle refresh. And by gentle, subtle refresh, we mean completely changing its character and appearance from a laid-back ’90s GT to a growling, V10-powered lightweight.

So welcome to Reyn Speed ​​Shop’s 858 CSL. And unlike modern BMW nomenclature, this badge actually indicates exactly what this car is. So yes, there’s a 5.8-liter engine lurking under that long, modified hood. And yes, it’s a real CSL.

First, the engine. The 8 Series’ original engine was replaced with a modified, enlarged version of the E60 BMW M5’s 5.0-liter V10. Why a screaming V10? “To maintain an exotic and technically advanced powertrain, the E60 S85 was the perfect fit for us,” Reyn Speed ​​Shop’s Rey Rivera told TopGear.com.

Rey enlisted the services of Carbahn – BMW fans will immediately recognise this as Steve Dinan’s tuning company – to convert the M5’s V10 to 5.8-litre “street” specification. Rey hasn’t dyno-tested his 858 yet, but reckons it will produce at least 630bhp and 650Nm of torque – significantly more than the V12 in an old, tired 850i.

Your arms might get tired, though. Avid BMW fans will also remember that a six-speed manual transmission was optional for the US-spec E60 M5, and that gearbox was fitted to this 858 to harness 630 horsepower, on the order of… some Speed. Rey hasn’t tested the power yet, but let’s just assume it’s going to be “a lot.”

The same goes for the noise. “The sound and the flexible power band that the engine offers are unbeatable,” said Rey.

Suspension? “The car sits on standard EDC shocks and struts front and rear,” said Rey. “We’re working with Moton on a four-way system for the 858 CSL because the car is 309 kg lighter than a standard E31 850i and we believe we can do a better job with this system.”

Six hundred and now what? Ah, right, that’s going to be the Very CSL part. Rey – in collaboration with Jon Sibal – has designed a modified body for the 858 that somehow removes 313 kg of mass from the 8 Series. This means that the car weighs about 1,500 kg. You’ll of course know Jon Sibal’s great catalog of previous models, who, together with Rey, decided to incorporate some very familiar elements into the 858.

“When Jon and I met the criteria, we had to stick to BMW’s classic M design elements,” said Rey. “I think you can tell when you look at the car.” On the E30 M3, he notices the flared wheel arches, the front bumper of the E39 M5, the integrated rear spoiler reminiscent of the E46 M3 CSL and even the beautiful Vader seats from an E36 M3.

“I’m just a small cog in a team of professionals who are putting a lot of effort into making Rey’s V10 vision a reality,” Jon added.

Naturally, all the body panels are made from carbon fibre – which explains the drastic weight loss – while the pop-up lights of the classic 8 Series have been replaced with vents, which probably help to further cool down the very angry V10 inside. Gives the old hulking car a cool modern twist.

“The design of the E31 is so timeless that we naturally kept the interior of the E31 and only integrated some controls from the E60 where necessary,” he added. With so much E60 M5 built into the 858 CSL and so much play, maintenance and sourcing spare parts would be a breeze.

In fact, that was part of the philosophy behind this build. So why, TG asked, did Rey choose the E31 and fill it with M5? “We wanted to create something special and more modern to expand our capabilities,” he said. He did a ton of research and found that the E31 and E60 could be fused together with creativity and wizardry thanks to many similarities between the platforms.

“An important aspect of our goal was to build a restomod that fully integrates OEM-level diagnostics, service and spare parts capabilities. We were able to achieve this by fully integrating all of the E60’s components into the E31 chassis.

“Here we are with the final result,” he added. And it is a result, the result of four years of hard work and countless hours in the garage.

And the train isn’t stopping there either. What’s next, we asked? Well, Rey merely mentioned that he has “some ideas,” including a 5.4-liter V12 with individual throttle bodies, a six-speed manual transmission, and an old E9. Another light, gentle refresh is coming…

Photography: @precisionsport/@klapped.media
Rendered by: @jonsibal