There’s a familiar pattern with modified BMWs. You buy the car with every intention of keeping things simple, make one or two carefully considered changes and, somewhere along the way, the original plan disappears completely.
That’s pretty much what happened with Hez’s BMW F82 M4.
Previous Build:
As part of the team here at R44 Performance, Hez is surrounded by modified BMWs on a daily basis, so perhaps an OEM+ M4 was never particularly realistic. What started with a set of KW V3 coilovers and BBS E88s has gradually developed into a seriously detailed F82 build, combining genuine BMW parts, carefully selected chassis upgrades and an increasingly substantial S55 engine setup.
Latest Version:
The latest version takes things considerably further. At its centre is a DocRace single-turbo conversion using a Turbosmart Kompact TS-7170, supported by a comprehensive fuel system, full CSF cooling package, Akrapovič titanium exhaust and an engine bay filled with triple-chrome and mirror-polished components.
The target is around 850whp, but the final power figure only tells part of the story. For Hez, this build has become just as much about sound, presentation and engineering as outright speed.
The Original Plan: An OEM+ BMW M4
Believe it or not, the original plan was fairly restrained.
“When I first bought the F82, I wanted to build an OEM+ car. That quickly changed as I had the opportunity to pick up a set of KW V3s and BBS E88s before even buying the car. It quickly turned into building a car that I could call my own and enjoy.”
Starting with KW V3 coilovers and 18-inch BBS E88 wheels immediately set the direction. Rather than simply lowering an otherwise standard M4, Hez started building around some of the best components available for the F8X platform.
The suspension was complemented by Vorshlag camber plates, a Powerflex double differential brace, ECS differential bushings and Pagid RSL29 brake pads. Together, those changes gave the car a much more focused chassis to match the additional power that would follow.
Visually, however, Hez resisted the temptation to completely reinvent the F82. Genuine BMW and M Performance components make up a large part of the exterior and interior specification, including an OEM European front bumper, MHC LDN GT Style front splitter, M Performance side skirts, OEM M Performance rear spoiler with the correct reinforcements, RKP rear diffuser and AutoTecknic mirror caps.
The lighting was also brought up to later F82 specification with OEM Icon headlights and OEM Shadowline LCI rear lights, alongside smaller details such as the LCI M4 badge and LCI seat badges.
Inside, there’s an M4 GTS steering wheel, SHFT paddle shifters, IND M1/M2 and start/stop buttons, IND painted roundels and genuine M Performance trim.
Despite how far the car has progressed mechanically, keeping those genuine BMW touches remains important to Hez.
“BMW has done an amazing job with their products. The factory M Performance and facelift items cannot be replicated, no matter how hard people try. The quality is just amazing on this chassis.”
“I’m a purist at heart, just with a large temptation to modify anything I can. I think the LCI upgrade was exactly what this car lacked when I first bought it, and I don’t regret the money I spent on it.”
550whp On The Factory S55 Turbos
The previous version of the M4 retained the factory S55 twin-turbo arrangement but added the supporting hardware needed to make considerably more power.
CTS Turbo supplied the charge pipes, downpipes, top-mount intercooler, heat exchanger and J-pipe, while an SSR Performance 4-pin crank hub addressed one of the best-known concerns associated with highly tuned S55 engines.
Fuelling and charge cooling were supported by a Bootmod3 Flex Fuel Kit, Snow Performance water-methanol injection system and Burger Motorsports stealth tank. NGK colder spark plugs were also fitted, while software consisted of Bootmod3, an XHP Stage 3 transmission tune and an F80Paul E85/WMI calibration.
The result was approximately 550whp and 642wtq.
For Hez, the torque and response were the highlights.
“I enjoyed the stock turbos thoroughly. It was incredibly responsive, and the torque was the thing that hit you first. 642wtq is a gnarly amount of torque at such low rpm.”
“It was quick, and the double diff upgrade made all the difference and helped put the power down. In the canyons, the power was there every time.”
It wasn’t simply a case of adding boost and forgetting about the rest of the car, either. Hez paid close attention to preventative maintenance, replacing items such as the turbo inlet and charge-pipe O-rings while making sure the supporting hardware was there to suit the way the car was being used.
The factory-turbo configuration worked incredibly well. The next stage wasn’t therefore about fixing a car Hez disliked. It was about creating something with a completely different character.
Why Single Turbo An S55?
Power is the obvious reason to fit a large single turbo to an S55, but it actually wasn’t Hez’s primary motivation.
It was sound.
The S55 is an incredibly capable engine, but its exhaust note has always divided opinion. Compared with the earlier N55, the twin-turbo S55 can produce a noticeably raspier tone, and changing exhaust components only goes so far in altering the fundamental character of the engine.
For Hez, moving away from the factory twin-turbo arrangement offered an opportunity to change that.
“I decided to go single turbo because of the S55’s infamous tone. Not really anyone enjoys the tone of the S55. It has always been compared directly to the N55, which has a much richer and smoother tone.”
“I could’ve gone with upgraded twins, but the tone would’ve been the same. While I was at it, I just decided to bite the bullet and go all-in on a single-turbo configuration.”
There was an engineering consideration behind the decision as well.
Many upgraded twin-turbo solutions retain housings based around the original S55 packaging. Hez wanted to move to a larger tubular exhaust manifold and single-turbo configuration with greater flow capacity as power increased.
“The other benefit I was keen on was backpressure. With upgraded twins, there can still be a lot of backpressure in the system. To negate that, the solution is to upgrade the physical exhaust manifold. In this case, that means a single-turbo tubular manifold.”
For the way Hez intends to develop the car, the single-turbo route therefore made sense on several levels: a completely different sound, greater potential for future power increases and a setup designed around the eventual goals of the car rather than simply its current output.
DocRace Single-Turbo Kit & Turbosmart TS-7170
At the heart of the new specification is a DocRace S55 single-turbo kit with the external wastegate dump tube option.
Hez already had plenty of first-hand experience with DocRace before choosing the kit for his own M4.
“I chose the DocRace kit due to my experience in the past with their S58 kits. I’ve done about seven or eight S58 kits and all of them went on flawlessly and performed amazingly. They all sounded amazing as well.”
Rather than choosing one of the more common turbo options, Hez paired the DocRace hardware with a Turbosmart Kompact TS-7170, which has also received a T51R modification by Daddy Turbos.
The turbo was chosen with both the immediate target and future development in mind.
“The Turbosmart technology has advanced really far with their new turbos. They spool much quicker than a lot of turbos on the market and perform well. The lifetime warranty on them is also incredibly hard to beat.”
“I opted for the 7170 due to my power goals of 850whp and to minimise backpressure. We do have bigger plans to fully utilise this turbo in the future, so even though it is a larger turbo, we do have the intention to fully utilise it.”
For this stage of the build, 850whp is the target rather than the limit.
The rest of the engine specification has been assembled accordingly. Supporting hardware includes ARP rod bolts, ACL rod bearings, 034Motorsport engine mounts, a Vargas billet valve cover, KLM Race billet catch-can system and an Evolution of Speed billet intake manifold with integrated port-injection rail.
The single-inlet charge pipe, intake manifold and numerous surrounding components have also received finishes that make this engine bay very different from a typical high-power F82.
More on those shortly.
Building The M4 Around Sound
If sound helped push Hez towards the single-turbo conversion in the first place, there was little point stopping halfway.
The T51R modification, external wastegate dump and Akrapovič Evolution titanium exhaust have all been chosen to emphasise different parts of the S55’s new character.
“I wanted to optimise all the features of this setup, allowing a very unique sound on the car and amplifying every aspect of it. Since the sound of the car is what our focus is to optimise, I looked into every avenue to amplify this.”
The T51R modification changes the turbo compressor housing to create a much more pronounced whistle. It’s a sound closely associated with certain high-power turbo builds and should make the M4 immediately recognisable before the exhaust even comes into the equation.
Then there’s the external wastegate.
Hez opted for the dump-tube configuration rather than recirculating the wastegate gases into the exhaust.
“The external wastegate has an awesome noise when it opens, making the car sound like it’s breaking in two. You can either recirculate it back into the downpipe or have it dump out the bottom. The recirculating option provides a cleaner sound, whereas the wastegate dump releases the exhaust gas underneath the car. It creates this piercing roar that sounds like a jet taking off next to you.”
Subtle, then.
Finishing everything off is a full Akrapovič titanium Evolution exhaust system with titanium-finish tips.
Akrapovič systems are never the inexpensive option, but the lightweight titanium construction, exceptional fabrication and distinctive exhaust tone made it the obvious choice for what Hez is trying to achieve.
“This is what the single turbo needs. The titanium will assist that higher-pitched note once you climb the powerband while maintaining a clean exhaust note.”
Together, the tubular single-turbo manifold, T51R compressor housing, open wastegate dump and titanium exhaust should make this M4 sound dramatically different from the typical tuned S55.
A Fuel System Built For More Than A Dyno Number
With an 850whp target, the supporting fuel system becomes every bit as important as the turbo itself.
Hez has deliberately avoided building a system that operates right at the edge of its capability.
“The fuel system and cooling system are always where you don’t want to skip. These are the make-or-break parts when it comes to whether your car is efficient, consistent and safe. You never want to short yourself on the cooling system or fuel system because these are the items that keep all that power safe.”
On the direct-injection side, the M4 uses a Dorch Engineering Lift Kit together with EU5 OEM injectors from the M5/M6.
Port injection is handled through the Evolution of Speed intake manifold and Injector Dynamics ID1050X injectors, controlled through a MOTIV ReFlex+ alongside an ethanol sensor and 0-10 bar pressure sensor.
The low-pressure side is even more substantial, with a Precision Raceworks Stage 4.5 fuel pump kit, upgraded fuel lines, secondary pump, regulator and in-line fuel filter.
It might sound excessive for an 850whp target, but that’s intentional.
“A lot of people ask why because we don’t have goals to run over 1,000whp yet. Isn’t it overkill? Running a dedicated pump for PI means it only feeds the PI side instead of sharing the load with DI, so neither pump is overworked.”
“The return line and regulator keep fuel circulating and pressure stable. The braided AN-6 lines and in-line filter also help protect the system when running E85. This is about system health, not just power capacity.”
That last sentence sums up a lot of the thinking behind this version of the car. Plenty of the components fitted could support more power than Hez currently intends to run, but the aim isn’t simply to find the minimum hardware required to produce an 850whp dyno sheet.
Keeping A High-Power S55 Cool
The same thinking carries over to cooling.
The M4 now runs an extensive CSF cooling package, including the CSF x DocRace single-inlet top-mount intercooler, CSF heat exchanger, CSF engine oil cooler, CSF transmission oil cooler and twin CSF auxiliary coolers. The exposed coolers also feature protective rock guards.
A Mosselman oil thermostat with titanium hardware has been added to the system as well.
Again, it’s a comprehensive specification, but repeated high-power pulls and hard road use put very different demands on a car than producing a peak figure once on a dyno.
Keeping intake, engine oil and transmission temperatures under control is crucial if the car is going to deliver its performance consistently.
The Triple-Chrome Engine Bay
Power might grab the headline, but walk up to Hez’s M4 with the bonnet open and the first thing you’re likely to notice is the finish.
The engine bay contains a huge collection of triple-chrome and mirror-polished components, turning hardware most owners would never think about into part of the overall build.
Interestingly, the inspiration didn’t come from another BMW.
“The idea came from the Honda and JDM scene. After attending Wekfest, I saw many clean examples of this finish.”
There are two different processes being used throughout the car. Triple chrome involves electroplating multiple layers onto the component, traditionally including copper, nickel and chromium, to create the deep reflective finish. Mirror polishing works directly with the base material through progressively sanding, compounding and buffing its surface.
Hez deliberately used both depending on the component.
“Triple chrome gives a deep, flawless, liquid-mirror gloss. Mirror polish is extremely shiny but looks more like bright raw metal with a slight warm sheen.”
“These details mattered a lot to me because the factory finishes aren’t the most attractive. I wanted to make sure all the details were taken care of beyond what had been done before.”
The list is extensive.
The DocRace single-inlet charge pipe and Evolution of Speed intake manifold have been refinished in triple chrome, along with the OEM strut brace, DRL module heat sinks, oil-filter housing, GoldenWrench caps, MMX air-conditioning caps and the faces and lips of the BBS E88s.
Elsewhere, the OEM fuel rail, injector tie-downs, top-mount intercooler hardline, intercooler bracket and even the OEM alternator have been mirror polished.
The Evolution Racewerks J-pipe receives the same treatment, while raw Downstar hardware is used to finish the presentation.
It’s the sort of detailing you only really appreciate when you spend time looking around the car.
“It was a perfect decision because I’ve been complimented more times than I can count for the attention to detail that I find so important.”
If you want to go down a similar route on your own S55, our S55 Ultimate Engine Bay Set is a good starting point.
BBS E88s, KW V3s & A Proper F82 Stance
The BBS E88s have been part of this M4 since virtually the beginning, so there was little reason to replace them for the latest iteration.
Instead, they were refinished.
Both the wheel faces and lips have now been triple chromed, tying them directly into the theme underneath the bonnet. Wrapped in Toyo R888Rs and sitting over the KW V3 suspension setup, they give the F82 an unmistakably modified appearance without moving away from the classic BMW race-wheel aesthetic.
The exterior itself remains relatively understated compared with what is happening beneath the bonnet.
That wasn’t entirely the original plan. A full MHC LDN GTX aero package had been earmarked for the car, but it didn’t arrive in time for the car’s release.
Rather than hold everything up waiting for it, Hez kept the M Performance side skirts and RKP rear diffuser already on the car and fitted the now-discontinued MHC LDN GT Style front splitter instead.
It’s a more restrained look than the full GTX programme would have produced, and it arguably sits better alongside the rest of the car’s OEM+ exterior. The GTX kit remains on the list for a future iteration.
The genuine European front bumper, MHC LDN GT Style front splitter, OEM M Performance spoiler, M Performance side skirts and RKP diffuser retain the F82’s original shape, while the Icon headlights and Shadowline LCI tail lights subtly modernise the car.
A full front-end and rear-end respray has also allowed the exterior to match the standard of the mechanical and engine-bay work.
It’s a good example of Hez’s slightly conflicting philosophy towards the car: modify almost everything, but make sure it still looks and feels fundamentally like an M4.
The Details You Don’t Immediately See
Some of the most important components on this F82 aren’t necessarily the ones that will attract attention at a show.
The Powerflex double differential brace and differential bushings, for example, were already making a noticeable difference when the car was running 550whp.
“The double diff upgrade made all the difference and helped put the power down.”
Likewise, the Vorshlag camber plates, KW V3 coilovers and Pagid RSL29 brake pads make sure the chassis hasn’t been forgotten while pursuing more power.
That’s something we always like to see in a build like this. It’s easy for the specification of a high-power BMW to become entirely focused on the engine, but the best builds treat the whole car as a package.
Hez’s F82 has been developed over time rather than assembled from one shopping list, and that’s reflected in how many different areas of the car have received attention.
Built With HTP Motorsport
As with any build at this level, the specification is only part of the equation.
The execution matters just as much.
A huge part of the latest version of Hez’s M4 has been completed with Henry at HTP Motorsport, whose attention to the smaller details helped push the engine bay much further than originally planned.
“I want people to respect the build quality behind it. As much brainstorming as I did, a huge amount of the credit is due to the person building it.”
“Henry at HTP Motorsport really helped me brainstorm all the details and modifications. This car wouldn’t have been so thought through without him.”
Henry’s background outside the BMW world also brought some different influences into the build.
“He came from the VAG community, so the key details were his bread and butter. His passion for making an install as clean and factory-looking as possible only helped with this.”
That shows up most obviously in the fuel system. Adding a dedicated port-injection feed, a secondary pump, a regulator, a return line and a full set of braided AN-6 lines usually means an engine bay that looks busier than it did before. Here, the entire system has been tucked away and routed so tightly that you have to go looking for it.
The same applies to the wastegate lines and MAC solenoid routing, which have been run neatly rather than simply plumbed in the shortest way possible. On a build where the boost-control and fuel hardware is doing a lot of work, keeping all of it out of sight is far harder than it looks.
Henry also went after the components that usually clutter the intake-manifold side of an S55. The PCV system components have been shaved, as have the fuel tank breather lines, removing a significant amount of visual noise from an area most owners simply leave alone.
It was Henry who encouraged Hez to look beyond the obvious showpieces and refinish items such as the factory strut brace, alternator, oil-filter housing, fuel rail, J-pipe, injector tie-downs and DRL modules.
“These wouldn’t have been refinished or fitted if it weren’t for him.”
That attention to components which could easily have been ignored is ultimately what separates this M4 from a straightforward big-turbo conversion.
What Comes Next?
For now, the target is around 850whp, with a custom E85 and water-methanol flex-fuel calibration from F80Paul bringing the hardware together.
But the TS-7170 was deliberately chosen with more capacity available.
Hez has already admitted there are plans to make greater use of the turbo in the future, so we’re not going to declare this M4 finished. The GTX aero package that missed the deadline this time around is another obvious addition.
The more interesting part of the build is that an eventual four-figure dyno number doesn’t appear to be the sole objective anyway.
This is an F82 where a polished intercooler hardline can matter just as much as another 50whp. Where an OEM LCI light is chosen because Hez believes BMW got it right in the first place, while the entire factory turbo arrangement is removed because he believes it can be made better. And where an 850whp fuel system is deliberately specified with considerably more in reserve because reliability and consistency matter as much as the number.
What started as an OEM+ M4 has become something much more personal.
And that’s probably the best description of the build.
“I want people to respect the build quality behind it.”
Judging by the specification and the level of detail that’s gone into it, we don’t think that will be a problem.
You can browse everything we stock for the chassis on our BMW F82 M4 parts page, or head straight to the F82 M4 engine & performance range.
Full BMW F82 M4 Modification List
Engine & Performance
- DocRace S55 Single-Turbo Kit with External Wastegate Dump Tube
- DocRace Single-Inlet Charge Pipe – Triple Chrome
- TrackBuilt TJ Inconel Embossed Turbo Heat Wrap
- Turbosmart Kompact TS-7170 Turbo
- T51R Turbo Modification by Daddy Turbos
- Turbosmart External Wastegate
- Evolution of Speed Billet Intake Manifold & Port-Injection Rail – Triple Chrome
- Evolution Racewerks J-Pipe – Mirror Polished
- Vargas Billet Valve Cover
- Vargas Triple-Chrome Billet Oil Cap
- KLM Race Billet Catch Can Kit
- ARP Rod Bolts
- ACL Rod Bearings
- 034Motorsport Engine Mounts
- Turbo Guard SF Plus – Raw & Polished Finish
- F80Paul Custom E85 + WMI Flex Fuel Tune
Fuelling
- Dorch Engineering Dorch Lift HPFP Kit
- OEM EU5 M5/M6 Injectors
- Precision Raceworks Stage 4.5 Fuel Pump Kit
- Precision Raceworks Fuel Lines
- Secondary Fuel Pump
- Fuel Pressure Regulator
- In-Line Fuel Filter
- Injector Dynamics ID1050X Injectors
- MOTIV ReFlex+ Control Unit
- Ethanol Sensor
- MOTIV 0-10 Bar Pressure Sensor
- Burger Motorsports Stealth Tank
- Billet Burger Motorsports Stealth Tank Cap
- Snow Performance Water-Methanol Injection System
- Snow Performance Boost & WMI Gauge
Cooling
- CSF x DocRace Single-Inlet Top-Mount Intercooler – Mirror Polished
- CSF Heat Exchanger – Polished
- CSF Engine Oil Cooler with Rock Guard
- CSF Transmission Oil Cooler with Rock Guard
- CSF Auxiliary Coolers x2
- Mosselman Oil Thermostat
- Titanium Mosselman Hardware
- Fall-Line V2 Front Oil Cooler Guard
Exhaust
- Akrapovič Titanium Evolution Full Exhaust System
- Akrapovič Titanium-Finish Exhaust Tips
- External Wastegate Dump Tube
Engine Bay Detailing
- OEM Strut Brace – Triple Chrome
- OEM DRL Module Heat Sinks – Triple Chrome
- OEM Oil Filter Housing – Triple Chrome
- GoldenWrench Caps – Triple Chrome
- MMX A/C Caps – Triple Chrome
- Downstar Deluxe Raw Hardware Kit
- OEM Fuel Rail – Mirror Polished
- OEM Injector Tie-Downs – Mirror Polished
- OEM Top-Mount Intercooler Hardline – Mirror Polished
- OEM Top-Mount Intercooler Bracket – Mirror Polished
- OEM Alternator – Mirror Polished
- Shaved PCV System Components
- Shaved Fuel Tank Breather Lines
- MHC Carbon Fibre Radiator Support
Suspension & Chassis
- KW V3 Coilovers
- Vorshlag Camber Plates
- Powerflex Double Differential Brace
- ECS Differential Bushings
Brakes
Wheels & Tyres
- 18-inch BBS E88 Wheels
- BBS E88 Faces & Lips – Triple Chrome
- Toyo R888R Tyres
Exterior
- European-Specification Front Bumper
- MHC LDN GT Style Front Splitter In Pre-Preg Carbon Fibre (Now Discontinued)
- XPEL Paint Protection Film
- BMW M Performance Side Skirts
- RKP Rear Diffuser
- Genuine BMW M Performance Rear Spoiler
- Genuine BMW M Performance Spoiler Reinforcements
- Genuine BMW Icon Headlights
- Genuine BMW Shadowline LCI Rear Lights
- AutoTecknic Mirror Caps
- Genuine BMW LCI M4 Badge
- Full Front-End Respray
- Rear-End Respray
Interior
- SHFT Paddle Shifters
- IND M1/M2 Buttons
- IND Start/Stop Button
- IND Painted Roundels
- Genuine BMW M Performance DCT Trim
- Genuine BMW M Performance Handbrake Trim
- Genuine BMW M Performance DCT Gear Selector
- Genuine BMW M Performance Floor Mats
- Genuine BMW M4 GTS Steering Wheel
- Genuine BMW LCI Seat Badges
Previous Performance Specification
Before moving to the current single-turbo configuration, the M4’s S55 ran a highly developed factory twin-turbo setup producing approximately 550whp and 642wtq.
- CTS Turbo Charge Pipes
- CTS Turbo Downpipes
- CTS Turbo Top-Mount Intercooler
- CTS Turbo Heat Exchanger
- CTS Turbo J-Pipe
- SSR Performance 4-Pin Crank Hub
- Bootmod3 Flex Fuel Kit
- Snow Performance WMI System
- Snow Performance Boost & WMI Gauge
- NGK Colder Spark Plugs
- Burger Motorsports Stealth Tank
- BMW M Performance Exhaust System
- Bootmod3 Engine Software
- XHP Stage 3 Transmission Software
- F80Paul E85/WMI Calibration
