UNDER THE SKIN: BMW M4 – THE NEW GODZILLA
The Sherrin Rentals BMW M4 on debut at the Bathurst 6 Hour – Photo: Rhys Vandersyde
The Sherrin Rentals BMW M4 debuted at the Bathurst 6 Hour to much fanfare. Though it has its reliability issues the Sherrin brothers, Iain and Grant, have shown the outright pace of the car, but what has gone into making this road car into a race car and why is this car so quick?
The BMW M4 was quick on debut – Photo: Rhys Vandersyde
Looking back over the history of production car racing in Australia, there has always been a dominant vehicle that has a reign for three or four seasons until a new model supersedes it.
Mitsubish’s Starion, the Toyota Supra, Porsche’s 911 and various incarnations of Mitsubishi’s Evo are all models that have had dominate eras in the class, but a new era is ready to take over as proven by last Easter’s Bathurst 6 Hour. The inclusion of cars such as the Mecedes-Benz A45 AMG and the Ford Focus RS has upped the game, though one car seems to have completely blown everything out of the water, the BMW M4.
When new rules where brought in after the 2013 season that raised the price marker from $125,000 to $150,000, it allowed cars such as the Audi TT and the aforementioned Mercedes to compete. Since then, the Sherrin brothers Grant and Iain, along with father Michael had been planning to replace their highly successful pair of BMW 135is, Grant takes over the story.
Inside the BMW M4 – Photo: Nathan Wong
“It was between the M4 and the M2 originally,” said Sherrin of the decision the team had to make.
“With the 135is, we wanted to take that next step. We were competing well with them, we had them reliable, we were up there with A Class but we wanted A Class and we were always in for the outright. We always thought M4, but when the M2 came out, we thought we might go M2, but we just weighted it up and M4 just seemed the way to go.
“We got it [the M4] at the end of November and took it to our workshop early December and then the process started.”
Once the team had received the car, it was a rapid turnaround as Grant wanted to drive the car before its debut event at Bathurst during the Easter weekend.
“We started stripping it right down, we had people over Christmas working on it, because once we acquired the car we put the other ones [the two 135is] up for sale, of which one was sold,” continued Sherrin. “It was straight into it and we thought, we got until Easter and there is a fair bit to do, and we’d like to have it on track before then.
“Then there are the unknowns of whether you can get parts for it or not, so we had the roll cage go in just before Christmas, it was getting painted between Christmas and New Year, and it was back in our shop by the fourth or fifth of January. We had all the suspension and everything sorted by the end of January.”
Having previously developed the 135i, the Sherrin team knew what to expect and had the knowledge to turn BMW’s high-powered two door coupe from road car to race car. Thanks to the amount of technology in the car, the build did hit frustrating snags and continues to give the team troubles when we spoke to the team at the second round of the Australian Production Car Series at Winton.
More interior details of the BMW M4 – Photo: Nathan Wong
“There was always little things that were popping up that we had to learn about with all of the computers and things like that,” explained Sherrin.
“When you’re unplugging things and you go to plug them back in once you’ve stripped the car down, it’s like ‘now it doesn’t work and why?’ Talking to a lot of people, you always face those sorts of things.
“It’s got five ECUs in it, it’s crazy. If you put something in the wrong spot, then it’s not happy. It’s like the problem before the first race with the fuel pump, which was just a bent over pin that clips into the ECU, then for some reason decided not to work. It’s been working all weekend fine until this morning. Those things pop up, so they’re the hard parts of the build, which is figuring out how we make this thing work once we put it back together.”
The changes to the car have been minimal apart from some modifications allowed by the regulations, plus time hasn’t allowed the team to tune the engine. In essence, the car is fairly stock.
“You’re allowed to tune it but at the moment it standard straight out of the box, what it is,” said Sherrin.
“The M4’s [gearbox] has three levels; comfort, sport and sport plus, which we have been running. With some cars, the radiators can be a bit bigger, but there are percentages that you can make them a bit bigger. We have done all that stuff that we’re allowed to do, so radiator, brakes, suspension and removing the excess weight to make it race ready.”
The BMW M4 runs a Murray Coote suspension package – Photo: Nathan Wong
The car runs a Murray Coote suspension package and AP brake calipers, which replace the stock standard BMW calipers, dferring to the AP’s ability to hold heat for a longer period. The fuel system is interesting; it’s a dry-break system, which is a standard item in production car racing these days, but the 100lt tank is a custom item for the car, as Sherrin further explained.
“That was a part of the build as well. We pulled the tank out and we made a dummy one up out of cardboard and got someone to build us a tank so we can fit it in. The standard tank’s gone, but then we have a tank that we’ve built that fits back into that space.”
Though the car is not fully developed yet, Sherrin can already tell that the car is a complete all-rounder. The main strength of the car is its straight line speed; it hit in excess of 277kmh on Conrod Straight, but Sherrin says that the M4s braking and road holding are also strong strengths of the car. Another feature of the car is the dual-clutch transmission, which has forced Sherrin to drive his driving style and the way he positions himself in the seat.
The Sherrin Rentals BMW M4 on track at Sydney Motorsport Park – Photo: Nathan Wong
“There is an automatic transmission in it, which is a dual-clutch transmission, it’s awesome,” enthused Sherrin.
“To drive around with that is just great, you can grab gears whenever you like, or when you don’t want them you can shuffle down them pretty quick. It takes a little bit to get used to at the start.
“When we first took it out I thought ‘Geez, I have nothing to do with my left foot because there’s nothing there’. Heading into Turn 3 at Queensland Raceway wondering ‘Geez what do I brace myself with?’ so I’ve had to change my body position to get it a little bit better in the car and really use my left foot to brace myself up against the foot rest, because it’s not doing anything now. You’re less busy in the car, but you get to concentrate on a lot more things then and it allows you to concentrate on your braking.
“The system in it is quite good, but you have to get used to it though because it has the auto blip in it, so you don’t have to try and blip, it does it for you. Then there are offsets to that if you try and grab a gear when you’re coming off throttle when you would normally upshift and then kind of come off, it doesn’t like that. So we have to work our way around those sorts of things, otherwise it upsets it.”
The BMW’s M tuned S55B30 3.0-litre straight six unit with two turbochargers – Photo: Nathan Wong
The engine is the stock standard M tuned S55B30 3.0-litre straight six unit using two turbochargers, resulting in 331kw of power. The Sherrins have not had the opportunity to develop the engine yet, which has been shown through the car’s lack of reliability. After their experience with the smaller 135is, Sherrin is confident the team will have an easier time getting the car reliable, while the development of the car as a whole will be a constant.
“It took us a good year and a half for us to get the 135is reliable and learn the intricacies of the German manufacturer, so once we learnt that, it took us from that point a couple of years to get the thing to handle good,” continued Sherrin.
“Then we’ll start to look at things to make it handle better and squeeze a little bit more out of the handling.
“Straight out of the box it handles quite well anyway. Our main goal is to get the reliability there and hopefully start getting on the podiums, because that’s where we believe it belongs. It has shown its potential that it can be there, we just need to get it to the end.”
During the Bathurst 6 Hour coverage, Iain was interviewed and quoted the car’s build price as $300,000; $150,000 to buy the base car and $150,000 to prepare it for the track. However, Grant told AA that this was inaccurate and though he didn’t say a figure, he emphasised the fact that it is still a relatively stock race car.
“That’s not quite the numbers,” Sherrin asserted. “It depends how you can get the car and we didn’t buy a brand new car off the showroom floor.
“Yes, off the floor they fit underneath the price bracket of the category, which is that. We went and got a second-hand car and the stuff that we have to do with it [to prepare it for the racetrack]. I think it was taken a little bit out of context when Iain was trying to concentrate at the time.
“It wasn’t a $300,000 build.”
During the Bathurst 6 Hour weekend, the BMW dominated, and led each of the practice and qualifying sessions, while during the race it broke the production car lap record for the track. Some of the races audience wondered whether the M4 had been too big of a step in both price and performance. But, as Sherrin explained, they lost out in their battle to keep the old price bracket and planned their next step once the raise was confirmed.
The exhaust system on the BMW M4 – Photo: Nathan Wong
“The thing that people need to realise is that we haven’t all of a sudden gone and got the M4, this has been in our planning for a while,” said Sherrin.
“Back in 2013 we actually didn’t want the price of the category to go up; the category manager at the time put it up to allow people to build an Audi [TTRS] or a [Mercedes] C63, so it went up. We were against it at the time, but we looked at it then and went well moving forward if they’re letting these cars in then where do we want to go, because they’re going to come in eventually. You look last year and the A45 turned up to Bathurst and did exactly what we did this year, it was fast, it left everyone for dead and everyone has caught that, we have taken that next step.”
So how much of a step up is the M4 compared to their previous giant-killing 135is?
“We have that little bit more in braking, obviously there’s more speed there now and it handles so it is a step up with speed and a bit more braking, but not much,” laughed Sherrin.
“I suppose the 135i gave us a good lead into the M4. Knowing how to drive the BMW, you can’t go out and throw it at anything; you have to be nice and smooth with them, they reward you well with speed and once you start trying to jump on the brake too heavy the computers don’t like it. It helped to get our head around it.”
Production Car racing is going through an era of growth, both at National and State levels, and nowhere can that be better shown by the variety of cars competing at the front. The A45, Ford’s Focus RS, current model Subaru WRX STI, Audi’s TTRS and the venerable Evo are all extremely competitive pieces of kit, though even the previously unfancied Australian HSV and FPV products are bridging the gap let alone the various BMW variants.
So, where does the M4 fit into this? It has shown that it has the outright pace, but its reliability and its component wear are still unknown, which makes it hard to place. However, this scribe thinks it won’t be as dominate as some people think it will be.
The Sherrin Rentals BMW M4 on track at Sydney Motorsport Park – Photo: Nathan Wong
STATS – BMW M4 GROUP 3E SPEC
Engine: M tuned S55B30 3.0 litre straight-six with twin-turbochargers
Power: 321kw
Torque: 550Nm
Body: Carbon fibre roof, aluminium bonnet and front guards, fibreglass bootlid.
Dimensions: Length: 4671mm
Width: 1870mm
Height: 1383mm
Wheelbase: 2812mm
Track: F: 1579mm
R: 1603mm
Gearbox: 7-Speed M-DCT transmission
Brakes: AP Brake Calipers 6-pot calipers, 19-inch M brake rotors.
Suspension: Murray Coote Springs
Weight: 1497kg
Fuel System: Dry Brake System, 100 litre custom tank
Heath McAlpine
For our latest Under The Skin feature pick up the next issue of Auto Action Magazine, on sale this week. In the meantime follow us on social media Facebook, Twitter, Instagram or sign up for our weekly email newsletter for all the latest updates.