One year after the release of the revolutionary Mi5, Schumacher have applied their now customary annual update, this time in the form of the Mi5evo competition touring car chassis.
We’re excited by the new chassis, and loving getting to grips with it. We’re delighted to bring you this initial review based on the build and our first racing experience.
The Evo is the product of a year of intensive learning and development on the Mi5 platform. The architecture of that car was so different to anything Schumacher have done before, it was bound to offer a host of development options. In fact, when the Mi5 was released, we said of the outgoing Mi4:
“it is time for some significant updates – and in this case with the Mi4 platform fully developed, that means an all new chassis.”
Schumacher’s engineers and factory drivers have been loving the development opportunities the Mi5 has offered – and that’s resulted in a steady flow of option parts for the car over the last 12 months. Along the way though, there have been more lessons learned than can easily be applied to the Mi5 in its current form – so while the new chassis retains the Mi5 platform’s name, in reality the number of changes mean that it is an almost entirely new car.
One of the main directions for development has been in the flex department. The Mi5 works brilliantly in low grip conditions, it’s flexing chassis generating grip even when there is none. For club level racing in Australia, that makes it quite a package. But when grip levels go stratospheric the car can start to struggle a little.
Enter the Evo.
We’ll talk about other changes, but one of the big ones is the basic structure of the car, and the options it enables. Schumacher have retained the same Mi5 architecture, but moved the dual top rails further apart, shortened them a little, and mounted them from the bulkheads rather than the shock towers on the original car.
That results in a slight reduction in flex in the Evo (over the original Mi5), but also a new capacity to stiffen the chassis much further by changing thickness of those top rails. Two thicker (and thereby stiffer) options area available, along with an additional stiffener to join the rails together. This one change alone (all but impossible to engineer into the original car) makes the car tunable to a huge range of grip conditions.
A further option to link suspension mounting blocks across the car enables further stiffening for responsiveness in high traction.
While we don’t get those kind of conditions in Queensland very often (or ever!), it means a lot to drivers who run on carpet or super high-traction indoor asphalt.
Even in low-medium grip, we’re expecting a car that is more responsive and direct in its handling than the Mi5 (which was so stable and forgiving to drive – a characteristic we really enjoyed).
What else is different?
Pretty much everything.
The major drivetrain components (rear diff, spool, driveshafts) are unchanged, but that’s about it. Revised suspension design and geometry, all new plastic mouldings, new shocks, new bulkheads, new motor mount (and 4.5mm closer to the centreline), new steering.
Even the bodyposts have come in for some long overdue attention.
Let’s get down to the build, and we’ll highlight some of the key developments in the Evo as we go.
Building the Mi5evo
The build starts with the chassis…a typically beautiful piece of 2.5mm soft weave carbon fibre goodness. If you’re into sanding and sealing the edges of your chassis and shock towers – now is the time.
One word of warning though, don’t seal the edges of the carbon fibre suspension arms – leave them in their natural state to ensure you don’t interfere with flex characteristics.
That done, it’s onto the suspension mounting system and carbon plate arms. The new mounting system features ball joints inside moulded composite inserts – that then slot into the carbon arms.
The insert is retained in the arm with an o-ring, enabling it to be relatively easily replaced. But it also packs a grub screw that can be tightened to reduce play in the ball joint – and should mean that for the life of the car, free play in the suspension mounting system can easily be adjusted out. Brilliant!
Before we go on, let us turn you over to Ed Clark. A local Schumacher driver, Ed brings an important tip for preparing the inserts – the information coming from factory driver Chris Grainger.
Take time before you install the inserts to make sure you have the correct insert matched up with each suspension arm. The “two-pip” inserts are used in right rear and left front suspension arms, while the “one-pip” inserts are used in left rear, and right front. It’s easy to miss this in the manual, and the consequences are bad. Take our word for it, check twice (or three times) and get it right the first time. It’s annoying to have to pull the arms off later and switch those inserts around.
Just don’t ask us how we know this!
The arms themselves are of revised design, with a wider mounting base for increased stiffness. A further tuning option is to hand-cut the carbon link between the two suspension mounting posts for further flex (a common modification made on the Mi5).
As before, toe-in on the rear of the car is adjusted by changing the carbon plate. Standard arms are 3.0 degrees toe-in, with 2.5 and 2.0 arms available as before. For the first time spec class racers will delight in two further options being available – 1.5 and 1.0 deg rear toe-in arms are on the options list. In the common (in Australia) 21.5 spec class, it’s definitely an option that has been on the wish list – and one we’ll put to good use.
Next up are the new transmission bulkheads. Reduced in size and weight, they’re a beautiful piece of alloy machining. They add a couple of other new features as well. First, the bulkheads include an integrated mount for the upper suspension link – with three mounting holes to enable fine tuning of camber gain, and vertically mounted ball studs to enable fine adjustment of roll centre. It’s both more conventional, and a much cleaner solution than the camber link plates of the last few Schumacher touring cars. Second, the bulkheads include a locking screw from underneath to secure the eccentric diff/spool carriers – which themselves are new and have a much finer adjustment for belt tension than the outgoing car.
The motor mount is once again secured right on the centre-line of the chassis to enable perfect linear flex, while a redesign of the part (and the layshaft/belt pulley) moves the motor 4.5mm in toward the centre line (for a more laterally balanced chassis).
Super strong 4mm carbon shock towers, and the wider-spaced upper deck rails complete the basic structure of the car. A neat alignment jig helps ensure everything is perfectly aligned for a smooth and free-running transmission.
Main layshaft continues to be a left-side mounted floating unit – with the layshaft static and spur/pulley spinning on the standard rubber-sealed bearings. We’ve had no problems whatsoever with this basic design – except that the bearings are under high load and it’s worth keeping an eye on their condition – particularly if you’re running modified class motors in dusty conditions.
Steering time, and….yes….it’s all new. The same basic 3-bearing mounted rack design continues, but with the inclusion of adjustable travel stops, and forward facing ball joints for easy Ackerman adjustment. As with the previous car, take car as the steering system beds in over the first few runs to keep adjusting the rear bearing for a nice smooth, slop free operation – and be sure to keep the rack itself free of tyre debris and dust (a cotton bud sprayed with brake cleaner is the perfect cleaning tool).
Transmission continues with the rear gear diff. It’s unchanged in design from the original Mi5 unit – and we’re more than happy to continue with it. Take time to apply a little Team Associated Green Slime to the o-rings for a good seal, and you should be good for trouble-free service We have never yet had to replace any diff internals in the Mi5 diff – so a long life should be expected. I have a full range of Team Associated diff fluids (from my nitro off-road habit) so start with 2000cst fluid from AE – but the kit 2000cst fluid is good, and Schumacher have a full range of different viscosity silicon fluids available so you can fine-tune handling.
The spool too is unchanged. Lightweight, strong and low wearing – there’s no reason to change it. Schumacher continue to offer a Spec-R built gear-diff as an option for the front of the Mi5evo. We have one and use it on some tracks, preferring the spool on others. Our front diff is fitted with 1000000cst “fluid”.
Both diff and spool are retained by a carbon plate that secures the bearing/eccentrics in place – and also stand as the new mounting location for the all-new anti-roll bar systems both front and rear. The bars are better located for more direct response, secured to prevent lateral float, and laser engraved for thickness (naturally a full range available for both front and rear in 0.1mm increments). This too, is an area of useful improvement.
Onto the suspension plastics, and we’re pleased to see lighter end pieces both front and rear, together with grub-screw secured 2.5mm hinge pins. This is another change that will help prevent the development of play over the life of the car.
Front end continues with the single king-pin micro castor blocks – 4 degrees as standard, and 6 as an option with some minor detail changes to improve consistency and again reduce play.
Steel turnbuckles, revised ball joint ends (stronger, stiffer and yes, less play) complete the suspension structure. Steel driveshafts at both ends are fixed with the o-ring secured drive hex – 1mm wider on the rear to provide wider rear track. Alloy rear drive shafts are available as a lightweight option, while we opted to install the optional double-jointed shafts up front for slightly smoother performance through the full range of steering lock.
Attention then turns to shock absorbers, and yet another all new set of components. Starting from the top the shocks now feature a ball joint upper mount, and a shock cap that is pre-prepared for drilling so you can easily run a vented shock setup (and just as easily re-seal the shock caps with a grub-screw). The shock cap is lower profile as is the lower seal cartridge which has the effect of placing the machined piston in a different part of the body at rest for more consistent performance. A slight revision to the lower seal pack including the provision of shims to enable a tighter or looser seal depending on your preference (for the record, I added two shims per shock, and used the factory supplied seals). I also opted for 450cst CORE shock fluid, following the tarmac test setup at the rear of the instruction manual as a starting point.
Springs are carried over, the new line proving excellent in consistency and performance. I know springs are one of the areas that people like to experiment with a lot, but I have to say I’ve been very pleased with the Schumacher springs released with the Mi5 last year. I’ve started with the standard green spring all round (very, very similar to the classic “HPI Silver” spring that graces so many touring cars around the world.
Last of the structural work is the new front bumper and all new body post system – a full alloy clamping system replaces the old grub-screw system and enables a much finer adjustment.
Just as the Mi5 did before it, the Mi5evo swallows all the electrics easily. There is just so much room behind the transverse mounted servo that clean electrical install is possible even for me. I did add the optional alloy servo posts for a slightly more rigid mounting system for the servo. Take the time to make sure you get your servo spacing right, and ensure the drag link clears the servo and steering rack at all parts of the steering travel.
We loaded up our usual components – Futaba 9550 servo, Hobbywing V3.1 ESC, WTF fan, Sanwa MT4 radio and topped it off with a Protoform LTC-R bodyshell – the body I have preferred all through the life of the Mi5 for outdoor tarmac racing.
For horsepower we loaded up the Thunder Power 4.5t. Yes, you did read that right. Though I have “officially” retired from modified, I wanted to run this test with the full house mod-motor horsepower delivering the ponies.
There were two reasons. First, a bunch of my mates race modified, and it’s fun to race with them. But second, I think modified instantly reveals the underlying character of a race car. I feel sure that the basic handling and performance “style” of the car will be immediately apparent with mod-motor horsepower on board.
The build itself? Apart from my self-inflicted struggles with the suspension inserts (at 42 years of age you would think I have learned to read instruction manuals….but apparently not!) it was an effortless build. I had to just knock the inner edge of suspension arm plates with a points file to ensure free clearance, and as I noted on the way through, added a couple of options in the form of alloy servo posts and DCJ front driveshafts.
The finished product is a thing of beauty….and I was desperate to get trackside with it.
Race Day: Bayside R/C (Brisbane, Aus)
For our first test we headed for Brisbane’s Bayside R/C, a fantastic outdoor facility, packing some super high-speed sweepers, long straights, and a tight and twisty uphill section – along with plenty of bumps to give the suspension a real working over.
Bayside R/C – Photo from Team ARGO
The track has been cleaned recently, and with Peter D spending a solid session on the blower to clear the lust of dust and grass clippings, conditions were good.
As I said, it’s been a little while since I ran modified, so my expectations were low, just hoping for a solid hit out with the car and to get a feel for its potential.
Mid-way through my first run I found myself switching gear and bumping up those expectations a notch. The car was fantastic.
Right out of the box (remember, I was using that Tarmac Test setup from Chris Grainger) the Mi5evo was dynamite, demonstrating a sharpness and agility that we had to work hard to generate in the Mi5.
Initial turn-in is so crisp, mid-corner rotation is whip-fast and even on-power steering is brilliant. For a while I felt like I might need to calm the car a little while I got used to mod-motor speeds again. Fast time in this initial run was 17.7.
For my second run I switched to the Protoform Speed 6 body – renowned for its smooth handling aero. It did exactly what I hoped for, just slowing down the responsiveness of the car a fraction while I got my head around what was going on.
I also reduced rear camber a little from the specified 2 degrees down to 1.5 to get a little extra rubber on the road. Same fast time of 17.7, with perhaps a touch more consistency.
For my third run (and first qualifier of the night) I went back to the LTC-R – expecting the track to have gripped up a little as temperatures dropped and rubber went onto the clean (but green) surface. Just as I hoped, the car was now right in the sweet spot – and I was slowly remembering how to drive Mod TC. Best lap this time down to 17.3.
I left everything as-is for the fourth run, expecting track conditions to have improved again – and the car to respond accordingly. I have to say I was thoroughly enjoying piloting the evo in these conditions. Best time down to 17.1 in this run, with overall time about 3 seconds quicker.
As we prepared for finals, I slipped the front diff into the car – knowing that at Bayside it’s usually the better choice than a spool. A little extra turn-in in the twist uphill section, and smoothness through the sweepers often pays dividends in a car that is easier to drive fast.
Just as we warmed up, the rain came down. I snaffled a couple of quick laps before conditions deteriorated – and the car felt fantastic – better again than it had been all night. Such a shame that weather stopped play.
At the same time I was having a blast with my first runs in Mod, my Dad was on track with his Mi5evo running in the 21.5 spec class. He built a near standard car, only adding the DCJ front shafts, grey (soft, low drag) belts, and 2.0deg rear arms. Electrical issues slowed his charge, but the car flowed beautifully and looked great all night.
Customer cars are being prepared all over Brisbane, and we’ll be back on track soon, so it won’t be long before we have a heap more experience and feedback for the Mi5 in a range of track conditions.
For now though, I couldn’t be more delighted with my initial experiences with the Mi5evo in low-medium grip conditions.
It is sharp, agile and responsive, and I can’t wait to get to the track again. That’s the sign of a great race car.
We’ll keep you up to date with our experiences, and try to scour the net for other news as the Mi5evo develops.
