DM Motorsport String Alignment at Zen Garage

Justin Fox01/10/2013

I love old world craft. The Dent Hero guys continue to amaze me with the metal work they do on dent removal days at Zen Garage and I’d been looking out for something else (that’s unique) that we could host.

Enter Dale from DM Motorsport who dropped in to Zen last Saturday to do an old-school string alignment on my MX-5.

Sadly my coilovers didn’t make it from Japan in time for a private track day I had booked, so Dale just aligned the OEM set-up as best he could.

The results were instantly noticeable on the drive home. The car steered straight better and felt much more planted than before. On the freeway the car was fine and on the circuit the car was a hoot to drive. The set-up so neutral that you could choose whether you wanted to slide the car around or grip drive for a lap time (1.18 was the best I could do on the day).

For more information, visit:
http://www.dmmotorsport.com.au
https://www.facebook.com/dmmsydney

The best part is reading Dale’s thoughts on the day. I’ve pasted his words in below:

Before Spec
FL 2mm toe in @ -3.2 degree camber
FR 5mm toe In @ +0.25 degree camber

RL 1mm toe in @ -1 degree camber
RR 1.5mm toe in @ -0.8 degree camber

After spec:
FL 1mm toe out @ -2.2Degree camber
FR 1.5mm toe out @ -1 degree camber

RL 1mm toe in @ -1 degree camber
RR 1mm toe in @ -1Degree camber.

Being the original suspension it was going to be a tough ask to get the car to drive straight and get the figures back into ballpark where we want them considering the wear on the bushes and variances in ride height due to aged springs. Ideally with the MX5 because its a such a nimble and light car and being rwd we have to be careful not to make it too light in the rear end and still keep good mechanical grip, yet making it friendly to turn in and keeping mid corner grip! Being factory suspension i was mindful the ride heights were above ideal so the centre of weight gravity is a little high in the rear along with the roll centre being a little higher than a track prepped vehicle. This is nothing bad for the street as the car was designed for road compliance and to deal with a wide range of varying road surfaces and conditions being factored into ride heights and suspension geometries out of the box. For me the aim of this alignment was to generate as much mechanical grip as possible and trying to compensate for the worn suspension bushings to still keep the car friendly and firm to drive on the road!

I choose to go with a toe out setting on the front to help turn response and keep the steering feeling sharp and firm. Obviously keeping in mind the bushings in the front end were worn, i still did the best i could. I know the MX5 wont be setting land speed records for outright speed, so for Justin to make the best times he can at the track will be through corner entry and midcorner speeds. If he can get this right and steer the car well playing to its strengths the car will be very fun even for a stocker. Toe out generally makes for more lively response and better turn in response. Unfortunately with the camber angles being restricted due to the worn bushings i had to compensate with a little extra toe out on the drivers side to keep the car straight and to also help match the mechanical grip through both the front wheels. With the passenger side front reading up in the 2degree bracket there is a small amount of difference in tyre contact patch size comparing with a wheel that’s running barely 1 degree – so to keep the car steady under brakes and steering straight i gave the drivers side tyre a little more toe out than the passenger side.

I think generally as a term a wheel alignment is misunderstood out there. For some, an alignment is to straighten the wheels, and keep the car driving on centre and make sure the tyres are wearing evenly. For me its generating mechanical grip and factoring in settings such as camber and caster and toe to ultimately keep the tyre planted in the ideal position through most angles at the track(unfortunately some aggressive settings do chew tyres, but its nature of the beast – grip or trye wear?!). The MX5 is a brilliant car for this out of the box as it has adjustable camber, toe and caster! Not to mention double A arm designed suspension which keeps camber and caster on travel very consistent and liner, something that McPherson strut styles struggle to do without compromise.

First thing Dale did was check how level our floor was, which amazingly, was level!