Team MightyBoy

Hi! Sometime lurker, first time poster. Just got an '85 Mighty Boy today and the plan is to set it up for motorkhanas and khanacross events.

Will still need decent suspension travel for the dirt events, but want as much grip in the front as possible for the tarmac events. Stock wheels on the rear should be sufficient, but I'm looking to buy another set of wheels for the front; one pair with tarmac tyres, one pair with dirt tyres.

Not at all adverse to cutting guards and adding flares. What's the widest tyre people have got under the front? I've got a stupid cheap source for 215/45/13 slicks so that would be ideal, but I'm assuming I'm pushing my luck with that, even with flares. What have others done?

Anyone have any experience on dirt with their Mighty Boy?

You'll never get enough heat into 215 tyres on a MightyBoy. A friend with a 330hp Swift is dropping back from 215 because he can't heat them enough in sprint races around QR!

I run 6.0/21.0-13 AVON semis and they're a great improvement over any street tyre. Best part is that they tuck under standard (rolled) arches. There's also a 7.0 available if you want to run flares.

Forum member 'gazuga' has experience driving in dirt events, he might be able to give you some tips there.

That also makes sense.

Which model Avons/where from?

Brayden wrote:
I run 6.0/21.0-13 AVON semis

Formula Ford fronts?

Yep. Formula Fords run 6" on the front and 7" on the rear, but most people chase the 7s for larger cars, making the 6s easier to get cheap. Last set I bought cost me $120, and they'd only done one heat cycle (5 laps).

Ahh, that makes sense. All my sources came from the PRB series but yes, Formula Ford tyres would work well. Thank you!

I've got a set mounted on wheels if you want to buy them.
http://www.teammightyboy.com/forum/view ... =16&t=7577

You will still need decent tyres on the back, especially on the dirt. These things are so light in the backend you need as much help as possible on an autocross/ khanacross track. For the motorkhana the stock wheels are fine on the back just pumped to like 40psi to help it slide. I used to run Yokohama A539r's all round and loved them.

Thread bump, now with a slightly higher base knowledge level.

Haven't made it to any of the dirt events yet due to scheduling conflicts, but have done four tarmac events and it tripods like a boss. Setup was mostly stock MB; ie 30 year old shocks and springs. Currently running Formula Ford Avons on 13x5.5 Ford Festiva alloys at the front (thank you Brayden), and 50psi in the stock tyres/wheels on the rear (handbrake works good). Last major project was upgrading to a G10A engine and gearbox. This has doubled the power and presumably only made the weight balance more pronounced.

Problem now is that a horrendous lack of power is no longer my weak point. I have zero experience in setting up a FWD car and hear many conflicting opinions on how to improve the handling. Three wheels was fun, but two wheels was scary.



Standard advice for FWD handing is more rear sway bar. However with the amount of body roll we've got, in my mind adding more torsional strength to the rear would only exacerbate the issue. Right?

Therefore stiffer springs and shocks up front would be the go? Therefore I should be looking for a set of shocks/springs/hubs from a mk1 Swift?

What about rear springs? I'm assuming more stiffness here would help keep the inside wheel on the ground, but also I don't see lifting the inside rear as an entirely bad thing. If the inside rear lifts, weight will predominantly transfer to the outside front. Keeping weight equal across the front is presumably ideal, but getting more weight over the front is better than nothing? If I did want to go down that path, what can I do to stiffen the rear? Springs from a Hatch are stiffer? What about shocks?

What about general chassis bracing? I'd guess that there's more body roll than chassis flex at the moment, but if that was the problem, where/how would you brace?

I'm certainly not an expert on suspension, but my ute is pretty well balanced. It does have a tendency for snap oversteer, but that's only started happening with the current wheel/tyre combo.
Here's what I've learned from the evolution of my ute:

1.  Stiffer front springs make a big improvement. You can fit KSFL12 to the standard MB shocks and you will notice an instant reduction in roll (and pitch under corner braking).
2.  The rear springs are okay if you fit decent shocks. Stiffening or resetting them makes the ride far too choppy, although if you're not concerned with road handling then it is less of an issue.
3.  Front/rear swaybars will minimise entry understeer and mid-corner oversteer. Front only makes the rear end unpredictable.
4.  Solid weight behind the rear axle (in the tray, close to the tailgate) does wonders for handling. Try it and see for yourself.

 Jeo,

Remember this - a Suzi MB is a Jap version of a Morris/LeyLand Mini ute mate....
East/West motor + box all up the front so you will lift those rear wheels all day
long with more HP added.
In the good old days before I bought a bunky MB, I have flogged plenty of
Minis/Mokes on tarmac m/khanas - we all had at least 1 wheel off the ground
on a regular basis - good clean fun I say!!!
A quick Cooper S on a full circuit track will regularly lift the rear wheels (at least
the quick WA peddlers do it at Barbagallo here in Perth.
I like the idea of strategically placing weight in the ass near the tailgate to hold her
down - old school style like the old Holden/Ford 1 tonner utes at the drags.
Too much wheel spin with a carby v8 but if ya chuck some weight in the back of
the old hack she squats and goes!!!
Anyway, glad to hear you are having a ball with motorkhana Jeo - it is good clean
fun - good to get kids into and learn car control so when they turn 17 they don't
wipe themselves out on the highway.

Stiffer front springs (and shocks if they appear) as the first port of call it is.

Brayden - which shocks for the rear? Can I grab them from something else, or do you just mean new, not 30 year old shocks?

G man - I'm not saying lifting the inside rear is bad, but lifting both inside wheels certainly wasn't much fun. Inside rear limiting means weight transferring to the outside front, giving me more traction to pull out of the corner. That works great until I'm lifting the inside front as well, at which point the car just rolls if it goes to far. Problem is that I am now lifting the inside front as well.

Lower and wider would help that problem too, but I'm conscious the stresses that puts on the other components. I do have a set of 13x7 Hotwires which are currently fitted with a shagged set of slicks. The stupid thing here though is not just how they look, but rather that even with the giant slicks, they're less than 500g heavier than the stock wheel and tyre. Even if they weren't dead though, I couldn't run the slicks in my class so will need new tyres. The lower offset means that the do 'fit' (seriously, the inside clearance is nearly perfect with these tyres) but because of the offset, even though the weight is similar, it's further out which effectively has more leverage.

God I want some meaty bolt on flares though...

Jeo wrote:Brayden - which shocks for the rear? Can I grab them from something else, or do you just mean new, not 30 year old shocks?

Any decent gas shocks will do. There are a handful of manufacturers that sell a bolt-in product. You'll see the difference before you even fit them when compared to OEM units.

SA Swift shocks/springs - do I need the hubs as well?

KSFL-12 springs (for a MK1 Swift) are a perfect fit for standard MB struts.