2004-07-14

2004-07-14

I've spent a couple of days planning, designing suspension, and tidying ready for some serious fabrication work.

Here's the state of the garage….

The engine's now at the right height, ie the final height it'll end up. I've had a good tinker with it today, and it's a nice bit of kit. At least it would be with no melted pistons etc 😕

All ready for the new front end.

Firstly, another goodie!

It's a second hand AP sprung paddle clutch for the T5. I'll need to get the pug flywheel redrilled to fit.

Here's the flywheel.. note the crank timing teeth next to the ring gear! bit of a weird way of doing it!

it's quite heavy, but pug have taken quite a considerable amount of material out of the back of it to lighten it. even so, I'd say it was around 8-9 kg. I must get some scales! If I want to lighten it further, then I'll probably need to get a flywheel made from scratch, as the ring gear is offset towards the crank relatibe to the mounting. due to the offset, there's probably very little machining possible to lighten it without weakening it considerably.

I've finished the suspension design. The more I do, the more I realise I don't know or don't quite understand. I've done it top the best of my current understanding and ability, and while I'm sure I'll be able to do a better design next time, I'm going to stick with it.

here's the stats from the simulation, if anyone's interested.

code:1

Outer wheel (LH) roll centre
camber caster kpi scrub tramp toein offset height fvsax
0.00 roll 0.00 1.00 4.72 0.00 0.00 0.00 0.00 43.71 2721.49
0.50 roll 0.36 1.04 4.36 0.00 0.05 0.00 -2.87 43.74 2500.22
1.00 roll 0.70 1.07 4.02 0.00 0.10 0.00 -5.65 43.82 2311.52
1.50 roll 1.03 1.11 3.68 -0.01 0.15 0.00 -8.28 43.95 2148.44
2.00 roll 1.35 1.14 3.36 -0.01 0.20 0.00 -10.66 44.13 2005.90
2.50 roll 1.66 1.17 3.06 -0.02 0.26 0.00 -12.73 44.37 1880.08
3.00 roll 1.95 1.21 2.76 -0.02 0.32 0.00 -14.42 44.67 1768.07
3.50 roll 2.23 1.24 2.48 -0.03 0.38 0.00 -15.64 45.01 1667.60
4.00 roll 2.50 1.26 2.21 -0.04 0.45 0.00 -16.33 45.41 1576.89

Inner wheel (RH) roll centre
camber caster kpi scrub tramp toein offset height fvsax
0.00 roll 0.00 1.00 4.72 0.00 0.00 0.00 0.00 43.71 2721.49
0.50 roll -0.37 0.96 5.08 0.00 -0.04 0.00 -2.87 43.74 2985.03
1.00 roll -0.75 0.92 5.46 0.00 -0.09 0.00 -5.65 43.82 3304.90
1.50 roll -1.14 0.88 5.86 -0.01 -0.13 0.00 -8.28 43.95 3702.16
2.00 roll -1.55 0.84 6.26 -0.01 -0.16 0.00 -10.66 44.13 4209.96
2.50 roll -1.96 0.79 6.68 -0.02 -0.20 0.00 -12.73 44.37 4883.58
3.00 roll -2.39 0.75 7.11 -0.03 -0.23 0.00 -14.42 44.67 5822.63
3.50 roll -2.83 0.70 7.55 -0.04 -0.26 0.00 -15.64 45.01 7226.66
4.00 roll -3.29 0.66 8.00 -0.05 -0.29 0.00 -16.33 45.41 9562.40

LH wheel rc roll centre height
camber caster kpi scrub tramp toein offset chassis ground fvsax
100.00 bump -3.58 1.45 8.30 -0.65 0.98 0.00 0.00 49.83 -50.17 1109.83
80.00 bump -2.62 1.38 7.33 0.46 0.74 0.00 0.00 46.91 -33.09 1275.36
60.00 bump -1.78 1.30 6.50 1.10 0.52 0.00 0.00 44.96 -15.04 1484.69
40.00 bump -1.07 1.21 5.79 1.26 0.33 0.00 0.00 43.85 3.85 1759.98
20.00 bump -0.48 1.11 5.19 0.89 0.15 0.00 0.00 43.47 23.47 2142.83
Static 0.00 1.00 4.72 0.00 0.00 0.00 0.00 43.71 43.71 2721.49
20.00 droop 0.36 0.88 4.35 -1.44 -0.13 0.00 0.00 44.46 64.46 3721.22
40.00 droop 0.62 0.74 4.10 -3.45 -0.23 0.00 0.00 45.60 85.60 5938.14
60.00 droop 0.75 0.59 3.97 -6.03 -0.31 0.00 0.00 47.01 107.01 15665.87
80.00 droop 0.76 0.43 3.96 -9.21 -0.37 0.00 0.00 48.54 128.54 -20644.88
100.00 droop 0.63 0.26 4.08 -12.98 -0.40 0.00 0.00 49.97 149.97 -5772.64

Equivalent suspension travel due to chassis roll
inner (RH) outer (LH)
0.00 roll 0.00 0.00
0.50 roll -6.55 6.54
1.00 roll -13.10 13.08
1.50 roll -19.65 19.62
2.00 roll -26.20 26.15
2.50 roll -32.76 32.67
3.00 roll -39.31 39.19
3.50 roll -45.87 45.70
4.00 roll -52.42 52.21

Side view swing axle and instant centre
IC IC axle
length height height angle
100.00 bump 19926.61 -13.61 -1.73 -0.04
80.00 bump 16505.79 49.43 7.58 0.17
60.00 bump 14075.53 93.07 16.73 0.38
40.00 bump 12262.34 124.78 25.74 0.58
20.00 bump 10856.22 148.69 34.65 0.78
Static 9730.27 167.23 43.48 0.98
20.00 droop 8803.27 181.91 52.28 1.18
40.00 droop 8020.60 193.67 61.09 1.38
60.00 droop 7343.88 203.10 69.97 1.58
80.00 droop 6744.78 210.56 78.98 1.79
100.00 droop 6201.22 216.23 88.22 2.00

LH
brake drive
a-dive% a-lift%
100.00 bump -0.3 0.0
80.00 bump 1.1 0.0
60.00 bump 2.5 0.0
40.00 bump 3.8 0.0
20.00 bump 5.1 0.0
Static 6.4 0.0
20.00 droop 7.7 0.0
40.00 droop 9.1 0.0
60.00 droop 10.4 0.0
80.00 droop 11.7 0.0
100.00 droop 13.1 0.0

Rack and pinion RHD, front steer (auto-calculated chassis pivot)

Ackermann point – behind front axle cl 10337.19
– behind rear axle cl 7807.19 308.58% of wheelbase
Wheel toe reference length 471.00

Bump steer absolute
degree mm
100.00 bump 0.04 0.32 toe out
80.00 bump 0.02 0.16 toe out
60.00 bump 0.01 0.06 toe out
40.00 bump 0.00 0.01
20.00 bump 0.00 0.00
Static 0.00 0.00
20.00 droop 0.00 0.00
40.00 droop 0.00 0.01
60.00 droop 0.01 0.05 toe in
80.00 droop 0.02 0.13 toe in
100.00 droop 0.03 0.26 toe in

Right hand turn. LH wheel is outer, RH wheel is inner.
Toe out in turns Rack Camber (actual) Camber (change) Jacking effect
Outer Inner travel Outer Inner Outer Inner Outer Inner
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
5.00 -5.03 9.65 -0.07 0.10 -0.07 0.10 -0.08 0.12
10.00 -10.11 19.28 -0.10 0.24 -0.10 0.24 -0.11 0.28
15.00 -15.24 28.81 -0.10 0.42 -0.10 0.42 -0.10 0.47
20.00 -20.40 38.16 -0.06 0.63 -0.06 0.63 -0.06 0.71
25.00 -25.59 47.25 0.02 0.88 0.02 0.88 0.03 0.98
30.00 -30.79 55.99 0.13 1.16 0.13 1.16 0.16 1.28

/code:1

Rockers are out, as they add to the cost and the complexity, and really don't provide me with much extra! I've eliminated bump steer, and the camber change on roll is nice and smooth. The scrub radius is static at 0 for most of the time, which means minimal steering effort. I've not worried about anti dive much, I want to keep it as simple as possible. I'm sure it isn't the best possible design, but it should keep me on the road. I can always refine it once I've driven it.

Of course, now I've got to build it!

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