Harewood 29th August 2004

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Back to Harewood again and as I now feel I am quite consistent here it was time to try a few suspension tweaks.

 

Harewood hill climb course map.

The course is 1448.25 metres long. The map is from www.harewoodhill.co.uk

 

 

 

Set Up: I decided to try stiffer springs for this meeting. I was concerned that the soft springs I was using may be allowing too much body roll using up suspension travel (actually going onto the bump stops) and causing the wheels to go into positive camber. So I fitted 200 lb springs on the front (170 LB before) and 250 LB to the rear (200 LB before) These were not the ideal springs to use but it is all I had. The idea is to maintain the front to rear ratio of wheel rate. Ideally to get 25% stiffer I should have used 213 LB front springs. Hopefully by running the front anti roll bar stiffer I can still maintain a balanced vehicle.

One problem of fitting the stiffer springs is that the ride height is increased. I could lower the spring seats but this would mean that the spring would rattle loose on full droop, which is not good. So the front is 16mm higher and the rear 12mm too high. I adjusted the pushrods to lower the vehicle but they are their shortest adjustment so this did not gain much. The fronts were wound two turns which is 5mm lower. (1/2" UNF x 20 TPI thread)

I also added 0.25 degree of negative camber to the rear (One complete turn of the adjuster) to compensate for the higher ride height.

I took the car on a test run with my video camera on the rear coilovers so I could observe how much suspension travel I was using. Under hard cornering under power there was about 15mm of travel left before the bump stop came into play (the bump stops are soft and progressive). However on bumpy roads the bumps really came into use.

Springs: (Front 200 LB/inch, Rear 250 LB/inch)
ARB: Drop link on the rocker in the outer hole and 25mm softer from the neutral position on the bar.
Dampers: Front Bump 6, Rebound 6. Rear Bump 4, Rebound 3.
Differential : 3.91 Open (7 1/2")

Graham Blackwell was also at Harewood in his Sports Libre Zetec powered Fiesta on slicks. I walked the course with Graham and tried to explain the correct lines up Harewood.

1st Practice Run                    Grahams
64ft...........2.50 secs              2.75 secs
Split 2........27.02 secs           27.33 secs
Split 3........16.95 secs           15.91 secs
Split 4 .......18.06 secs           17.83 secs
Split 5 .......12.09 secs           12.24 secs
Speed ........70 mph                
Time ..........76.62 secs          76.06 secs

Notes: Track was damp so I took it steady, plus I had different springs on the car. I lost over a second to Graham in split 3!

2nd Practice Run                    Grahams
64ft...........2.56 secs              2.60 secs
Split 2........25.06 secs           25.41 secs
Split 3........15.36 secs           14.68 secs
Split 4 .......16.87 secs           16.53 secs
Split 5 .......11.51 secs           11.16 secs
Speed ........72 mph                
Time ..........71.36 secs          70.38 secs

Notes: The track was practically dry with just a few damp patches. Still loosing a big chunk of time from split 2 to 3.



1st Timed Run                        Grahams
64ft...........2.68 secs              2.73 secs
Split 2........25.53 secs           25.37 secs
Split 3........15.46 secs           15.26 secs
Split 4 .......16.93 secs           17.10 secs
Split 5 .......11.57 secs           11.65 secs
Speed ........73 mph                73 mph
Time ..........72.17 secs          72.11 secs

Notes: The track was slightly damp from rain at lunch time. I was held on the line for 10 minutes which meant my tyres were cold. I normally do a few burn outs to heat the tyres for the start. If I had done my normal 64 ft time I would have beaten Graham on this run. However we both did quite well on this run. I was 40th quickest overall and Graham 38th.


2nd Timed Run                      Grahams
64ft...........2.59 secs              2.64 secs
Split 2........24.37 secs           24.04 secs
Split 3........15.39 secs           14.54 secs
Split 4 .......16.46 secs           16.23 secs
Split 5 .......11.42 secs           11.00 secs
Speed ........74 mph                
Time ..........70.23 secs          68.45 secs

Notes: The rack was dry. I tried to carry a lot of speed into the corners and scared myself. I was shaking after the run! I had very slight understeer. The front tyres were not showing signs of getting hot with rolling melted rubber as per the last Harewood meeting.

3rd Timed Run                 
64ft...........2.52 secs              
Split 2........24.52 secs         
Split 3........14.98 secs          
Split 4 .......16.90 secs          
Split 5 .......12.26 secs           
Speed ........                
Time ..........71.18 secs          

Notes: Track dry, but a big oil spill around Farmhouse Bend about 15 cars before I ran. Graham went home before this run. I went as fast as I could until Farmhouse Bend then took it easy so the first 3 splits are true, splits 4 and 5 are slow due to me backing off.

Summary: The car was slower today even though I felt I was driving as fast as previously. So this could be caused by me not driving consistently, the track being slower or the springs making the car slower. It was good to have Grahams times to compare against. I am loosing a lot of time between split 2 and 3. Willow bend is fast with no run off plus if I take it in 3rd gear I am just off cam coming out, but 2nd gear feels too low.

 

These are the split times from this meeting arranged in a table for easy comparison.

Split1: 64 ft, Split 2: Entrance to Country Corner, Split 3: Exit of Orchard Corner, Split 4: Exit of Farmhouse Bend, Split 5: Finish line.

Split
1
2
3
4
5
Time
Speed
Best from 1st Aug
2.47
24.05
14.92
16.39
11.03
68.86
75
Aug 29th Run 2
2.59
24.37
15.39
16.46
11.42
70.23
74
Aug 29th Run 3
2.52
24.52
14.98
16.90
12.26
71.18
Graham Best Run
2.64
24.04
14.54
16.23
11.00
68.45
M Geen
2.59
23.72
14.60
16.50
11.00
68.47
P Short
2.60
23.14
13.95
15.17
10.65
65.51

M Geen is on road tyres in a modified 1.4 litre Peugeot 205. He is the class record holder. P Short is in an extensively modified Mini 148bhp on wide slick tyres. Phils time was from the 1st August meeting. These times are for comparison.