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6 May 2012, 21:23 (Ref:3070380) | #1401 | ||
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Clive:
Those are the rear tyre size today. The wheels spin, certainly do not bog down! The Impreza was 1250 Kg/370 bhp and 4 x 4 on 205 section slicks, lsd rear diff open front. The 911 is 1000Kg/230 bhp 2 rear drive on Kumho V70 soft spec tyres, open diff The Lola is 580 kg/ 250 bhp (without me), 12" tyres, Quaife diff. Engine is set at 6400 due to Porsche specs (rod bolts not the strongest). Red line is actually 6250 so I'm over the top a little as it is.. On another note! In my history of the car I thought Bernie Garwood owned the Lola. He did not! In 1980 in the Caribbean Airlines race Peter Newman raced the car. He (Peter) owned it! I've had an informative pm from Peter's nephew tonight who recalls the car and his uncle Peter. Thus the history is Perter Sadler bought it new, Peter Newman bought it from Peter. Interesting Paul Wilkins bought it from Bernie!! Last edited by 911thillclimber; 6 May 2012 at 21:38. |
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7 May 2012, 07:19 (Ref:3070508) | #1402 | |
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Glad things are going well after all your troubles. Only been to Shelsley Walsh once but enjoyed it.
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7 May 2012, 09:40 (Ref:3070570) | #1403 | ||
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Maybe softer rear springs to increase the traction off the line?
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7 May 2012, 14:10 (Ref:3070670) | #1404 | ||
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....but softer rear springs will exacerbate the problem with the rear tyres fouling the arches in roll.
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7 May 2012, 14:26 (Ref:3070674) | #1405 | ||
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Springs are 20Lb heavier than Lola specified for the car due to heavier engine /box.(300lb)
Fronts are as Lola spec. |
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7 May 2012, 16:53 (Ref:3070740) | #1406 | ||
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I've been giving some thought to the business of the car being slow on initial take-off, which is of course vital for a hill climb car.
What rear tyre pressures are you running? At what is the the rear toe set? How much negative camber has the rear suspension got? Isn't it nice just for once to be talking after an event about fine tuning, rather than misfires, recalcitrant gear changes, and gearbox/clutch problems! |
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7 May 2012, 18:00 (Ref:3070768) | #1407 | |||
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Quote:
I don't know a lot about running slicks in historics (my knowledge was contemporary), but nowadays earlier (e.g. treaded tyre) cars tend to run springs that are considerably stiffer than original because current tyres have more grip (possibly because they are wider rather than the compound differences). I know even less about hillclimbs, but the needs must be rather different to circuits since you don't have time to fully warm the tyres, so I would expect you to need different settings for hillclimbing. Modern tyres will always be different to original tyres and will consequently benefit from non original suspension settings and softer rear springs should be worth a try. |
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7 May 2012, 18:04 (Ref:3070770) | #1408 | |
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Traction
I was wondering more about dampers and also anti squat geometry. Can you add more rear anti squat by altering the holes the radius arms go through onto the chassis? I think on a 492 you have a few options on the lower arm, but then if you do that you may have to re-set the bump steer too. All fun!!
Glad the engine is now on song!! Mark |
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7 May 2012, 18:45 (Ref:3070788) | #1409 | ||
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This car will never be finished!
Hillclimb slicks are strange things, compound is A15 AVON (soft as you dare go for a dry track tyre) and heat up very quickly. to fully spec for you all; Rear geo: 0.25" toe in, 0.50" neg Camber. Rear tyres about the same temp at the top of the hill right across the width (12" tyre) Front tyre temp is cold but even across the tread. Car drives a dream on track. Tyres are crossplies not radials. Pressures are 16psi Fr and 18psi Rr. Checked and set 5 mins before each run. Rear springs are 300 lb Car weight without me but wet = 591Kg Ride front = 3.25" Ride rear = 4.75" The 492 has 3 positions for each radius arm to the rear bulk head,, all are in their middle holes. Corner weights set. When I started choosing engines for the car i seem to recall the mighty 3.2 Porsche engine (alloy crank case and alloy gearbox case) was 20Kg heavier than the Pinto and a Hewland Mk8 The car now has a magnesium cased gearbox, so 3 or 5 Kg lighter. Clive: Yes, great to me considering the fine tuning rather than the blunt issues I've been through! One thing for sure is if there are any changes to be made it will be Sean at McClurg Motorsport who will tweek it. I know my limits... |
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7 May 2012, 19:10 (Ref:3070805) | #1410 | ||
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Hmmm.... I'd be inclined to try on one run on a practice day maybe 4lbs off the front tyre pressures, and two lbs off the rear. This might get some heat into the fronts, and improve the traction off the start for the rears. If the fronts are still cold, I'd be inclined to dial in a wee bit more negative camber.
Against this, given that the engine and gearbox are working properly, you now have to learn how to drive the car on its own merits, so slow but steady progress should be the order of the day! |
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8 May 2012, 07:03 (Ref:3070991) | #1411 | ||
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Sounds like another morning at Curborough is required
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8 May 2012, 16:37 (Ref:3071296) | #1412 | ||
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That is the best solution Andy I agree.
Barbon Manor this Sat then to Italy for a holiday (to a certain Italian race) then a string of hillclimbs. Hard to get a day off in between but July should be possible. Dropping 4 psi from 16 to 12 sounds quite a drop, but worth creeping up to it! I also need to find the level of lateral grip too, and that is where Curb would be a good thing. |
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8 May 2012, 17:22 (Ref:3071319) | #1413 | ||
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16psi to 12 is quite a change, but given that the rears are probably a little too hard at 18psi for best traction of the startline, and that the fronts are coming up cold, given the limited running that a hillclimber gets, it's probably worth the punt. It's about the sort of cold pressures at which I would run a mid-engined two litre Special Saloon (Stiletto, Skoda, or even a KG), but they had the luxury of warm-up laps!
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8 May 2012, 19:50 (Ref:3071391) | #1414 | ||
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Points well taken Clive.
Here is a little clip of the starts last weekend: http://www.youtube.com/watch?v=uBRjq...yer_detailpage |
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10 May 2012, 22:18 (Ref:3072448) | #1415 | |
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It's hard to tell from the clips but is 1st very short? Have you tried a practice start in 2nd?
Agree about dropping the pressures, sometimes it is worth quite a big change just to see if it is in the right direction. Hope it all goes well at Barbon. |
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11 May 2012, 05:32 (Ref:3072531) | #1416 | ||
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It is a stock Porsche road going gear set in 1st and the tyre dia is close to 911 dimensions.
Will try a start in 2nd, but suspect it will bog down. I need to calm-down my launch. In the 911 with huge weight transfer 'quality' off the start it is 4000 rpm and lift your left leg asap. Bags of traction, first 64 feet = 2.16 secs In the Impreza on slicks it was 6500 and lift the leg very asap to avoid clutch slip. Tons of traction with 4x4 and 64 feet in 1.86 secs (well over 1 G) I need to think a police man is there watching me start... Lola = 2.3 secs |
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11 May 2012, 12:21 (Ref:3072653) | #1417 | |||
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Quote:
It may be that all the ratios in your box are too low; we currently suspect that first may well be, and know from your Shelsley Walsh escapades that fourth certainly is. Is there a taller CWP ratio available for your Porsche gearbox? Does a turbo gearbox have longer overall ratios, and if so, would it be a direct swap for the present unit? As I said earlier, now the car is running properly, the fun really starts.... |
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11 May 2012, 13:48 (Ref:3072681) | #1418 | |
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12 May 2012, 20:57 (Ref:3073255) | #1419 | ||
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BLOODY HELL!
Today we ran Barbon Manor, I think the shortest of the hills in the UK, and set in Kirby Lonsdale. I love this tight fast hill. 5 in the class, including an Audi Quattro short wheel base, that looks like a Pikes Peak runner, just the most beautiful car and having sat in the thing it just so fits me you cannot believe, a fab car. The Lola was faultless gentlemen. Others suffered issues but the Lola was 100%. Took time out of the hill bit by bit to within 0.2 sec of my class record in the Impreza. I dropped the tyre pressures slowly (easy as two leak...) down to 13 / 16psi It simply ran and ran, what a game! The engine was fab, the gearbox was fab and I felt there was tons of time to be collected along the way. Truely fantastic, and such a joy to have and to thrash the bollo"x off. I so enjoyed telling people that it was working and there was more to come if the old fart of a driver had the b££lls to go for it. It has been a long time coming, but it really was great. |
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13 May 2012, 16:24 (Ref:3073819) | #1420 | ||
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This is great news, Graham. First the pain, now the gain.... I'm sure that, given that the engine and gearbox continue to co-operate, you will now be able to concentrate on learning the car, and the times will continue to improve.
Were you able to gain any impression as to the benefits or otherwise of running lower tyre pressures? Specifically, did lower rear pressures improve the traction off the line, and did the reduced front pressures improve the turn-in to corners? All in all, a great pecursor to your well-earned break in Italy. |
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13 May 2012, 17:36 (Ref:3073876) | #1421 | ||
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Things do look on the 'up' at last Clive.
Funny just how many people come up and say, 'I've been following your thread on 10/10ths and...' even at a little hillclimb meeting. I started the day on 16Fr/18Rr as I have always run the car since the suspension set-up with McClurg Motorsport at Curborough early last year. Traction off this very green (but swept) track was poor, and i was not the only one to grapple with it. I had two practice runs and two race runs. I dropped to 14/16 and the car seemed the same to me but starts were better but I did calm down and pretended a Police Man was standing there... Then for the last run 13/16 which seemed good to! Bends/braking etc all seemed much the same but I would have to say the car felt more stable though I think that is just me focusing now on driving it. Barbon is a very narrow track and it sweeps through some very old bloody big trees, so the first two runs were a bit tentative I am absolutely sure there is another second to come from the car in my hands if I had another two runs yesterday! The guy who built the gearbox has his shop just a few miles from the hill and Mike dropped-in to see things for himself. I think we have agreed to pop another taller diff into the box which will jack all the ratio's up. Will have to wait to do this, but can i resist doing it in July? Depends if Italy is expensive (!) We are going to the Mille Miglia next thursday and then 10 days on Lake Como to chill-out and take stock of all things in life, especially work! Weekend after we are at Shelsley Walsh again and I have a plan for that to find 0.5 or even a whole second. Means taking a certain notorious bend in 4th instead of 3rd.... |
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14 May 2012, 16:41 (Ref:3074446) | #1422 | ||
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http://i183.photobucket.com/albums/x...g/S1050106.jpg
http://i183.photobucket.com/albums/x...g/S1050108.jpg http://www.youtube.com/watch?v=tRu0V...yer_detailpage Last edited by 911thillclimber; 14 May 2012 at 16:58. |
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15 May 2012, 21:59 (Ref:3075043) | #1423 | |
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Well done, glad you are enjoying it. It looks & sounds quite civilised.
Now, how far is it from road legal......? |
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20 May 2012, 17:18 (Ref:3076923) | #1424 | |
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26 May 2012, 15:44 (Ref:3079543) | #1425 | ||
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Road legal?
I know to 3 T 492's that are/were road registered! One is going back to track-only once all the glued-on carpet and handbrake is removed... Just back from the hols in Italy. If you have never been to the Mille Miglia, just do it. You WILL be most impressed. Shelsley Walsh next weekend, 7 in class, going to be tough. Another Libre car in the form of a Saker will be appearing, just to make it worse.. 2 years ago I was alone, now I am not. My car is the oldest, but I'm not the oldest pilot. |
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