Right then, what spares would be worth carrying?

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mac
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Re: Ok then, what do I NEED to do to the car, and me

Post by mac » Fri Feb 13, 2009 8:38 am

If your in a road class and your car requires a CAT to pass MOT, roadside emissions tests etc then it should be fitted, but from this year on all cars from 1999 onwards require a CAT even if they aren't in road classes (certain exemptions apply)

I'm quite pleased I bought a 1997 kit built caterham :D
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Re: Ok then, what do I NEED to do to the car, and me

Post by Victor Meldrew » Mon Mar 02, 2009 10:32 pm

Victor Meldrew wrote:Home for in 2009

SSC Round 1 12 April 2009 Kames
SSC Round 2* 24 May 2009 Kames
SSC Round 7* 04 July 2009 Boyndie
SSC Round 8 05 July 2009 Boyndie
SSC Round 10* 01 August 2009 Kames
SSC Round 11 02 August 2009 Kames
My dates now clash with my mates Stagg Night, so Golspie is now out... (Beer and Boobies always come first :lol: )
SSC Round 12* 12 September 2009 Golspie Littleferry
SSC Round 13 13 September 2009 Golspie Kylestrome
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Re: Ok then, what do I NEED to do to the car, and me

Post by Victor Meldrew » Sat Mar 14, 2009 12:20 am

heading to Kames Saturday to get the car checked over. Anyone else going?
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Re: Ok then, what do I NEED to do to the car, and me

Post by Victor Meldrew » Sun Mar 15, 2009 12:13 am

Well that was interesting.

Arrived at Kames around lunchtime. Was made to feel very welcome by everyone there. Car went through the checks fine, the MSA scrutineer gave it a good going over and was happy with everything that had been done, all I need to do is fit the catalyst. (was going to do it yesterday but it was raining)

Lesley let me run the afternoon test session as there had been a few cancelations so that was a real bonus, I only went to get the car looked over. Noops was quickly drafted in as photographer and pit crew.

The TPMS was lashed up and works very well. We did some messing with different tyre pressures to see if there was any changes over the course of a two lap run. Very surprising the way the tyres behaved.

I remember reading a Toyo motor sport publication saying that the optimum "hot" pressure for 888"s is 39 psi or slightly less for a lighter car. So we kept pushing the pressure up the way until we got the car ending the run with 35/35 psi front and 38/38 psi rear. The car just got better and better each run. We dropped the front down by 2 psi and had another run but lost front end bite again.

It is probably the first time I have been able to really feel the difference that tyre pressure has, due no doubt to the significantly harder springs that the Hofmann's spec Nitrons have, the Hofmann's spec anti roll bar still has to go on yet so that should help front end bite a bit more.

So.. ended up going against convention and ran a cold pressure of F33/33 - R36/36

One other thing I did learn is that I cant change down gears and brake at the same time.... so.. maybe another visit to Walshy would help with that. But for now I will drive round it by braking a few feet earlier.
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Re: Ok then, what do I NEED to do to the car, and me

Post by Victor Meldrew » Sun Mar 15, 2009 12:56 am

Will need to make a few phone calls to those in the know to see if they have found similar results..
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Re: Ok then, what do I NEED to do to the car, and me

Post by Andy G » Mon Mar 16, 2009 11:29 am

jesus - suppose with 3 laps you arent going to get much temp in them, but stunned tyre pressures that high were any good at all - you must have been up to the best bit of 40PSI after 3 laps of hammering it :shock: :shock: :shock:

Did you try dropping them to low 20's?

From Cold my psi for Elise trophy was 16F and 16.5R, with A048's for your info :wink:
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Re: Ok then, what do I NEED to do to the car, and me

Post by fd » Mon Mar 16, 2009 12:45 pm

Victor Meldrew wrote: So.. ended up going against convention and ran a cold pressure of F33/33 - R36/36
Were they timing things ? Does seem very high but if it works for you then great . . .

Kames at the best of times is a tyre killer at full pace, I only get 2 laps out of my tyres on the caterham before they really start going off, rears especially get completely destroyed . . . it's the harshest event in Scotland on tyres by a fair margin I think . . .
Victor Meldrew wrote: One other thing I did learn is that I cant change down gears and brake at the same time.... so.. maybe another visit to Walshy would help with that. But for now I will drive round it by braking a few feet earlier.
I'm sure anybody who knows how to H&T could teach you in an hour or so it really isn't difficult, then you just need to practice . . . but under pressure at somewhere like Kames is almost certainly not the place to learn . . . I'm assuming that your comment above relates to H&T rather than something else ;-) . . . I would also suggest short cutting all gear changes and ignoring intermediate gears, so 4-2 instead of 4-3-2, there just isn't enough time to be fannying about with unnecessary gears . . . you probably don't even get to 4th in the Elise on Kames do you ?

Fd

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Re: Ok then, what do I NEED to do to the car, and me

Post by Victor Meldrew » Mon Mar 16, 2009 10:23 pm

Andy G wrote:jesus - suppose with 3 laps you arent going to get much temp in them, but stunned tyre pressures that high were any good at all - you must have been up to the best bit of 40PSI after 3 laps of hammering it :shock: :shock: :shock:

Did you try dropping them to low 20's?

From Cold my psi for Elise trophy was 16F and 16.5R, with A048's for your info :wink:
About f23/23 R26/26 and the car had very little front end bite and the tyres felt as if they were falling off the rims. There was no significant increase in pressure over the run, possible issue was the 195/50 tires on 6j wheels but the rear end felt as if it was falling over as well.

We fitted the TPMS system the day before so we could monitor the pressure through the run.

I remember reading a Toyo technical leaflet stating the optimum "hot" pressure is 39 psi. (or less if the car is lighter) so over the course of the day we increased them in stages. There was no timing but the car felt better and I was able to go for third coming out of the hairpin later in the day so I am sure I was carrying a fair bit more corner speed.

The only logical explanation is that it was running on the centre section of the tyres and I was therefore able to get more heat into them quicker. Narrow contact patch heats up quicker. :?:
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Re: Ok then, what do I NEED to do to the car, and me

Post by Victor Meldrew » Mon Mar 16, 2009 10:30 pm

fd wrote:
Victor Meldrew wrote: So.. ended up going against convention and ran a cold pressure of F33/33 - R36/36
Were they timing things ? Does seem very high but if it works for you then great . . .

Kames at the best of times is a tyre killer at full pace, I only get 2 laps out of my tyres on the caterham before they really start going off, rears especially get completely destroyed . . . it's the harshest event in Scotland on tyres by a fair margin I think . . .
Victor Meldrew wrote: One other thing I did learn is that I cant change down gears and brake at the same time.... so.. maybe another visit to Walshy would help with that. But for now I will drive round it by braking a few feet earlier.
I'm sure anybody who knows how to H&T could teach you in an hour or so it really isn't difficult, then you just need to practice . . . but under pressure at somewhere like Kames is almost certainly not the place to learn . . . I'm assuming that your comment above relates to H&T rather than something else ;-) . . . I would also suggest short cutting all gear changes and ignoring intermediate gears, so 4-2 instead of 4-3-2, there just isn't enough time to be fannying about with unnecessary gears . . . you probably don't even get to 4th in the Elise on Kames do you ?

Fd
The problem with the brakes is the rear locking when the clutch goes down... classic schoolboy error.. if you watch the "Walshy video" it shows exactly what I was doing wrong. I just don't know the best way to correct it. The problem is going from third to second prior to the turn in for the hairpin. Its defiantly a weakness that has been seen before on track..

Oh, nearly getting to fourth before the entry to the hairpin but to chicken to go for it because of the brake issues. (I had one overshoot and had to pick the escape road, after I tried dropping the pressures again, didn't have the same front end grip)
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Re: Ok then, what do I NEED to do to the car, and me

Post by fd » Mon Mar 16, 2009 11:44 pm

. . . you should get someone else to drive the car and make sure the bias problem is not abnormal . . . you really have to be able to press the clutch pedal whilst braking heavily without locking the rears . . . else the car is going to be very limited . . .

Fd

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Re: Ok then, what do I NEED to do to the car, and me

Post by BiggestNizzy » Mon Mar 16, 2009 11:45 pm

Did you try measuring tyre temps across the width of the tyre ?
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Re: Ok then, what do I NEED to do to the car, and me

Post by Victor Meldrew » Tue Mar 17, 2009 12:23 am

fd wrote:. . . you should get someone else to drive the car and make sure the bias problem is not abnormal . . . you really have to be able to press the clutch pedal whilst braking heavily without locking the rears . . . else the car is going to be very limited . . .

Fd
Its going down to Dans to get the geo sorted.. he has been given free reign to rag the nuts out of it to see what he thinks... I don't think its a bias problem as it has the larger AP front disks... anyone who can pedal are welcome to have a shot to see what they think.

We didnt measure the temp.. although I did have a digitherm in the bag... forgot all about it until I was on the way home.
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Re: Ok then, what do I NEED to do to the car, and me

Post by alicrozier » Tue Mar 17, 2009 9:42 am

Yeah, measuring tyre temp across the width would give you the info you need on pressures.

Not sure about locking the rears, bias is normally too far forward and with your bigger fronts will be even more. I assume it was dry. What sort of rpm were you changing down to? i.e. what were the revs when you let the clutch up in 2nd?
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Re: Ok then, what do I NEED to do to the car, and me

Post by Andy G » Tue Mar 17, 2009 10:18 am

HI John

Regarding locking the rears, brake all the way to the corner, and change down last thing. Ali Crozier is probably the best person to watch do this, I'm sure he could point to some of his in car stuff to see what i mean, exceptionally smooth, and no wasted effort/gear changes etc. (which in turn will reduce the amount of locking up)

The RLC would lock up, but this was due to the car being able to generate way more braking force than the tyres could cope with (RS14's & AO48's), and changing gear just excerabated the entire thing. Loosing engine braking was enough to trigger this. While you can minimise this, I ultimately just drove through it, while trying to reduce it as much as i could. Slight brake pedal moderation at this point may help?

Start braking with increased pressure, and leave the gear change till way later if you can.

With regards to the tyres feeling like they are falling off the rims, mine used to feel like that for the first 2 corners....ultimately though if you think its working for you, ignore us, just trying to help. If you are more confident (being the key to it all) with the tyres at higher pressure, then that will most likely count for more time improvements regardless.

Kames, as FD has said, is also very hard on the tyres, the Atom just hated the place - although it was awesome to drive round it - it was very very hard on the car and tyres.

When you said the front wasnt gripping, do you mean it wasnt turning in? In this case is it not more likely that the difference between the nitron settings front to rear wasnt enough or the front was set to hard?

What settings did you run at?
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Re: Ok then, what do I NEED to do to the car, and me

Post by Victor Meldrew » Tue Mar 17, 2009 11:13 am

alicrozier wrote:Yeah, measuring tyre temp across the width would give you the info you need on pressures.

Not sure about locking the rears, bias is normally too far forward and with your bigger fronts will be even more. I assume it was dry. What sort of rpm were you changing down to? i.e. what were the revs when you let the clutch up in 2nd?
Not sure about the rev's, wasn't really thinking about it, just running on instinct. Needs more work. It was mostly dry, very cold.
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