Mantorp - slicks vs CR500

Mantorp, again. A new personal best, again - 1.21,8!!! That is 1.5 seconds faster than last time, and I haven't changed anything except put on a new set of (second hand) rubber. I never thought I could reach laptimes like that!

At the end of the day I mounted a set of standard 15" rims with Avon CR500 tires just to see the difference compared to the Dunlop Radical slicks. 1.24,8 or 3 seconds. That is a big difference, no questions about it, but with the CR500 the car suffered tremendously from understeer and I think the difference would be less if I took the time to adjust the suspension to suit the tires better. Not to mention tires with better dry performance than CR500.

Slicks in red, CR500 in blue.

I also put zip-ties on the damper rods and that confirmed my suspicion that the front dampers bottoms out onto the bump stops. I don't know if it is while cornering or while braking, but that is something I should look into next time.

Riding on the bump stops is not necessary a bad thing. Read an article here.

OptimumLap simulation software

I got an invite to test a new software for simulation of how fast a car can run one lap on a race track, called OptimumLap. It uses a simplified model of how a car behaves on a race track, but according to the company, despite the simple model it gives results that are accurate within 10%.

I have only good things to say about the software, and if you get the chance I suggest that you should try it out. Atleast for me it was a bit of an eye opener.

In the software I constructed seven variations of my car, and run it in the simulator on two Swedish tracks. The simulated lap times was a bit from my real world actual lap times, but it is still very useful for finding out what changes to the car could make a significant improvement.

Mantorp - A wide track with a long straight and high average speed.

1. Current setup: 85,72s
2. 10% more tire grip: -2.43s
3. 160N more downforce @100 km/h: -1.05s
4. 10% more power at rear wheels: -0.80s
5. 10% less drag: -0.28s
6. 30 kg less weight: -0.26s
7. All of the above: -5.66s

Gotland Ring - A very technical track with hills and cambered corners.

1. Current setup: 83.81s (I wish...)
2. 10% more tire grip: -1.55s
3. 160N more downforce @100 km/h: -1.34s
4. 10% more power at rear wheels: -0.31s
5. 10% less drag: -0.19s
6. 30 kg less weight: -0.04s
7. All of the above: -4,60s

The results are quite interesting.

• Tyre grip is very important, of course. No big news here.
• Some extra horses would be nice on Mantorp, but expensive and 10% more hp is a lot.
• Working on reducing drag is nice, but not that much to work on.
• Reducing weight does almost nothing on Gotland Ring!
• Adding downforce does a lot! Over a second on both tracks, that is really something that could be improved!

Adding downforce to a seven type car is almost as swearing in church, but what if it is a wing that could be removed when not on a track? I have no idea of how much downforce a wing could provide, but to me 160N at 100km/h doesn't sound completely unreasonable? Of course the drag would increase as well, but it would still be an easy and cost effective way to loose some lap time. I believe a front wing would be most beneficial since I use to experience some understeer on high speed corners, probably because of lift.

A quick Google search gave me this: Levante front wing 

I'll start looking for options...

Paddle shift

Here is a can't miss video of a CSR 260 with Geartronics Paddle shift and a straight cut Quaife 60G 6 speed sequential gearbox.



Unfortunately the price tag for a system like this is up at the roof, and personally I'm not sure I could live with the gearbox noise even if my car is quite track oriented.