TimeAttack - "King of Mantorp"

Valtonen Motorsport RX-8

Normally I don't like to compete but somehow I participated a Time Attack competition this weekend. Seven type cars are not allowed in their series, but this time they had a "no limits" class. Some of the competitors car's was completely insane, as the tube frame, all carbon RX8 to the right, accompanied by a complete race team.

Photo: Felix Eriksson

I managed to get the 4:th place. I'm really satisfied with that. Not so much for the final time (1.23,4), but that I kept my head together and managed to get a good run in the super final which was one lap only!

In fact, the qualifying lap and final lap was one second faster than all my practice laps during the whole day!


The official noise check reported 97.5 dbA drive-by which they said they allow today but not tomorrow. I'm getting there...

Everything else worked very good, except....

Gearbox problems!

Just when the day ended something happen with my gearbox on the cool-down lap. I works but makes some chirp noises and the gears are hard to engage. .... .... ghh

Update: I got a couple of seconds of fame in this movie:

Finally some driving!!

A "test drive a Radical SR3" event at Mantorp. I was also invited but drove my own car.

The engine runs great! The car handles great! Even the weather was great! My driving - not so great, but who cares? Well not that bad, today's best was 1:22.3. Compared with my all time best 1:21.8 it is all right considering I had no "rabbit" in front of me and I was feeling a bit rusty. The Radicals didn't stand a chance with those inexperienced drivers.

But of course...

Fuel surge and alternator problems!!

This spring when my engine broke, it was because of the small wire from the alternator went loose and it stopped charging the battery. The fuel pump couldn't keep up with the lower voltage and the engine run lean. Things got hot inside the cylinders and the engine got damaged.

Today the alternator broke completely.

The same symptoms - no power on the long straight. But this time I knew, and backed off the throttle immediately. Also the no-charge light on the dash was lit this time.

I also experienced fuel surge in the long right hander "Parisern" when the fuel level was below half. I always had that problem, even with the stock CSR200 engine. Today it annoyed me more than ever before.

I need a more robust fuel system! I can't risk loosing my engine because the alternator fails, or if a connector jumps loose.

Anyway I got five or so laps on film. Here are a couple of them. I'm not very satisfied with my driving here, as soon as I try to push hard I get sloppy and miss the apexes.

Mantorp first time 2013

This years first trackday was a warm day with blue skies on Mantorp and a huge mix of different types of cars.

Things didn't go that well. It started with me being a bit late.

Then there was a Porsche that spilled oil on a long section of the track. (Those German cars....)
Then someone else went off and one corner was covered with gravel and the track was closed again.
When I finally got the tires warm there was too much traffic and no clear laps.

Engine problems

Lost top end power and the top speed on the straight was a bit too low. It got worse and worse, so I stopped driving and went home instead, worried that there was something very wrong with the engine.

When I got home I did some troubleshooting and found out the alternator warning light connector was broken, and that prevented the battery being charged. (Stupid design!) My speculation is that the battery's voltage went down during the day and caused the fuel pump not being able to keep up the pressure when the fuel demand was peaking, making the engine run lean. Running an engine like this lean is not good at all and could cause fatal pre-ignition.

I need some way to prevent this from happening again.

I would like to be able to log the fuel pressure, and have some warning system for a fuel or oil pressure drop.

Here is a video I found describing how voltage affects the fuel pump flow:
http://www.youtube.com/watch?v=RjykWzDr1Kk

Noise check

A couple of months ago I bought a cheap noise meter from Hong Kong, and today I asked someone to measure the drive-by noise of my car.

The guy told me it made 106.4 dbA!

In many race circuits in this country have from this season a drive-by noise limit of 95dbA.

I started measuring the other cars, and no-one, except a stock Corvette, was below that limit.

Then I moved a little, and all readings changed. Then the wind changed, and the readings changed as well. Then I realized I could not get the same reading twice for the same car.

It seems like measuring noise at a race track is not an exact science.

I refuse to think my car makes as much noise as 106db, but I'm not surprised I have to do something about it if I'd like to drive on other circuits. I just don't know what yet.

What about all the work done this winter?

All good!

The roll cage... stayed in place. 

The suspension bushes hold together. The car felt nice and precise.

The exhaust manifold was not leaking!

The silencer mounts did not break.

No oil spew from the catch tank.

Engine did not leak oil from the front cover

Overall the car feels wonderful. Too bad I was worrying about the engine instead of enjoying myself.

I did not have the aeroscreen mounted as I didn't think it would do much difference. At the end of the straight the force against the helmet was overwhelming. I must put the aeroscreen back on.

Mantorp wear and tear

An humid day at Mantorp with rain in the morning and dry after lunch. One of those days when nothing felt good. I pushed harder and harder but the lap times stayed high and today's best time was 1:23.0. A Camaro cup team confirmed that the track was slower than usual because of slippery rubber from drift cars the days before. Still I didn't feel like I drove as good as I could have.

A couple of other things didn't go very well either.

Cracked wing with zip tie

First my right front wing went loose and cracked. Back in the pit I drilled a small hole and put it back with a zip tie. The next lap the left wing went loose...

The oil catch tank got full and spew oil in the engine bay. I don't know how that is possible but that is what happened.

The exhaust manifold sealant didn't hold and the leak is back. Another winter project.

The orange colour is where the pad material ends.

Rear brake pads worn out completely. I have ordered a new rear set of Pagid RS4-2 (1158 for my calipers). When the front pads wear out I'll try a different brand and see how they compare. I'm also considering installing a pressure reducer valve to rears and use the same compound on both ends. (Right now I use Pagid RS14 on the fronts and RS4-2 on the rears)

The A frame bushings are worn. At least I think so. When I brake I can see the wings move much more than they did before. I'm thinking of replacing them with Powerflex bushings during the winter, but they sure are expensive!?

One more trackday before the winter, this time at Gelleråsen. Lets hope it doesn't rain.

Min Stora Dag charity event

Min Stora Dag, or in english something like "My Special Day", is a non-profit charity organisation that tries to fulfil wishes from very sick children. The last three years they have organised an event on Mantorp where sportscar owners drives them around a racetrack. This sunny autumn day it was more than 100 very nice and fast cars that have come to the race track, and about 100 sick children with their families.

My car was very popular and I drove lots of children and their parents. Some older children asked me to "Go as fast as you can!" and it was always fun to see them shaking when getting out of the car, and then see if I could make their parents even more terrified than their children :-) Just to be clear - I never pushed any limits this day. An accident on a day like this would be disastrous.

One of the strongest impressions were this blond little girl Sigrid. I asked her if she wanted to go slowly or fast around the track and she responded "I know these are very fast cars. So please start off slowly and maybe you can go faster after a while." We agreed that she'd use the thumbs-up sign if she wanted to go faster, and thumbs-down if she wanted me to slow down.

When we got out on the fast straight she raised her hands above her head, just to feel the wind, and I could see she laughed loudly inside her helmet.

Back in the pit she laughed and said it was fantastic, and the big smile on her face was enough of reward for me for the the whole day. My body shivered for several minutes just for seeing how happy she was and how much she enjoyed it.

A great day and very rewarding, for everyone I think!

A day like this it would have been so much fun just to go around with my camera taking pictures, but I was so busy driving I didn't take a single shot. These are from various sources and I hope no-one mind that I'm using them here.

Progress

Sometimes it is fun to look back and see how much progress has been made over the years. I'll never forget  my first track day with my Caterham. I'd traded in my Porsche 996 C2 for a Caterham and was terrified and a bit regretful because the Caterham experience was so much more in every way and I was not sure I was ready for it. I'm the first to admit I was not very good at driving back then.

2008-09 Green 1:38.87
First visit. Windscreen, terrified. CR500

2009-08 Brown 1:30.76
Getting confident, got some tutoring by a professional driver. CR500

2011-10 Red 1:27.69
Best time with old engine, ACB10

2012-08 Blue 1:21.78
New engine and second hand slicks

Over the years that is an improvement of 17 seconds!

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.

Mantorp and two new sets of slicks

Back to Mantorp. It may appear as it is the only track I go to, and yes, that is sadly true.  I wish I could go to more tracks but Mantorp is both convenient and economical for me. 

Increased front neg camber with 0.5 degrees (two turns).
Little more tyre pressure than last time. (about 22-23 psi. 19.5 psi cold.)

And I shaved off another big second from my personal best! - 1.23,3.

I ended the day early because I didn't want to ruin a good day by breaking something.

I found a new source for second hand Radical slicks from whom I picked up two complete sets on the way home.

Mantorp

Very windy, sunny day. The wind kept the top speed down on the long straight.

Used 13" Radical slicks. Started with ~20 psi hot, but it got slippery a couple of turns if I pushed a bit too hard. Raised to ~22 psi after a talk with the Radical guys. It certainly improved but I think I could go even higher.

Inertia switch released twice on the straight! Then I short wired it...

Experienced some mid corner oversteer when pushing hard. Maybe the rear suspension bottoms out? Next time I'll investigate this.

I've always had problems with fuel surge in long right hand corners when having about 1/4 of fuel, but it was even more obvious now. The fact it is in the right hand corners doesn't make sense to me, since the fuel pump is on the left side of the tank. Here is an interesting thread on Blatchat.



Best time 1:24.3!!! That is almost two seconds faster since last visit!

I need a better microphone to my GoPro.

Mantorp graduation

A big day today, I have done so many modifications since last track day before the winter.

In short I have

• Fitted 13" rims and modified the rear brake calipers to fit.
• Bought an used set of Radical 13" slicks, which are radials and totally different than the Avon cross-ply slicks I have tried before.
• Rebuilt the whole engine and added much more power.

"April weather"

In sweden we use the expression "April weather", because the weather can't be trusted at all this time of year. Some days are warm spring days, but suddely the snow come back when you least expected. This is what happened the day before. Lots of snow and below zero degrees temperature. I had to knock away ice from the trailer when loading, and my neighbour had to help me to push the Caterham because I couldn't get it out of the garage. 

A few hours later when I got to the track the weather was complely different. +8 degrees, dry and sunny?!

First the good parts. I have so much power I now need to learn how to master. No other car (ok the turbo charged 350-400 hp Atom excluded) had any chance to keep up with me, but most of my driving was like an on/off switch, and my mind played tricks on me so all brake points were too early. I gained about two seconds on the main straight, but lost much of the gain because I braked way too soon! The higher top speed made the grass at end of the straights really intimidating!

Red line this day, black line last year.
Very good acceleration, very poor braking!

The tires worked flawless. The asphalt was cold today but there was no overheating and good balance. My impression is that the tires are more forgiving than cross-plys, and not equally sensitive to camber/pressure and slip angle.

Best time today 1,26.1 but the car has for sure potential for sub 1,24 times!

Then the less good things.
My temporary catch tank was too temporary and spew oil all over the engine room. Yuck!

The rear calipers scraped on the inside of the new 13" rims. I have to do a damage check on this, more about this later.

Mantorp, last time this year

A sunny but very cold day started with below zero degrees Celsius. The cold asphalt made the car both oversteering and understeering in different corners and all I could do was pretty much just play around. Late in the afternoon the temperature increased and the grip was much better.

On one of the day's last laps I beat my personal best: 1:27.7 on a very old set of ACB10!

I also met up with my new "pusher", who sold me one and a half set of second hand slicks at a very good price. Hope this works out, it would make a significant effect on my personal economy.

More about that later.

Trackday at Mantorp - test of slicks

A very hot day at Mantorp Park again - with slicks for my first time!

The lap times where not that much better, only about a second. A bit disappointed actually. But probably it is my driving to blame, I'm (yet) not capable to take advantage on the extra grip! I felt the biggest difference in one of the high speed corners (the fast left before the hairpin), where I now could keep the pedal floored - when I dared!



Today's Best: 1:26.9
Most laps where constantly around  ~1:27.5
Previous all time best with ACB10: 1:27.9

The day that started with oversteer problems, especially when trailbraking into corners. Reduced when lowered rear pressure to 18.5 psi. A contributing factor could have been the new front discs and pads messing up my brake balance. Overall the car balance was good - I just need to learn how to drive faster!

Avon 15" ACB0 crossply slicks (see previous post)

Front: 19 psi
Rear: 18.5 psi

At the end of the day the engine started to sound loud! The reason was a cracked exhaust manifold. I left the car for the tech guys at Mantorp Park and hopefully they'll be able to weld it together in situ. The manifold cracked most likely because the rear silencer bracket went loose, again, which caused stress on the manifold.

Another lonely day at Mantorp

A nice and sunny day at Mantorp Park! The day started out well being the faster of the two cars on the track.

...then this guy came along with his brand new Formula Renault...

The driver is only 15 years old and compete at european level against adults! As a comparison he had lap times around low 1:15 and I got at best high 1:27. When I was 15 I had a moped...

Anyway the day went on well and I had time to experiment with some toe settings. Previously I had neutral toe both rear and front. This day I first tried some toe-in on the rears which really made the car more stable and predictable. I didn't had the same problems with corner exit over-steer as before and my lap times went down. Later I also tried some toe-out on the fronts which made the car easier to rotate on corner entry. No difference on the lap times but it felt good and I think it is an improvement. My top speed was really low this day but I don't know if it depends on the toe settings or the fact it was a bit windy.



I polished my personal best with a few hundreds, but my tyres are long gone and I think with a fresh set I can really improve the time!

The day ended when I ran out of battery and the engine stopped! Apparently I have a bad connector to the alternator.

Tyre pressure 19 psi warm all around.

Mantorp

It was pretty lonely this day, three cars total

This years first track day was on Mantorp Park.

I had the opportunity to talk with a professional race team engineer about my wheel alignment and got the suggestion to make a small increase in negative camber all around, but overall the settings are good.

Best lap time 1.28,66 - No personal best but I blame the dirt after the long straight and in the the fast left after the hill. The race team I shared the track with said they lost 2-2.5 seconds because of the dirt and lack of rubber on the track. I doubt I lost that much time but maybe a second or so.

I experienced that when applying power after a corner that I lost traction on the rears, but when applying even more power I got the traction back!? Is it the LSD that locks up too late? Or is it just something to accept and learn to live with?

Avon ACB10
19.5 psi all around warm pressure  (It was too much! Remember until next  time)

Mantorp trackday movie

Movie clip from Mantorp this summer. Personal best 1:27.94!

Avon ACB10 tyres
Filmed with a GoPro HD