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DHI Cup with Serpent 411 Sport kit (16/01/2013)

By:: Reporter
Linked to:: Serpent S411 190mm Sport

The idea
As I signed up for the DHI Cup in the modified class, I thought why not race in the Superstock class too? Normally there is plenty of time between each round, so I would not get any stress to race a second class. My second car I had used for spares, so I needed a car, and then the idea came to me: why not try the Serpent S411-S - the cheaper version of my TE race car? I made a deal with Serpent. I got a Sport and I should race the Sport version as stock as possible. Here are my experiences with the Serpent S411 Sport version.

The building of the Sport
The Sport version comes in a box like my TE - only with different writing outside. All the parts are sorted in bags with numbers on, so the building could easily start with sorting the bags. The chassis (like the shock towers, the top deck and the servo mount plate) is not made of carbon fibre but of a composite material. Therefore, I had not to glue the edges. That is good.

The building of the Sport was really easy as every part fitted right on spot. The first time I did a difference to the manual was, when I built the differential. I did not use the two shims behind the two small gears. I found it to be too tight when using them. I also used some damper grease on the silicone o-rings at the out drives. I filled the differential with 2000 cst oil, as I from experience knew, the 1200 cst, that comes in the box, is too thin for the expected grip level on the track at the DHI Cup. The differential worked perfect and smooth with no edginess at all, although all the gears inside of the differential were made of steel.

When I came to build the steering, I had for the first time a problem - later I would discover, it should be the only one. One of the bushings in the steering rack was too short, and when I tightened the screw into the steering arm, the steering was tight and could not work. I tried different shims, I had in my bag, but nothing worked well. Therefore, I went up not tighten the screw and using thread lock as the manual showed. I can here already mention that I later on had no problem at all with the steering rack.

The next time I did a difference to the manual was when building the shocks. First I was surprised to find the shocks were the same as on my double priced TE. All in aluminium. Instead of using oil on the silicone o-rings I again used some damper grease. The track at the DHI Cup is not very even but at bit bumpy (read later why it is so), therefore, I used 450 cst oil in the two front dampers and 400 cst oil in the rear dampers. I put Serpent grey springs on in front and white in the rear. The orange and yellow springs, which comes in the box, I find too hard. In front I mounted the dampers using the inside hole on the shock tower, in the rear using the second hole from the inside.

I finished the building with only one thing to mention. The ball studs are in aluminium, and when I screwed them into the plastic, I several times was near to kill them. The first time you screw them into the plastic, they are very hard and tight to get in. Tip: use a normal screw to cut a thread in the plastic.

Option parts
As I mentioned above I wanted to drive the Sport as stock as possible. The only option part that I allowed me to use, was the anti roll bar set with 1,4 mm wires - part no. 401575. Here I had my last little problem. I tried to mount the anti roll bar using the small plastic cups in the bearing blocks as the manual showed. Although I used the cups for the 1,8 mm wire, still the anti roll bar was too tight. The anti roll bar could not work at all. I decided not to use the cups and tighten the wire directly into the bearing blocks.

Equipment in the car
The Sport car got equipped with the following electronics: Sanwa R451 receiver, Graupner HBS 790 servo, Hobbywing V3 ESC, LRP X12 13,5 T motor (DHI Cup rule for the superstock class) and GM Vmaxx 6800 mAh 70 C batteries. I also used a fan on the motor to cool it down. As body I got a pre painted Serpent Lex-IS - part no. 401571 from Serpent, which I painted with an orange and backed silver metallic colour. The body is very stiff and a tick too heavy. When I had finished the cutting and had mounted the spoiler, the body weighs about 40 grams more than my normal used Protoform Mazdaspeed LW. At the DHI Cup we all had to use hand out LRP CPX tires.

Setup
I put a setup on the car, which I thought would be OK for the DHI Cup. I have already mentioned the oil in the differential and the dampers and the springs. Ride high I had set to 5,0 mm front and rear. Link positions like manual but in the front I put another 2 mm shims under the inside link mount. Down stop I had set to 6 mm in the front and 5 mm in the rear. Front wheels I had set to 1,0 degrees toe out. Camber I had set to -1,5 degrees all around. I made a check of the balance of the car, using the two small holes front and rear in the chassis. Result: 100% in balance. Then I put the car on the weight. Ooopsss. 1455 grams!! That is 100 grams too much, as the rules said 1350 grams. I have made a setup sheet of the final setup I ended up with at the DHI Cup - see attachment.

Practise before the race
My goal was to do some practise with the car on different types of tracks during the Christmas and New Year vacation. But one thing is a goal, and another thing is reality. Due to a very big and important project at my study to an engineer at the university, I had to study right up to the last day before travelling to the DHI Cup. I had two exams in the week up to the DHI Cup, and one right after the race. Therefore, no practice with the car at all, and the roll out would be at the first practice round at the DHI Cup. Sorry - but I could not do anything about it. My study is more important.

Practice at the DHI Cup
I was put into the 8th of 12 heats in the superstock class. The track was very slippery in the first practice round, but I was very surprised how reactive the car was. It felt almost like my normal TE - only a tick lazier due to the overweight. During the round I tried different driving style to see the reaction. I found, that the car had a small setup problem at the rear. I made the following setup changes for the next round: link inside front I added another 1 mm shim, link inside rear I added 2 mm, and outside in the upright I changed to the outside hole and added 0,5 mm shim. In front I changed the toe out to almost zero to settle down the steering, and camber was changed to 1,2 in front and 1,8 in the rear.

The changes were right on spot. The car was now so easy and fun to drive. I could push in all the corners and the rear was stable. I had some contacts with other drivers, but the stiff body had afterwards no sign of the contacts.

In the third practice I had the first body roll. I knew it would come. The track at the DHI Cup is not very even but a bit bumpy. It comes, because for every about ten meters there is cable groove in the floor. It is covered with plates, which can be taking up. Unfortunately, these plates are not very even with the floor but have a difference to the floor of up to two, three millimetres or even more. The DHI Cup crew have tried to minimize that difference but still there were some bumps. Those bumps were exactly in some of the corners. When the grip came up, the cars got unstable on the bumps and the tires hooked into the carpet - traction roll. That is my explanation, because the traction rolls came only in some of the corners, and those corners were the bumpy ones.

Before the fourth and final practice I made the last change for the whole race. I glued the side wall of the tires. In the fourth practice I tried to push as hard as possible in the corners. Nothing happened - or more correctly - nothing not wanted happened. The car drove perfect.

During the practice rounds several drivers was passing my pit table. I had not driven in the superstock class for a long time, and they had heard, that I was using a 200 Euro expensive - or cheap - car. They were all surprised of the performance of the car, because it looked so good on the track.

Qualification at the DHI Cup
The race setup for the DHI Cup saw four qualification rounds with the two best to be count - round by round - EFRA rules. The first qualification round was Friday evening. I tried to make a safe but fast round. I had some minor problems lapping some other drivers, but all in all I was very happy with the round. After all 95 drivers had done their first round, I was listed as 10th. Wouw - maybe an A final would be possible. I wanted the qualification to stop now and went directly to the finals.

Saturday was coming and in the next round of qualification I was five seconds faster, but I ended up as 13th in the round. Overall I was now dropped down to the 11th place. In the third round I got faster once again and made a lap more, but I made "only" a 14th in the round. I dropped back to the 13th place overall.

In the fourth and last round of qualification I pushed really hard to try to make the A final - all or nothing. I made very good and consistent lap times with the fastest to be 13,712, which were only two tenths of a second behind the hot lap at that time. The forecast for my run was four seconds faster than my run in the third round. Then I hit a curb and lost about two second - and for worse - I got out of my rhythm. I made some more minor errors. Then I stopped, because I could see, I had no opportunities to get a good result. I did not want to split the car in a stupid crash.

After the qualification I was listed on the 16th spot, which meant I had to drive the B final - i.a. together with the driver, who is leading the Danish championship. He neither made the A final with his Russian Awesomatix. I was very happy with the result and I was even happier about the car; how it was to drive and how fast it was.

B main at the DHI Cup
Saturday evening the first round of finals was to run. To start in the middle of ten cars on the straight is not the easiest, but when everybody is a bit careful, it is possible. The first start went well, but before the first lap was driven, the big crash came. I was in the middle of it as I was pushed from behind. I was the last car back on track, but due to some other crashes I was soon driving in the fifth position. I then had a fight with a German driver. He was a bit faster than me, but he could not pass me. Twice he pushed me, and twice he waited for me. Good sportsmanship - until he pushed me again for the third time in the very last lap. This time he did not wait for me, and also another car passed me due to the push, and I ended up as 7th. I was a bit angry with the German driver, but his only comment was to raise his shoulders and say race accident.

The second final was run on the Sunday. I again made an ok start and came through the first laps without any big crash. The run was safe and good and I ended up as 5th. The last final was almost the same. After some ups and downs I ended up as 6th in the last final. With the total of eleven final points I ended up as 18th at the DHI Cup with my Serpetn S411 Sport. The driver in the 17th position also had 11 final points and the 16th driver had 10 points. The accident in the first final cost me two positions on the board. Anyway - I am afterwards very happy with the result.

After the race
During the whole race I had no faults on the car. No tweaks, nothing broken, no maintenance at all. Only whipped dust out of the car and checked the setups. OK - a bit of the chassis is scratched off, but that would have happened with a carbon chassis too. Unfortunately, one of the plates, which covered the cable grooves got through the carpet in the middle in the track. I was the first and only to hit it, because it was fixed just after my accident.

About the setup - one thought came afterwards to me: maybe I had better changed the link mount outside in the rear uprights back to the inside hole. I think the car would have reacted faster in the corners. Sad - now it is a bit late to try it.

Another thing would also have been nice to try. The car was with its 1455 grams way too heavy. A lot comes from the body, but also the car itself is too heavy. What would have been possible, when I could have optimized the weight? A question not to be answered, but the 100 grams overweight was for sure a problem during the race. I did not change anything, as I wanted to race the car as stock as possible.

I talked to many drivers about the car, and they were all astonished about the performance. The comment, which almost everybody came with, was: why buy a car for 400, 500 or even 600 Euros, when a car for 200 Euros can do the same?

I will let the car be like it is now and take it with me, when I go for the next practises and races. I will let everybody try the car. Maybe one will change to Serpent.

Pros and cons
If you have read my report right until here, you will know, there will be more pros than cons.

Pros      - cheap and non expensive car
      - but certainly not cheap in performance
      - good driveability
      - good materials
      - durable
      - interchangeable with other S411 cars
      - very easy to built, all parts fits
      - fully adjustable
      - dampers

Cons      - a bit weak steering due to the plastic arms, although no problems during the race
      - hex goes off, when you remove the tires
      - the car is too heavy

It was a very nice experience to built and drive the Sport version. A car half the price, but certainly not half the performance. Perfect for drivers, who wants to have a non-expensive car, but still wants a car with good performance and durability. I can highly recommend the Serpent S411 Sport!!!

Please attached find a setup sheet of the final setup and some pictures.

http://serpent.com/product/400006/setups/

I would like to thank Serpent - Ronald Baar and Jiri Hassler - for the sponsoring.

Best regards
Rasmus Tobias Callesen - Denmark