Sedan Racing

 Tires

"80% OF CAR SETUP INVOLVES THE PROPER SELECTION OF TIRES & INSERTS."TIPS: Instead of buying a bunch of tires and inserts that don't work in your particular track, go to to the fast racers(Those that are wining) and ask. A short and simple question can save a lot of time and money in the long run. Don't get me wrong you should have alternate tires to experiment but if it's opposite to what works on that track you are probably wasting money that can be better spent on fuel or other racing necessities.

The good and the bad things about traction:

1.Typically you try to always get more traction than what you need on a particular track. It sometimes becomes a question of whether you want your tires to melt in the 10 Min Main or will you go conservative to have your rubber last you a couple of weekends. Typically I get enough traction on the rear so my back end wont turn before the front and usually sacrifice some steering to achieve this. You will find that it's all a balance between front and rear traction. You always want more traction on the rear or you wont be able to control the car on the corners. On the other hand if your front tires are too hard/stiff you will loose steering when accelerating out of the corners and hit the wall. Traction is typically easy to get rid of but hard to get if you don't have the right set of tires to begin with. You have too much traction when your car rolls over in the corners. This can be minimized by going to heavier shock oil and by lowering you cars ride height.

1A. The newer generation of tires, have more than erased the one race tire syndrome that we where seeing in the beginning of the Nitro Touring car scene. The next generation of tires coupled with smarter setup and the proper selection of inserts has almost but erased the trend. On the other side of this argument is the exponential companies offering tires and inserts for racers. Typically this is a good thing, unfortunately the "meoium" insert from company "A" is different from the "medium" insert of company "B" . I suggest you stick with a brand of inserts that works for you and try to avoid getting three medium inserts from three different companies and end up with no clue what to expect on the track. I'll tell you this, I've been there and it's not fun when you have to throw $25 bucks every time you want to experiment with a new brand. I usually keep my eyes and ears open at the track and check what's working for the winners. I then use this to make an informed choice. I can tell you that belted tires just seem to give better results for me and better wear than non-belted tires.

2.The Nitro 4-Tec comes with 2.0 rims instead of the typical 1.9 . If you have the larger diam tires in the front the car will pull the rear end in the turns causing the back to slide. If you have the larger diam rims in the rear the rear will push the front tires and in the turns you'll loose steering.

3. Note: 1.9 or 2.0 = rim diameter and has nothing to do with tire diam. all tires are made for 1.9 diameter rims. By using 2.0 rims you can reduce side wall felx by forcing the tire to strech even more over the rim. Now that manufacturers came out with the LP and LP2 tires this 2.0 rim is really not needed because the tires already are low profile. I have been seing a few racers use 2.0 rims on LP2 tires. They appear to be more like black rubber bands than sedan tires. Who nows this could be the wave of the future ?

1-10 (Higher scores indicate better performance and longer wear)

Extra Comment:

Folks, Are you seeing the trend? HPI Belted 26mm B15-40 w/ HPI soft round(yellow) insert mounted on HPI MESH 26mm rims are working better than anything I have ever tried. The real amazing thing is the tires look virtually new! I can't believe it myself. I'm going to bronze these tires when the rims break in half, cause these tires appear like they are new. 4 solid weekends of racing on prepared asphalt and on plain smooth concrete and they are asking for more. Don't even think of doing this with a proline tire. I'm going mount a set with hard molded inserts to see if I can reduce the traction... I'm going to experiment some more with the B-15-40 to see if I can make my back end stick with these. Don't you just love it when your tires age like fine wine ?

Well I am really surprised with the next generation tires. I'm still using tires that I bought last summer. Not just to "pratice" I put my tires through a dozen 5 minute runs plus a 15 min A-main. They look just like did in the morning when I was inspecting the tire seem for unglued areas. Most of my "dead" tires are more attributed to a bent wheel than a worn out or torn tire. This really brings a smile to my checkbook :) Now I can buy the shiny aluminum screw driver. It has to make me faster! or should I buy the titanium one...

Shocks

The shocks are an integral part of your cars setup. The shocks control the roll of the car, this can be used to your advantage to gain traction in the corners. There are two main functions in a shock absorber. a: The Damping, slows down the motion of the car as you are accelerating/breaking and/or turning. b: The ride height and rebound and general stiffness of the shocks. I've been learning quite a deal about the proper way of setting suspensions on turing cars. Here it goes: 1: Use two hole pistons and 50-80 weight Shock Oil 2: Install one 1.5mm spacer inside the rear shock to shorten shock length(More if needed) 3: install medium/light springs on the car. At the beginning have the same rate spring on all 4 corners.

Gearing

There are some people that complain that the Nitro-4-TEC has poor acceleration. 80% of the problem is engine tuning and clutch tuning. 20% of the problem is that the engine is slightly over geared. I've provided links to resolve 80% of the real problem.

Here is how to solve the other 20%

There are four combinations of gears for the Nitro 4-Tec. All Stock, using either optional spur or clutch gear, and using both optional sets at the same time. 1: Large clutch gears (stock)/ Large Spur gear (Option Part) Most of the people who race the N-4-T run this combination. You get good Acceleration and a good top speed. This is a very versatile setup. You can lock out the high speed gear for tight parking lot tracks, where 2 speed can actually be a hindrance and you can adjust the 2 speed tranny for a good top end on larger open tracks... for all out domination.

Tuning Rules of Thumb

UPDATED

1. If your car is swaying badly in the turns (getting out of shape) because of excessive body roll, increase the weight of the shock oil. 60-80 weigth a good all around viscosity.
2. If you have Pro-Compound,S3 or H13 with soft inserts and your back end is swinging (and everyone else seems to be running well) then your suspension is too stiff).
3. To soften a suspension setup A: Go to the next softest spring b: remove excessive spring spacers. C: Change shock oil (This is a last resort)
4. If you use different rate springs on the front vs. rear use the stiffer one on the front.
5. the front of the car needs to be stiffer than the rear. The front tires must slide before the rear or your car will hook in the corners. Be prepared to change springs as you fine tune and balance the chassis. You could go as much as a three step spring stifness difference between front and back.
6. Even if the "stock" springs are working for you right now, you should get one step softer one step harder as a tuning aid. Springs are cheaper than tires...
7. Shock spring spacers are used for adjusting ride height only. If you are using them to vary spring rate you are only making the car more twitchy. Because there is potential energy stored in the springs at all times. It makes the shock oil seem thinner than what it really is, and the car no longer has a neutral ride( you will hop on every imperfection on the track)
8. If your car pushes (Front end plows through the corners) Steering will be less sensitive. A hard front insert and Medium Traction tires will give you this condition. To get rid of excessive push, try softer/stickier round-tires and go to a softer front spring. Note: Some tires need a long warm-up period before they hook up (Like Proline S3 and S2)
9. If your car's rear end slides when making a turn. Soften the rear suspension and/or go to a stickier tire. Rear tires should typically use a softer insert than the front. New tires can sometimes act like this on the first couple of laps before they break-in.
10. Round front tires give you better steering under power. But the same effect can be accomplished using more caster.
11. If your rear ends swings " wildly " in the corners and your suspension is in the soft side, swap your fornt/rear tires.
12. Some tires need to warm up before they hook up.
13. If you have no traction after a pit stop. You probably have fuel all over you front tire. Also make sure that exhaust residue from the pipe is not getting on your tire.
14. Use an anti sway bar to fine tune suspension setups. Sway bars are used to lower body roll. Remember body roll= Traction. You do not want to eliminate body roll. Note: Sway bars will not transform a setup from bad to good. Use your sway bar to fine tune your traction. More Steering/ Less steering et.
15. All the little holes on the shock tower/ suspension arm are primarily for fine tuning body roll. It's secondary job is chassis ride height, but shock spacers work much better :). If you need more damping the extra mounting positions could be your ticket to the right setup.
16. Upright shocks promote body roll. Lay Down shocks stiffen up the suspension.
17. A little body hop is not going to kill you, but if your swinging the rear end it's and indication that your too stiff. 18. Never under estimate the traction robbing sound of a lexan body scraping the concrete in a tight turn. That noise is taking your traction away.
19. Drag brakes( slight engagement of the brakes on neutral throttle servo position) Transfers some weight to the front of the car giving you some extra front traction. Note: Don't try this if you have a plastic brake disk. Try to adjust your transmitter trim so that you can either increase or decrease it on the fly. Your transmitter will need to have end-point adjustments for the throttle servo.
20. For the car to generate traction you must have a free suspension. If the suspension can't move freely you will slide all over the track. Push down on the shock towers, if it feels mushy then re-fill the shocks. Make sure to use thicker oil in the front and less viscous oil in the rear.
21. For increased traction on fast sweeping corners increase your ride height.

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