Originally Posted by Serpentd
Dude hey! This set up you gave for gensei doesn't seem too far out there. What is unique to me is how you make the front shocks softer then the rear ones. You might of seen on one of my posts that I have yet to run my G4S due to weather. But does the rear end on this car have that much bite (traction) to do such a set up? You mentioned your track being abrasive, how about the rest of it? Is it smooth...meaning no bumps, is the traction high-med or low and then is the layout more tight or more smooth and flowing?
I can see you getting some good rear traction with the 3.5 degrees of toe in and a flat sway bar. But overall, I will have to admit that this is a "unique" set up. But I like to hear or see things like this. A very different approach to what the "norm" usually is. One last question...how do the tires hold up as far as wear goes? Do they seem to have adequite life out of the tires? That might be hard for you to answer if you only run on your abrasive track. I was just curious. Thanks for posting this set up for all to see!
Gensei, let us all know how this works out for you.
Later guys!
OK, let's try to give out the best answers I can...
Itīs difficult to say where to start.
Front shock oil. I changed it from 50 to 40 because there was a small bump at the end of the straigthaway. The slightly thinner oil cured the tendency to go airborne into that section. Other than that small bump the track is fairly smooth.
Did not want to go too soft either because there was a high speed sweeper right after. So try to picture going full throttle for the long straightaway, briefly lifting and then heavy throttle again for the sweeper. This is where the rear toe-in helped a lot!!
It is weird really, but the blue spring and heavy front antiroll bar contributed to keeping the car from rolling too much into that sweeper. Harder springs made the car push. Lighter springs caused a little tire wobbling.
The 3.5° rear toe in gave me the confidence of running into the sweeper at high speed. 3° did not feel as good. The 50k wt rear diff does not act as much going into the turns as it does when applying throttle again. This gave me back the on-throttle steering I needed when exiting the tight U-turn positioned at the end of the sweeper.
Three heavy braking zones kept me away from using a one-way, but a locked diff induced push. That mandated using a diff.
During test I could not handle a 50k oil front diff because that induced too much on-power steering. I could not use lighter oil than 50k at the rear because the car pushed out of the hairpins. So why not reducing rear toe?? 3° of toe made the car feel a little uneasy after the straightaway and into the high speed sweeper. If I loose speed into it then the car in front is gone!
One thing drove me to another. So I had to compromise a little turn in with a 70k front diff. It did not take away too much steering into the turns. That wasn't too bad!! Again, less toe was not an option.
The blue springs and position actually came as a result of trying several combinations for the front. Blue springs gave me the best steering. Softer and harder felt less aggresive.
Well, the rear shock oil is different at the back because I just felt I did not need to touch it.
Anti roll bar selection resulted simply from testing the best combination. Hardest at the front, lightest at the rear. Other combinations just did not feel right. Same goes for the rear roll center. I gave off-power steering a priority over on-power, but the hard rear diff gave me back the tight turning out of the hole!
Our track layout is extremely mixed!! Our track times are at the 21.5 sec range. We have a very long straightaway (70 mts) starting off at a full-on-throttle chicane. Then comes the fast sweeper ending into a harpin.
Next is a set of light switchbacks (right-left with about 1/4 throttle) with the second harpin of the track at the end. That U-turn is then followed by another light right turn and a 135° left. Then comes the 30 mts long pit straight into the third hairpin of the track, turning left. That was the heaviest braking zone of all, immediately after changing to 2nd gear. 90° right hander, 10 mts shoot and then the fourth hairpin. This hairpin was extremely critical to have good on power steering because it is followed by a 30 mts long straight. To finish off the circuit comes a 1/2 throttle, wide radius 135° turn. Its radius is about 7 mts. Then comes the trickiest part of all and that is to initiate the quick chicane into the long straightaway, for the next lap.
Track is abrassive. I had to start the 40 min main with all tires at different diameters. Front left 40 shore at 61.5mm, Front right 40 shore with 62.5 mm, rear left 40 shore with 63.5 mm and new-out-of-the box 42 shore rear right tire. All nitro shoes tires with serpent rim. Diameters all ended up within 1 mm, but with overdrive. Fronts finish larger than rears, that is, even over the natural split the ED transmission requires. When the tires are at this point, the car has a ride height of about 5mm front and rear. I worry about final ride height rather than initial, which probably yields a tall standing car at the start of the race. I prefer that, though, to loosing time going wide if the chassis bottoms out during the last minutes.
Grip is tipically very low as the track gets dusty easily. Only during big races does the race line clean up a bit to mid-bite condition.
So we have a long straight, four hairpins, three heavy braking zones, two mild switchbacks, one fast chicane, one fast sweeper, one half-throttle wide key-hole and a great fun track!
Just in case you are curious, I finished 2nd at only 5 secs behind the leader. We lapped the rest of the field in a 106 lap race. I hit the fast speed chicane once and was lucky to have the car fall out the track into the grass on all four. The engine did not stall. Just had enough time to let off the throttle a bit before the incident.