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Full Version: What is a good CS percent to start with?
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I have a HPI Sprint 2 chassis, I know not the best, but I plan to CS it. I'm thinking instead of ordering $60 worth of pulleys from 3Racing and trying all different percents or ratios, and then trying to fit and figure what belt(s) I will need, I will start with 50% CS or 1.50 CS Ratio, try that and go up or down from there. I will get the 9T pulley from Finger Robotics and the 18T pulley from 3Racing. This pulley has a 3mm bore and will need to be drilled out to 4mm, but that isn't a problem for me.

My rear belt has a little stretch, so I think I might be able to run the 18T center rear with the stock 58 Tooth belt if I set the center shaft to the rear angle bearing slot. This will also take up some of the slack on the front belt.

I thought of starting with the 9T pulley in the front, then it will open up my options for all sorts of CS % and higher ones if I want to try that. With some measuring and guessing I don't think much bigger than the 23T pulley from 3Racing will fit on the car for the rear center pulley and still clear the motor.

Then with the stock 32T front and rear diff sizes and a 9T front and 23T rear I could go up to 156% CS/2.56 CS Ratio.
1.4 to 1.6 is a good start
(09-12-2013, 03:02 AM)HAYASHI Wrote: [ -> ]1.4 to 1.6 is a good start

1.5 is perfct for beginners and can eventually be tuned to feel like more or less cs
1.5 is what I started with on the HPI Sprint 2 also but you do need to make sure you have everything else working properly on the car. Cali Drift Tech do a CS kit for it which is not that expensive if you are in the US.

When I got it, it was great but got a little too wild since my servo was poor and badly setup car. Now with a new chassis and regular attention, cs is great. Majority of people I know run 1.6-1.8.
You are correct, I need to make sure everything else is working properly. I'm sure I will need to upgrade my servo next. I also plan to shave down the C hub stops and get CVDs. I'm sure I will be able to use the extra steering angle with CS especially being new at it.

I can't perfectly drift 50/50, but I feel I'm ready for CS since I get the concept and understand how real cars work in this regard.

With 50/50 I'm can enter a turn and drift, but have a hard time holding the drift angle before the car wants to pull out of it. Before going CS I've tryed to set the chassis up for more tail wip. Stiffer rear, softer front, weighted front end, Locked rear diff. It is a little strange to drive the car like this, but I've gotten used to it. Right now it take a throttle blip to break the rear tires, then the rear end will come around when letting off the throttle a little. Then a little throttle to hold the drift until exit. It is hard to get switch backs down on a figure 8, right now I can get about 1 in 6 fairly close to my markers.
thats actually not a bad tune for CS.

i always go soft front and hard rear, with a locked rear and a front one way
I didn't want to do too many changes at once. But I think when I go CS at the same time I'm going to add a front One way diff, CVDs, and shave C hubs.
^^^ yes. All helpful upgrades, I did all of those before CS and it drives like a charm now.

Not sure what motor you are running but in my case I am running a 19T pulley for the rear and it makes the belt rub a little bit, just FYI in case you were actually planning on doing anything bigger than that.
(09-14-2013, 03:40 PM)Driftotron Wrote: [ -> ]I didn't want to do too many changes at once. But I think when I go CS at the same time I'm going to add a front One way diff, CVDs, and shave C hubs.
I did end up doing the front one way diff, CVDs, and shaved the C hubs before I tried the CS pulleys, they took longer to ship, and I'm still working on belt length and fit.

This is for the HPI Sprint 2 chassis, upgrade order:

#1. At the very least get some CVDs and shave the C hubs, I noticed, take them out and put them in a vise. I used a coarse and fine file to take the bump stop off. It is safe to completely take the stop down to flush with the C hub, this is perfect for the max angle the CVDs will provide. The extra turning angle is great for anyone with or with out any other upgrades. This is the first think I would recommend every one do. You are also going to have to put the bottom mount of the front shocks in the inner hole for the wheels to clear and not rub.

#2. The HPI front one way is the next great thing, it really make a difference how the car enters and exits a turn. Not to mention backing up is not longer the same!

#3. Locking the rear stock diff also helps with initiating the drift. The Ball differential does close to the same thing, but lets you dial in the rear grip. I noticed this is nice, I only have the front CS pulley on with about 120% CS (not much), and the car handles a lot different. I wasn't able to dial in all the grip I wanted with the shock angle mounting point. This is why I was glad to have the adjustable ball diff. If you cut out the rear diff guard on the HPI Sprint 2 (this is really the first thing a person should do with this chassis) then a small screw driver can be placed perpendicular into the slot in the ball diff and lined up the the adjusting screw. While holding this the right rear wheel can be spun forward or reverse to set the tension of the spring in the ball diff. No need to take a wheel and dog bone off to get a screw driver in there for adjustment.
Can you show a pic of how much steering angle you're getting with your S2

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