HPI Sprint 2
05-22-2010, 02:12 PM
#1
HPI Sprint 2
I just picked up a HPI Sprint 2 and am wanting to get into onroad racing a little. I was wondering if anyone has some setup tips and or recommended upgrades to make it more competitive. I will be running either a 10.5 or 13.5 oval class on an asphalt parking lot. I am definately looking to upgrade to aluminum threaded shocks and am thinking of the ones on rcmar, just as something cheap since I am on a budget. Also the ball diffs later on. Any and all help is greatly appreciated.
05-22-2010, 09:04 PM
#2
RPM ball cups all around and put another spring under the left servo saver.
05-22-2010, 10:04 PM
#3
The Sprint 2 is a great budget car with decent tuning options. I currently use one to race in a Vintage Trans Am class and am happy with it. The RPM ball cups work great to get rid of slop compared with the factory ones. I am still using the stock shocks but have moved up to a much heavier shock oil and use Associated springs from their TC line. I also recomend using HPI's alloy spur gear mount #100670 and a quality spur gear such as one from Robinson Racing as they spin more true and are stronger. Besides that a thicker viscosity grease in the front diff to make the steering less "darty" for oval would probably be a good idea. Don't forget to play gith your camber link length with mounting locaton and droop settings, they affect your roll center and weight transfer.
05-23-2010, 07:11 PM
#4
The Sprint 2 is a great budget car with decent tuning options. I currently use one to race in a Vintage Trans Am class and am happy with it. The RPM ball cups work great to get rid of slop compared with the factory ones. I am still using the stock shocks but have moved up to a much heavier shock oil and use Associated springs from their TC line. I also recomend using HPI's alloy spur gear mount #100670 and a quality spur gear such as one from Robinson Racing as they spin more true and are stronger. Besides that a thicker viscosity grease in the front diff to make the steering less "darty" for oval would probably be a good idea. Don't forget to play gith your camber link length with mounting locaton and droop settings, they affect your roll center and weight transfer.
05-23-2010, 09:13 PM
#5
Keep in mind that these are not sealed diffs and too much or thin of a fluid will leak out. That being said, the best results I have had was to open the diff leaving the factory installed grease in and adding small amounts of diff fluid. The added fluid will give more viscosity (resistance) and mix with the thick grease not allowing it to leak out. I have added 30,000 wt in the front and have not touched the rear. It has helped calm down oversteer issues at higher speeds. One other note, silicone fluid does not change viscosity much with temperature changes unlike the pre-installed grease. This will make the diff feel like it has too much resistance but after running the car for a couple of laps it will lighten up as the grease thins. Ball diffs are far superior in consistancy but this my help you use what you have.
05-24-2010, 08:12 AM
#6
Tech Regular
iTrader: (3)
The Sprint 2 is a great budget car with decent tuning options. I currently use one to race in a Vintage Trans Am class and am happy with it. The RPM ball cups work great to get rid of slop compared with the factory ones. I am still using the stock shocks but have moved up to a much heavier shock oil and use Associated springs from their TC line. I also recomend using HPI's alloy spur gear mount #100670 and a quality spur gear such as one from Robinson Racing as they spin more true and are stronger. Besides that a thicker viscosity grease in the front diff to make the steering less "darty" for oval would probably be a good idea. Don't forget to play gith your camber link length with mounting locaton and droop settings, they affect your roll center and weight transfer.
05-24-2010, 12:58 PM
#7
I own 3 sprint 2s and I love it. all 3 are drfters though and I love them.
05-24-2010, 02:04 PM
#8
I am using the HPI Pro Linear springs Front is 13# & Rear is 12.1# with 30wt Trinity oil & 2 hole pistons.
05-24-2010, 02:06 PM
#9
I am using 50wt oil all arround, blue associated springs in the rear and copper associated springs in the front. If this gives too much steering into a turn then move to a purple front spring. Top of rear shocks mounted in the outter most hole and top of the fronts in the middle hole. I also find the 4deg caster blocks work well with this set up. Different bodies will also affect handling. I find the HPI 68 camaro body gives me the best downforce, least drag and lowest and most balanced center of gravity.
05-24-2010, 02:11 PM
#10
RPM heavy duty rod ends 4-40 size pt#73375. These are blue but they also come in different colors. These work on the whole car but may rub on the inside of certain wheels.
05-24-2010, 09:47 PM
#13
A lot of great info here. Lets try and keep this and keep this thread going for others that may need help. I will be getting to the track, or atleast a parking lot to try out a few setup changes and different things to figure this car out.
05-25-2010, 11:07 AM
#14
What type of battery are you using? what type and size of track? What exactly is a "silver can" motor? motor timing? All these are important variables.
05-25-2010, 09:55 PM
#15
Tech Regular
iTrader: (3)
silver can motor is another name for tamiya 540 j motor. the local club where I race uses that as a spec motor for vta we can use any esc and up to 2s 40c 5000mah lipo. I will personally be using my sidewinder esc in brushed mode and a 3200 25c lipo. As far as the track goes longest straight is approximately 65 feet one shorter one @ 40 feet, some chicanes a 180* and a couple long sweepers. sounds to me from what I have gathered starting as close to 5:1 as possible but I am not 100% sure on that any help would be greatly appreciated