86LikesHpi Pro 4
02-18-2006, 04:14 AM
Tech Master
Originally Posted by floodo1
heres how i make packs, never had any problems:
take cells, put individual shrink wrap on them.
take cells and lightly sand (dremel w/ sanding drum) the end of each cell (both ends) where you plan to solder too, nothing agressive or anything.
now put all ur cells in your jig.
now tin all of your battery bars.
now use a HUGE soldering iron to solder ea bar on. try to be quick.
now glue your pack together.
in the past i didnt sand the ends of cells. the reason i do now is that when i didnt sand the cells i could take pliers and pull the battery bar off, without a ton of force, and usually no solder would be stuck to the cell, it would all be on the battery bar. now that i sand its as if they are welded on, no pulling them off with pliers
also a large iron helps to heat the bar and the surface of the battery to soldering temperature quicker, and SEEEMS like it keeps the cell overall cooler. idk.
as for the soldering itself, if you pretin the bar you should have enuf solder between the bar and the cell, so you just need to add solder around the permiter usually. also you dont need solder on top of the cell, just under it, and along its edges where it contacts the cell.
idk if that helps, but thats how i does it
take cells, put individual shrink wrap on them.
take cells and lightly sand (dremel w/ sanding drum) the end of each cell (both ends) where you plan to solder too, nothing agressive or anything.
now put all ur cells in your jig.
now tin all of your battery bars.
now use a HUGE soldering iron to solder ea bar on. try to be quick.
now glue your pack together.
in the past i didnt sand the ends of cells. the reason i do now is that when i didnt sand the cells i could take pliers and pull the battery bar off, without a ton of force, and usually no solder would be stuck to the cell, it would all be on the battery bar. now that i sand its as if they are welded on, no pulling them off with pliers
also a large iron helps to heat the bar and the surface of the battery to soldering temperature quicker, and SEEEMS like it keeps the cell overall cooler. idk.
as for the soldering itself, if you pretin the bar you should have enuf solder between the bar and the cell, so you just need to add solder around the permiter usually. also you dont need solder on top of the cell, just under it, and along its edges where it contacts the cell.
idk if that helps, but thats how i does it
02-18-2006, 06:58 AM
Tech Apprentice
Hi guys, I am preparing my car for the upcoming season, and I need little bit of help here. I race my pro 4 last season (this season too) on a temp asphalt track with robber tires. I just can’t seem to get enough steering. I tried one way, but the car is too responsive and not consistent. I also tried front spool, but the car chatters like crazy when off power. It has a lot of steering coming out of corner, but understeer or pushes like a dump track off power. I am running the original pro 4 with stock 2.5mm chassis. Will change to a 2.0mm chassis give me more grip?
02-18-2006, 10:47 AM
Originally Posted by thegreatimpulse
Hi guys, I am preparing my car for the upcoming season, and I need little bit of help here. I race my pro 4 last season (this season too) on a temp asphalt track with robber tires. I just can’t seem to get enough steering. I tried one way, but the car is too responsive and not consistent. I also tried front spool, but the car chatters like crazy when off power. It has a lot of steering coming out of corner, but understeer or pushes like a dump track off power. I am running the original pro 4 with stock 2.5mm chassis. Will change to a 2.0mm chassis give me more grip?
Whats your complete set up and also tires & inserts you are using?
02-18-2006, 10:53 AM
Tech Apprentice
We might need a little more info in order to help out.
What caster blocks, any kickup, sway bar, tire compound, ride height, springs etc. How is your roll center setup?
Have you checked out HPI's site? They have numerous setups for rubber tire outdoor tracks. That might help you baseline the car and then you can adjust to your track form there.
Give us a little more info tho and maybe someone can pick out something in your setup that is causing the problem.
Greg
What caster blocks, any kickup, sway bar, tire compound, ride height, springs etc. How is your roll center setup?
Have you checked out HPI's site? They have numerous setups for rubber tire outdoor tracks. That might help you baseline the car and then you can adjust to your track form there.
Give us a little more info tho and maybe someone can pick out something in your setup that is causing the problem.
Greg
02-18-2006, 11:09 AM
Tech Apprentice
Here's my current setup. I had something more radical. Toe F/R: 1.0 out/ 3.0 in, Spring: white/white (6545, the next one up from gold), damper: 50/50. Camber: 2.0/1.5. ride height: 3.5mm/4.0mm. Roll bar: black/black. droop 5mm/5mm. Shock upper: 2nd from out/ 1st from out. shock lower: outer/middle. kick up/anti-dive are stock. Front roll center is stock. Rear roll center: inner is stock, but I relocated to the inner hole on the hub.
thanks.
thanks.
02-18-2006, 11:11 AM
Tech Apprentice
I mostly run CS27, but I ran RP24 at the last race of the season. Temperature got down to upper 40's mid 50's.
02-18-2006, 11:22 AM
Tech Apprentice
HPI's site was the first place that I checked, but all the setup except one are using spool. I am running front and rear ball diff. 4 deg fron't castor block.
02-18-2006, 12:43 PM
Tech Apprentice
My first guess would be to loose the roll bars both front and rear. I think it is making the front too stiff and not allowing the car to roll.
See if that helps and then maybe go back to the oneway if more steering is needed.
With the car loaded and ready to race how much chasis rise do you get when you hold the tires down and lift up in the shock tower? This is how I check for droop and is a great help on balancing where I want my traction front to rear.
Greg
See if that helps and then maybe go back to the oneway if more steering is needed.
With the car loaded and ready to race how much chasis rise do you get when you hold the tires down and lift up in the shock tower? This is how I check for droop and is a great help on balancing where I want my traction front to rear.
Greg
02-18-2006, 01:08 PM
Tech Apprentice
Thanks Greg, I'll give that a try. Regarding to your droop test method, do you lift the car up when the car is at static ride high? I don't think you would push the car until it's bottom out then lift it up. I'll probably switch to light damping oil and softer front spring if take out the roll bars doesn't help.
The track that I race on is very small and with several tight turns. Is it just me or Pro 4 has a lot of slops in the steering and suspension? I really didn't expect this from a HPI Pro car. It almost makes me wanted to try out a X-ray car.
The track that I race on is very small and with several tight turns. Is it just me or Pro 4 has a lot of slops in the steering and suspension? I really didn't expect this from a HPI Pro car. It almost makes me wanted to try out a X-ray car.
02-18-2006, 03:32 PM
Tech Apprentice
Yeah, what I do is hold the tires down and lift up on the shock tower. This tells me how high the chasis would rise on power for the front and off power for the rear. Since I run foams on carpet I can't really use a droop gauge as the settings change too much as the foams wear. Once you get used to checking it this way it's more of a feel thing than trying to hit a number on the gauge.
If the track is tight then I would keep the diff in the front as you will need it for additional braking. Switching to lighter oil in the shocks will allow the car to absorb bumps in the track and roll a little quicker in the tight sections.
You can shim out the slop in the suspension with teflon washers like what you would use for motors. There is a member I think it's KVRC that sells them fairly cheap. The slop is not causing your problems tho so focus on the bigger issues and then fine tune to your liking. Just remember the more stuff you add the more you have to maintain.
Greg
If the track is tight then I would keep the diff in the front as you will need it for additional braking. Switching to lighter oil in the shocks will allow the car to absorb bumps in the track and roll a little quicker in the tight sections.
You can shim out the slop in the suspension with teflon washers like what you would use for motors. There is a member I think it's KVRC that sells them fairly cheap. The slop is not causing your problems tho so focus on the bigger issues and then fine tune to your liking. Just remember the more stuff you add the more you have to maintain.
Greg
Last edited by Greg45231; 02-18-2006 at 07:07 PM.
02-18-2006, 05:52 PM
Tech Apprentice
Thanks Greg 
. So, what is 2.0 mm chassis go for? other than lower the center of mass slightly? Stock pro 4 with upper deck is pretty stiff, and I wonder if that's going to help it to flix some front to back or side to side.
. So, what is 2.0 mm chassis go for? other than lower the center of mass slightly? Stock pro 4 with upper deck is pretty stiff, and I wonder if that's going to help it to flix some front to back or side to side.
02-18-2006, 06:52 PM
You can also mod your topdeck like the in here http://www.rctech.net/forum/showthre...page=462&pp=30 scroll down to post 13846. I did this to my topdeck and made my chassis more flexible.
02-18-2006, 07:01 PM
Tech Apprentice
thanks for the info, Raptor.
02-18-2006, 07:46 PM
Tech Master
Originally Posted by thegreatimpulse
Hi guys, I am preparing my car for the upcoming season, and I need little bit of help here. I race my pro 4 last season (this season too) on a temp asphalt track with robber tires. I just can’t seem to get enough steering. I tried one way, but the car is too responsive and not consistent. I also tried front spool, but the car chatters like crazy when off power. It has a lot of steering coming out of corner, but understeer or pushes like a dump track off power. I am running the original pro 4 with stock 2.5mm chassis. Will change to a 2.0mm chassis give me more grip?
02-18-2006, 08:12 PM
Tech Apprentice
btw, the track that I race on is only 40' by 80' with 5 hairpins. The last time I tried one way, it wasn't too bad, but I had to let off the throttle early at the end of the 80' straight. On average, the back end would jump around about twice in a 5 min race, which completely killed the race. So, I figure that I better stay with front diff. Thank's for the input, everyone.
