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Bad Pushing Problem(w/ hyper PCR)

Old 06-13-2006, 07:44 PM
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Jammin Jake
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Default Bad Pushing Problem(w/ hyper PCR)

We have a real push problem... we have done some serious experimenting with the diffs. We have the servo turning 100%. We have done the combination 1-1-1. Then we did 10-1-1 and still no response in anything..it still pushes. The track(clay ball dirt) will be both wet down or dry and still does the same problem. It actually turns better 1-1-1 i dont how that it is but it does. We've been told to run 3-1-1 and that is our next attempt to make this thing turn. Before all this baloney experimenting we ran 5-7-1i in the diffs but still push. Its just when we enter a sharp corner and try to exit while sliding all it will do is push into the walls. The only way i can get it to make a somewhat good turn is too hit the brakes and try to whoop it around(which actually works better). Does any one out there have any suggestions or have the same problem but got it right. Im a real good driver here at my lhs and have competed against good drivers with high dollar stuff and have come close if not win.
Servo:steering:airtronics 94358
Controller: JR Xr3i
Good Ofna hump pack.
New set of panther k2's
Steering is not in a bind.
These are the things i run, might help resolve problem.
Old 06-13-2006, 08:15 PM
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bspate
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Are you running the C-Hub or PBS setup??

If you have the C-Hub setup, then I can suggest two things to help out your steering to be tighter.

Let me know and I will take pictures to help my descriptions.

- bspate -
Old 06-13-2006, 08:16 PM
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AlGio
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Default RE: Bad Pushing Problem(w/ hyper PCR)

It sounds like you are not getting enough traction with the front end. Have you tried different tires and possibly stiffening the rear suspension so that you get less wight transfer to the rear as you accellerate and keep the front planted down more? or possibly stiffer springs in the rear.
Old 06-13-2006, 08:37 PM
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Jammin Jake
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Im ruinning the PBS setup, In reply to Algio, the panther tires are a new set. And we have really made the rear end tight, and the front really sits low...but ive thought about what you are saying. As far as the springs go there stock. Sometimes it actually looks like what your are talking about. Il be in a open field and turn all the way one way and the rear end squats the front picks up, then the fronts will just spin and the rear will just roll. Just today i drove one of those good racers buggy's same car just he had a Novarossi p5x w/ stock springs w/ proline crimefighters. Man that thing would turn on the dime, just sit there and do doughnuts in one spot. Also he had 40 oil in the front shocks and 60 rear, i guess so that the wieght wouldnt transfer like you sed.
Old 06-13-2006, 08:41 PM
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Rs43EVOman
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Ive found a good set-up for the Hyper 7 PCr to be 5 front, 5 mid, and 1 rear. Also A good base set-up is too have the car leaning slightly backwards. I have 40 WT in mine, and The stock sway bar in the rear, and i took a replacement swaybar for the rear (same as sotck one), cut a little bit off of the ends, and am using that in the front. Tthe sway bars they makes for the front really dont fit well at all, at least not the 2.4mm. I happen to ahve 7 worth preload spacers in the front and 6 worth of preload spacers in the rear, and mine seems to handle very well.
Old 06-13-2006, 08:45 PM
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Jammin Jake
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Default RE: Bad Pushing Problem(w/ hyper PCR)

That makes turn pretty good eh. What tires are your running? Motor? Will it turn pretty sharp, hardly no push if not none?
Old 06-13-2006, 08:56 PM
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kx250ryder
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Default RE: Bad Pushing Problem(w/ hyper PCR)

After spending some time on OFNA's forum, I found that team drivers often ran unconventional setups where the rear diff had the thickest fluids. Where the recommended baseline setup for most cars was something like 5k front, 7k center, and 1k rear, the guys running the PCRs mentioned a setup more like 3k front, 3k center, and 5k rear. This freed up the rear end quite a bit according to them.
Old 06-13-2006, 09:02 PM
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Jammin Jake
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Default RE: Bad Pushing Problem(w/ hyper PCR)

I really dont see how that is. You want the front to plant so you stiffin it up by putting thick oil in the front diff, and then you want a good power transfer but not crazy power transfer so you puit somewhat thin oil in the middle but then you want the rear to frelly spin up and around the turn so you put real thi oil in the back. I just dont get how 3-3-5 would make the back come on around without pushing like a tank? Got me man
Old 06-13-2006, 09:14 PM
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kx250ryder
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Thinner fluid means less resistance, and that means the diff will be more likely to naturally spin the easiest end. That means that you won't break the outside front tire loose as easily since weight will shift outward, (instead power will go more to the inside front tire) giving you more front traction under power. Thinner center diff oil means that it will send more power to the front under acceleration (since weight will shift rearward), but thicker rear fluid means that what power does go to the rear will be divided more evenly, causing both wheels to break loose easier, giving you the ability to slide the rear end around.

My buddy runs 5k/10k/10k in his Hyper PCR and it works well for him. I think its too tail happy, but he likes it.
Old 06-13-2006, 09:58 PM
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Jammin Jake
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Well you see those diff combinations you explained sounds like a setup used for big wide open tracks where your on it alot. The track i race on has a few u-turns and maybe a 75 ft straight. So your avg speed on this track is like 4mph. So i dont need something to where it is setup to pllant the tires and go i need a setup that is for a very slow lazy track that has sharp turns.
Old 06-13-2006, 10:29 PM
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Try with more toe-out in the front. That'll give you more turn-in for sure.
Also try the rear holes on the Ackerman.

Light oil in the front and rear diffs will make it easier to turn too (off power).
Old 06-14-2006, 12:22 AM
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MoJoe
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Default RE: Bad Pushing Problem(w/ hyper PCR)

firslty run c-hub 20 degrees....
toresen in front
5000 oil centre
3000 oil in rear

it will be dialed.
Old 06-14-2006, 05:20 PM
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Run the least amount of caster possible, put your top shock mounting points on the inside for front and outside in rear (this should help atleast a little), more toe out in the front, less toe in on rear, more anti-squat in the rear is supost to give more steering but I never tried it myself, eveything else that you can do has already been said. If you still need more steering I guess clip off some tread from your rear tires [:@]. I had a hyper 7 PBS for my first buggy and I couldn't do anything to make it turn like I wanted it to.
Old 06-15-2006, 05:52 AM
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Default RE: Bad Pushing Problem(w/ hyper PCR)

The PBS Hyper 7 has pathetic steering lock. You can dremel out your wheel hubs a bit or install mugen hubs and PBs which helps a lot.
Old 06-15-2006, 01:25 PM
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Rs43EVOman
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Default RE: Bad Pushing Problem(w/ hyper PCR)

The steering on my Hyper 7 PCR is preatty good, but i could use just a little but more. I'm already planning on putting diffreent oil in the shock but i have a question, will putting thicker oil in the front give my car some more steering?If Ive heard that 40 rear and 45 front is good combo for my track with my car, but what are the pro's and con's of thicker front oil?
Old 06-15-2006, 02:12 PM
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LSUsportsfreak
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Remove the front sway bar if you haven't done so already.... it will help the pushing issue.
Old 06-22-2006, 02:34 PM
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Metal Steering servo arm helped my PBS PCR Pro as the stock plastic one would flex a fair amount and under load while driving I dont think it handled the job too well at all.

Less castor also helped. And I run softer springs on the front which also seemed to help get it turning.

I run 60wt Associated oil in the front and 40wt Associated oil in the rear shocks.
Tyres are Proline Step-Ups with firm moulded inners.

Front shocks:
Top shock mount is on the inside of shock tower.
Bottom shock mount is in holes closest to wheels (outer holes).

Rear shocks:
Top mount is in the middle of the holes and on the lower mounting holes.
Bottom is closest to wheels (outer holes)

(Edit)
Forgot to mention the dif oils.
Front: 7,000
Centre: 5,000
Rear: 3,000

I dont run much toe out in the front and not much rear toe in. (cant tell you exactly but its not much).
Camber is also very minimal on my hyper front and rear.

Out of all those things the ones that made the biggest difference were the metal arm for the steering servo and softer front springs.
Our track is a mix of very hard packed clay to loose sandy clay in sections and average surface ie: sometimes bumpy sometimes fairly smooth.

One other thing to check is the nuts on top of the ackerman plate where the steering arm ball mounts onto it: this nut touches the plastic suspension arms if you pull all the weight off the buggy and turn the steering servo. So on mine I had to wind the grub screws out on the lower arm so when weight was lifted off the buggy the wheels didnt droop quite as far at full travel and this let the nut pass by the arm without contacting it. Shouldnt affect steering effectiveness but something to look out for while you are messing with all this stuff :P
Old 06-22-2006, 07:07 PM
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Rs43EVOman
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Default RE: Bad Pushing Problem(w/ hyper PCR)

Yah hes right i forgot about the servo arm if you loom when you tunr the stock servo arm flexes alot. Im using a sirtronics servo so im using tyhere heavyduty servo horns, and it doesnt flex at all. its reinforced with aluminumn, and is very strong plastic. Hre are the ones im using, [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXTT14&P=0]http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXTT14&P=0[/link]

Also as long as your track isnt really bumpy you want to get a sway bar in the front, i know it doesnt come wityh one. Maybe im confused abotu sway bars, but LSUfreak said that you should take it off, im preatty usre thats wrong, a swaybar helps the car turn better, you just dont want to use it if your runnign on a very bumpy track. All i know is after putting a sway bar on my car (I modded the rear one to fit the front) ands now my car turn better.

Oh i just noitced that you have the 94358 (so do I) and this servo comes with this arm, and if your using the one that comes with tyhe car make sure you switch it out for this one, you just need to drill the hole bigger where the linkage hooks up.

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