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1/8 suspension tuning questions.

1/8 suspension tuning questions.

Old 03-10-2010, 08:48 PM
  #16  
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Here's a couple of set up sheets on the z-car website:

http://www.z-carusa.com/downloads.htm

Btw, since you live in Santa Clarita, do you club race at HRH?
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Old 03-11-2010, 09:44 PM
  #17  
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Thanks for the tip on the setups. I will certainly take a look at them.

I am curious how much my weight distribution differs from the normal nitro setup, let alone the 1.5 pounds or so of extra mass I am hauling around?

Yes, I live just 2 miles from Hot Rod and I hope to actually make a few races again soon. Between my work and this messed up weather, I have not been able to make a race since I got the Z-Car. I have done many hours of practice, and Jimmy even drove it for a solid 15 minutes on a set of batteries when they did the Fri night practice session. My average laps were in the low 20 second range and I got into the mid 19 second lap range on about 10 laps. Jimmy turned consistent low 19's and a best lap of an 18.6 even with the push trying to get onto the straight. The current latout is a lot of fun. The big "S" curve through the middle is a make or break for a fast lap. When I hit it right, I can tell right away. It is all in the left kink as you come down the hill in front of the scoring booth. Get too wide and you are in the marble pit in front of the driver's stand. During the open practice I passed a ton of people right there. When I got it right, I actually had to be careful on the jump to the table. I have to use only 1/2 to 3/4 throttle to down side the far end of the table top. Any more on a good "S" curve entrance, and I end up flat landing it way out in the marbles for the right hand 180.

The only bad part on the track for me right now is the WORST place to have a handling problem. The last 60 degrees of the big sweeper onto the straight. My car just starts to push so bad I have to get way out of the power and try and get it to tuck in before I can get back into it down the only long straight. The only saving grace is the huge forward grip and power I have in my car. The Neu 1512 2050 on 4S with a Mamba Max is a huge power house. My data logger is showing consistent 1500 to 1800 watt peaks as I get on it onto the straight. I also see that much power at the end of the "S" curve into the jump onto the table top when I nail the line and get it lined up straight.

My car is a bit of an overweight pig at over 8.5 pounds. But it is a durable brick with plenty of acceleration.
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Old 03-11-2010, 10:38 PM
  #18  
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Ahh, yea the end of the sweeper going into the straight is all about throttle control. If you're trying to gun the throttle through there, it's not gonna happen. You gotta either take the sweeper somewhat slow or go fast going in it, let off quickly towards the end to let the rear rotate, then gun it when it squares up.

That "S" area always gives me a hard time. The corner before it, I always have to remind myself to exit wide to prep for the S. Sometimes I make it smoothly, but most of the time I find a way to scrub too much speed or end up traction rolling.. err.
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Old 03-12-2010, 06:30 AM
  #19  
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I know what you mean, that 180 at the top of the hill before the downhill to the "S" is a tricky turn for sure. I am still not even close to mastering the line, but the trick I saw the fast guys using, including Jimmy with my car was to give the brakes a bit of a stab right before you crest the hill on the way up. This plants the nose down, if you take any air into that 180, you are in trouble. I had mine just float off the ridge, and when I tried to turn in, it traction rolled, going over about 3 times right over the pipe to the wood board. Because it was light from the loft off the ridge, it was at the topo of the suspension travel, os it was turning on stilts. The brake stab sure makes it slow down, but then you can take a fairly tight turn and get on the power down the hill so much sooner. My other problem there is turning in a hair too soon for the "S" and catching the inside pipe right in front of the timing booth. I am so afraid of going wide and getting in the marbles, it is actually a very tight entry for a 10 foot wide track.

As for the sweeper, I agree, it is not as fast as you expect it to be, and you can't hammer it early, but even under drop throttle or steady state, my car is pushing there, way more than any of the other 1/8 guys I watched. I am not expecting a miricle with a chassis adjustment, I just want to be able to hang with the other cars, and not give up 10+ feet on the entry to the straight every lap. Jimmy is a great driver, and he was able to minimize the damage and turn some great laps, but he said it was killing him to have to slow so much compared to the other cars. He has the reactions, ability, and self control needed to be able to slow as needed even in a dicey battle. That is not so easy for me, I tend to over drive when I am trying to close on someone or keep from being passed. I just need a bit more front grip there,m and I think I will get into the low 19's or even crack into the 18 because the car is so quick everywhere else. Of course, Jimmy cut a 17.9 in his own 1/8 nitro buggy. That is why I run sportsman and he runs expert. If I get that push dialed out a bit, I bet he could turn a high 17 with mine. The electric is faster out of the slow corners, and was able to pull away down the straight too. It just needs to turn a little better. The 8.5+ pounds is not helping there.
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Old 03-12-2010, 06:48 AM
  #20  
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Yea Jimmy and the other experts are fast. I also race expert in nitro but I'm always in the bottom half. Some can say I don't believe in the class, but I definitely enjoy it more than when I raced with Sportsman as it teaches me to drive better. I raced 1/8E this past Tuesday but raced with the Sportsman nitro and didn't do too well. I'm still getting used to my car and I kept traction rolling or hitting the brakes too hard and flipping over. Still getting used to it, but getting there. Hopefully Saturday's race will turn out better.
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Old 03-12-2010, 07:04 AM
  #21  
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I can't wait to do another race, it has been way too long. Right now I am in Texas, won't get home until too late to race Sat. night, and of course, I am back out of town for work Tues, so I will miss that one too.

If all goes well, and my wife is not too insane after having the kids alone for 3 days, I plan to hit the track on Sun to test my suspension changes. It will be a total test/tune session. I will only be doing a few laps at a time to try all kinds of changes etc. Once I feel I have it dialed (if I ever do) then I will time d=some laps. I have a fresh set of Hole Shots, actually found a pair of M2's I will try on the back if it is still not loose enough for me. If I am not alone there, it would be nice to try and water it like a race night too as that seemed to make the push a little worse. I turned some pretty fast laps when it was totally dry a week ago.
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Old 03-14-2010, 09:22 PM
  #22  
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Okay, I broke the rule, I made 4 changes at once to try and make my buggy a little looser on the end of the sweeper. Well, it worked, it actually was a little looser than I would like. I was a good boy though and I did take notes of everything thing I did. My question now is what should I dial back. Worst case was the tail getting a little too loose under drop throttle. This made the "S" curve very tricky. I got it too sideways several times.

Here are the changes I made to loosen it.

1) Rear toe from 3 degrees in to 2.5 degrees in per side.
2) front upper arm changed to lower inner mount position, only 2 choices.
3) rear camber link, a little longer with inner mount now in and up one hole.
4) front caster increased, moved upper arm back 2 mm.

I ran new Pro Line Hole Shots. M2 on the front and M3 on the back was better, with M3 in front and M2 on back it was even looser.
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Old 03-19-2010, 07:57 AM
  #23  
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No one responded to this one, Hmmm. After quite a bit of talk on the diff oil thread that I started, I still decided to revisit this because the car was just a bit too loose and I felt the diff oil alone was not the proper fix as the car balance just changed a little too much from the quad change I did here. So I changed back only one thing. I put the rear upper link back to the stock location. This makes it a hair shorter and moves the inner end lower and out a little. This should result in a better camber curve to maintain a little more rear grip when the car leans into the turn. This is very easy to adjust, so I can do it at the track if i find it brings too much push back. Now back to Diff Oil..
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Old 03-19-2010, 09:19 AM
  #24  
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Go back to 3 deg of rear toe will re lock in the rear end.
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Old 03-19-2010, 10:28 AM
  #25  
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Thanks for the suggestion. I have the 3 degree bushings ready to go in my box. I will do a few laps at 2.5 to see if it is needed. My quick 3S pavement test was rock stable with the adjusted camber link and 7000 from diff oil. Oe of the great things on this chassis is how easy it is to adjust thing like the rear toe.
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Old 03-19-2010, 09:08 PM
  #26  
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I know this is kind of a double posting. I shuld join the suspension setup and diff oils threads into one.

I again made 2 changes at once. I put the rear camber links back to original box setup position and changed the front diff oil to OFNA 7000. The diff oil seemed to help the power on corner exit, and also the ability to correct it while under power. The camber link change got rid of the drop throttle oversteer issue I picked up when I made the previous changes.

All in all, the current setup seems amazing. I drove it to within a cpl tenths of my fastest lap ever at Hot Rod, but did it on a broken up dry dusty rutted track with a couple holes on my preferred line. I didn't expec to be anywhere near this fast on the surface when I saw the condition. They will start grooming it in the morning for the races starting at 4PM tomorrow. I have missed so many races, I am just hoping not to choke too bad. I certainly have no excuse for a poor showing besides my driving. The car is handling great and has the acceleration and top speed to run with anything out there. I will fill in a setup sheet for the car to keep as my eference. I still have the rear toe at only 2.5 degrees. It was stable as a rock under acceleration or steady state, and just got a hair loose as I would drop throttle mid corner. Just enough to help rotate it around the tight stuff.

The flying fast "S" curve was a major pain. Right in the middle of my preffered line there is a 3 inch deep hole. I caught it a few times and it just bites the right side tires and barrel rolls the car all the way to the outside of the track. I did it about 5 times because the car really wants to drift to the point on the track. I hope they can fill it in or smooth it out when they groom it for tomorrow night. With the color and texture of the dirt, it is so hard to see the hole from the driver's stand. I could not believe how bad it was when I went down on the track and looked across it. I ended up slowing a bit early for the "S" and driving inside of the hole. and then powering through the second half. It is not as fast of a line, but with how well I was able to turn under power I ended up cutting into the 19's again.

There were also 3 other places where ruts have develped that will flip a car if you hit them wrong. The others didn't cost me as bad, and they were not as deep, so I could go through them without loosing it if I just pedalled it a little. If I was alone at those points, I just went a little wider and was able to carry good speed, but when trying to overtake or protect your position, you end up hitting the ruts. My soft shock setup is helping a ton on the rough areas, but it does bottom if I don't downside the jumps. It is so hard to not overjump the double.

I will be posting the race results, hopefully I will have something good to report.
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