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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi Tire Chatter/Racepak Graph HelpGo | New | Find | Notify | Tools | Reply | |
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| DRR S/Pro |
A guess a shock travel sensor would answer the question.............. | |||
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DRR Sportsman |
This is a comparison of 2 converters, same car same day, same track, same tires, same suspension set up, etc. Both converters ran nearly identical except one doesn't shake. 1.006-1.008 60', 4.311 to 4.306 660' at 160 mph and 6.778 to 6.780 at 197 mph. The Hughes 9" 7SC1 and 9" converters from other manufacturers with similar configurations are prone to tire shake like in the graph. They are fast but very sensitive to track conditions.[IMG]  [/IMG]Steve Casner  | |||
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| DRR Top Comp |
No sir, it's an objective fact shake is an out of phase imbalance between the two tires resulting in inadequate damping, high damper shaft speeds of 20-30 inches per second during shake, so we know the rear end is moving un-dampened/uncontrolled. This is an objective fact anywhere the shake occurs early in the run. .This message has been edited. Last edited by: Mike Rietow, | |||
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| DRR Top Comp |
The trouble for the red converter starts where the tire hooks abruptly and flat lines the rpm and drive shaft knocking the tire out of round. Tighter rebound setting may solve that evidenced by more wheel speed (driveshaft) on the red than blue, just before the tire abruptly hooks and flat lines the red rpm below the blue.  | |||
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| DRR Top Comp |
Angry tire  | |||
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DRR Pro |
steve do you know what the difference is in the two convertors honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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DRR / Crew |
Rusty - of course he does. He builds them. And he is very sharp. Thanks for posting up the info stretch. SL... | |||
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| DRR Elite |
Can you elaborate on what you mean by describing it as an out of phase imbalance between the two tires? I always assumed that the shake was due to the tire not being able to keep the integrity of its shape at some applied torque level, and the nice flat friction surface becomes unglued from its dead hook. Then it spins a little and hooks and goes through this oscillation. I just welded up some broken parts on my dragster from tire shake that I seem to be getting under control. The biggest helps seem to have been significantly lowering the tire pressure, and completely tightening the extension and significant tightening of the compression on the shock. My combo seems to be pretty picky, as it's hard to find that line between too much wheel speed and not enough. And really good 60' times have been difficult to come by. My power comes on a little weird compared to most though. It really comes around about .5 seconds into the run. Working to get more earlier. But I don't need to pollute this thread with those details. Foxtrot Juliet Bravo | |||
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| DRR Pro |
lol, i knew that was just hoping for some info.i know steve and agree with you.also know some secretes dont get shared honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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| DRR Pro |
to add more to the discussion,my car has been .990s lately with no shake.our other car is more prone to shake at.08 to .1.tires are now the same and converters have been used by some of the best builders.so i have some interest in this mystery also.just trying to learn.lol honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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| DRR S/Pro |
Mike Shake and chatter are two different animals. Once a car goes into real tire shake, all bets are off and the only option is to lift and try again. So under real tire shake, the kind that breaks chassis, I could believe your 10 to 20 IPS shock speeds. But in this case, there is no way shock speeds are even close to 10 never mind 20 IPS. Not to mention that a car with this kind of power should even be able to "Shake" the tires,,, unless they try too with a crazy setup. Promod power levels can and do drive into tire shake this far out but not these deals. And yes, this is my opinion just like yours. The track conditions where not good on the run shown, even the 1-2 gear shift upset the tires. Based on the data presented and info listed here so far, I can tell you one thing for sure! There are way more questions than answers at this point! | |||
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| DRR Top Comp |
Out of phase imbalance would be two egg shaped tires out of phase or one egg shaped tire and one round tire, which naturally would be out of phase as well. Tire shake. Post a pic graph drive shaft and rpm, you like on your car. It looks like the converter that works well isolates power through the problem area by limiting engine acceleration evidenced by a dipping line to the shift in comparison to the two converters which graphs indicate, evidenced by a fairly straight line to the shift (if you throw out the hump where the shake is) which indicates engine acceleration.   | |||
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| DRR Pro |
https://imgur.com/hHU73ID honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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| DRR Pro |
sorry for the link i am having trouble with pics honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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| DRR Pro |
 honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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| DRR S/Pro |
How much power do you have, once you get to a certain point its all about managing wheel speed vs power applied. BTW that's very early in the run to get into a shake issue! Are those times correct or typo? | |||
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| DRR Sportsman |
Hello Rusty, The red engine rpm line and green driveline are using a Toyota core 9" converter and the Blue engine rpm and yellow driveline are using a 258mm(10") core. Are you coming out to Vegas again this year?This message has been edited. Last edited by: Cazman, Steve Casner | |||
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| DRR Pro |
the plan is to see there providing all goes well,longs way to drive for fun but oh well honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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| DRR Pro |
old age and typo,.8 is more accurate.these cars are hard to get wheel speed. mine is usually at 1050 to 1100 at .25 honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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| DRR Top Comp |
You need a two way adjuster on the compression side of the damper/shock with as much down pinion angle as you can get away with and low tire pressures for wheel speed. Run the high speed stiff and low looser/normal so it's not like being on a pogo stick / bumpy tracks, as the rear end slows down.This message has been edited. Last edited by: Mike Rietow, | |||
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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi Tire Chatter/Racepak Graph Help
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