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Old 02-26-2005, 01:32 PM   #1186
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Wow, how to confuse what is a fairly simple thing, just because the loose terminology that we seem to accept in this sport.

Front end:
When the front of the arm is lower than the rear - this is actually ANTI_DIVE and will result in less initial off-power steering because when you lift off the weigh of the car moving forwards will not cause the front to dip (as much), the hinge pin line will to a degre counter the dipping of the chassis, in extreme cases is can even cause the front of the chassis to lift!

With the rear of the arm lower than the front - this is PRO-DIVE, where lifting off the power and the foward shift of weight to cause increase the front chassis dip, and increasing the roll axis bias - like suddenly lowering the front roll-centre. Having this will increase your initial off power steering.

Rear end:
When the front of the lower arm is lower than the rear is call PRO-SQUAT as it will increase the tendancy for the rear of the chassis to drop when power is applied.

When the front of the arm is higher than the rear, this is ANTI-SQUAT as the rearward movement of the weight of the car will resist the tendancy for the rear of the car to squat down producing the equivalent of a stiffening effect of the rear suspension.

Like all these things, this isn't the end of it, as for each and every link or geometry change, at least 2 other things alter as a result. Such as camber change rates, weight transfer speed and roll centres, each with their own side effects.........

As has been said, 2 deg pin angle plus 2 deg castor is NOT the same as zero pin angle and 4 deg castor, the resulting characterisics are totally different.
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Old 02-26-2005, 01:36 PM   #1187
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MIke-on the anti-dive and pro-squat-I have to tell you I use them when I feel something the cars doing and as dumb as this sounds-I think or know anti-dive or pro-squat will help and I try it.
For the antidive-its usualy a situation where the car feels like it needs to retain turn in-but also needs more exit steerig. So I will go to 6 deg caster for more on-powr steerng, but put in the antidive and that keeps it cutting in well.

I also try anti-dive in front when i feel the cars digging. By that I mean you turn the wheels and the front end feels like its screwing itself into the carpet and scrubbing speed. antidive sees to keep the front end up.

For the prosquat-I tried it at a race and I took it out to see if I still needed it and my car was slower. I am sorry i cannot explain it any better than that. My HPI Pro4 was the same way-it liked a touch of pro-squat always. The TC3 and Xray-not good!!

Ray
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Old 02-26-2005, 01:45 PM   #1188
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It's quite obvious physics.... With antidive(front of arm lower than rear, in front of the car), the arm will go backwards and downwards into a turn holding the chassis up.. With kickup the arms will go upwards and backwards, the front will dive...
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Old 02-26-2005, 01:45 PM   #1189
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Ray exactly you are dead right! The magnitude of the effects of the lower hinge pin angle depend greatly on the relative (to that hinge-pin) of the locations of roll centres.......so one cannot make statements that apply across ALL cars, the variations in the mechanics of the geometry just don't allow it.

It is not uncommon for us to run with a measure of anti-dive on the front in high grip carpet situations when we dont want to run with a stiffer front spring, since this would load up the tyre even more. The ANTI angle bit produces a virtual stiffening of the car at that end which increases as more weight transfers.

And you are quite right Ray, like droop, lower hinge pin angles are very powerful and often overlooked handling tuning aids.....probably because the confusion that the loose terminology is/has caused.
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Old 02-26-2005, 05:43 PM   #1190
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Quote:
Originally posted by rayhuang
MIke-on the anti-dive and pro-squat-I have to tell you I use them when I feel something the cars doing and as dumb as this sounds-I think or know anti-dive or pro-squat will help and I try it.
For the antidive-its usualy a situation where the car feels like it needs to retain turn in-but also needs more exit steerig. So I will go to 6 deg caster for more on-powr steerng, but put in the antidive and that keeps it cutting in well.

I also try anti-dive in front when i feel the cars digging. By that I mean you turn the wheels and the front end feels like its screwing itself into the carpet and scrubbing speed. antidive sees to keep the front end up.

For the prosquat-I tried it at a race and I took it out to see if I still needed it and my car was slower. I am sorry i cannot explain it any better than that. My HPI Pro4 was the same way-it liked a touch of pro-squat always. The TC3 and Xray-not good!!

Ray
WOW!!!

Did I open up a can of worms or what???

Actually, I appreciate ALL of the replies and I think that I will try some of these ideas out at my next test and tune!!

Thanks again, Mike
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Old 02-26-2005, 06:53 PM   #1191
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Actually Mike-we need a lot more discussion like this on here. So ask away nd hopefully when someones tried just what your asking about-well all learn. Sorry I couldnt explain pro-squat-its just soething I try when I feel something the cars doing on the track. LIke now-I usually cannot remember why I used it-so I take it out and find out I still need it lol

Ray
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Old 02-27-2005, 01:13 AM   #1192
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Quote:
Originally posted by rayhuang
Actually Mike-we need a lot more discussion like this on here. So ask away nd hopefully when someones tried just what your asking about-well all learn. Sorry I couldnt explain pro-squat-its just soething I try when I feel something the cars doing on the track. LIke now-I usually cannot remember why I used it-so I take it out and find out I still need it lol

Ray
I have to agree with all statemenst made in the last few posts.
Also I think sometimes, a question is missunderstood which sometimes leads to senceless bickering.
But a deep and good discussion, with a clear explination is allways very welcome for every serious racer IMHO.

Keep up the good work guys.



Just wondering.
Ray you race carpet-foam right?
Mike/Martin you race carpet-rubber/molded right?

You do all agree on these statements.
Do you think if any of the settings has a bigger effect on foam or rubber?
Or equal?
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Old 02-27-2005, 10:24 AM   #1193
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Drove the dual diff car for the first time yesterday. My first impression of the car is that it is beautiful. Everything fell together. Once I had it on the track I ran into some problems though. My rear diff seemed to unload turing in one direction. Off the track I noticed something was very wrong with this diff. I carefully took it apart, and couldn't find anything wrong. After some diagnosis, I found it was the thrust bearing (pre assembled) was trash. It was made out of a very thin metal and was falling apart. I'm not sure if anyone else has had this problem? I kind of expected some bugs, but was dissapointed with this. Luckily the Xray thrust assembly fell right in and felt much better. Other than that the car seems awesome. With more tune time this car will be a beast!
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Old 02-27-2005, 10:27 AM   #1194
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actually alot of people have had this problem, and yes the xray thrust bearings work and also if you have a few extra assassin diffs, those thrust bearings work as well

i have changed both thrust bearings because they both were thin metal
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Old 02-27-2005, 10:29 AM   #1195
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Factory had a problem with the pre-installed thrust, but this has been recognised and addressed using the same spec thrust as in their previous cars.
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Old 02-27-2005, 10:30 AM   #1196
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Anybody have binding in the cvds at full lock, still 3-4mm away from the shock so it's not too much angle?
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Old 02-27-2005, 10:30 AM   #1197
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Is Corally stepping up to replace existing pieces?
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Old 02-27-2005, 10:42 AM   #1198
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call corally usa and see if they are, i honestly dont know if they are

and i dont have any problems with the cvd's, just with a spool in the front and a strong 19 turn, i bend them easily
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Old 02-27-2005, 12:02 PM   #1199
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Default Thrust Washers

There were some problems as the supplier for Corally provided the wrong ones when the RDX was coming out. The problem has been addressed and we are awaiting a shipment of the brass washers. Call Corally as I believe Rob is still covering the old washers that blow out.


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Old 02-27-2005, 12:05 PM   #1200
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Default Anti-Dive

Ok, after making my earlier reply and getting corrected I looked around the net and found this pretty darn good explaination of Anti-Dive.

Check out the article here.... http://www.circletrack.com/techarticles/80727/

They really talk about how it helps cornering and actually has a picture of a real car and tells you how you can read the type of angle they are using.

Jeff
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