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Old 04-20-2012, 12:33 PM   #2056
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Originally Posted by EAMotorsports View Post
He ran stock top deck and chassis.

EA
But Hagberg did run the 2mm chassis.

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Old 04-20-2012, 12:57 PM   #2057
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But Hagberg did run the 2mm chassis.

JR
Yes Alex did with a 2mm top deck but the list he has is from Zdenko's car I believe and is what Mark was referring to.


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Old 04-20-2012, 09:30 PM   #2058
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Oleg....
Just placed an order
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Old 04-21-2012, 09:33 PM   #2059
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I had a really fun race day here at NorCal. Competition was high, as was the heat. Quite a few of the racers had failures due to heat. My car was finally on pace, and feels like what I'm looking for out of this ride. I would still like the car to get into the corner slightly better, as the rear of the car was nothing but purely planted, but it also had great corner speed, and was very consistent steering throughout the corner and the race. Very happy.

The grinding and shimming I did on the transverse gears made a difference, but the car is still pretty loud. It's gotten less distracting now that I know what to expect, but the "cute" remarks on it's noise are tiring. I'm looking forward to the possible plastic gear to replace G01 or G02.

I personally would like to see some effort to move the motor forward a little bit more, as I think my front to rear balance is nearly as good as it's going to get and it's still 52% to the rear. It's measurably further back from other TCs as well.

Setup is pretty darn close I think, car was easy to drive and was fast.

Thanks everyone for your help previously, and thanks to Dominic for donating his spare top deck that I broke in practice, before races.
Attached Files
File Type: pdf asphalt norcal 4-21-2012.pdf (342.2 KB, 158 views)

Last edited by erchn; 04-21-2012 at 09:35 PM. Reason: clarity and spelling
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Old 04-21-2012, 09:37 PM   #2060
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Great job! What kind on incident at Norcal can cause a broken top deck
Quote:
Originally Posted by erchn View Post
I had a really fun race day here at NorCal. Competition was high, as was the heat. Quite a few of the racers had failures due to heat. My car was finally on pace, and feels like what I'm looking for out of this ride. I would still like the car to get into the corner slightly better, as the rear of the car was nothing but purely planted, but it also had great corner speed, and was very consistent steering throughout the corner and the race. Very happy.

The grinding and shimming I did on the transverse gears made a difference, but the car is still pretty loud. It's gotten less distracting now that I know what to expect, but the "cute" remarks on it's noise are tiring. I'm looking forward to the possible plastic gear to replace G01 or G02.

I personally would like to see some effort to move the motor forward a little bit more, as I think my front to rear balance is nearly as good as it's going to get and it's still 52% to the rear. It's measurably further back from other TCs as well.

Setup is pretty darn close I think, car was easy to drive and was fast.

Thanks everyone for your help previously, and thanks to Dominic for donating his spare top deck that I broke in practice, before races.
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Old 04-21-2012, 09:40 PM   #2061
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Originally Posted by MDawson View Post
Great job! What kind on incident at Norcal can cause a broken top deck
I got tunnel vision at one point, thought I was outside of a fellow racer and hit him pretty dang hard from the rear. His car was fine, I lost my center shaft and broke my top deck. I felt really bad, but Jay was a nice guy and didn't give me too much crap. haha
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Old 04-21-2012, 10:21 PM   #2062
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Ethan your car is money, seeing it convinces me to try transverse now….your hard work with transverse paid off. Great racing today well done
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Old 04-21-2012, 10:39 PM   #2063
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Ethan your car is money, seeing it convinces me to try transverse now….your hard work with transverse paid off. Great racing today well done
Thanks Dom. I appreciate you sponsoring me some parts lately! Hahaha
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Old 04-21-2012, 11:53 PM   #2064
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Ethan's car was on point today. Great watching him wheel the "Sputnik" around the track. NOSTROVIA!!!
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Old 04-22-2012, 12:17 AM   #2065
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Originally Posted by DJGonzo69 View Post
Ethan's car was on point today. Great watching him wheel the "Sputnik" around the track. NOSTROVIA!!!
Thanks Gonzo!

Now back to your normally scheduled RC thread. ;-)
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Old 04-22-2012, 01:11 AM   #2066
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Ethan, please inform your battery position.
Can you move CG further to front by means of battery instead of motor?

Some comments concerning relationship of rear/front suspension stiffness and
rear to front weight balance:
We have found that good setups for A700 ( but without swaybars or at equal rear/front swaybars) have rear/front suspension stiffness = rear to front weight balance + 0,5...2% to rear.
For example the latest Freddy's setup has 55%/45% rear/front suspension stiffness at 53/43 rear to front weight balance.
I think that this +0,5...2% rear addition is due to more rear body's downforce existence and depends on body type, body front/rear offset and rear wing.
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Old 04-22-2012, 09:49 AM   #2067
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Quote:
Originally Posted by Oleg Babich View Post
Ethan, please inform your battery position.
Can you move CG further to front by means of battery instead of motor?

Some comments concerning relationship of rear/front suspension stiffness and
rear to front weight balance:
We have found that good setups for A700 ( but without swaybars or at equal rear/front swaybars) have rear/front suspension stiffness = rear to front weight balance + 0,5...2% to rear.
For example the latest Freddy's setup has 55%/45% rear/front suspension stiffness at 53/43 rear to front weight balance.
I think that this +0,5...2% rear addition is due to more rear body's downforce existence and depends on body type, body front/rear offset and rear wing.
Check my setup sheet. I'm at F1 with the battery. Right now, according to my calcs, I'm at 48% weight front, and 47% suspension stiffness front (93g / (93g+103g)). 1mm sway bars all around.

Last edited by erchn; 04-22-2012 at 12:59 PM.
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Old 04-22-2012, 04:43 PM   #2068
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Oleg....check your PP
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Old 04-29-2012, 05:28 PM   #2069
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It's been quiet in here, so I thought I'd post about something I worked on earlier today, which is how to shim out bump steer after changing caster. The simple way is to use a level on the link after changing caster, but that's too easy and is full of trial and error, so let's make it harder.

I'll start out by saying that this is probably obvious, but I thought it might still be useful to some. It's been said that achieving zero bump steer is maintaining a level link, I think it'd be at level ride height, or possibly level at 50% into maximum compression.

I'll begin with the rear, as it's a little easier in my mind, as both links mount from underneath. According to the stock setup sheet (page 42 of the manual) having a 1.0mm spacer under the outer toe link on the rear upright and no spacer on the inner toe link should give zero bump steer at -2.5 degrees of caster.

The manual shows the algorithm for determining caster is (h1-h2)*2.5, and with the 1mm under the outer link we can deduce that the outer h1 measurement is 2mm higher than the inner link by default:
((h1 - h2) = 1mm) * 2.5 = 2.5 degrees of caster; add the 1mm of stock outer shim = 2mm

Every 2.5 degrees of caster we should shim the inner link down 1mm to achieve a level toe link. Take 4 degrees of rear caster for instance, that would be a difference of 1.6mm from h1 to h2:
(h1 = 1.6 - h2 = 0) * 2.5 = 4 degrees of caster


So, if we went from the stock -2.5 degrees to -4 degrees we should add .6mm of shim to the inner toe link, or remove .6mm of shim from the outside link (2mm - .6mm) to maintain level. I prefer to leave the outside link alone and just shim inside as I never go under the stock -2.5 degrees.

The front is exactly the same except you start with a delta of 2.5mm to achieve level, 1.5mm on outside dropping the outside of the link and 1mm on inside raising the inside of the link.

Going from the stock 4 degrees of caster:
((h1 - h2) * 1.5 or (2.667 - 0) * 1.5)) = 4 degrees

to 6 degrees of caster you would have to remove some shims from one side to achieve that level link:
(4 - 0) * 1.5 = 6 degrees

Ok, final simple algorithm to determine shimming needs for rear (shimming inside link down):
(desired caster - 2.5) / 2.5 or (6 - 2.5) / 2.5 = 1.4mm

Final simple algorithm to determine shimming needs for front, removing shims from outside link:
(desired caster - 4) / 1.5 or (6 - 4) / 1.5 = 1.3mm

Obviously these are almost exact numbers and that's not reasonable under normal circumstances, so round up or down as appropriate.

BTW, I'm bored. :-)
Ethan

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Old 04-29-2012, 05:51 PM   #2070
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Quote:
Originally Posted by erchn View Post
It's been quiet in here, so I thought I'd post about something I worked on earlier today, which is how to shim out bump steer after changing caster. The simple way is to use a level on the link after changing caster, but that's too easy and is full of trial and error, so let's make it harder.

I'll start out by saying that this is probably obvious, but I thought it might still be useful to some. It's been said that achieving zero bump steer is maintaining a level link, I think it'd be at level ride height, or possibly level at 50% into maximum compression.

I'll begin with the rear, as it's a little easier in my mind, as both links mount from underneath. According to the stock setup sheet (page 42 of the manual) having a 1.0mm spacer under the outer toe link on the rear upright and no spacer on the inner toe link should give zero bump steer at -2.5 degrees of caster.

The manual shows the algorithm for determining caster is (h1-h2)*2.5, and with the 1mm under the outer link we can deduce that the outer h1 measurement is 2mm higher than the inner link by default:
((h1 - h2) = 1mm) * 2.5 = 2.5 degrees of caster; add the 1mm of stock outer shim = 2mm

Every 2.5 degrees of caster we should shim the inner link down 1mm to achieve a level toe link. Take 4 degrees of rear caster for instance, that would be a difference of 1.6mm from h1 to h2:
(h1 = 1.6 - h2 = 0) * 2.5 = 4 degrees of caster


So, if we went from the stock -2.5 degrees to -4 degrees we should add .6mm of shim to the inner toe link, or remove .6mm of shim from the outside link (2mm - .6mm) to maintain level. I prefer to leave the outside link alone and just shim inside as I never go under the stock -2.5 degrees.

The front is exactly the same except you start with a delta of 2.5mm to achieve level, 1.5mm on outside dropping the outside of the link and 1mm on inside raising the inside of the link.

Going from the stock 4 degrees of caster:
((h1 - h2) * 1.5 or (2.667 - 0) * 1.5)) = 4 degrees

to 6 degrees of caster you would have to remove some shims from one side to achieve that level link:
(4 - 0) * 1.5 = 6 degrees

Ok, final simple algorithm to determine shimming needs for rear (shimming inside link down):
(desired caster - 2.5) / 2.5 or (6 - 2.5) / 2.5 = 1.4mm

Final simple algorithm to determine shimming needs for front, removing shims from outside link:
(desired caster - 4) / 1.5 or (6 - 4) / 1.5 = 1.3mm

Obviously these are almost exact numbers and that's not reasonable under normal circumstances, so round up or down as appropriate.

BTW, I'm bored. :-)
Ethan

You need to get back out on that track!
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