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Old 10-11-2005, 03:35 PM   #11326
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That is just what i did to solve problems i was having. i chacked everything and changed a lot of things to find out in the end that what i needed was a better servo.
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Old 10-11-2005, 03:45 PM   #11327
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Thanks guys, theres a lot of input here.

Servo - I've run 3 different servo's in the car since I've had it - no difference.

There's no binding in the steering - though it does have a fair bit of slop (which will be fixed soon).

Most of the adjustments suggested I've tried and they haven't really helped - often making the car better in one area and worse in another

The dual-rate might be something to try - I usually run at around 70% only because I thought running higher might scrub too much speed in the turns - but I suppose I might need more lock for the tight turns so I'll try that.

Cells back always gives me LESS turn-in, not more.

With tyres, I generally run what the fast guys at the track do - that way I can generally eliminate that as a potential problem.

I haven't played with the ackerman - it's set at 40.8mm because thats what most others run and I don't see it change don the setup sheets much. By shortening it, where will I gain steering? Turn in, mid corner, or exit steering??
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Old 10-11-2005, 06:08 PM   #11328
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going back to the Alloy rear hubs, the distance between the centreline of the axle and the Lower outer hingepin on the arm is actually greater than the standard hub.

the standard hub has a 13.5mm gap
the alloy is 15mm gap.

talking to Phil Booth the change had improved steering when lowering that outer hingepin closer to the wheel

The E.C car has changed offset, the hingepins sit deeper inside the wheels, as close to the wheel centreline as possible, to reduce the jacking effect caused by castor. This is said to be quite an improvement, requiring the wider arm spacing on the chassis and thinner wheel hexes to maintain track width.

Im not sure if the height of the outer pin attachment point on the new rear hubs has changed again.
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Old 10-11-2005, 06:34 PM   #11329
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Bender I suggest there is something amiss with your car, your findings dont correlate with what you should be seeing.
Antisquat is supposed to give more exit steering, allowing the car to square up quicker on power.
Lowering the front R.C should give you more off power steering, as its giving more mechanical grip to that end of the car by increasing its roll moment. Perhaps not snappy initial steering but once the cars nose dips it will give more grip to the front tires.

Raising the rear roll center shouldnt have a large impact on corner entry, more mid corner to exit. As we a concentrating our efforts on increasing the front tires grip, look to make adjustments to the front end first, as a last ditch effort in desparation should we look to unstick the rear end of the car, as it is gripping, therefore doing its job. Only if we cant get the front end to do an equally or better job at gripping the track to we handicap the other end of the car, lowering the chassis overall cornering grip potential.



Cells back usually make the car very responsive initially as there is less static weight over the front tires, it does also induce a pendulum effect once the car begins rotating and can cause mid corner oversteer .
The idea of the cell placement on the teemu chassis is to give as close to perfect static balance, the rearward cells almost perfectly offseting the weight of the motor. (confirmed by my digital scales with minimal ballast on the electronics).

On a low grip surface, you are wanting weight transfer to give grip to the end of the car requiring it. A softer front end (shuey white) will allow more weight to be transferred to the front end as you lift or brake for a corner.

Hence why I am confused about your incurable understeer. Your findings dont compare with what I have found in the 2 years with the Mi2. My track (tftr) Is generally low / medium grip.




It sounds to me you are desparate, so try these suggestions 1 at a time in the following order.

remove your front riser plate all together, just run 1mm shim underneath the mounting blocks (if alloy mounts) .5mm shims for plastic mounts.

Leave the rear riser plate in place, with a 1mm shim underneath each arm mount. (generally the rear mounts 1-2 mm higher than the front acheives a good roll balance.

2 degree castor with spool, really smartens up the steering response and gives back the lost turn in when using a spool. generally 4 degree with a oneway. Disregard anti-dive / squat at this point.

Schumacher white springs front and rear, AE blue at the most! for low grip conditions you shouldnt be using schuey green, too hard, limiting forward transfer off power, hence less chassis rake on corner entry to Mid corner and resultant understeer.

Ae blue front and Ae silver rear is a tried and tested combo by team drivers all over the world,with lots of drivers of late going to the schumacher white springs front and rear(similar in rate to AE silver).
In my opinion they can allow the chassis to dump over in high speed corners if not driven smoothly. which can cause understeer due to too much weight transfer, overloading the outer front laden tire.

Try cutting the topdeck the same as the Euro car, chassis compliance will be your friend in low grip conditions you describe.

please report back...I want to get to the bottom of this.

G
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Old 10-11-2005, 06:41 PM   #11330
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I personally always use steering throw limiters, In my case I have a tiny hole drilled in the steering block at the point it contacts the castor block, In to which i screw a tiny button head hex screw. I screw it in all the way, but have to option to back it out a little to give even less throw.
Ive never found the need for full throw on the Mi2, all it does is scrub the tires out (already beyond any reasonable slip angle, wear out your cvd's quicker and rob you of cornerspeed. the only place I might want that little extra lock would be an indoor technical track - slow speed.

I really am puzzled at your incurable understeer, Ive never been to a track where i have suffered this (unless wet) haha

Each adjustment is going to improve one area, but worsen another to a degree. This is the dillema we always face in tuning a chassis, so we need to decide carefully on each adjusment. Choosing something which we can sacrifice in one area for overall laptime gain.

For instance reducing castor to gain turn in response, yes we are going to lose exit steering a little, but that is an area we can perhaps improve by working on the rear of the car, slightly stiffer rate / angle etc...

Stick a fork in me, Im done..(brain dump)
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Old 10-11-2005, 08:26 PM   #11331
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Damn Gavin! That was good. And thanks for correcting my mistake. I was at work and obviously not thinking right.
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Old 10-11-2005, 09:54 PM   #11332
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Thanks for the help

Quote:
Originally Posted by King-G
Bender I suggest there is something amiss with your car, your findings dont correlate with what you should be seeing.
Don't I know it!

Quote:
Antisquat is supposed to give more exit steering, allowing the car to square up quicker on power.
In all my years racing I have never found that. My experience with anti-squat is that it provides less rear grip off-power (thereby effectively increasing turn-in), and MORE rear on-power, which logically would mean less steering on-power.

I have often gained turn-in by using Anti squat - but I can't recall a situation when I've gained power-on steering with it.

Quote:
Lowering the front R.C should give you more off power steering, as its giving more mechanical grip to that end of the car by increasing its roll moment. Perhaps not snappy initial steering but once the cars nose dips it will give more grip to the front tires.
From all the handling guides I've read, they say that lowering the front roll centre gains mid corner steering, therfore losing turn-in, which you sort of suggest by saying "not snappy initial steering".

I have tried lowering the front roll centre, even as far as 2mm (no riser or shims) and I cant say that I felt a big difference, and of course the loss of that initial turn-in created as many problems as it solved.

Quote:
Raising the rear roll center shouldnt have a large impact on corner entry, more mid corner to exit.
Not a large impact, but still noticable, especially if your turn-in is already bad
I'm not sure if I've tried lowering the front RC and raising the rear RC at the same time so I will try that.

Quote:
As we a concentrating our efforts on increasing the front tires grip, look to make adjustments to the front end first, as a last ditch effort in desparation should we look to unstick the rear end of the car, as it is gripping, therefore doing its job.
Couldn't agree more, though in my case I'd be happy to sacrifice rear grip. I don't have a problem drivng a car thats very loose.

Quote:
Cells back usually make the car very responsive initially as there is less static weight over the front tires, it does also induce a pendulum effect once the car begins rotating and can cause mid corner oversteer .
Again, I can't really notice. Perhaps if the car is already "in the ball-park" then these small adjustments would be noticeable, but, in my experience, when the car is so far from being ideal, then these adjustments on their own don't amount to much.

Quote:
On a low grip surface, you are wanting weight transfer to give grip to the end of the car requiring it. A softer front end (shuey white) will allow more weight to be transferred to the front end as you lift or brake for a corner.
Another area that I have found the opposite. I have always found softer front springs to reduce turn-in, exactly because of the weight transfer you describe When the weight is transferred forward, you have a heavier mass for the steering to move from the original direction (straight) to the new direction (left or right) - so it doesn't move from one direction to the other quickly enough.

With stiff front springs, I feel they are pushing the tyres onto the surface with more pressure (therefore increasing their grip), and reducing the weight the front wheels have to turn by reducing weight transfer - both of which lead to quicker steering response IMO.

Green springs give me the best turn-in, but obviously they compromise the car everywhere else. However, I don't see the point in having good mid-corner or exit steering if you can't get to the apex in the first place

Quote:
My track (tftr) Is generally low / medium grip.
Perhaps by your standards then the tracks I race on are VERY low grip. Your best bet here is to ask Andy Cooke or Andy Abbott what the Meakin Park and Wynumm (Bayside) tracks are like as they've both raced there. It might give you a better understanding of how much or little grip there is here.

To me, they feel like decent grip tracks simply because finding rear grip isn't an issue for me


Quote:
Ae blue front and Ae silver rear is a tried and tested combo by team drivers all over the world,with lots of drivers of late going to the schumacher white springs front and rear(similar in rate to AE silver).
In my opinion they can allow the chassis to dump over in high speed corners if not driven smoothly. which can cause understeer due to too much weight transfer, overloading the outer front laden tire.
That's what I think - and that's why I usually run green fronts.

I wont be racing for another fortnight, but I might see if I can get to a track for some practise.

The craziest thing is that Iain's and my setups are probably 90% the same - yet when i drive his car it feels so much better
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Old 10-11-2005, 10:22 PM   #11333
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Quote:
Originally Posted by bender
The craziest thing is that Iain's and my setups are probably 90% the same - yet when i drive his car it feels so much better
That right there tells me there's something else wrong with the car. When I drove Losi's I had one of those. It wasn't my first one. I built the car with my normal setup on it that had been really good on my other car and it was a pile of junk. No matter what I did, that car wouldn't keep the back end on the ground. I went and bought another kit and built it with the normal setup and it was just fine.
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Old 10-11-2005, 10:43 PM   #11334
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exactly jonn, no 2 cars are the same. Chris Putnam and I find the same things, and are currently experiencing this. Our cars can be identical in setup, yet Chris's car can exhibit corner exit oversteer and entry understeer, Yet I feel mine is just how I want it.

Subtle things can make big differences when combined, something you might not think would even matter, belt tension, placement of weight, the way you build your shocks, free movement of moving parts such as arms etc..

What insert do you run when running Takeoff 27, and also sorex 36, we might as well start from the ground up.

What additive do you use, compared to Ian?..

I suggest trying the Protoform A.P stratus 3.0 has neutral handling with improved grip front and rear.
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Old 10-11-2005, 11:08 PM   #11335
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I only have 1 set of takeoffs, they have sorex med-b inserts.

Virtually no one up here runs take offs, but I like them as my lap times are better with them, they seem to free up the car a little.

With sorexs, I use either med-b or med-c inserts, like everyone else does up here. Most drivers prefer the med-c, especially on the bumpy Wynumm track, but I prefer med-b because they provide more consistant steering.

The med-c's tend to steer initially then wash out, with plenty of on-power understeer.

At Wynumm no one uses additives as it is worse. At Meakin we run Hybrid Dip or Ground FX2.

Forgot to mention both tracks are currently running at night, and they have more grip than during the day.

I know what you mean about 2 cars never being the same - when I was racing offroad I had a Losi XXX that was terrible, so I sold it after only a couple of months. Bought another one 2 years later and it was much better - even with the same setup
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Old 10-11-2005, 11:29 PM   #11336
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your running Sorex 36 at night?...there lies your problems with understeer

seriously at night, use Takeoff 22 - 27. with std Takeoff Medium Inserts. I wouldnt use Sorex inners in Takeoffs, never had much success with that.

I would use Takeoff 22's with standard Medium Inserts, M.S inserts for slow speed technical track.

What track temparatures are you seeing at night?...
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Old 10-11-2005, 11:34 PM   #11337
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Quote:
Originally Posted by King-G
your running Sorex 36 at night?...there lies your problems with understeer

seriously at night, use Takeoff 22 - 27. with std Takeoff Medium Inserts. I wouldnt use Sorex inners in Takeoffs, never had much success with that.

I would use Takeoff 22's with standard Medium Inserts, M.S inserts for slow speed technical track.

What track temparatures are you seeing at night?...
Thats not his problem..... I run 36's at night, remember we are in sunny Queensland....
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Old 10-11-2005, 11:51 PM   #11338
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Quote:
Originally Posted by King-G
your running Sorex 36 at night?...there lies your problems with understeer
No, because as Iain said - everyone else runs them too, so where are their understeer problems?

And I have the same problem during the day too (ie at the very hot QLD titles!)

I run the same tyres as everyone else to eliminate one possible variable in tuning the car.
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Old 10-12-2005, 06:09 AM   #11339
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Default Understeer!!

I have been racing my Mi2 for about 2 months now and are also have understeer issues I race on a low grip asphalt surface and have tried heaps of stuff to fix or limit the problem sound like it could be an Aussie thing??
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Old 10-12-2005, 06:22 AM   #11340
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Maybe your chassis is Tweaked.

The are a couple of sponsered people in my area, and I know they have gotten brand new cars. They said they could never get the cars to hook up good, turns out the new chassis they got, came tweaked right from the factory. I have heard this happen more than one time.

See if you can try a new chassis.
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