jdeadman

iTrader: (41)

I's running my fttc4 in 17.5 TC now and and its working pretty good. But I'm fighting traction rolling something fierce.

I was on harder springs (gold/blue) but it was worse and now I have upped the shock oils to 47.5/45 on #2 pistons with silver/green and it's a whole lot better.

This wide chassis likes to play dirty with the carpet so I have my ride height up a tad @ 5.5mm

silver front roll bar and black rear.

Roll center I have zero shims on the a-arms and 2mm on the upper Camber link in the front which is on the most inside hole and in the rear I have .5mm shim on the most inside. and inside hole on the hub.

3 degree rear toe to keep the rear in check. Anything less and the rear wants to be first.

Shocks are second from the outside on the tower and outside on the arms

All of the internal bracing is gone.

Camber f/r is 1.5/2 degrees running 4 degree caster in the front

Sweep 32 degree tires with Paragon ground effects (Black can) Full rears 1/2 fronts


Any Suggestions TC4 gurus


Thanks

Brian McGreevy

iTrader: (10)

First thing I would change is to take away some camber. Can you tell if the vehicle is picking up the front or rear first? If so, reduce camber by 0.5 deg at that end, and perhaps all around. I would actually try keeping the softer springs you have and reduce your oil weight to 40/35 or 35/30. Heavier oil will slow things down but will also put more force into the tires in bump. Laying the shocks down a hole or two will soften the rates but also make them more progressive, and this tends to help as well.

anr211

iTrader: (11)

In addition to the already mentioned reduced camber a quick one to try is adding droop (move uptravel) It sounds crazy and backwards but it actually lets the car roll over further before it bottoms out the droop screw and starts to jack the car up. If the front end is digging in and causing it to roll over mid corner then less caster will probably help too.

jdeadman

iTrader: (41)

My last shock setup was 32.5 and 30 F/R with stiffer springs. So my thinking was the speed at which the car was leaning over in a corner was the issue.

It's better not than it was. but still looking for less tendancy to roll over. I know if I hit a Track dot that's to be expected but we ahve a rough track and one corner is reall bad coming off the straight through the sweeper and the sharp apex has a ripple in the floor that catches the car as it's off power.

More droop that does sound crazy but hey I'll give anything a go at this point. Currently I'm running 1.5mm over ride height so I double it and see what happens.

So for sunday I am going to first try less camber int he front as that is where I feel it's lifting first.

Second I'll lay down the front a hole and try that.

then I'll try the droop


Thanks

bertrandsv87

iTrader: (2)

All very good points so far, but I have to add track width(190mm exact f/r), chassis rake(higher front ride height then rear by 0.5mm), make sure you don't go lower then silver springs in the rear, try to power through the turns to put more weight on the rear(more traction), take out all the swaybars if all else fails....

Brian McGreevy

iTrader: (10)

The springs and anti-roll bars control how far the car will lean, oil does little to change that. Not only that, most of the force applied to the tire is due to spring/ARB force, even though damper force is significant. The lighter oil will reduce the "pack" in the shock, which is important because damping force increases as velocity increases, not shock displacement. Quick direction changes will cause higher forces from the dampers. The most effective way to reduce "pack" is to go to pistons with bigger/more holes, but oil changes it too.

1.5 mm droop is borderline too low. What's happening is that you're limiting roll but keeping the same amount of weight transfer - this increases lateral grip. I would go up to 2 mm over ride height, maybe 2.5 mm. Too much droop with low roll centers like you have can also cause traction rolling, as the car will roll so much that the vertical component of the force on the car's CG becomes larger than the horizontal (lateral grip) component of the force. I would never recommend more than 3 mm over ride height.

DesertRat

iTrader: (2)

I would ask Martin Crisp long before putting it to this crowd.

bertrandsv87

iTrader: (2)

If you have nothing to add Desert, don't post !!!
I agree with Brian on the droop too low at 1.5mm, and will add that it will make the Car's reaction very sudden, not smooth, which will cost you time... The Car will seem to have no traction all of a sudden, and that will kill your confidence ... 2mm to 2.5mm is good, but you have to make sure your acceleration and braking are also smooth, in order to not upset the Car's balance too much....

DesertRat

iTrader: (2)

I have nothing to add because I am willing to admit that I don't know what would fix it, because there are countless ways to fix traction roll or make it worse. Therefore I offered the most constructive advice I could think of: Ask a pro, specifically a Canadian national champion who willingly gives free advice.

jdeadman

iTrader: (41)

Thanks for the Notes guys. I have been reading the threads Martin started Ie. ask Martin and how to reduce traction rolling

I will be putting a post up in there just wanted to hear from the TC4 group first

Thanks DesertRat I will be talking to Martin

bertrandsv87

iTrader: (2)

I use to traction roll my tc4 too, but now I don't have that problem anymore by applying all of the above.... I am sure Martin will have a deeper insight on what needs to be done, but all the other guys here also have good inputs, and they should not be denigrated or insulted, OK...... Value and respect their opinion too !!!

wacko37

iTrader: (9)

hey guys how competitive is the TC4 with all the new cars out now? I always enjoy competing in the top 5 in club races with old cars. (i still battle for first all the time with a XXXT)

bertrandsv87

iTrader: (2)

As a rule, to solve traction roll you need, flat shocks, low roll centers(4mm inner camber links f/r), softer springs, and lower droop(sometimes down to 1mm or less), but you will compromise traction, drivability, laptimes, and you'll have to decide what to change slightly to lower laptimes....
Another thing to consider is chassis flex to gain traction while not changing anything else... On the tc4 Ft , you can gain chassis flex by backing off the screws on the Center spline, and the first screws on each of the corner of the top deck that go through the diff cases....
I also run the shortest wheelbase possible, to maximize traction at both ends of the Car, but to gain rear traction, it might be best to lengthen the front while shortening the rear...

THEBIGBULL

iTrader: (5)

A couple of questions??

I have a TC3 with the IRS graphite conversion for VTA. Is there any advantage in using the TC4 shock mounts and chassis braces, I already have them in carbon???? If I do this do I have a TC3.4 LOL!!!

I have no difficulty balancing my TC3 or TC4 side to side, is there an ideal front/rear weight, right now both TC3 and 4 are 48% front and 52% rear.

bertrandsv87

iTrader: (2)

I've cut my tc4 braces, and don't know about the shocktower difference. I also run my Car heavier on the motor side, and no front to back preference, as long as the total weight is somewhat close to minimum weight( less than 70g)....