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nato_wp Enthusiast

nato_wp

Posted
Posted

I was recommended this book a year ago by someone on NS, bought it, EXCELLENT. It's old publication, yes, but the principles haven't changed.

How to Make Your Car Handle - Fred Puhn

5190G876QYL.jpg

  • 1 month later...
  • 3 months later...
RBceffy25 Rising Star

RBceffy25

Posted
Posted

How to fix axle tramp

Basically put your coil overs in, adjust your rebound, possibly lower the rear spring rate, and put solid (aluminium) spacers and bushes in your sub frame.

Read on for an informative explanation into this.

Ok this is all basically summerised/quoted from an issue of BOOST (ZOOM)

Understanding axle tramp: Consider the job of the rear wheel for the moment. When it becomes driven, it is - in turn - driven in a direction that is not only forward, but also in a vector angle that is tied into the pinion angle of the diff. Rarely it is ever a case of straight thrust that has the car pushing straight down the road.

Axle tramp occurs when the vehicle is suddenly shocked (dumping the clutch etc) and the driven wheels wind up energy in the shocks, springs and ultimately the vehicle subframe mount that impart a huge backload against the driven wheels as a reaction. In many cases the effective damping of the system is so poor that once you start the wheels tramping, the effect of the whole process becomes self-generating. So for each and every tramp there is a storing and release of energy that keeps the whole thing going and going and going.

Shocks and springs: First point is to consider the affect of the rear shocks and springs of your vehicle. It is indeed the job of the shock to control oscillations of the rear end, but there is really only so much work you can expect the shock to perform. If you have adjustable shocks, you need to work through the bump and rebound settings to check how much of an affect this has on your vehicles willingness to tramp. Regardless of the fact that most people will tell you that too much rebound will encourage tramp, winding some (rebound) out will ensure that the rear end stays smooth under all conditions. You want the most stiffness as possible but still soft enough to be able to control some of the tramp.

Tyres and Pressure: All that you will find with different tyre and pressure combinations is that having a different overall traction point will delay the onset of wheelspin long enough to mask the effect of tramp.

Bushes: Rubber bushes have a tendancy to 'wind up' and store energy which can be released as tramp when the wheels start spinning. Pineapples add a measure of stiffness to the rear end, along with a different stack height that can, in turn, change the directional vector of the rear wheel by altering the pinion angle of the diff. If you rum a thin pineapple(or put it one side of the mount) its good for grip and the opposite is good for drift. Stiffer bushes help to fix tramp by not contorting to the point where it 'winds up' the rear cradle. Full solid, aluminium bushes are made for this exact reason as they do not contort and wind up the sub-frame in any way. The downside is that there is increased harshness being transmitted from the road through to the cabin, which is why manufacturers use such soft bushes in the first place.

Springs: If all else fails then change the rear springs. The softer the spring, the easier time the rebound of the rear damper has in controlling the oscillation of the spring. It’s this basic mismatch of damper and spring that contributes to tramp in the first place hence why sport cars do the tramping and luxury cars just drive away.

Wheel Alignment: Always make sure your wheel alignment is up to par before you tackle any axle-tramp issue. It is quite possible to have a toe misalignment on the driven wheels which tries to pull the vehicle one way under acceleration, which can have the unintended affect of not only starting tramp conditions, but also exacerbate the condition.

I hope this is informative and helps you in some way.

Cheers!

RBceffy25 Rising Star

RBceffy25

Posted
Posted
  R34 -_- said:
yes that helps basically tells you that an Aluminum sub frame locking kit = harsh ride :D

Guess pineapples would be the way to go or just a plastic locking kit instead

It also tells you that is the best way to tune out axle tramp.

Read the article 'carefully' and study it.

You cant always have your cake and eat it.

Thats the world of modifying. Most of the time it comes down to a "COMPROMISE".

Its the nature of the beast of the world we live in, governed by the laws of physics.

If you dont want any axle-tramp do the full solid job. A lot of manufacturers give you a choice between polyurethane or aluminium. Depend what your goals are with your cars aplication.

On a side note:

Why is it that there is always some dickhead who has to cut someone else down because of their own 'personal' opinion.

I have spent considerable time studying this and posting up this info for everyone's benefit. If you dont like it then don't read it or apply the knowlede given. Just remember that most of the time this sort of information comes from experts or individuals who have spent much of their life doing what the info refers to for a living.

  • 3 years later...
D.I.Y. Mik Veteran

D.I.Y. Mik

Posted
Posted

Got this the other day

post-89755-0-53225500-1378520945_thumb.jpg

So simple, its a good introduction to handling.

Even though its for rc cars, it translates well. For example: shock oil is shock damping, so when they say thicker oil it means more damping.

Theres nice simple diagrams, flowcharts and tables. Its very basic, and thats why i like it.

  • 1 month later...

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