Traction bar

[RichardsGST]

I was woundering if anyone makes a traction bar for eclipses? I have bad wheel hop and i need to get rid of it. I would like some help if you guys can!

 

[jtmcinder]

Have you already done the obvious first step: urethane roll-stopper inserts?

- Jtoby

ps. Am I the only one annoyed and amused (yes, you can be both at once) by all this babble about traction bars?

 

[RichardsGST]

I got the new mounts. but still got the wheel hop pretty bad

 

[jtmcinder]

OK, if you've done the motor mounts, then the next step is the suspension bushings. Replace the inboard ends of the lower LCAs and those in the eye-bolts at the inboard ends of the upper A-arm (only the front end is necessary on your car, of course). Wheel-hop in a car with double-wishbone (or modified double-wishbone) is caused by energy being stored in various bushings and then released all at once when traction drops below a certain point. You want to eliminate all of the places where energy can be stored. Step One is the motor mounts ... done. Step Two is the suspension bushings. Steps Three and Four are optimized springs & shocks and softer sidewall tires. Traction bars are not on the list.

- Jtoby

 

[RichardsGST]

I have the KYB adjustables and eibach springs the prokit. i dotn know too much about suspension. i dont really know what you are talking about?

 

[jtmcinder]

When the engine applies torque to the wheels, a variety of things can happen. The car can move forward (obviously), or the tire can slip (also obviously), but the energy can also be used to twist and squish the various soft parts between the engine and the tires. These include the motor mounts (which squish and allow the engine to roll) and the suspension bushings (which also squish and allow the control arms to twist).

If that were the whole story, then this wouldn't be a big deal. Yeah, some of the initial torque would be "wasted" squishing various bushings, but, after that, all the power would go to more useful places.

But that isn't the whole story. What happens is that, when the bushings refuse to squish any farther, all of the engine's torque suddenly goes to the wheels. This often overloads the tires and they break loose and then all of the energy stored in the squished bushings is released all at once. When that's done, the amount of power going to the wheels drops off and the tires grab and the whole process starts over. This can repeat several times per second, causing what people call wheel-hop. Go to an autoX and watch a Stock-category Honda launch (Stock doesn't allow motor-mount inserts, but does allow R-compound tires, so all the ingredients are there for some serious wheel-hop); what you see and hear is a dut-dut-dut-dut launch. Nasty wheel-hop.

There are only two solutions to this: launch softer (booo!) or stiffen the bushings so that less energy is stored and it's less likely to be suddenly released. This is done by swapping in urethane bushings at every place that is squished on the launch. #1 is at least putting in urethane insert roll-stoppers. (Or an AWD, this is usually all that you need, it seems, but maybe I just need to try a car with more power, so take that one with salt.) An entire set of motor mounts is probably better, but does make for less fun on the street. #2 is to replace the front suspension bushings. Good news: the latest Energy Suspension kit is a heck of a lot easier to install than some previous kits, because the new bushings for the inboard end of the lower lateral control arm (LCA) is in three pieces and is a snap to install (after burning out the old bushing and cutting out the sleeve). If you are still having problems, stiffer springs and shocks with lots of rebound damping can help, too. Over-damping the front suspension reduces any tendency to oscillate, which is what wheel-hop is all about.

KYBs do not have a lot of rebound damping. A Koni Sport, for example, at a half-turn from full stiff has more than twice the rebound damping while still having less compression damping than a cranked up KYB. Having a high rebound-to-compression ratio is critical when running stiffer springs or trying to reduce oscillations. Koni Sports are also a lot shorter than KYBs, which allows you to lower the car more without hitting the bumpstops. In other words, Konis aren't just for autoXers; they're for anyone wanting a better car.

- Jtoby

ps. today I had the point about not hitting the bumpstops really drummed into me. I ran a zip-tie test and found that, now that I'm back on R-compounds, I was out of travel in the outside front in corners. I raised the nose just a quarter of an inch (and reset toe) and knocked 3 seconds off a 60-second course. The loss of front-end grip from hitting the bumpstops is that serious.

 

[RichardsGST]

i got the polyurethane engien mount set form road race engineering. DO you know where i can get the other things i need? I went to auto store and asked them what i need for a new install of struts and springs. They sold me some kind of bushings and rubber pieces for the top of the strut. Is that what you were talking about.

 

[leet]

You can get the polyurethane suspension bushings from RRE, as well.

Prothane, or Energy Suspension.