FWD steering knuckles on an AWD

[dsm1kenobe]

Anyone do this mod with a lowered 1g? It's supposed to help retain stock steering geometry on a lowered car. What are your thoughts on this? Any noticable improvements? Thanks.

 

[Morphius]

Originally posted by dsm1kenobe
Anyone do this mod with a lowered 1g? It's supposed to help retain stock steering geometry on a lowered car. What are your thoughts on this? Any noticable improvements? Thanks.

Last set of AWD/FWD knuckles I looked at, they were the same. Why would then have different camber angles?

-DaimlerChrylser Engineer

 

[dsm1kenobe]

The FWD knuckles allow the tie rods to mount 1" lower than the AWD ones. Camber is the same on both units.

I was told that they improve steering feel/response on a lowered car.

 

[jtmcinder]

What you were told is correct; at least with regards to the effects of moving the steering mounting point on the knuckles. I'll try to explain.

Things that vertically move the point that the steering arms mount to the knuckles are usually called bump-steer kits. The goal of such things is this: as the angle of the steering arm differs from flat, vertical wheel movement causes a change in toe. If the steering arm angles down (from rack to knuckle), then upward wheel movement causes toe in (because our steering arms are behind the steering axis). This is what most engineers prefer for street cars. That's what a 2G has at the stock height. (I'm not sure about 1Gs, but I'd guess it's the same.) After you lower the car, however, the steering arm might be flat or angle up. Now when the wheel hits a bump (or the car rolls to that side in a turn), it toes out. This is often sub-optimal for handling, since it acts to add understeer. Why? Because as you steer into the turn, the car rolls, and the roll makes the outside front wheel steer out, so you must add more steering input as the car rolls, so the car seems to be fighting you. Not fun.

Lowering the mounting point on the knuckle will help counter the up-angle of the steering arm on a lowered car. (The alternative is to raise the rack.) So, if it's really true that you can swap in lower-mount knuckles and not screw something else up in the process, then I'd say do it. And I'd also ask if any such thing is available for a 2G AWD.

- Jtoby

 

[dsm1kenobe]

Thanks for the explanation jtm, but I knew that it works on paper. I just wanted to know whether or not the mod feels as it should on paper.

I made some phone calls, and it turns out that FWD steering knuckle mod is inexpensive - $50 with new bearings packed with redline grease with me doing the work.

 

[jtmcinder]

Serious racers (who work under rules that allow bump-steer kits) swear by them. If someone told me that I could reduce understeer and get a car that responds to inputs, instead of fighting them, and that it only cost $50, I'd do it in an instant. But each of us has a unique priority structure, no?

- Jtoby

 

[BUCK]

So would there be a handling advantage on a non-lowered car? - Is it worth doing when it comes time to replace the stock 1G AWD Knuckle?

 

[jtmcinder]

Doubt it. Go out and look at your steering arms. If they already angle down from the rack to the knuckle (which means that the car toes in under bump), then it will increase this and you don't really want it. If the arms are flat, then be thankful and leave it alone. If they angle up, then the mod might help.

- Jtoby