CSG and RCE tag-team suspension Q&A thread! Ask us anything!

[Racecomp Engineering]

Quote from OptimumG:

"On a car where rules allow, and you choose to do so, a suspension system can be designed where damping adjustments can be made that isolate ride, roll, and pitch. Finding an ideal baseline for roll and pitch damping are discussed below, however, most cars due to their suspension design are forced to make a compromise between the three (this explains the point mentioned above with successful cars using non-ideal damping ratios in ride)."

A lot of people overlook this fact and wonder why people aren't going for the 2.2 Hz number and leaving it at that.

It's also one reason why there is some wiggle room in the damping ratios.

- Andy

[cdrazic93]

Originally Posted by Calum

Have you studied control systems at all? That's all this really is, in a very basic form. Natural frequency, impulse response, dampers, settling time... If you haven't studied controls yet, than this is going to be a great crash course. Just remember your instructor knows 'best'.

Nope not yet! This is all inundating my brain and like slamming a dictionary on my head hoping to learn lol jk

I've dealt with frequency before, only in audio though.
I know nothing about impulse response, dampers and settling time.

[Racecomp Engineering]

Originally Posted by Calum

The subject of roll resistance keeps coming up, and guys like me keep getting told in some form or another that it doesn't matter, only conforming to the road surface matters. If that were true rock climbers would make the best tarmac race cars ever, with their 20 odd inchs of wheel travel and rolling like an old Corvette in a storm. Maybe I'm too old, or have read too many 'yo dogz my car iz stiff as nuts dog, coiloverrrzzzz!!' on the forums, but I can't get away from the idea that roll stiffness is still a large factor here. We need to prevent the weight from transferring around too much so the outside tires don't get overloaded and so the car can react to direction changes quickly. What am I missing?

With regards to this part, there are a couple things:

1. Remember that total weight transfer is not affected by spring rate in a given corner. You can alter the proportion of weight transfer front and rear, but not the total.

2. Firmer suspension means quicker reactions and quicker weight transfer. The car changes direction quicker and feels nice. Very quick weight transfer can overload a tire rather than loading it up nice and progressively, so there's a balance.

3. Firmer suspension (and less roll) is a good way to minimize camber loss and suspension geometry changes.

- Andy

[Racecomp Engineering]

Originally Posted by cdrazic93

Nope not yet! This is all inundating my brain and like slamming a dictionary on my head hoping to learn lol jk

I've dealt with frequency before, only in audio though.
I know nothing about impulse response, dampers and settling time.

Take your time and read a lot. Don't let it get to you that you have to read things a couple of times for them to make sense. I've reread the same articles dozens of times before they "click".

How To Make Your Car Handle by Fred Puhn is a good book. Old, but good.

- Andy

[cdrazic93]

Originally Posted by Racecomp Engineering

How To Make Your Car Handle by Fred Puhn is a good book. Old, but good.

I'll look into it! I hope there are some good puhns...

[Racecomp Engineering]

Originally Posted by cdrazic93

I'll look into it! I hope there are some good puhns...

- Andy

[cdrazic93]

So after a little reading, who is going to under take the hidiously enormous task of converting a 86 into a double wishbone suspension

[7thgear]

Originally Posted by cdrazic93

So after a little reading, who is going to under take the hidiously enormous task of converting a 86 into a double wishbone suspension

cheaper to buy a miata

but really, given the application requirements, the only problem we have from being on struts is limited adjustability in stock form

[wparsons]

Originally Posted by cdrazic93

So after a little reading, who is going to under take the hidiously enormous task of converting a 86 into a double wishbone suspension

911's and M3's do just fine with macpherson struts...

[hakkoo]

Quick question, I have the ST Coilovers, do i need to get camber bolts to adjust front camber or is it okay w/o it since ST's are slotted

Thanks

[cdrazic93]

Rather than going for the cheaper option, miata or the like, I would attempt this only due the fact of how different the car would sit and feel on the road and track, the unique appeal also has some allure to it as well

[cdrazic93]

Originally Posted by 7thgear

cheaper to buy a miata

but really, given the application requirements, the only problem we have from being on struts is limited adjustability in stock form

From the difference in design is there any way in which the double wishbone is better?

[Calum]

Originally Posted by Racecomp Engineering

With regards to this part, there are a couple things:

1. Remember that total weight transfer is not affected by spring rate in a given corner. You can alter the proportion of weight transfer front and rear, but not the total.

Wait, side to side weight transfer isn't affected by roll angle? I thought stiffer springs would help manage roll which will help manage weight transferring to the outside tires.

2. Firmer suspension means quicker reactions and quicker weight transfer. The car changes direction quicker and feels nice. Very quick weight transfer can overload a tire rather than loading it up nice and progressively, so there's a balance.

This I understand, I think. The near instantaneous deceleration of the roll of the car can cause a great deal of force on the tire, and thus can possibly over load it...?

3. Firmer suspension (and less roll) is a good way to minimize camber loss and suspension geometry changes.

This makes sense as well.

- Andy

My comments are in bold.

[7thgear]

Originally Posted by cdrazic93

From the difference in design is there any way in which the double wishbone is better?

it's generally easier to make the wheel maintain a desired angle to the road during suspension movement... even a lot of movement