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

[CSG Mike]

Originally Posted by kster1

I'm not in the market but just curious. Years ago, when I had Tein RAs on my Miata, I couldn't find anyone local (San Francisco Bay Area) to do rebuilds on them. Are there any shops in CA that rebuilds Teins now? I was very happy with the RAs but found local support to be limited from the race shops.

One reason why I went with Ohlins is because Performance Shock is nearby and they do rebuilds of them (along with Koni, Motons, Penske)...
http://performanceshock.com/index.php?main_page=product_info&cPath=1&products_ id=677

Thanks,

Tein USA is the shop to contact.

http://www.tein.com/service/price_list.html

Mmmm I have a lot of respect for PSI.

[Racecomp Engineering]

Originally Posted by solidONE

Your right, a spring's rate does not magically change when you compress them.

But, lets say we have 2 springs of equal and linear spring rates. One spring is compressed an inch the other left static. Wouldn't the compressed spring offer more effective rate then the static one at the next inch of compression?

Sorry, not here to argue. You are right, you should just go by whatever Ohlins recommends. Carry on.

Spring rate on a linear spring is linear.

It would be providing more force but the rate doesn't change.

If you preload a 100 lbs/in spring a half inch, you have a force of 50 lbs upwards. It will still need another 50 lbs to go that next half inch.

Now drop 750 lbs of car on it and you'll understand why I don't bother messing with it. With a LOT of preload, you can change how much it takes for the spring to move, but it takes a lot.

- Andy

[RYU]

Can we talk *comfortable* coilovers for a second?

I've been on the search for a comfortable coilover package that is adequate for street tires with enough adjustability for the occassional trackday. The car will never be on anything stickier than RS3s and even then that'd be a rare occassion. I will mostlikely just drive it to the track in the same trim as how I'd drive it to work (year round, summer tires).

I rode in a prototype CSG Spec Tein SRC and the suspension was amazing but it may have also been Mike's inhuman driving skills. With that said, I still prefer something more compliant for the street. I've had the RCE Yellows on the stock damper. Spent a good amount of time on the KW V3s and now i'm on the RSR Sports-i setup. These are not what folks consider high end coilovers and I'd have bought "expensive" coilovers by now but I want my final decision to be final. I'm also not yet convinced I can find a good coilover for this car in a single adjustable format. I'm even considering just dropping down to a Koni insert or whatever Bilstein comes up with or going back to stock.

I am thoroughly convinced this car has either
A. very limited suspension design (mcpherson, multi-link rear vs. say double wishbone) (why is the rear shock travel so damn short???) OR
B. few have put in the R&D into a proper suspension package for this car

I've also noticed that the label on the coilover is not nearly as important as the amount of effort given to tune that coilover specifically for that car. In other words, i've been in cars where say.. a KW V3 was crap but on another car a KW V3 was pretty darn good. Both were adjusted by "professionals". I have to correlate that to the amount of tuning effort allocated for that platform. Am I incorrect?

Not sure how many folks here know of Tsuchiya's previous suspension company(s) (K-Office > DG5). His philosophy for tuning was not to sell race car level suspensions but instead to build a properly balanced sporty car that can be adjusted for a fun day at the track but also incredibly comfortable for daily driving. This resulted in a broad range of adjustment but via just one knob. Guys like me don't want to tinker anymore with adjustable this.. adjustable that. I'd rather have a company find the critical damping point for the car in an easily adjustable suspension. Which coilover system out there employs this philosophy?

Also to add to my previous point, it's my understanding the DG5 coilover is overrated - fine. I can see that happening on platforms were there wasn't enough R&D allocated to the car (say the S13). On the NSX the DG5 is absolutely amazing. I heard its pretty awesome on the original 86 also. On the NSX it rides like a sporty sedan on the street but can be dialed up to perform better than a Type R on the track all via a one-knob, easy to get to adustment. It also ships with stiff spring rates (11k/14k) so I know spring rate isn't the only factor to a comfortable ride. Tsuchiya himself uses this suspension on his NSX-R which can likely explain all the R&D attention this coilover has gotten. Do we need some cocky Japanese "Drift King" ex JGTC champion to design a coilover for our 86? I sure hope not!

I'm hardly a DG5 fanboy but on the NSX i've tried many coilovers including the KW V3s (not bad), Motons (too many adjustments), JRZ (R/R1s), Tein (mono, RAs), and Bilsteins. I prefer the DG5 and it's not even the most expensive of the bunch.

Maybe i'm asking for too much here and I should just go back to the stock suspension.

SIGH

[CSG Mike]

Originally Posted by ayau

How do you find the balance of lowering the car's center of gravity (lowering the car) and not destroying the factory suspension geometry? Is one more important than the other? For example, is keeping the factory suspension geometry (stock ride height) better than a lower center of gravity?

What exactly gets ruined when you lower the car too much? Can you provide some examples? Is it the fact that the front struts gain positive camber when you lower it too much?

Is there any weirdness with the wheels under compression? For example, do the rear tires toe out/in under compression?

Thanks!

Finding the balance is dependent on application.

At the most basic level, I tell people this: If you have trouble getting around, e.g. over speed bumps and into/out of driveways, you're too low.

For the enthusiast, I tell people to lower their car to their preferred height, and align based on wear, and to keep an eye on both the inner and outer shoulders.

For an enthusiast that wants to understand how it works:

The front camber curve goes negative as you drop, and then goes positive as you keep dropping. The rear camber curve stays and gets more negative as you drop. Imagine cornering with *positive* camber on your loaded tire. That outer edge is going to get shredded!

Additionally, dropping the car too low will drop your roll center, hurting response (at the basic level) at corner entry. Here's a picture shamelessly pilfered with a google search.



Here's an article that goes into depth re: roll center:

http://www.motoiq.com/MagazineArticl...ll-Center.aspx

The rear wheels do toe in slightly under compression (bump steer).

[ZDan]

Regarding frequencies, for each corner, you can use:
fn = [sqrt(wheel rate/sprung mass)]/2pi
Easiest if you just use metric units: wheel rate in Newtons/meter, mass in kilograms

Wheel rate is the spring rate divided by the *square* of the motion ratio.

On my FD, one corner = ~3000lb/4 = 750 lb
Unsprung mass per corner ~50 lb.
sprung mass per corner ~750-50 = 700 lb, divide by 2.205 lb/kg = 317 kg
11kgf/mm springs, multiply by 9.81N/kgf = 108 N/mm = 108,000 N/m
motion ratio ~1.6 front, so wheel rate = 108,000 N/m / 1.6^2 = 42,188 N/m
motion ratio ~1.4 rear, wheel rate = 108,000 N/m / 1.4^2 = 55,102 N/m

fn front = sqrt(42,188N/m / 317kg)/2pi = 1.8 Hz
fn rear = sqrt(55,102N/m / 317kg)/2pi = 2.1 Hz

~2Hz is a pretty damn stiff street ride, pretty damn soft track ride, a decent-enough compromise...

[CSG Mike]

Originally Posted by Dezoris

this is a perfect place and time.

So Turbowski and I will be doing our install video on the Ohlins Road and Track. I know Mike does not like it but suspending that for a moment understand the build goal is a near perfect street car that has little compromise for the track. It needs to be almost OEM on the street or better not raising any red flags to casual drivers or the hard core. But when on track can do 80% of what a track prepped car can achieve without changing much of anything.

Impossible right? Thats the goal.

so the road and track on paper is one of the better kits for this purpose. Yes its not double or triple adjustable but it doesnt need to be for a street car.

So onto the questions, pre load do you really want to play with it?
Ride height, they recommend 20mm front 15mm in rear I think it is too much for our area. Would a 15mm 10mm or less hurt that much.
How long to let settle before corner balancing and final alignment?
Damper settings, typically firmer in front than rear?

The lesser drop should be just fine, IMO. You may need to get a LCA for the rear to get the proper camber for maximum cornering grip, but that may or may not be ideal for a dual duty car.

I'd try to drive it around town for a day or two; usually driving 50 miles will get all settling out of the system.

You should be okay without messing with preload. If there's no play, you'll be fine.

The damper settings are analogous between the front and rear. Based on my personal preference, given the default spring rates offered on the Ohlins R&T, I'd probably end up with slightly more damping in the rear to induce rotation via loss of grip. This would be better addressed with a rear sway and possibly tire pressures as well.

My biggest issue is that it is single adjustable. If it were double adjustable, then it would:

- Offer more flexibility with spring rates
- Offer more fine-tuneability for maximum comfort AND performance
- It's really friggin expensive for a single (although the JRZ RS1 is even more!)

[solidONE]

Originally Posted by Racecomp Engineering

Spring rate on a linear spring is linear.

It would be providing more force but the rate doesn't change.

If you preload a 100 lbs/in spring a half inch, you have a force of 50 lbs upwards. It will still need another 50 lbs to go that next half inch.

Now drop 750 lbs of car on it and you'll understand why I don't bother messing with it. With a LOT of preload, you can change how much it takes for the spring to move, but it takes a lot.

- Andy

I suppose I used the wrong term when I said "effective rate." I was thinking of it from a motorcycle suspension set up standpoint when I was talking about preload adjustment.

After the spring rates are selected, the preload is set by checking the suspensions sag, then adjusted accordingly on a motorcycle. The preload on a motorcycle greatly effects how it's suspension performs. When you set the front forks, for example, with less sag or more preload it makes the front suspension stiffer. This adjustment is often made when we switch to a softer compound, track oriented tire from a harder compound street tire. For the rear shock, sometimes people will use a hydraulic preload adjuster to jack up the preoad when taking on a passenger. I suppose on a car it would effect performance to a lesser extent, but shock absorbers are shock absorbers. They should have somewhat the same type of effect when done on a car. (preload adjustment, I mean)

[solidONE]

Originally Posted by Racecomp Engineering

Swaybars have an effect on roll damping, but it is essentially zero in ride (i.e. 2 wheel bump). When you use 4 dampers total like most cars you are making a compromise between ride and roll damping ratios.

Add another 4 dampers if you don't want to compromise at all.

- Andy

lol Hmmm how can I mount some swaybar dampers...

[CSG Mike]

Originally Posted by RYU

Can we talk *comfortable* coilovers for a second?

I've been on the search for a comfortable coilover package that is adequate for street tires with enough adjustability for the occassional trackday. The car will never be on anything stickier than RS3s and even then that'd be a rare occassion. I will mostlikely just drive it to the track in the same trim as how I'd drive it to work (year round, summer tires).

I rode in a prototype CSG Spec Tein SRC and the suspension was amazing but it may have also been Mike's inhuman driving skills. With that said, I still prefer something more compliant for the street. I've had the RCE Yellows on the stock damper. Spent a good amount of time on the KW V3s and now i'm on the RSR Sports-i setup. These are not what folks consider high end coilovers and I'd have bought "expensive" coilovers by now but I want my final decision to be final. I'm also not yet convinced I can find a good coilover for this car in a single adjustable format. I'm even considering just dropping down to a Koni insert or whatever Bilstein comes up with or going back to stock.

I am thoroughly convinced this car has either
A. very limited suspension design (mcpherson, multi-link rear vs. say double wishbone) (why is the rear shock travel so damn short???) OR
B. few have put in the R&D into a proper suspension package for this car

I've also noticed that the label on the coilover is not nearly as important as the amount of effort given to tune that coilover specifically for that car. In other words, i've been in cars where say.. a KW V3 was crap but on another car a KW V3 was pretty darn good. Both were adjusted by "professionals". I have to correlate that to the amount of tuning effort allocated for that platform. Am I incorrect?

Not sure how many folks here know of Tsuchiya's previous suspension company(s) (K-Office > DG5). His philosophy for tuning was not to sell race car level suspensions but instead to build a properly balanced sporty car that can be adjusted for a fun day at the track but also incredibly comfortable for daily driving. This resulted in a broad range of adjustment but via just one knob. Guys like me don't want to tinker anymore with adjustable this.. adjustable that. I'd rather have a company find the critical damping point for the car in an easily adjustable suspension. Which coilover system out there employs this philosophy?

Also to add to my previous point, it's my understanding the DG5 coilover is overrated - fine. I can see that happening on platforms were there wasn't enough R&D allocated to the car (say the S13). On the NSX the DG5 is absolutely amazing. I heard its pretty awesome on the original 86 also. On the NSX it rides like a sporty sedan on the street but can be dialed up to perform better than a Type R on the track all via a one-knob, easy to get to adustment. It also ships with stiff spring rates (11k/14k) so I know spring rate isn't the only factor to a comfortable ride. Tsuchiya himself uses this suspension on his NSX-R which can likely explain all the R&D attention this coilover has gotten. Do we need some cocky Japanese "Drift King" ex JGTC champion to design a coilover for our 86? I sure hope not!

I'm hardly a DG5 fanboy but on the NSX i've tried many coilovers including the KW V3s (not bad), Motons (too many adjustments), JRZ (R/R1s), Tein (mono, R1s), and Bilsteins. I prefer the DG5 and it's not even the most expensive of the bunch.

Maybe i'm asking for too much here and I should just go back to the stock suspension.

SIGH

It's just a matter of demand in the market, and an appreciation for a truly well designed coilover.

The problem with the market nowadays, is that there are just two many low end (i.e., imo, garbage) offerings, that are good for lowering the car, but do not really bode well in terms of both performance AND comfort.

Given the resources, I'm 100% confident that ANY company can dedicate the time and manpower necessary to create such a 1-way adjustable damper. All you'd need to do is choose a middleground spring rate (I'm thinking maybe 7.5k/9k or 6k/7.5k), and then determine a few differing pairings for a less damped street setting, and a more damped track setting. Once the pairings are made, it needs to be transferred into an internal construction in the damper; this is the more difficult part, as the single adjustment has to have purpose-designed crosstalk to simultaneously adjust both compression and rebound, and adjust both by specific amounts so that they're properly balanced.

Would the ROI be there for the suspension company and/or shop? Unfortunately, probably not. 10 years ago when we didn't have all of these cheap taiwanese/chinese brand setups, it was much more viable; selection was limited, and EVERY manufacturer was getting a larger share.

With the amount of R&D cost involved in designing the damper internals to get that exact curve, the end cost very well may end up higher in cost than a good double-adjustable damper.

For every damper setup CSG dials in, we always show the owner how to properly make the adjustments, and give them different settings for different scenarios.

If I had the resources, believe, I'd have already done exactly what you want. It would be so easy to adjust...


Have time to ride in the latest re-valve on the prototype CSG-Spec SRC? We're currently focusing on street comfort. I just put it in last night, so I need to dial it in tonight...

[Dezoris]

Originally Posted by CSG Mike

The lesser drop should be just fine, IMO. You may need to get a LCA for the rear to get the proper camber for maximum cornering grip, but that may or may not be ideal for a dual duty car.

I'd try to drive it around town for a day or two; usually driving 50 miles will get all settling out of the system.

You should be okay without messing with preload. If there's no play, you'll be fine.

The damper settings are analogous between the front and rear. Based on my personal preference, given the default spring rates offered on the Ohlins R&T, I'd probably end up with slightly more damping in the rear to induce rotation via loss of grip. This would be better addressed with a rear sway and possibly tire pressures as well.

My biggest issue is that it is single adjustable. If it were double adjustable, then it would:

- Offer more flexibility with spring rates
- Offer more fine-tuneability for maximum comfort AND performance
- It's really friggin expensive for a single (although the JRZ RS1 is even more!)

I have whiteline rear upper control arm eccentric bushings for camber adjustment. My target alignment for street and track is -2.0 F and -1.6 R.
And that maybe too aggressive for street. Thoughts?

All I want to end up doing at the track is dropping in pads, adjusting pressures and damper clicks. No pre and post corner balance alignment and height change.

Thanks for thoughts on settling.

I agree about the price, believe me. In this case we are not testing price we are testing the product. But that will be apart of the conclusion of course.

[Dezoris]

Originally Posted by Racecomp Engineering

Ohlins will work well for you.

I don't recommend playing with preload. Just get it snug...a few mm. It doesn't change things as much as people think unless you really go to town. It has zero effect on spring rate, which is a common misconception.

15mm drop front and 10mm drop rear would be fine.

Should settle within a day. Drive it carefully.

Damper settings front vs rear...don't think about it in those terms. The front and rear damper do not have the same valving for Ohlins so click 5 on the front is not click 5 on the rear. Same neighborhood maybe. You need to find a setting that is firm enough that the car isn't bouncy but soft enough so that it doesn't crash over bumps. Do your best to separate the front and rear of the car in your head.



Makes it easier to take apart for one, and if anyone ever uses different than standard springs.

- Andy

Thanks for that, how many customers in the wild do you have with the Ohlins? What are the impressions thus far and do you have any advice etc?

[CSG Mike]

Originally Posted by Dezoris

I have whiteline rear upper control arm eccentric bushings for camber adjustment. My target alignment for street and track is -2.0 F and -1.6 R.
And that maybe too aggressive for street. Thoughts?

All I want to end up doing at the track is dropping in pads, adjusting pressures and damper clicks. No pre and post corner balance alignment and height change.

Thanks for thoughts on settling.

I agree about the price, believe me. In this case we are not testing price we are testing the product. But that will be apart of the conclusion of course.

That camber should be fine. It's aggressive for *just* street driving, and not aggressive enough for track driving, but between the two, it should result in somewhat even tire wear.

I prefer zero toe, front and rear, on this car, but you can dial that to your preference. Depending on how you are with bump steer, you may want a hint of toe-in in the rear (maybe 1/16" or 1/8" total toe-in).

Toe is what really eats up tires, so 0 toe will be nice for wear.

[Racecomp Engineering]

Originally Posted by Dezoris

Thanks for that, how many customers in the wild do you have with the Ohlins? What are the impressions thus far and do you have any advice etc?

Myles has the majority of the seat time with them and will be taking them to the track soon. Look for a write-up soon.

- Andy

[TheseColorsDontRun]

Yes, I did start a thread with this exact same question, but I want to know what the pros have to say.

Ok so I know we have all experienced the drivetrain slop in these cars. Lots of transmission and diff bouncing that make this car extremely difficult to drive smoothly at low speeds, especially during your clutch catch-point learning phase. Don't blame my driving style, I have not driven an automatic regularly in a decade.

So, I know there are bushings available to help alleviate this. I am looking at the rear shifter bushing, the transmission mount and the diff bushings. I'm thinking that stiffening all of these up will help with the earthquake of movement that the stock bushings allow. I'm ok with a but more NVH (because racecar) but I don't want to weld the tranny and diff to the body or anything.

Am I on the right track with my goal here? What have your experiences been with this slop and your solution for it?