Suspension tuning - dampers, spring rates, etc.

[Little_Nolan]

Read through this thread and a lot of great info.

I am looking to swap up the suspension in '97 #305. Currently running Koni/GC with 425f/375r rates. The ride is not overly harsh and it performs well enough in spirited driving, but there is just something off about it that I am not a fan of. I have stock F/R sway bars with new bushings and endlinks.

Looking at going to a bilstein (or other monotube) setup instead. I have bilstein B6's with Neuspeed SofSport springs on my EK sedan and I really appreciate the dampening curve and overall feel of the setup.

Currently Considering:
-H&R Street Performance Coilovers
-Bilstein B8's with H&R Sports or Tanabe TGF041's for springs
-Tein MonoSports
-Koni Yellows with stock ITR springs

I do not want overly harsh spring rates and prefer something tolerable for the road. The only track event the ITR will probably see is Type R expo.

Input, suggestions and discussions are welcome.

[aw614]

I ran the Bilstein B8 with ITR springs for about 5+ years and was really happy with their overall performance, it was a good medium of not too stiff and and dailyable. I haven't driven on newer ITR shocks to compare, but I was happy with it. Still on the fence about them with coilover sleeves

Wanted to try the Koni Yellows/ITR spring setup on my EK beater coupe, but I lost the spring perches for the front so I can't test it out, just have it on the rear and with some front GC sleeves. Doesn't seem too bad at all. The konis I had came with GC OTS rates but I felt like I wasn't a fan of the setup. Not sure if my shocks were going in the rear, but they felt overly stiff through parking lot speed bumps. The ITR rear springs fixed the issue and I dont have to crawl at really low speeds through speed bumps. The fronts felt fine to me.

I will say if you already have the Koni/GC kit already, just get the perches and put the stock springs and see how it is. You might like it. You also have the option of just getting softer GC springs too.

[Little_Nolan]

Thanks for the reply and insight.

I am going to put the Tanabe TGF041's on my Koni's and see how they are. The spring rates are close enough to stock ITR and are progressive so it might be a win. Look for a new thread on it.

[aw614]

I have a question on the kingpin machine compliance bushings as I recall the old forums talked about what their benefits were, but I am going off memory and want to clarify some stuff about them vs the stock or mugen bushings.

From what I remember, the eg/dc chassis suffer from toe out under hard braking and are people experiencing any front any wiggle/instability say from 100mph to like 50-70mph hard braking at the track? The kingpin compliance bushing should lessen that?

How are they on the street? I recall several posts saying if there is one set of sphericals to run, while keeping the rest dd friendly, it would be those.

So I did a private track day and from an event over a year ago, I've noticed my front end likes to wiggle under really hard braking it isn't confidence inspiring. But I also have over -3 degrees of front camber and around -2.3 in the rear, so that might not be helping with stability..

[coolhandluke]

Read through this thread and a lot of great info.

I am looking to swap up the suspension in '97 #305. Currently running Koni/GC with 425f/375r rates. The ride is not overly harsh and it performs well enough in spirited driving, but there is just something off about it that I am not a fan of. I have stock F/R sway bars with new bushings and endlinks....

...I do not want overly harsh spring rates and prefer something tolerable for the road. The only track event the ITR will probably see is Type R expo.

Input, suggestions and discussions are welcome.

Can you expand on what feels "off"?

[Little_Nolan]

Feels like the the shocks are not dampened enough for the springs at low speeds. When driving aggressive and on the limited track time the koni/GC has seen, it feels great and is very smooth and easy to control at the limit, but felt somewhat soft. It's the normal street manners and specifically low speed driving that I did not enjoy. I have tried several spring rates, manufactures and have tried both progressive springs and linear (eibach ERS). I have played around with the adjustability of the konis but still couldnt dial it in just right.

I am now going to try a different shock.

[KIngpinMachine]

I have a question on the kingpin machine compliance bushings as I recall the old forums talked about what their benefits were, but I am going off memory and want to clarify some stuff about them vs the stock or mugen bushings.

From what I remember, the eg/dc chassis suffer from toe out under hard braking and are people experiencing any front any wiggle/instability say from 100mph to like 50-70mph hard braking at the track? The kingpin compliance bushing should lessen that?

How are they on the street? I recall several posts saying if there is one set of sphericals to run, while keeping the rest dd friendly, it would be those.

So I did a private track day and from an event over a year ago, I've noticed my front end likes to wiggle under really hard braking it isn't confidence inspiring. But I also have over -3 degrees of front camber and around -2.3 in the rear, so that might not be helping with stability..

So I may obviously be biased but I really do think I try to look at things from an enthusiast first and a manufacturer second. I never recommend running sphericals on the street. It isn't that I view them as inherently bad on the street but rather that A) good ones are expensive and excessive miles are going to wear them out more quickly and B) the compliance and forgiving nature of a rubber/steel bushing can be a very good thing on the street. After all, you don't expect to have potholes on a track and with the possible exception of Sebring most tracks are going to be much smoother and more predictable than the street. Sphericals transmit NVH much more of course and I suspect they could make a car more "darty" over rough or uneven pavement.

Anyway, the rubber bushings in the OEM compliance bushing assembly are so damn soft and so thick that I think they basically steer the car under very hard braking. That is what introduces that tail wag feeling you get under hard braking. Wag too hard and you can easily get the rear chasing the front. I have talked to high power time attack guys that swear the car is trying to drive itself left or right off track when hard on the power. Same problem in reverse. Some people attribute that to the RTA bushings but I would be willing to bet most, if not all, drivers can't tell the difference between a fresh OEM RTA bushing and say a PCI RTA bearing. Given the way the RTA moves I just don't think that bearing provides that much benefit back there. I mean, the arm is allowed to slide some left and right whether you run rubber or a bearing.

The compliance bearing is an entirely different deal. Once you go spherical there that son of a bitch triangulates the rear of that arm rigidly and all movement is rotational only at that point. Period. The tricky part is that the front LCA inner pivot point can still deflect some and will having the rear triangulated and the front not introduce any ill handling effects? I personally think the benefits of having just compliance bearings with spirited driving overcome any negatives but I would not want to run any toe out for sure! The car turns in right damn now compared to stock and transitions much more quickly. Get it wrong on soft springs and grippy tires and easy to chase the front. Compliance bearings have such a dramatic affect on steering and braking feel that I think they feel odd after driving a Teg without them. I wish you lived closer so you could drive my car around right after driving yours to see what I mean. Like any mod, I guess they are a trade off at the end of the day. Going all spherical in the front LCAs would probably be best but even making this stuff for a living I haven't plunked down the money to do that.

[coolhandluke]

....The (front lower) compliance bearing is an entirely different deal. Once you go spherical there that triangulates the rear of that arm rigidly and all movement is rotational only at that point. Period...

Thank you for chiming in Chris, as I value your experience and knowledge on this topic.

I attempted to reply earlier and got distracted when trying to articulate the benefits of the front lower sphericals. Coming from my previous experience with Full-Race traction bars, the goal had been to strengthen or "box in" the front lower arms to prevent the rear end wiggle under hard braking. Your (Kingpin Machine) front lower compliance bushings did just that, with the added benefits of dropping weight and gaining ride comfort on the street. I've run them in all my track cars ever since.

[aklackner]

The compliance bearing is an entirely different deal.

I've run them in all my track cars ever since.

Thanks for the additional info around these!

I've been very curious about trying the kingpin compliance bearings for my ITR project but its pretty likely to see some street mileage\cruising. Sounds like I should pick up a set and maybe plan to swap them in for track days. Or would repeated swaps likely create an issue with the alum. spacers?

Chris,
Are the integra compliance bearings in stock or do you have a sense of what lead time is?

[coolhandluke]

I've been very curious about trying the kingpin compliance bearings for my ITR project but its pretty likely to see some street mileage\cruising. Sounds like I should pick up a set and maybe plan to swap them in for track days. Or would repeated swaps likely create an issue with the alum. spacers?

Chris,
Are the integra compliance bearings in stock or do you have a sense of what lead time is?

Kingpin front lower compliance are the only spherical bushings I recommend for street cars who see the track. They have little/no impact on street driving comfort and the wear is minimal. There is no need to swap them in and out for track days.

My car sits 51 weeks out of the rear and is mainly driven to and from the track, so my PCI rear trailing arm sphericals and my upcoming upgrade to Kingpin Machine front LCA's are of little concern wear and comfort wise.