Thread: Beam Bending

I might have to look into that. Any increase in harshness? I'm guessing you used ES bushings. I already have ES in the front with the SuperPro caster bushings.

That's a very good start. My advice would be pretty similar... but based on labor and initial cost.

1: ES Rear trailing arm bushings + Rear Swaybar + Front LCA rearward Caster bushing + Front Shifter Bushing
All very easy to install and wont hurt the bank.

Rear trailing arm bushings make HUGE difference on softer spring rates <300lbs.

Rear swaybar makes another HUGE difference

Poly LCA rearward bushings are stiffer thus will help reduce wheel hop, plus caster bushings will help turn in and negative camber gain while turning. The only reason I don't suggest front facing LCA bushings, in my personal experience gains were minimal but NVH increase was major.

Shifter bushings help improve the overall shifter feel.

These steps should increase NVH very slightly, thus the car will still be very comfortable still.

2: Stiffer Springs and Shock/Strut + ES tophat bushings, Front Camber plates, if you can go straight to coilovers!
Lowering the front will give you good amount of neg camber that will last your driving for a while.

If you have $1k go straight to coilvers. I wish I knew about BC racing coilovers when I was building my P11's suspension. I have more then $1k in different shock/spring combos and am still not satisfied with it. I went from Tein Basic's to BC's on my B15 and loved both setups (BC little more since they have more features for the same price).

Another benefit of going straight to coilovers is they will usually come with front camber/caster adjustment (Not applicable on B15's )

NVH will be worse at this point but still very manageable.

3: Stiffer Springs (300-600lbs) if you haven't already + Thrust Angle Fixing
I've found that a lot of beam issues can be negated with even 330lbs front and back springs. Mike Kojima suggests having rear be 25-30% stiffer, I am about to play with his suggestion and see if it makes the car be better overall.

Mike K suggests having rear be 25-30% stiffer then front (this follows OEM spring rates too). Keep this in mind when you buy new springs.

I'm also about to try out SWIFT springs, will know if they handle better and reduce NVH compared to stock BC springs.

Our beams shift to the passenger side when you lower the rear even slightly. This causes a negative thrust angle which combined with stock toe in will hunt you in turns. You can try to realign the beam by unbolting all bolts, or get a QT link

4: Bent Beam to 0* Toe + Spec V SRL Link
This would be my first suggested step if it wasn't so difficult to find a person to get this done. If you have a P11 or B15 with 1/8" toe in, then this is not as important as B14's with 1/4" toe in.

If you don't plan on going to Step 5 and getting a panhard done, get yourself a Spec V SRL link, it's much beefier then B14/P11 one and should help with keeping the rear on the ground.

2017 Update: If your gonna get a panhard bar, which you should because it's the single best thing to do to our rear ends, you should NOT bend your beam, otherwise the car will be way too tail happy with 30-40% stiffer rear springs and rear swaybar (mine is tail happy even without a rear swaybar).

5: Panhard Bar Conversion + Front LCA Bushings
Panhard fixes the high roll center and beam binding that SRL link has. From what I'm seeing the panhard will benefit the people with softer spring rates the most, >300lbs. My B15 with 400lbs front and back springs doesn't overload the front springs nearly as much as my P11 with B&G springs (unknown progressive rates, feels like around 200-250lbs).

Your going to increase NVH through panhard, might as well do front LCA bushings too.

2017 Update: On my P11, even with stiffer rear springs (10k = 600lbs), panhard bar made a night and day difference. I had to install 8k (450lbs) rear springs to make it be less tail happy.

Also NVH did not increase with my panhard bar with heim joint rod ends.

Guys, i want to go for coilovers but i dont know what brand to buy as here where i live most of the people go for Ksports but i have heard that they are no good. Any recomendations?

BC's hands down best bang for the buck. Love my set.

Fortune Auto? BC?

Hard to say because I went from stock springs to 330lb spring at the same time I did the bushings. It did get a firmer with both of those mods, but I wouldn't describe it as harsh. Firm is a better word. My guess is the bushings didn't add much NVH. I'd say going to a solid damper mount would do more to hurt the ride quality than the bushings. I'm running stock rubber mounts. It did the 2000 miles of driving to and from the convention comfortably.

I had the same results. The rear bushings barely increased NVH. Going to delrin bushings for the shocks made NVH go up MAJORLY (pictured below). Same with lower control arm front bushings.



Now Hank what are your front springs rated at, I know they are progressive, but any particular rates that they are similar to?

P.S. did you find the issue with the brakes?

They're Hypercos. I think they're suppose to be 280lb when compressed to a certain point...

I haven't addressed the brake issue yet. My gut tells me it's the wheel bearings. It only happens after corning on the limit. The phenomenon is called "knockback". Good write-up on the topic:

Pad Knockback

IIRC, the Gen 2 Hypercos are supposed to be 290 lb/in front and 190 lb/in rear. This refers to the constant spring rate of the stiffer (further apart) coils, which become active once the softer (closer together) coils are fully compressed against one another.

However, what I have learned is that it is safe to assume this is the actual spring rate for almost all instances of bump (compression), because the weight of the car is enough to keep the softer coils fully compressed. This means the softer coils only come into play during rebound and only when rebound is beyond the normal ride height of the car (such as a sudden dip or pothole). This probably also an effect on the inside wheels during heavy cornering.

Hope that made sense, just some interesting info that I've figured out and thought I'd share.

Hyperco for a B14 spring rates are....

Front - 300 lb/in rate with 1" drop
Rear - 250 lb/in rate with 5/8" drop

Hyperco B14 Spring Deal - IT'S ON!!!! - SR20 Forum

And yes, silly progressiveness. I dislike the springs, make it impossible to predict behavior of bump and rebound in extreme cornering, in my opinion.