Bilstein B8+RCE Yellows vs Tien Flex A's

[gpvecchi]

Using B6 or B8 will give different spring preload, right?

[Var]

After having RCE Yellows with PP shocks, (NOT GOOD) and having tein Flex As now, it's a no brainer. Coilovers are the only way you're going to get a properly matched springs and damper valving. Otherwise you're just ballparking and settling for a solution for no apparent reason. Just go buy yourself some coilovers

[ZDan]

Originally Posted by Var

After having RCE Yellows with PP shocks, (NOT GOOD)

Did you have camber plates too?
I find this a bit surprising as my only problem was with bump travel. To the small degree I was able to "fix" it (spring spacers brought front ride height up from around -1.5" to -1.25", factory bump stops cut down from 60mm to 25mm), I saw improvements. I would have guessed that with the increased bump travel available from springs that don't lower the car as much, combined with factory or Pedders offset top mounts (instead of camber plates with roller bearings that take away bump travel) that the ride should be fine, or at least close to stock (which the stock Sachs/PP dampers do have excessive high-speed compression damping).

and having tein Flex As now, it's a no brainer. Coilovers are the only way you're going to get a properly matched springs and damper valving.

You'd like to think so... In my experience, unless you have high-$$$ dampers with separately adjustable high- and low-speed compression and rebound damping, you might be better off with good non-adjustables.

Ferinstance, I like the high- and low-speed rebound and compression damping *better* with non-adjustable Bilstein B8s on my BRZ than I could manage with single-adjustable Ohlins Road-and-Track setup on my FD, which to me could have used a bit *more* compression damping for the level of low-speed rebound.

[Var]

Originally Posted by ZDan

Did you have camber plates too?
I find this a bit surprising as my only problem was with bump travel. To the small degree I was able to "fix" it (spring spacers brought front ride height up from around -1.5" to -1.25", factory bump stops cut down from 60mm to 25mm), I saw improvements. I would have guessed that with the increased bump travel available from springs that don't lower the car as much, combined with factory or Pedders offset top mounts (instead of camber plates with roller bearings that take away bump travel) that the ride should be fine, or at least close to stock (which the stock Sachs/PP dampers do have excessive high-speed compression damping).

You'd like to think so... In my experience, unless you have high-$$$ dampers with separately adjustable high- and low-speed compression and rebound damping, you might be better off with good non-adjustables.

Ferinstance, I like the high- and low-speed rebound and compression damping *better* with non-adjustable Bilstein B8s on my BRZ than I could manage with single-adjustable Ohlins Road-and-Track setup on my FD, which to me could have used a bit *more* compression damping for the level of low-speed rebound.

My friend has Ohline R&T on his FD and my Flex A's are better. I've never ridden in a car with shocks and springs that rode better than what I have now and had the versatility to stiffen up to a track-worthy setup.

As far as camber plates, no I didn't. The front shocks had too much bump for the twice-as-stiff as factory springs. I don't think it was a bump stop issue. The whole setup goes out of whack when you do mods like that. I'm sorry but you can't just throw random springs and shocks together and expect them to work properly. I've learned this the hard way and I stopped going that route. Even if Bilsteins are great shocks out of the box. My friend has Tein Flex Zs and I'd run those over a bilstein and random spring rate setup any day.

[ZDan]

Originally Posted by Var

As far as camber plates, no I didn't. The front shocks had too much bump for the twice-as-stiff as factory springs.

RCE Yellows are ~59% stiffer front, ~43% stiffer rear, not twice as stiff.

In my case, running Swift BRZ Sports which are only 34% stiffer in front, 43% stiffer rear, I did not feel like I had insufficient damping front or rear. At the track the setup was 85% OK, and surprisingly competitive. As stated my biggest issue was lack of front bump travel with 1.25" lower ride height and further ~3/4" loss of bump travel due to camber plates...

I don't think it was a bump stop issue. The whole setup goes out of whack when you do mods like that. I'm sorry but you can't just throw random springs and shocks together and expect them to work properly.

Worth noting that you only have to change damping by the *square root* of spring rate change to have exactly the same %age of critical damping. What this means is that a given set of dampers can work quite will for a surprisingly broad range of spring rates.

That said, I could see that with +59% stiffer front springs (RCE Yellow) you might feel closer to being "underdamped" with factory PP Sachs struts. I did not feel that way with the 34% stiffer front Swift BRZ Sport springs.

My friend has Tein Flex Zs and I'd run those over a bilstein and random spring rate setup any day.

The Bilstein B8s honestly feel about perfect on road and track with the Swift Spec R springs I'm running now (+55% stiffer front springs, +68% stiffer rear vs. stock '17 BRZ).

My impressions, fwiw...

[Var]

Originally Posted by ZDan

My impressions, fwiw...

Welp, I highly disagree. You said you had to get camber plates and cut the bump stops, which I did not do. And most people won't.

My impressions were a pushy and crashy front end.

[ZDan]

Originally Posted by Var

Welp, I highly disagree. You said you had to get camber plates and cut the bump stops, which I did not do. And most people won't.

If you want enough camber to compete on track, you're gonna want camber plates for sure. Or at the very least offset upper mounts and maximum camber bolts. This car *needs* more than 3 degrees front camber at the track, preferably more like 3.5 degrees...

My impressions were a pushy and crashy front end.

What was your front camber?

"Crashy" to me implies insufficient front bump travel and/or too much compression damping. Mine was *definitely* crashy upon initial installation, improved quite a bit by raising the front 0.25" and cutting down front bump stops from 60mm to 25mm. But I needed to be able to go further and didn't want to lose front camber, so went with the Bilsteins, which have significantly more usable front bump travel.

[Var]

Originally Posted by ZDan

If you want enough camber to compete on track, you're gonna want camber plates for sure. Or at the very least offset upper mounts and maximum camber bolts. This car *needs* more than 3 degrees front camber at the track, preferably more like 3.5 degrees...


What was your front camber?

"Crashy" to me implies insufficient front bump travel and/or too much compression damping. Mine was *definitely* crashy upon initial installation, improved quite a bit by raising the front 0.25" and cutting down front bump stops from 60mm to 25mm. But I needed to be able to go further and didn't want to lose front camber, so went with the Bilsteins, which have significantly more usable front bump travel.

So we agree that RCE yellows and PP shocks give a crashy result. Unacceptable result for me. Definitely not acceptable to have to raise the car and cut the bump stops for most people. It's just not a good solution. By the time you buy camber plates and bilsteins, pay for labor 2 or 3 times, pay for alignments..just no. Lowering springs are not a good modification. And you're also going to be limited on what size wheels you can run. You don't have adjustability. And you're ballparking the damper and spring rate marriage. Tein Flex As are the correct answer here.

You'd have to be insane to hodge podge this solution when the price and quality of coilovers are where they are today.

[ZDan]

Originally Posted by Var

So we agree that RCE yellows and PP shocks give a crashy result. Unacceptable result for me. Definitely not acceptable to have to raise the car and cut the bump stops for most people.

My setup was first 1.5" lower up front, then I adjusted to be 1.25" lower than stock.

The Raceseng camber plates actually *lowered* the front of the car, I had to raise it with spacers .25" to compensate for that effect.

I.e., this is nothing to do with "RCE Yellows + PP/Sachs".

Cutting bump stops to run lower springs is perfectly normal and done all the time, and isn't necessarily "bad".

It's just not a good solution. By the time you buy camber plates and bilsteins, pay for labor 2 or 3 times, pay for alignments..just no.

There are other things at play here... But suffice to say doing labor myself or with help of friends reduces cost a lot, and alignments happen semi-regularly anyway given track events and time trials.

Lowering springs are not a good modification.

Not true, lowering springs *can* be a great mod! And "coilovers" *can* be a BAD mod...

And you're also going to be limited on what size wheels you can run.

If you want to run 9" wheels, you have to choose offsets with care.
I'm running 17x9 +35 and also 17x9 +40 with 3mm spacers. It's no that big a deal. with 17x8 and 225/45-17s it's less of a deal...

You don't have adjustability.

"Adjustability" at the price range and setup-experience-level we're talking about is massively overrated.

And you're ballparking the damper and spring rate marriage. Tein Flex As are the correct answer here.

I'm sure they're fine. They are *an* answer. There is no one "correct" answer. Bilsteins + RCE Yellows or Swift BRZ Sport or Spec R springs are another "correct" answer.

You'd have to be insane to hodge podge this solution when the price and quality of coilovers are where they are today.

There's more than one way...

[Var]

Strongly disagree with everything you are doing, but I'm sure we enjoy our cars equally, so

[ZDan]

Originally Posted by Var

Strongly disagree with everything you are doing, but I'm sure we enjoy our cars equally, so

Damrite!

[jflogerzi]

Wow what happened with this threads

There is one or more way to skin a cat. Also you don't need camber plates. I like the current dampers with yellow springs. (17 non pp) going to add peedlers top hats to get some camber without loosing any height or droop travel. Combine this with camber bolts I can get -3 degrees of camber if I wanted.

Sent from my GM1915 using Tapatalk

[itschris]

FWIW, the Spec R spring rates are extremely close to the springs rates at ride height on the B14 kit, which has identical valving to the B6/8. The Spec R is 4.4f/5.3r vs the B14's 4.2f/5.5r. The damping should be well matched.

[ZDan]

Originally Posted by itschris

FWIW, the Spec R spring rates are extremely close to the springs rates at ride height on the B14 kit, which has identical valving to the B6/8. The Spec R is 4.4f/5.3r vs the B14's 4.2f/5.5r. The damping should be well matched.

I think B14/B16 springs are progressive and start out with much softer rates than Spec R. Main reason I went with Swift Spec R/B8. Also no height adjustability saves me 42 lb. for car classification for time trials!
https://www.ftspeed.com/part/47-2283...a#.X73BQMhKhPY
https://www.ftspeed.com/part/48-2282...t#.X73B9MhKhPY
Front: 2.5-4.5kg progressive
Rear: 3.0-7.0kg progressive