Tim86's Journal - Silver 86 AT - DD & occasional track (East of England)

[Tim86 24]

6 minutes ago, Lauren said:

Hydro bump stops are a nice addition to the Flex A's. I have the older Flex (been on my car for over three years and 70K miles now). I'm guessing you were told they don't need them because they don't have them. It's a bit of a USP for the Flex A's. 

In regard to spring rates, I was able to spec my own spring rates and also had the rear dampers shimmed to increase the damping by 20%. It's the personalised touch I value. 

This is what i was told Lauren, interested in what you guys think to that :

The FlexA have this hydraulic bump stop because of it's twin-tube design.
Not that it is a bad thing, but certainly isn't something new, been around for decades.

The ZetaCRD is a mono-tube damper, so it is in a completely different performance category.
Having high pressure charge gas makes a huge difference in the dynamics the damper provide.
Not to mention having much more control over smaller damping movement.

Generally speaking, you try to keep off the bump stop than to ram into it.
We haven't had any bottoming out issue because there is almost 5 inch of travel in the front and just over 4 inch of travel in the rear.
Damper stroke travel is something that the 86 lack, so it was a very knife edge design in what will work and what will not.

[Lauren 2259]

Sounds like marketing blurb to me. I would expect it is still possible to hit the bump stop, I don't see why a monotube design is immune. 

The better answer would be that the Flex A has a hydraulic bump stop as it's designed for road use and helps you take bigger hits without it feeling like it crashes through the shell. So the aim is to give you a better ride and on the odd occasion you hit a big depression or pothole it won't feel as bad. I am quite happy to put you in touch with Yukiko at Tein who could doubtless give you a better explanation. I would suggest that the Monotube Teins (Monosports) don't have hydraulic bump stops because they are more track orientated. 

I think what you was told simply doesn't answer the question. 

[Deacon 1357]

7 minutes ago, Tim86 said:

This is what i was told lauren:

The FlexA have this hydraulic bump stop because of it's twin-tube design.
Not that it is a bad thing, but certainly isn't something new, been around for decades.

The ZetaCRD is a mono-tube damper, so it is in a completely different performance category.
Having high pressure charge gas makes a huge difference in the dynamics the damper provide.
Not to mention having much more control over smaller damping movement.

Generally speaking, you try to keep off the bump stop than to ram into it.
We haven't had any bottoming out issue because there is almost 5 inch of travel in the front and just over 4 inch of travel in the rear.
Damper stroke travel is something that the 86 lack, so it was a very knife edge design in what will work and what will not.

Definitely marketing blurb I'm afraid. Lots of rally dampers have 'proper' hydraulic bump stops and are monotube. The bump stops in most dampers are rubber - in the flex A's they're a spring. It's basically the same thing just different sprung mediums and the spring design works better to reduce the bump you feel when hitting the bump stops than the rubber bump stops generally do. The performance advantage that monotubes have is they are more consistent at high temperatures (as you could see on track for instance) than twintubes but twintubes ride better.

I should also point out I don't have the flex A's anymore so it's not just a case of owner bias!

[Tim86 24]

Loving the input.

Both a great setup imo, I paid 715 for my coilovers so quite a bit cheaper than 1k for the Tein. Still feel a huge improvement and i'm happy for now. Throw in the ARB and it'll hold up fine. Maybe it sounds odd to some but to me it most definitely feels more comfortable than stock on the road, and if i have lost any unnoticed comfort factor, i have most certainly and undoubtedly gained more confidence and mobility.

As for having a small bias towards understeer without an ARB in comparison to stock: Always safer and more predictable on the road than going further in the opposite direction .

@Cerastes I'm confident you'd be happy with both, each being a noticeable upgrade. Just depends on your budget as with most things.

@Lauren due to budget constraints i'll probably stick with these coilovers until i've done everything else, i'd imagine it would be hard for me to get a refund at this point even if i did change mind. And there's more, much much more other stuff to come..

[will300 812]

@Tim86 did you weigh the wheels by any chance?

[Tim86 24]

3 minutes ago, will300 said:

@Tim86 did you weigh the wheels by any chance?

I have the weights somewhere i'll try dig them up. Be warned they arent light, the original Rays 57C6 are known for being heavy (for a Rays wheel), but i'd say don't let that put you off unless you're building a fully forged track/competition monster.

I think @rob275 might have bought some from another member.

[will300 812]

Thank you, that would be very useful. I have been looking at the new Gram Lights 57CR 5-Spoke's, however I'm not 100% sure on them. In some pictures they look great in others I think they look terrible. 

[Tim86 24]

18 hours ago, will300 said:

Thank you, that would be very useful. I have been looking at the new Gram Lights 57CR 5-Spoke's, however I'm not 100% sure on them. In some pictures they look great in others I think they look terrible. 

@will300Just found it again, 20.5lbs (9.2kg) for the Vordoven Forme 6 18x9.5 +38 (only size they do in 18) so 0.1 kg heavier than the stock 17" wheels. Heavy for Rays? Maybe, still light for 18x9.5? Definitely - Source:

https://my350z.com/forum/wheels-and-tires/611052-replica-wheels-do-they-deserve-the-bad-reputation-i-aim-to-find-out-2.html

[Guest]

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[Ade 517]

 

On 5/9/2017 at 7:55 PM, Deacon said:

 

 

Definitely marketing blurb I'm afraid. Lots of rally dampers have 'proper' hydraulic bump stops and are monotube. The bump stops in most dampers are rubber - in the flex A's they're a spring. It's basically the same thing just different sprung mediums and the spring design works better to reduce the bump you feel when hitting the bump stops than the rubber bump stops generally do. The performance advantage that monotubes have is they are more consistent at high temperatures (as you could see on track for instance) than twintubes but twintubes ride better.

 

 

 

I should also point out I don't have the flex A's anymore so it's not just a case of owner bias!

 

 

 

Hydraulic bump stops are not a spring @Deacon. The spring acts to apply a linearly increasing force on the relief valve. It works to increase the damping force as the spring presses hard into the relief valve. So you get a nice progressive increase in damping towards the end of damper travel that feels a bit less jarring than a rubber stop. They still have tradition rubber stops though, just very thin ones, but they still need something to avoid metal on metal contact at full compression. 

 

 

 

In the case of the tein flex A it makes it easier to do it with a twin tube. 

 

 

 

Motorsport dampers have external canisters and the HBS can be incorporated to limit bleed into the external canister under the last (predefined)% compression and thus they can still use a monotube. 

 

 

 

[Deacon 1357]

1 hour ago, Ade said:

Hydraulic bump stops are not a spring @Deacon. The spring acts to apply a linearly increasing force on the relief valve. It works to increase the damping force as the spring presses hard into the relief valve. So you get a nice linear increase in damping towards the end of damper travel that feels a bit less jarring than a rubber stop. They still have tradition rubber stops though, just very thin ones, but they still need something to avoid metal on metal contact at full compression. 

In the case of the tein flex A it makes it easier to do it with a twin tube. 

Motorsport dampers have external canisters and the HBS can be incorporated to limit bleed into the external canister under the last (predefined)% compression and thus they can still use a monotube. 

Yes I was simplifying quite a bit.

[Ade 517]

1 hour ago, Ade said: Hydraulic bump stops are not a spring @Deacon. The spring acts to apply a linearly increasing force on the relief valve. It works to increase the damping force as the spring presses hard into the relief valve. So you get a nice linear increase in damping towards the end of damper travel that feels a bit less jarring than a rubber stop. They still have tradition rubber stops though, just very thin ones, but they still need something to avoid metal on metal contact at full compression. 

In the case of the tein flex A it makes it easier to do it with a twin tube. 

Motorsport dampers have external canisters and the HBS can be incorporated to limit bleed into the external canister under the last (predefined)% compression and thus they can still use a monotube. 

Yes I was simplifying quite a bit.

Fair enough just wanted to clarify to people reading.

 

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