Jump to content

Joseph@TheZStore

KONI Sports for Classic Z's

Recommended Posts

On 2/15/2019 at 4:13 PM, Carl Beck said:

Hi Lee: Great to have you here for this discussion. A further comment about our experience with gas pressure shocks several years ago.  Front corner weights on the 240Z’s were 562 lbs and 604 lbs for 1972 as an example. (and varied a little 70/71).

 

We measured the load it took to compress the Tokico Gas Pressure Shocks (non adjustable) at 80 psi. at a local machine shop.  So it was easy to see that a 240Z with a spring constant of 83 lbs/in wound up sitting about 1” higher after installation. As for taking accurate and comparable measurements - a lot of the people involved are Engineers and pretty picky about accuracy. So lets hope your new offering are closer to the 3 Bar than the 5 Bar. At any rate better to know in advance of installation, so any necessary adjustments to spring rates or installed length can be made ahead of time.

PSI is a unit of pressure, not load. Load would be the pressure multiplied by the area that the pressure pushes on.

Along similar lines, the gas charge is a pressure inside the damper, not a spring rate. The force exerted by the gas charge, and thus spring rate, depends on the piston damper rod size and pressure. This can be measured but you need to do some math if it's done using a hydraulic press, which I imagine is how that machine shop did it.

For example:

F=P/A (pressure measured in press / area of press piston)

k=F/x (the above force is calculated at two positions around center of damper travel, difference in force / difference in damper travel = effective spring rate)

Edited by LeonV

Share this post


Link to post
Share on other sites

I know that @Carl Beck is quite competent to defend his posts but nothing in his last statement suggests equating the compression force on a Tokico to spring rate.  Simply put - where the OE hydraulic shocks were passive in the suspension setup, the Tokico shocks are an active suspension ingredient by creating downforce with 80 pounds of pressure.  With the springs as a constant, ride height is affected.  I have these shocks with Eibach Progressive springs and can attest to a degraded ride quality.  His statement to Lee says nothing more than a hope that the pressurization does not approach the Tokico level of 5+ bars and a request that the pressurization be a disclosed specification.

My unsolicited $0.05 worth!

Share this post


Link to post
Share on other sites
6 hours ago, LeonV said:

The force exerted by the gas charge, and thus spring rate, depends on the piston size and pressure.

I'm no suspension expert and I'm going to go out a little too far on my limb here, but I don't think that's quite right.

I believe the force exerted by the gas is proportional to the diameter of the strut shaft where it exits the cartridge, not the diameter of the internal piston. I don't think the diameter of the internal piston has any effect in this case.

My understanding goes like this:

The more the strut is compressed, the more of the shaft is INSIDE the strut.
The additional volume of the shaft (A*L) inside the strut assy will displace oil inside the body.
That volume of oil displaced will compress the gas inside the strut, but only by the amount of VOLUME of the strut rod which has entered the strut.

The internal gas pressure is static across the internal piston. At least that's how it appears to me way out on my limb here.  LOL

shockdesigns.jpg

  • Like 1

Share this post


Link to post
Share on other sites
13 minutes ago, Captain Obvious said:

I believe the force exerted by the gas is proportional to the diameter of the strut shaft where it exits the cartridge, not the diameter of the internal piston. I don't think the diameter of the internal piston has any effect in this case.

So in you diagram the plate (red arrows) inside the strut that the shaft is attached to has holes so the oil flows through the plate and it's the additional shaft volume inside the strut that compresses the gas. This plate is to keep the shaft centered in the strut. This does make sense to me.shockdesigns.jpg.ab0612f1974dc26e3bd9e3576536d31d[1].jpg

Share this post


Link to post
Share on other sites

The plate you pointed to is the main hydraulic piston where the damper valve(s) are located. There is a seal around the outside of that plate and valves built into it. It does keep the bottom of the shaft centered, but that's not the only thing it does. That's where the primary "function" of the damper is located.

Here's what I'm talking about with the gas compression. When fully extended, there will be some preload factory set pressure in the gas.

And then when the strut is compressed, the gas does get compressed some, but it does not see compression proportional to the diameter of the main internal piston. It only sees compression proportional to the diameter of the shaft that enters the strut assembly:
shockdesigns2.jpg

Share this post


Link to post
Share on other sites

Thanks for the clarity, I thought that's pretty much what I said about the shaft volume increasing in the strut is what compresses the gas. Since these new Koni's are adjustable, I'd guess that the adjustment is to what you refer to as the "damper valve(s)" which changes how easily the oil can move through the plate attached to the shaft. The more open the Damper valve(s), the softer the ride.

Edited by w3wilkes

Share this post


Link to post
Share on other sites
2 hours ago, w3wilkes said:

Since these new Koni's are adjustable, I'd guess that the adjustment is to what you refer to as the "damper valve(s)" which changes how easily the oil can move through the plate attached to the shaft. The more open the Damper valve(s), the softer the ride.

With the adjustable KONIs, you are adjusting the rebound (the upward stroke) damping forces generated when oil flows through the piston (the "plate" you reference) valving.  By turning the knob higher or lower, you are closing or opening piston rod orifices and increasing or decreasing spring preload holding valves closed against the piston blocking other piston orifices. This provides changes in damping force from the slightest piston motion through very high pistons speed and lets the KONI Engineers finely contour the damping curve for optimizing both control and comfort.  The lower the adjustment setting is, the more open or less restrictive the damper valving is and the softer the damping force is.  That means you have less motion control but that doesn't necessarily mean that you have a softer or more comfortable ride quality because sometimes insufficient control can provide an uncomfortable ride quality.

  • Like 1

Share this post


Link to post
Share on other sites

My pleasure. I'm just glad I didn't fall off my limb.

One last thing while I'm here... I forgot to emphasize above that the gas in these struts is not intended to be a "lifting" device. It's simply in there to help inhibit foaming of the oil, not to provide any springiness. The fact that the shaft self extends due to the internal pressure is probably considered an unwanted side effect of the gas pressurization. I'm assuming (and KONI Lee would be the perfect expert to provide real insight) if they could get oil that never ever foamed ever, they wouldn't need to gas pressurize at all. Cheaper to manufacture and there wouldn't be all these people talking about how gas shocks raised their car's level.

But the point is these aren't the old "air shocks" that you put on the back of your dad's station wagon back in the 70's and pumped up to get that really cool body rake. Everyone did that, didn't they?  LOL 

Share this post


Link to post
Share on other sites

This is great access, Koni — thanks for the info. So based on all this, what would define “Sport” ride and performance characteristics at their softest setting? What I’m getting at is how would the Sport Koni distinguish itself from a Brand X non-adjustable gas shock in a stockish suspension (other than by its range of adjustment)? Lots of owners these days are opting for preserving the original flavor of these cars.

Share this post


Link to post
Share on other sites
18 hours ago, Captain Obvious said:

I'm no suspension expert and I'm going to go out a little too far on my limb here, but I don't think that's quite right.

I believe the force exerted by the gas is proportional to the diameter of the strut shaft where it exits the cartridge, not the diameter of the internal piston. I don't think the diameter of the internal piston has any effect in this case.

My understanding goes like this:

The more the strut is compressed, the more of the shaft is INSIDE the strut.
The additional volume of the shaft (A*L) inside the strut assy will displace oil inside the body.
That volume of oil displaced will compress the gas inside the strut, but only by the amount of VOLUME of the strut rod which has entered the strut.

The internal gas pressure is static across the internal piston. At least that's how it appears to me way out on my limb here.  LOL

You are correct, thanks for catching that. Everything else I said stands. 😉

Share this post


Link to post
Share on other sites

Koni Test Drive Z Owner Ian Stewart’s Impressions

Ian_Stewart_test-Z.jpg

"Hello everyone, my 260Z was used as the test vehicle for the new Koni struts. The car was the perfect candidate as I had already rebuilt the suspension with new ball joints, Urethane bushings throughout (both front and rear), stiffer springs and Illumina struts. The only change that was made for the testing was replacing the Illumina’s with the Koni’s. 

The Koni’s are an improvement over the Illumina’s in my opinion. You need to get used to not having a way to tell where you are at as the Koni does not have an indicator, but the adjustment range is much wider and you can really feel the difference when you make a change. I never really noticed differences when I adjusted the Tokico’s, whereas I can definitely feel the difference when I adjust the Koni’s. My car is fitted with 160in-lb front and 180in-lb rear springs that lower it about 1.5 inches from stock. Note that these spring rates are similar to most aftermarket spring sets for Z-Cars, at roughly 2X stiffer than stock springs. At full stiff on the Koni adjustment the car is too harsh, but at full soft, it is comfortable (to me) for street use, I like the ride. I have not auto-crossed the car yet, but expect the full stiff setting will work very well." Ian Stewart.

  • Like 1

Share this post


Link to post
Share on other sites

I have a question regarding the diameter of the new 240 and early 260 shocks. Given that the race versions (8610 and 8611) are about 1 thousandth or more larger than the strut tube are the new "Sport" Konis smaller than the Race versions?

How do I know they are larger? Ask me how much paint is still on my new 8610s (none) or how much time I've spent honing out each strut tube. When my street 240 needs shocks it would be nice if I didn't have to go through this again.

Share this post


Link to post
Share on other sites
10 hours ago, gnosez said:

I have a question regarding the diameter of the new 240 and early 260 shocks. Given that the race versions (8610 and 8611) are about 1 thousandth or more larger than the strut tube are the new "Sport" Konis smaller than the Race versions?

How do I know they are larger? Ask me how much paint is still on my new 8610s (none) or how much time I've spent honing out each strut tube. When my street 240 needs shocks it would be nice if I didn't have to go through this again.

The new Z-car KONI Sports are a perfect drop in, easy fit to the factory Z-car strut housings so there is no need for any modifications to make them fit.  The KONI RACE inserts are not Z-car specific but are a generic fit-all insert valved specifically intended for racing usage with a range of dimensional options in a wide range of cars including Mustangs, Porsches, Nissans, Mazdas, etc..  There are a number of vehicles that really respond well to the RACE valving but the factory strut housings are very tight such that one might need to take extra efforts to increase the ID of the strut housing (hone or bore) or decrease the OD of the RACE inserts (sanding down paint, etc.).

If the car is a dedicated racing car, the extra effort to fit the KONI RACE into a Z-car is worthwhile and has been proven with a number of championships.  If the car is used for the normal and performance street driving, autocross, track days, etc. but not up to the level of racing with very high spring rates, the KONI Sports are the right answer.  Also, the KONI Sports do carry the full normal KONI Warranty because they were made for street use on that specifica car whereas the KONI RACE carry no warranty because they were specifically designed for racing on a wide range of cars. 

Share this post


Link to post
Share on other sites
11 hours ago, Joseph@TheZStore said:

 

The Koni’s are an improvement over the Illumina’s in my opinion. You need to get used to not having a way to tell where you are at as the Koni does not have an indicator, but the adjustment range is much wider and you can really feel the difference when you make a change.  ..." Ian Stewart.

Thanks for the review and feedback, Ian. 

For clarification on knowing where your KONI adjustment settings are, just use the physical hard stop at the full soft setting (clockwise until it stops)  and then the number of full  or partial turns counter clockwise up from that point. Example: Full soft, 1/4 turn from soft, 1 1/8 turn from soft, etc..  This is always repeatable and easily matched side to side, front to rear if desired.  In general most people probably use 1/4 turn adjustment increments but you can do larger or smaller increments if you want.  We have a highly respected and picky BMW tuner whose recommendations go to the 1/16th of a turn.  If you can discern judge that small an incremental change in your car, more power to you but most people are probably more in the ¼ turn range.  Unlike the Tokicos that had only 5 defined adjustment settings, the KONIs can be adjusted to many more settings across a larger overall adjustment range min. to max. with broader affect across the working piston speed range.

Share this post


Link to post
Share on other sites
15 minutes ago, w3wilkes said:

@KONI Lee Do you know how many turns from full soft to full hard?

I don't have a Z-car damper readily at hand to check one but most KONIs have a roughly 2.0 to 2.25 turn adjustment range from the stop at full soft to the stop at full firm.  Depending on any minor stack height difference of the internal valving components used in that application, there is some possible variation but rarely does it go less than 1.75 turns or more than 2.50 turns.

Because all KONIs have greater than 1 full turn of adjustment, having external numbered markings like the Tokico would not work.

Share this post


Link to post
Share on other sites
5 hours ago, w3wilkes said:

@KONI Lee Do you know how many turns from full soft to full hard?

5 hours ago, KONI Lee said:

I don't have a Z-car damper readily at hand to check one but most KONIs have a roughly 2.0 to 2.25 turn adjustment range from the stop at full soft to the stop at full firm.  Depending on any minor stack height difference of the internal valving components used in that application, there is some possible variation but rarely does it go less than 1.75 turns or more than 2.50 turns.

Because all KONIs have greater than 1 full turn of adjustment, having external numbered markings like the Tokico would not work.

On the demonstration strut we received, it was just what Lee said, roughly 2 turns. The red KONI "Triangle" on the knob sort of works like an arrow to see how far you have turned 😎

Share this post


Link to post
Share on other sites

I am in the process of switching out my Tokico HTS shocks for a set of Koni 8610-Race because I am increasing the front springs from 375# to 450# which many folks believe is too much for the HTS's to handle before blowing. While this might not be true, having to replace a shock or shocks at the track would be a PIA not to mention that HTSs are NLA. Like the Koni the HTS had a wider range of adjustment with no numbers to go by just the requirement to remember how many turns you made. Unlike the Koni the HTS could not be rebuilt. These Koni "Sport" shocks look to be a perfect solution for every type of driving one might do.

That Koni and MSA are now producing a Better replacement shock for our Zs is wonderful news and I salute their efforts to ensure we can continue to enjoy these great cars for many more years.

I've attached a picture of the Race shock adjuster which I assume is similar to the one used for the Sport version (once it's set you would remove it from the shock and Koni suggests that you put it in the glove box).

koniadjuster.jpg

  • Like 1

Share this post


Link to post
Share on other sites

The first wave of 240Z  and early 260Z Sport struts have arrived from Koni.  Pre-sale orders have already shipped if you were one of the early birds.  A special thank you to @KONI Lee for his knowledge and support for the Z community.  Koni has done an outstanding job and we are extremely proud to be teaming up with them to offer such an amazing product.  I will update everyone once the batch of late 260Z and 280Z struts arrive as well as for the 280ZX.  Thank you!

pallet02.jpg

  • Like 2

Share this post


Link to post
Share on other sites
On 2/22/2019 at 3:13 AM, Joseph@TheZStore said:

Koni Test Drive Z Owner Ian Stewart’s Impressions

 

 

Ian_Stewart_test-Z.jpg

"Hello everyone, my 260Z was used as the test vehicle for the new Koni struts. The car was the perfect candidate as I had already rebuilt the suspension with new ball joints, Urethane bushings throughout (both front and rear), stiffer springs and Illumina struts. The only change that was made for the testing was replacing the Illumina’s with the Koni’s. 

 

 

The Koni’s are an improvement over the Illumina’s in my opinion. You need to get used to not having a way to tell where you are at as the Koni does not have an indicator, but the adjustment range is much wider and you can really feel the difference when you make a change. I never really noticed differences when I adjusted the Tokico’s, whereas I can definitely feel the difference when I adjust the Koni’s. My car is fitted with 160in-lb front and 180in-lb rear springs that lower it about 1.5 inches from stock. Note that these spring rates are similar to most aftermarket spring sets for Z-Cars, at roughly 2X stiffer than stock springs. At full stiff on the Koni adjustment the car is too harsh, but at full soft, it is comfortable (to me) for street use, I like the ride. I have not auto-crossed the car yet, but expect the full stiff setting will work very well." Ian Stewart.

I don't see how your car would be the perfect choice, you've large wheels, small tyre profile, hard bushings everywhere and used springs.

  • Like 2

Share this post


Link to post
Share on other sites

 

1 hour ago, Jason240z said:

I don't see how your car would be the perfect choice, you've large wheels, small tyre profile, hard bushings everywhere and used springs.

It is a good example of how these cars are regulary upgraded with more modern wheels, tires, springs, bushings, etc. that many people use today.  Each of those steps takes some compliance out of the suspension's motion and sharpens the feedback up to the driver and passenger.  These cars will normally use a slightly higher initial rebound damping adjustment setting than will a truly stock car with softer springs, taller sidewall tires, etc. might.  The stock cars will normally be adjusted to at or near the full soft adjustment setting and the modified car will likely have a higher initial setting however it will rarely be even halfway into the full available adjustment range. 

This helps show that the new KONI Sport option meets its goal to cover a broad range of enthusiast Z-cars, whether fully stock, upgraded with modern parts but still needing a very streetable characteristic, or for even more aggressive cars for autocross. track days, etc..  If we had fixed damper valving with no damping adjustment to help work with a range of stock or upgraded performance parts, then there would be greater concern about needing multiple strut part numbers to cover the range of cars. Being adjustable lets the car owner match to his own upgrades, handling and ride preferences, local road conditions, weekend competition goals if any, and also compensate for long term wear.

  • Like 2

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.