Type-S Zero Project Suspension

[NSXGB]

I suppose it depends on what your definition of sensible is. Here is what I found on JP Parts:

Rear Damper Set (x 2) : 52610-SL0-903 ---> $1,739.86 each
Front Left: 51602-SL0-903 ---> $1,519.41
Front Right: 51601-SL0-903 ---> $1,519.41

S Zero has the same part numbers. Total for the full setup is $6,518.54

I love OEM Honda, but that is a lot of love right there...

There are other part numbers listed under the S-Zero suspension page for some reason, running from $450 up. Looks like the -903 part is definitely the correct one - From Amayama the total would be $5062 and I'm sure Marc Perez could tickle that price a little more...

 

[Honcho]

There are other part numbers listed under the S-Zero suspension page for some reason, running from $450 up. Looks like the -903 part is definitely the correct one - From Amayama the total would be $5062 and I'm sure Marc Perez could tickle that price a little more...

For some reason, the site shows all of the available parts for that model year, regardless of trim. I noticed if you select "S Zero" from the list, for example, it will add the S Zero unique parts, but not delete the non- S Zero parts. Same for NSX-R, etc. So, you have to intuit somewhat what the additions are. The $450 parts you see are for the standard NA2 NSX coupe and T.

 

[Honcho]

B6 vs B8 Length Considerations

[MENTION=10201]goldNSX[/MENTION] [MENTION=12356]Mac Attack[/MENTION]

You guys were discussing this in Dave's PSI thread, but I did not want to derail that discussion, so I'm putting this here. If I do go the custom Bilstein route, below is what I am envisioning (couldn't quite get the Swift orange color right though lol). Top is OEM Honda and bottom is my proposed Bilstein/Swift coilover.

I have all the parts already spec'd out, but I am still confused about effects of overall damper length, spring length and 1G compression on ride height.

I always understood ride height to be affected by changes to total damper length as measured from center of eyebolt to the top of the tophat mount. IN the diagram below, that is A - B = change in ride height. Vance posted a picture long ago comparing the NSX-R front shock with the regular NSX front shock to demonstrate the height difference:

However, in looking at aftermarket coilovers, the spring perch usually is closer to the top hat versus the OEM shocks, as in my diagram. Does this also affect ride height? It must because by adjusting the spring perch, you can set ride height, right? I need to know because if I choose a B8 damper, which is 0.875 shorter than OEM/B6, am I limiting myself to a max ride height that is 0.875" inches shorter than stock? Which dimension matters? I'd like to be at -0.75" F and -0.5" R. Am I better off with the B6? What about spring length? 7" F and 8" rear?

 

[goldNSX]

The pics are a little bit confusing. Normally, you put the shocks on the ground vertically or level out the bottom of them (eye to eye) and do the measure. Then you'll likely see that the level of lower spring seat is the same between the standard and Type R version. But the top hat is lower in the Type R version than OEM, so the whole strut is shorter and easier to mount anyway. That's because the spring wouldn't be preloaded if the strut is fully expanded (changing wheels, autocross ). A loose spring in the strut is not a desireable thing to have and can be pretty dangerous. So the Type R shock has a limited expansion/stroke, realized by a rebound within the shock itself (normally a piece of rubber), maybe 1''. When both cars (NSX-R and OEM) are both off the ground you can see the difference of negative suspension travel very clearly.

Also the Type R spring is not linear initially like the OEM. The Type R is slightly lowered. This is the result of the 3-4 upper windings of the spring going on block (see the rubber? anti-noise...) which results in less resistance/force as the spring begins to compress, so the car sits lower even though the lower spring seat is at the same height as OEM and even though the spring rate is 3x higher than OEM. If both were linear the Type R would be even higher than stock.

Back to your scenario: the needed rebound (not the valving, just the limiter of stroke) of a shock is determined by the desired height AND length of the used spring. The lower you want to go the higher the rebound (in mm) has to be to ensure that the spring is preloaded by >50 kg or 10 mm in ANY circumstances. That's the point to start with. Fit the shock and spring together and screw the top hat on them and see if it's pretentioned enough. You don't know the actual ride height at this time, you only know your preferred ride height. So you have to mount them on the car, drop the weight of it on them and measure your ride height (always from center of the wheel to the fender) and decide what the lowerest height level will be you'll ever want to go. Don't go too low. Then do the calculation.

In my very first run, I've decided to install a rebound of 40 mm, which was a little bit too much for the Zanardi springs. Now, I'm at 20 mm on B6 which is exactly what B8 are. B8 is nothing more than the added rebound of 20 mm. As you might have to send the shocks several times to Bilstein for revalving you'll always have an opportunity to correct the rebound. The higher the spring rate - the lower the car - the more rebound is needed - the less negative suspension travel. Too low suspension travel is not a desireable thing to have. The wheel must be able to 'follow' a pothole or example.

One more hint: even the Zanardi springs (linear 6.5/5.0) need a rebound of 20 mm front and rear if you install them on the lower perch of a B6 because the springs are shorter. Even more stiffer springs need even more rebound. Now imagine the negative stroke of a combo like 12.0/10.0 TEINs with linear springs...insane.

Hope this helps. As it gets very technical it might be obvious that English is not my mother language.

 

[Mac Attack]

As Gold said, first make sure the springs are snug. The distance between the center of the lower eye bolt and the top of the top hat is just one of the inputs to ride height. The spring rate differences play the other part.

Say you have a 400 lb/in spring on the Type R front shock and a 200 lb/in spring on the standard front shock. If you used them on the same car corner, then the coilover with the 400 lb/in spring will compress half as much as the coilover with the 200 lb/in spring. So, you'd take any difference between the uncompressed coilover length and then have to add in the compression factor due to spring rate differences.

The spring rate equation is F = k * x, where F is your load (for example, the corner load in pounds), k is the spring constant (for example, pounds per inch), and x is the resulting spring deflection (in inches if you use the units above). The equation holds for progressive springs, but since manufacturers don't include the variable spring constant and where in the deflection it applies, it's going to be hard to estimate the expected deflection. Constant spring rates are much easier to design around, you just need to be able to estimate your corner weights or front/rear balance.

You've heard about spring preload too, so any preload you apply to the spring you're just going to raise up that corner by the same amount (well, factoring in the suspension motion ratio of course).

 

[Mac Attack]

Hope this helps. As it gets very technical it might be obvious that English is not my mother language.

You're doing much better than I would be!

 

[CB72]

Just to add my 2 cents comment to this discussion.
For years I ran Bilstein shocks with Zanardi springs combined with 22 mm Dali bars.
The rear was on the highest setting and the front on a special groove between the high and low setting.
The car was well balanced front to rear but lacked the gokart feeling to allow me to "throw" the car into the tighter bends ( on track of course)
Following the recommendation of some Prime members, I upgraded the system to KW V3 clubsport's.
After spinning the car on a wet track, I decided to go back to the OEM ( 17mm ) rear bar.
Surprisingly enough the car didn't understeer that much and now the car can really be "bullied" in the slow turns and when the turbo goes in full boost the car will not go into oversteer unless the tire pressures go off scale.
From a timing perspective, I have gained 1.5 seconds per lap allthough I feel there is room for improvement if I played with the damping settings.
That is the issue by the way!
On a given track day, I would need some help to time my laps, change the settings and start all over again.
With the Bilstein/Zanardi combo the only issue is the driver.
BTW from a comfort perspective the Bilsteins felt harder than the Clubsports WHEN I had the 22 mm rear swaybar!
With the 17 mm bar it feels fine to me.
I've published videos elsewhere where you can see how the car compares to more modern track weapons...

 

[jwmelvin]

^^^ that’s was the point I tried to make above. You would get better performance and better comfort by using a better damper than the Bilstein street dampers. I don’t think you should be afraid of adjustability.

 

[Honcho]

The pics are a little bit confusing. Normally, you put the shocks on the ground vertically or level out the bottom of them (eye to eye) and do the measure. Then you'll likely see that the level of lower spring seat is the same between the standard and Type R version. But the top hat is lower in the Type R version than OEM, so the whole strut is shorter and easier to mount anyway. That's because the spring wouldn't be preloaded if the strut is fully expanded (changing wheels, autocross ). A loose spring in the strut is not a desireable thing to have and can be pretty dangerous. So the Type R shock has a limited expansion/stroke, realized by a rebound within the shock itself (normally a piece of rubber), maybe 1''. When both cars (NSX-R and OEM) are both off the ground you can see the difference of negative suspension travel very clearly.

Also the Type R spring is not linear initially like the OEM. The Type R is slightly lowered. This is the result of the 3-4 upper windings of the spring going on block (see the rubber? anti-noise...) which results in less resistance/force as the spring begins to compress, so the car sits lower even though the lower spring seat is at the same height as OEM and even though the spring rate is 3x higher than OEM. If both were linear the Type R would be even higher than stock.

Back to your scenario: the needed rebound (not the valving, just the limiter of stroke) of a shock is determined by the desired height AND length of the used spring. The lower you want to go the higher the rebound (in mm) has to be to ensure that the spring is preloaded by >50 kg or 10 mm in ANY circumstances. That's the point to start with. Fit the shock and spring together and screw the top hat on them and see if it's pretentioned enough. You don't know the actual ride height at this time, you only know your preferred ride height. So you have to mount them on the car, drop the weight of it on them and measure your ride height (always from center of the wheel to the fender) and decide what the lowerest height level will be you'll ever want to go. Don't go too low. Then do the calculation.

In my very first run, I've decided to install a rebound of 40 mm, which was a little bit too much for the Zanardi springs. Now, I'm at 20 mm on B6 which is exactly what B8 are. B8 is nothing more than the added rebound of 20 mm. As you might have to send the shocks several times to Bilstein for revalving you'll always have an opportunity to correct the rebound. The higher the spring rate - the lower the car - the more rebound is needed - the less negative suspension travel. Too low suspension travel is not a desireable thing to have. The wheel must be able to 'follow' a pothole or example.

One more hint: even the Zanardi springs (linear 6.5/5.0) need a rebound of 20 mm front and rear if you install them on the lower perch of a B6 because the springs are shorter. Even more stiffer springs need even more rebound. Now imagine the negative stroke of a combo like 12.0/10.0 TEINs with linear springs...insane.

Hope this helps. As it gets very technical it might be obvious that English is not my mother language.

B8 are available, but cost prohibitive for the project. Looks like I will struggle with B6 instead. I understand about limiting rebound- I think the trick is to make sure the compression and rebound strokes fall between 20% and 80% of the spring compression travel. You can limit compression travel with a bump stop.
Maybe makes sense to use helpers on both front and rear because of the huge droop travel of the B6 dampers. I was thinking of a 6" front spring and 8" rear spring. Looks like I really have to measure the assembled unit to figure all of this out!

As Gold said, first make sure the springs are snug. The distance between the center of the lower eye bolt and the top of the top hat is just one of the inputs to ride height. The spring rate differences play the other part.

Say you have a 400 lb/in spring on the Type R front shock and a 200 lb/in spring on the standard front shock. If you used them on the same car corner, then the coilover with the 400 lb/in spring will compress half as much as the coilover with the 200 lb/in spring. So, you'd take any difference between the uncompressed coilover length and then have to add in the compression factor due to spring rate differences.

The spring rate equation is F = k * x, where F is your load (for example, the corner load in pounds), k is the spring constant (for example, pounds per inch), and x is the resulting spring deflection (in inches if you use the units above). The equation holds for progressive springs, but since manufacturers don't include the variable spring constant and where in the deflection it applies, it's going to be hard to estimate the expected deflection. Constant spring rates are much easier to design around, you just need to be able to estimate your corner weights or front/rear balance.

You've heard about spring preload too, so any preload you apply to the spring you're just going to raise up that corner by the same amount (well, factoring in the suspension motion ratio of course).

I think using helper springs will help alleviate any ride height issues, as the helpers will keep the springs tensioned no matter where I set the height. I don't know though... maybe it's just easier to buy a used R suspension...

Just to add my 2 cents comment to this discussion.
For years I ran Bilstein shocks with Zanardi springs combined with 22 mm Dali bars.
The rear was on the highest setting and the front on a special groove between the high and low setting.
The car was well balanced front to rear but lacked the gokart feeling to allow me to "throw" the car into the tighter bends ( on track of course)
Following the recommendation of some Prime members, I upgraded the system to KW V3 clubsport's.
After spinning the car on a wet track, I decided to go back to the OEM ( 17mm ) rear bar.
Surprisingly enough the car didn't understeer that much and now the car can really be "bullied" in the slow turns and when the turbo goes in full boost the car will not go into oversteer unless the tire pressures go off scale.
From a timing perspective, I have gained 1.5 seconds per lap allthough I feel there is room for improvement if I played with the damping settings.
That is the issue by the way!
On a given track day, I would need some help to time my laps, change the settings and start all over again.
With the Bilstein/Zanardi combo the only issue is the driver.
BTW from a comfort perspective the Bilsteins felt harder than the Clubsports WHEN I had the 22 mm rear swaybar!
With the 17 mm bar it feels fine to me.
I've published videos elsewhere where you can see how the car compares to more modern track weapons...

At this point in my life, I'm just driving on the track for fun. I'm not chasing lap times anymore and I don't care if my car is faster or slower than other cars. If I cared about those things, I would be looking at MCS, Penske, Ohlins, JRZ, Moton etc. I just want the car to feel like a S Zero.

^^^ that’s was the point I tried to make above. You would get better performance and better comfort by using a better damper than the Bilstein street dampers. I don’t think you should be afraid of adjustability.

Yeah, I get it. I've driven a lot of those suspensions and while definitely better, honestly the best one I ever experienced was the NA2 R unit.

 

[Honcho]

Just a quick update. The debate can end, as I've picked up a Honda OEM NSX-R suspension. Special thanks to [MENTION=20915]RYU[/MENTION]!

 

[docjohn]

welcome to the club....a smooth road you will want....:biggrin:

 

[Honcho]

welcome to the club....a smooth road you will want....:biggrin:

Luckily we have good roads in Colorado, not the post-apocalyptic bombscape that is New York State. Funny how nice things can be when 90% of your funding doesn't get skimmed by Vinnie Boombatz Paving and Concrete first.

In any event, I've spent some quality time with the R suspension in a local friends car and I did not find it harsh. My Konis on the old NSX were way worse, even on the "soft" setting.

 

[docjohn]

like anything you get used to the elevated performance..I still remember my first drive in my car going from the koni/Z combo to the R and I was impressed with less understeer and overall faster corner speeds

 

[Mac Attack]

Luckily we have good roads in Colorado, not the post-apocalyptic bombscape that is New York State. Funny how nice things can be when 90% of your funding doesn't get skimmed by Vinnie Boombatz Paving and Concrete first.

Congrats! Are these pretty fresh dampers or are you going to have them rebuilt first?

I know what you mean about the DOT and their paving buddies. Out here they have tar and chip day where they just throw down a layer of tar and then crushed rock. Then they even bother painting markers on top of that crap. It's getting harder and harder to drive nice vehicles anymore.

 

[Honcho]

Congrats! Are these pretty fresh dampers or are you going to have them rebuilt first?

I know what you mean about the DOT and their paving buddies. Out here they have tar and chip day where they just throw down a layer of tar and then crushed rock. Then they even bother painting markers on top of that crap. It's getting harder and harder to drive nice vehicles anymore.

~45k miles- purchased new in 2005. So, they are probably pretty tired, but no leaks or anything like that. I'm debating about whether to put them on the car and just drive them until paint next year and then find a place to rebuild them. Or, I could send them out now. I was going to contact you about PSi and your note about better service during the winter months has me thinking maybe it is better to do them now. I'd have to check, but I think they might be willing to take on the job. At the end of the day, it's just o-rings, seals, oil and nitrogen. It's just a twin-tube shock, after all. Any "Honda magic" is in the valve and/or tuning, which is not changed during a rebuild. If anything, I bet PSi uses better shock oil than Showa did lol.