Zanardi springs/Revalved Bilsteins Install

[goldNSX]

I was not very happy with my Eibach/Bilstein combo as it gave me very little steering-feedback and the whole car seemed to lean very strong in every corner. But it was perfectly low and very, very comfortable, two good things. It was also very predictable while driving hard. The most important thing.

I always favored the Zanardi setup but the height was not perfect IMO. My garage told me about revalving Bilsteins as they have racing experience and direkt contact to Bilstein Germany and that they were able to cut additional grooves. Ok, that's the way to go: Zanardi springs due to the spring-rate and Honda OEM and revalving Bilsteins to match the Zanardi spring-rate and modify the height.

I finally found a supplier (very much thanks goes to Chris/SOS ) for the Zanardi springs as Honda Europe was not willing to get these parts for us. Ok, there are always other suppliers worldwide.

The first step was to get some new Bilsteins to cut down the waiting time (as my first set was already on the car) and let them measure:
http://www.nsxprime.com/forums/showthread.php?t=62711
As expected the Bilstein are soft at the low end and hard at the top end, the front ones would definitly not match the Zanardi springs, maybe the rear would do.

 

[goldNSX]

So we got the Bilsteins revalved back. As the springs arrived we found out that the shocks need to be shortened due to the short springs and our desire to get her lower that stock. We sent them out and got the shocks back with the additional perches cut 0.4 inch below the lowerest on the standard Bilsteins. The top one is for stock height, 0.875 inch lower is the option to lower her. And the two other below them are ours.

First there's my car with a fresh coat of carnauba wax and Eibach/Bilstein at the upper perch, tire size is 215/40/17 and 265/35/18, very important on the appearance of lowering.

 

[goldNSX]

New shocks and springs ready for install.
Thrid pic is on the right side the OEM Bilstein and on the left side our shortened one. Shortening was -35 mm in the front and -45 mm in the rear, see forth pic. The second pic reveals why we need to shorten the shocks.

 

[goldNSX]

The goal was to reach the same ride height as with the Bilsteins. But I didn't know which perch to use. I suggested that the front will be on the lowest perch (-40 mm) and the rear -30 mm.
The rear was perfect! 2nd pic.
But the front? Have a look at the first and the third pic. The front was actually so low that the chassis still sat on the lift while the lift was already fully lowered. Actually I wasn't even able to drive from the lift. The car would have gone even a little bit lower So we had to correct.
I was doing the install myself and my mechanic who was there too told me that -10 mm on the shock mean about -15 mm ride height due to geometric reasons. I wasn't aware of that first but this was very simple too understand.
This was done in pic no. 5 with the front on -30 mm or one perch up. It was nearly perfect but it was about 5 mm lower than Eibach and we had to take into account that after a short drive it will be lower by some mm so this would have been too low and to correct it again.

 

[goldNSX]

So we went up to the lower Bilstein perch, means we didn't needed to cut perches at all but we didn't know that in the beginning. Try and Error. We did the install on the Zanardis only on the left side first to find out the height and let the right side with Eibach.

Some pics of them installed.

 

[goldNSX]

3rd pic: doublecheck if the stabilizer link if equaly distributed between both sides. The Bilstein would nearly rub to the tire if I would go with -40 mm despite my wheel size of 9.5/18/ET 38 mm.

 

[goldNSX]

SH*T! It has been a long time ago when I used to do some repairs and going to fitness. While the install of the Type-R swaybar I used a little bit too much muscle power and peng the screw was gone to nowhere. If I would have done this at my home I would have been shot but my mechanic helped me out. After an hour and due to his perfect job it was good again.

 

[goldNSX]

After some hours I couldn't wait for the final result. The car with Zanardis/Bilstein is now about the same height as with the Eibachs. Front is about 5 mm higher, the rear about 3 mm lower than before.

 

[goldNSX]

Well, my first impression of driving about 2 miles was that it IS very comfortable, not harsh at all. I expected much harsher ride in the front as the spring rate is more than twice of an OEM spring. It is now more eager in turn-ins. I was first almost shocked that the ride was so soft that I was also concerned about jumping and bumping of the chassis over bumps of different frequencies and altitude. None of it. I must say that Bilstein Germany did a really good job in revalving them. Of course I couldn't do a flying lap yet because I have to get used to her new driving behaviour first. The steering is very much more responsive, but ok it's not a S2000, I must admit. I expect a litte understeering due to the Type-R swaybar but we'll see.
For my taste the shocks could be a little bit stiffer to give even more initial corner grip but again this is only a matter of preferences. The greatest thing of all is that you just let Bilstein know what is important to you and they revalve them this way. Pretty cool. But again Bilstein did a really good job in revalving them as I asked them to save some comfort and that I didn't track my car. Really perfect!

Update on the shortening of the shocks: We did shorten them a little bit too much just to be on the safe side. I would now shorten the fronts by -20 mm instead of -35 and the rear by -30 or -35 mm instead of -45 mm to keep the spring in place if the car is lifted.

Well that was my last project on my NSX. But you'll never know. A BIG thank you to all who supported me in this project with parts, advices, pictures etc. Special thanks goes to Rikli Motorsport for the install and special input, SOS for the parts and Bilstein for the revalving.

Feel free to ask any questions if you like to do something similar.

 

[Hrant]

Looks good and congrats. Give us update of the driving/handling.

Regarding picture 3 in post #6, keep an eye on how close the link is to the Bilstein. The sway bars have a tendency to move and if you don't have solid collars to stop them (like the ones made by Al Terpak and now Dali has made some as well), they will eventually touch/hit the bilstein on heavy g loads.

Don't have a handy pic to show you, but here is a proof re how far the sway bar may move :biggrin:

http://www.nsxprime.com/forums/showpost.php?p=340001&postcount=4

 

[goldNSX]

Thanks for the input on the swaybar's moving. I had this problem with my former Bilsteins that the swaybar rubbed against the Bilstein. After resetting it was fine. I'll keep an eye on it.

 

[goldNSX]

... that -10 mm on the shock mean about -15 mm ride height due to geometric reasons.

I came to the conclusion that the -0.875 Bilstein perch actually lowers the car by about -1.3 due to the same reason, an observation I made on cars with only the Bilstein perch option.

 

[nsxhk]

I'm dying to know how it handles!! :wink:

Henry.

 

[goldNSX]

I'm dying to know how it handles!! :wink:
Henry.

I did a longer drive today and have a little bit more to tell you about the handling.
I'm very happy with the Zanardi/Bilstein combo as they are still very streetable and comfortable, not very far from OEM setup. Due to the harder springs and the Type-R swaybar the front turns in very quickly, there is definitly more grip due to horizontal vehicle stability which reduces camber changes. That's fine so far.
But in hard corners the car is not what I like it to be. I have too much understeering, esp. while accerlerating out of a corner very hard. The only way to reduce this is lifting the throttle. Not a nice/fast way. If there is a bump in the corner I definitly feel the front tires act NOT indepentently from each other, meaning I think the Type-R swaybar is too stiff for this setup. As I recall the Type-S/Zanardi setup has a stiffer swaybar in the rear. Adding a swaybar to the front would have been the wrong way at all. I'm think I have to go back to the OEM swaybar in the front and see how she behaves then. Maybe add the Type-S swaybar in the rear. But before this I have some alignment changes which improve the traction in the front.

To sum up: The car is much better with the Zanardi/Bilstein (revalved) than with Eibach/Bilstein. The ride is equal to the OEM setup but you get much more feedback on the steering wheel. The grip through corners is better. But it never beats a S2000.

 

[goldNSX]

I've recognized another problem: The rear Bilstein perch is too low as it scrubs against the OEM 17' wheel. I have to lift her by 5 mm.
I also found out that I need a new steering racket. My mechanic wants to try to lubricate it with grease.
I will go back to the OEM swaybar in the front as the understeering is not of my tastes. I sacrifice some of the steering response to neutralise the setup.

 

[Scin]

I did a Tein S-Tech Bilstein setup and I am very happy with it. I am guessing the lack of confidence you were feeling in your previous setup was due to the progressive spring rates in the Eibachi springs you had previously. While the handling with this setup was probably good it is somewhat of a confidence killer to quickly go through the lower portion of your Eibachi's progressive spring rates.

I also like the feel of a linear spring, and Tein S-Tech, Tanabe, and Zanardi would all be reasonable linear springs to use on the street.

 

[goldNSX]

After about 1k miles I decided that the swaybar has to go definitly. Turn-in is very crisp but the understeering is unbearable and dangerous too.

 

[Hrant]

It's great to read first hand the variables involved in tuning the suspension with such mods. I may be wrong but I believe your understeer is more due to the Type R bar than anything else. Remember that the Type R was used with the NSX-R suspension which is stiffer than the Zanaradi. It's a balancing act that may vary from track to track.

And if you go with R compound tires, you will start the tweaking all over again. I have had only one track event since I went with RA1 Witt the Type R bars and it was at Infineon - a technical track. I had to make adjustments immediately after the first session as my [edit] front bite from the Type R was still there but the rears started to act up now [edit]; so loosened the rear sway bar by one hole. I am looking forward to THill - a higher speed track - to see if I need to get to track specific adjustments ..........

 

[1BADNSX]

I had to make adjustments immediately after the first session as my understeer got worse so loosened the rear sway bar by one hole.

Hrant, you may have said it backwards, but shouldn’t you be stiffening the rear bar if you had understeer?

Bob

 

[Hrant]

You are correct. I had a bit of unstable rear with going to R compound using the same set up; acting a bit loose and weird on the rears, so I adjusted it to the middle hole, down from the stiffest position. I still have not done tinkering since (a) with 205/40/17 on the front and 255.40/17 RA1, I was expecting more understeer; and (b) still working on the optimal tire pressure - which may vary from track to track. The symptom could have been also due to the fact they were freshly mounted with no heat cycle and the first session they ran real hot - the shop said the RA1's don't need heat cycling especially if they were not shaved.

Good catch though :wink:

 

[RYU]

This is quite a good and useful thread. goldNSX, would you mind relinking the pictures please?

 

[goldNSX]

One of my old threads. We've all been young once. I'm sorry but I don't know which pics I did post on this one.

 

[ChadAtlanta]

I'm glad this thread was somewhat resurrected! I would love to find an identical suspension to yours- though I wouldn't know where to begin searching for a shop to revalve the bilsteins. I wish a vendor would sell this setup!

 

[eddie_82]

I'm glad this thread was somewhat resurrected! I would love to find an identical suspension to yours- though I wouldn't know where to begin searching for a shop to revalve the bilsteins. I wish a vendor would sell this setup!

You could try contacting Shaikh at FatCat Motorsports. He's a Bilstein guru and has done custom valving for a number of different cars, largely geared to solo2 and track setups.

http://fatcatmotorsports.com/contact.htm

 

[goldNSX]

I'm glad this thread was somewhat resurrected! I would love to find an identical suspension to yours- though I wouldn't know where to begin searching for a shop to revalve the bilsteins. I wish a vendor would sell this setup!

Bilstein USA does this kind of job.