bilstein shock Low and high adjustment?

[NSXBill2]

Pic of correct perch positioning on lower groove

 

[VADER33]

Good info in this thread guys. Thanks. A couple of questions though.

1. Keeping my stock springs and running Bilsteins on the lower perch, how much of a drop would this result in?

2. Eibach Springs and Bilsteins on the top perch, how much of a drop?

I guess if I want to drop the car 1- 1 1/2, why do springs and shocks if just shocks do the trick.

Thanks again,
Ray

 

[Hugh]

This thread is a perfect example of why God invented the fully adjustable coilover. :biggrin:
And perhaps why Dali sells a "coilover" collar to effectively transorm the Bilsteins into coilovers.

 

[ETLMD]

Good info in this thread guys. Thanks. A couple of questions though.

1. Keeping my stock springs and running Bilsteins on the lower perch, how much of a drop would this result in?

2. Eibach Springs and Bilsteins on the top perch, how much of a drop?

I guess if I want to drop the car 1- 1 1/2, why do springs and shocks if just shocks do the trick.

Thanks again,
Ray

Bilsteins with OEM springs on the lower perch lowers the car about 7/8". Bilsteins with Eibach springs on the top perch will lower the car about 1.2". I have Bilsteins with OEM springs on the lower perch. I feel that it is about as low as I want to go for a street driven NSX with OEM 16"/17" wheels. Any lower and I will scrape too often.

 

[Hothonda]

Bilsteins with OEM springs on the lower perch lowers the car about 7/8". Bilsteins with Eibach springs on the top perch will lower the car about 1.2". I have Bilsteins with OEM springs on the lower perch. I feel that it is about as low as I want to go for a street driven NSX with OEM 16"/17" wheels. Any lower and I will scrape too often.

+ it still allows you to get the car aligned close to factory specs!

 

[VADER33]

Thank you very much. I am running stock wheels as well. I think a 7/8 inch drop is perfect. If I want it lower, I could always go with the Eibachs.

One more thing. How harsh did your ride become after installing the Bilsteins on stock springs? The OEM springs are not progressive are they?

Bilsteins with OEM springs on the lower perch lowers the car about 7/8". Bilsteins with Eibach springs on the top perch will lower the car about 1.2". I have Bilsteins with OEM springs on the lower perch. I feel that it is about as low as I want to go for a street driven NSX with OEM 16"/17" wheels. Any lower and I will scrape too often.

 

[Hothonda]

Thank you very much. I am running stock wheels as well. I think a 7/8 inch drop is perfect. If I want it lower, I could always go with the Eibachs.

One more thing. How harsh did your ride become after installing the Bilsteins on stock springs? The OEM springs are not progressive are they?

Ride stays near stock....car corners better w/lower center of gravity.

 

[VADER33]

Thanks again. I was just curious what the lower perch did to the stock spring as far as compressing it further.

Ride stays near stock....car corners better w/lower center of gravity.

 

[comtec]

Ride stays near stock....car corners better w/lower center of gravity.

Wow Steve, your GPW looks fantastic.

Are you using Bilsteins on the lower perch with OEM springs?

 

[Hothonda]

Wow Steve, your GPW looks fantastic.

Are you using Bilsteins on the lower perch with OEM springs?

Thanks & yes..... On past NSX's I've done Eibachs but it's difficult to get them aligned + traversing every little incline to keep from scraping and ruining front spoilers gets old fast ...the 7/8 to 1 " drop is perfect for me.

 

[Daedalus]

I was just curious what the lower perch did to the stock spring as far as compressing it further.

The springs are compressed the same, since the weight does not change. There's a bit less travel before bottoming out, but hopefully that's not ever a concern.

 

[LJSB]

Thanks again. I was just curious what the lower perch did to the stock spring as far as compressing it further.

The springs are compressed the same, since the weight does not change. There's a bit less travel before bottoming out, but hopefully that's not ever a concern.

When the area in which the spring resides, is lengthened or shortened, the spring's compression changes.
It depends on whether the spring in question is linear or progressive if this compression affects ride quality.

 

[Daedalus]

When the area in which the spring resides, is lengthened or shortened, the spring's compression changes.
It depends on whether the spring in question is linear or progressive if this compression affects ride quality.

Not sure what you mean by lengthening the area under the spring. Spring compression is defined by d = k*F, where d is the change in free length, k is the spring constant and F is the force applied. Even a progressive spring follows this relationship, except k increases as F increases, so d is a little harder to solve. Since we're comparing 2 cases where F doesn't change (low perch vs. high perch), k doesn't change, and neither does d. Suspension components will rotate up or down until the force on each spring equals the sprung weight (or dynamic inertia) of the car at that corner.

 

[ETLMD]

Thank you very much. I am running stock wheels as well. I think a 7/8 inch drop is perfect. If I want it lower, I could always go with the Eibachs.

One more thing. How harsh did your ride become after installing the Bilsteins on stock springs? The OEM springs are not progressive are they?

As Hothonda stated, the car rides very close to stock. It is slightly stiffer in ride quality, but no where near the stiff ride quality of coilovers. Cornering feels much more planted with less body roll.

 

[LJSB]

Not sure what you mean by lengthening the area under the spring.

Hmmm. Didn't mention anything about the area under the spring.

Maybe this photo will help.
This is a coil over shock out of the car so it's easy to see.
When the gold ring(the lower perch) that the red spring is sitting on is screwed up wards (raised) the spring compresses. See?

Adjustable coil overs, like the one above, have springs with a linear rate. A linear spring has one rate throughout its deflection.
Perch goes up, perch goes down, same spring rate.

Progressive rated springs, like the Eibach, when compressed, the spring rate is increased.

Here's a nice web page that for folks who aren't engineers to learn some basics about coil springs and racing.
http://www.afcoracing.com/tech_pages/spring.shtml

 

[LJSB]

The OEM springs are not progressive are they?

Nope, but Eibachs are.

 

[VADER33]

Thanks folks, this info has been very helpful. I appreciate your time and assistance. I will post pics and comments after I install my Bilsteins.
Ray

 

[NSXBill2]

My experience with installing Bilsteins this past summer on my 91 on the lower perch with OEM Springs, Sways and 16/17 OEM wheels and Yokos is that the ride became very stiff in comparison. It may be that the ride was very squishy before with the 16 year old original shocks.

 

[goldNSX]

My experience with installing Bilsteins this past summer on my 91 on the lower perch with OEM Springs, Sways and 16/17 OEM wheels and Yokos is that the ride became very stiff in comparison. It may be that the ride was very squishy before with the 16 year old original shocks.

Bilsteins stiff??? Really must have been your old shocks pampering you backbone.
Bilsteins are soft at low velocity of wheel movements and get stiffer at higher rates. There is no difference in ride comfort in high/low perch. Except that the lower perch will let the shock go block a little bit sooner.