Suspension upgrade
10-07-2011, 10:32 AM
#46
Racer
Thread Starter
Project update... After a few nights of reading and playing with different spring and tender options on a spread sheet, I ordered my parts last night.
Ended up getting 6"/700# front and 7"/900# rear Hypercoil springs. Seems that they are used by many racing teams...
Tenders are: http://www.vorshlag.com/product_info...roducts_id=253 80mm extended (3.15") and 1" compressed, 114#/inch Also got their 60mm sliders/joiners...
My calculations show that with the tender springs extended I should fit nicely in the measured dimensions between perches I took of my shocks. 9" front and 9.375" rear. Turns out Tarett monoball/adapter has same dimensions as original rear mount.
I decided to go shorter (benefit: less unsprung weight) instead of longer with springs as I have more threads available upwards from where the perches are currently located.
Counting threads from my picture (as shocks are at Bilstein right now), I show about 20 front and 19 rear upwards and about 9 downwards from where lower perches are located. Pitch is 1.5mm (got to love Google!)... so I have 30mm upward (1.18") and 13.5mm downwards (.53") available for adjustment.
Computed compressed lengths (spring+slider+tender) for fronts were short by about .5" vs OEM, so plenty of adjustment left and rears were almost spot on. I based it on 3200# total weight, 38/62... 608#/wheel in ft and 992#in rear
Spreadsheet calculations with springs & rates (800/1000) that v12man is using puts me within a couple of mm of his setup. So I think it will be OK.
Will let you know how it turns out once I get my shocks back...
To be continued...
Ended up getting 6"/700# front and 7"/900# rear Hypercoil springs. Seems that they are used by many racing teams...
Tenders are: http://www.vorshlag.com/product_info...roducts_id=253 80mm extended (3.15") and 1" compressed, 114#/inch Also got their 60mm sliders/joiners...
My calculations show that with the tender springs extended I should fit nicely in the measured dimensions between perches I took of my shocks. 9" front and 9.375" rear. Turns out Tarett monoball/adapter has same dimensions as original rear mount.
I decided to go shorter (benefit: less unsprung weight) instead of longer with springs as I have more threads available upwards from where the perches are currently located.
Counting threads from my picture (as shocks are at Bilstein right now), I show about 20 front and 19 rear upwards and about 9 downwards from where lower perches are located. Pitch is 1.5mm (got to love Google!)... so I have 30mm upward (1.18") and 13.5mm downwards (.53") available for adjustment.
Computed compressed lengths (spring+slider+tender) for fronts were short by about .5" vs OEM, so plenty of adjustment left and rears were almost spot on. I based it on 3200# total weight, 38/62... 608#/wheel in ft and 992#in rear
Spreadsheet calculations with springs & rates (800/1000) that v12man is using puts me within a couple of mm of his setup. So I think it will be OK.
Will let you know how it turns out once I get my shocks back...
To be continued...
10-07-2011, 12:10 PM
#47
Race Car
just my .02 I've riden in Chuck's car with the zero rate tenders and the way that car changes direction is like nothing I've ever felt before. VERY confidence inspiring because you never have to wait for the car to take an initial set.
IF I didn't drive mine on the street much that would be the route I'd go in an instant....but I drove mine to work the last couple days and I can appreciate the helper springs for giving a little cushion.
IF I didn't drive mine on the street much that would be the route I'd go in an instant....but I drove mine to work the last couple days and I can appreciate the helper springs for giving a little cushion.
10-25-2011, 05:45 PM
#49
Racer
Thread Starter
Finally got a call today from Bilstein. Shocks are done and shipping today... They had them since the 3rd! Good thing track season is over... Will be posting pics as the reassembly process takes place. Lou
10-25-2011, 07:21 PM
#52
Racer
Thread Starter
10-25-2011, 07:24 PM
#53
Racer
Thread Starter
10-26-2011, 03:43 AM
#55
Instructor
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I am also waiting for my replacement springs to leave germany - they are apparently sitting waiting with the airline for a flight (along with another 1200 pounds of stuff in the crate)
Hopefully soon - I want to make an event on the 5th
Hopefully soon - I want to make an event on the 5th
11-02-2011, 11:17 AM
#58
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My replacement shorter front springs arrived in country this morning - now they have to go in, ride heights and aligned and corner balanced basically tomorrow and friday, for an event on Saturday - cutting this a bit fine would be an understatement.
11-04-2011, 11:08 AM
#59
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Front springs are in, car is aligned, corner weighted and ride heights are now a bit lower than stock - 10mm or so.
And its now parked in my garage at home - ready for tomorrow - next update Monday.
And its now parked in my garage at home - ready for tomorrow - next update Monday.
11-05-2011, 09:28 PM
#60
Racer
Thread Starter
Finally!
Well spent all day putting everything back together. A few observations...
I wanted to lower the car about 1/4". I had computed the final front height using the spring rate and estimated front axle weight. It worked out perfectly.
In the rear, I had estimated that the car was going to be too low based on spring rate and rear axle weight. I had raised the spring 10mm (6.5 turns). We'll that made the rear too high. I lowered the spring to its original height, but it was still too high. Ended up lowering perches another 6.5 tuns. This gave me the 1/4" drop from my original rear height.
Install went well... Just took my time. Only snag I ran into, was a heat protection plate that is located between the front rotor and ball joint & tie rod end. I accidentally bent them while laying the struts on the ground. I spent about 1/2 hr per side making sure the rotor did not rub plate while still clearing tie rods.
Also too the opportunity to update my sway bar links with Tarett ones. Just need to have corner weights checked and realigned. BTW, I did not drive it today. Hopefully tomorrow.
Including some pictures showing rear/front suspensions compressed (with just enough weight to lift car off jacks) and uncompressed at full droop. Also including pictures of the new drop links. Front ones replace pinch bolt holding strut to hub.
I'm happy with the way all the pieces went together. It is always a concern when mixing and matching parts from different vendors and hopefully I will get similar results as others have posted after doing the upgrade.
Feel free to ask any questions... Lou
I wanted to lower the car about 1/4". I had computed the final front height using the spring rate and estimated front axle weight. It worked out perfectly.
In the rear, I had estimated that the car was going to be too low based on spring rate and rear axle weight. I had raised the spring 10mm (6.5 turns). We'll that made the rear too high. I lowered the spring to its original height, but it was still too high. Ended up lowering perches another 6.5 tuns. This gave me the 1/4" drop from my original rear height.
Install went well... Just took my time. Only snag I ran into, was a heat protection plate that is located between the front rotor and ball joint & tie rod end. I accidentally bent them while laying the struts on the ground. I spent about 1/2 hr per side making sure the rotor did not rub plate while still clearing tie rods.
Also too the opportunity to update my sway bar links with Tarett ones. Just need to have corner weights checked and realigned. BTW, I did not drive it today. Hopefully tomorrow.
Including some pictures showing rear/front suspensions compressed (with just enough weight to lift car off jacks) and uncompressed at full droop. Also including pictures of the new drop links. Front ones replace pinch bolt holding strut to hub.
I'm happy with the way all the pieces went together. It is always a concern when mixing and matching parts from different vendors and hopefully I will get similar results as others have posted after doing the upgrade.
Feel free to ask any questions... Lou