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Help! What suspension modifications should I do?


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#1 JMortensen

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Posted 14 September 2006 - 11:29 AM

This is one of the most commonly asked questions asked here and it is also a tough one to answer, due largely to the varied usage of our cars. From the factory the only adjustable alignment angle available is the front toe. One of the main features of a high performance suspension is the ability to adjust the suspension angles, so as the stages progress the adjustablity increases.

IF YOU INTEND TO RACE YOUR CAR, GET THE APPROPRIATE RULEBOOK BEFORE YOU START ANY MODIFICATIONS TO MAKE SURE YOU REMAIN LEGAL!!!

REFURBISHING A STOCK Z CAR

If the car is a street driver and the intent is to have a cushy ride, it may be that a simple refurbish of the stock suspension is all that is necessary. A typical rebuild of the stock suspension will include:
1. New outer tie rod ends
2. New ball joints
3. New rubber bushings and steering coupler
4. Repack/retighten front wheel bearings
5. Replace rear wheel bearings if needed
6. New shocks (KYB GR2, Monroe, etc)
7. New springs OEM replacements and slightly stiffer Euro springs are available from www.courtesynissan.com

These few things will restore the ride to close to factory stock.

MODIFYING A Z CAR FOR BETTER HANDLING

If the goal is to stiffen up the car for better handling, then a lot more can be done. I'm going to attempt to show "Stages" of modifications. These are loose guidelines and parts can be mixed and matched, but these are what I feel are typical mods on the Z's that I've come in contact with over the years.

STAGE 1 replaces all old parts with stiffer components. This will give you a firmer sporty ride.
1. New outer tie rod ends
2. New ball joints
3. Polyurethane bushings
4. Repack/tighten front wheel bearings
5. Replace rear wheel bearings if needed
6. Aftermarket front and rear swaybars
7. Lowering springs (Eibach, Suspension Techniques, Tokico, MSA, AZC)
8. Aftermarket shocks (Tokico HP, Tokico Illumina, Koni Red)
9. Bumpsteer spacers

STAGE 2 is similar to Stage 1 but starts to allow adjustment of alignment angles.
1. New outer tie rod ends
2. New ball joints
3. Polyurethane bushings and Gmachine control arm bushings and TC rod kit (these allow camber adjustment front and rear and also toe adjustment in rear)
4. Repack/tighten front wheel bearings
5. Replace rear wheel bearings if needed
6. Aftermarket front and rear swaybars
7. Lowering springs (Eibach, Suspension Techniques, Tokico, MSA, AZC)
8. Aftermarket shocks (Tokico HP, Tokico Illumina, Koni Red)
9. Bumpsteer spacers

STAGE 3 takes adjustability a step further.
1. New outer tie rod ends
2. New ball joints
3. Polyurethane bushings and Gmachine control arm bushings and TC rod kit (these allow camber adjustment front and rear and also toe adjustment in rear)
4. Repack/tighten front wheel bearings
5. Replace rear wheel bearings if needed
6. Aftermarket front and rear swaybars
7. Coilover spring conversion to 2.5" springs. Street springs generally under ~250 in/lbs.
8. Aftermarket shocks (Tokico HP, Tokico Illumina, Koni Red)
9. Bumpsteer spacers
10. Biscuit style bolt in camber/caster plates (EMI, DP racing)
11. Strut tower bars front and back, preferrably triangulated to the firewall in front

STAGE 4
1. New outer tie rod ends
2. New ball joints
3. Adjustable control arms (Modern Motorsports, AZC, Z Select)
4. Repack/tighten front wheel bearings
5. Replace rear wheel bearings if needed
6. Aftermarket front and rear swaybars
7. Coilover spring conversion to 2.5" springs. Street springs generally under ~250 in/lbs.
8. Aftermarket shocks (Tokico HP, Tokico Illumina, Koni Red), might be thinking about sectioning strut housings and getting appropriate shorter shocks to fit at this stage
9. Bumpsteer spacers
10. Biscuit style bolt in camber/caster plates (EMI, DP racing)
11. Adjustable TC rods (TTT, AZC, Z Select)
12. Strut tower bars front and back, preferrably triangulated to the firewall in front
13. Roll bar

STAGE 5 - at this point you're pretty much race only
1. New outer tie rod ends
2. New ball joints
3. Adjustable control arms (Modern Motorsports, AZC, Z Select)
4. Repack/tighten front wheel bearings
5. Replace rear wheel bearings if needed
6. Aftermarket front and rear swaybars
7. Coilover spring conversion to 2.5" springs. Springs generally over ~250 in/lbs.
8. Aftermarket shocks in sectioned strut housings(Koni 8610-1437RACE single adjustable, Koni 8611-1259 double adjustable, Ground Control Advance Design, Bilstein Sport VW non adjustable P30-0032)
9. Bumpsteer spacers
10. Cut to fit camber plates (DP racing, Carrera, Ground Control, AZC, TTT)
11. Adjustable TC rods (TTT, AZC, Z Select)
12. Strut tower bars front and back, preferrably triangulated to the firewall in front
13. Roll cage with tie ins to front strut towers

Above and beyond Stage 5 you get into modifying the chassis itself to allow for modification of the suspension pickup points. There are also people who have adapted suspensions from entirely different cars into the Z chassis. We've had members install 240SX IRS, Corvette C4 rear suspensions. Also for drag racing there have been quite a few "backhalves" where the entire rear section of the frame is cut off and a new frame built in the rear to allow installation of a solid rear end. Popular choices seem to be Ford 8.8 and 9 inch and Chevy 12 bolt rears.

Front suspension swaps aren't as popular as of yet, but many GT2 Z racers have fabricated their own SLA (short and long arm) front suspensions.

Modifying your suspension is potentially dangerous and you do so at your own risk.

Jon Mortensen, owner/operator www.petdoorstore.com


#2 MatMan

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Posted 14 September 2006 - 11:42 AM

Great info, Jon!

Where are you at now, Stage 8.5?
MatMan
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#3 johnc

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Posted 14 September 2006 - 11:42 AM

Made a couple edits: Koni part numbers and changed "strut" references to "shock."
----- John Coffey, Fabricator at Benton Performance, LLC

#4 tube80z

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Posted 14 September 2006 - 11:56 AM

should caster plates read camber plates?
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#5 JMortensen

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Posted 14 September 2006 - 12:01 PM

Not if you install them with the slot front to back!!! ;-)

Thanks for catching that Cary, I changed it.

Jon Mortensen, owner/operator www.petdoorstore.com


#6 srgunz

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Posted 01 October 2006 - 07:20 PM

Jon. One thing I did not see mention of was quick steering knuckles. I have those installed with lowered springs. I think they are adding to my bump steer problem. I do not have any strut bump steer spacers installed. I am thinking I will go back to the stock knuckles and bump steer might be better. What do you think?
Steve
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L28. Mikuni's. 5speed. MSD. Koni's

#7 JMortensen

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Posted 01 October 2006 - 08:09 PM

I don't think the quick steer knuckles would have any effect on bumpsteer. Ackerman yes, bumpsteer no. Have you checked out the bumpsteer FAQ? It might help you out: http://forums.hybrid...ad.php?t=103886

Jon Mortensen, owner/operator www.petdoorstore.com


#8 endurorider

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Posted 13 February 2007 - 05:18 PM

Arizonazcar.com has some nice stuff too. think i am going to get the wilwood brakes from him.
Fred
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#9 stony

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Posted 23 February 2007 - 01:08 PM

STAGE 5 - at this point you're pretty much race only
1. New outer tie rod ends
2. New ball joints
3. Adjustable control arms (Modern Motorsports, AZC, Z Select)
4. Repack/tighten front wheel bearings
5. Replace rear wheel bearings if needed
6. Aftermarket front and rear swaybars
7. Coilover spring conversion to 2.5" springs. Springs generally over ~250 in/lbs.
8. Aftermarket shocks in sectioned strut housings(Koni 8610-1437RACE single adjustable, Koni 8611-1259 double adjustable, Ground Control Advance Design, Bilstein Sport VW non adjustable P30-0032)
9. Bumpsteer spacers
10. Cut to fit camber plates (DP racing, Carrera, Ground Control, AZC, TTT)
11. Adjustable TC rods (TTT, AZC, Z Select)
12. Strut tower bars front and back, preferrably triangulated to the firewall in front
13. Roll cage with tie ins to front strut towers




John are the front struts you mentinoned above actually shorter then the stock front strut length? I need a strut that is about 3 inches shorter then what the stock fronts are.

5.3 truck motor, BTR stage 2 cam, BWs480, custom intercooler, AEM Infinity, 2 speed powerglide, Fully built Ford 8.8, 4:56 gears/spool, 4 link suspension.


#10 JMortensen

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Posted 23 February 2007 - 01:21 PM

I am not aware of any commonly available strut insert that is shorter than about 1.625" or so than the stock 240Z. They may be out there, but I'm not aware of any.

Jon Mortensen, owner/operator www.petdoorstore.com


#11 stony

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Posted 23 February 2007 - 04:37 PM

OK an 1.625 shorter may work. Is that the Vw insert listed above?

5.3 truck motor, BTR stage 2 cam, BWs480, custom intercooler, AEM Infinity, 2 speed powerglide, Fully built Ford 8.8, 4:56 gears/spool, 4 link suspension.


#12 JMortensen

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Posted 23 February 2007 - 04:52 PM

The Illumina BZ3099 is the MR2 insert and is the right size, I think the VW insert is the same length.

Jon Mortensen, owner/operator www.petdoorstore.com


#13 stony

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Posted 23 February 2007 - 04:59 PM

The Illumina BZ3099 is the MR2 insert and is the right size, I think the VW insert is the same length.


So the MR2 strut is shorter by 1.625 as stated above?

5.3 truck motor, BTR stage 2 cam, BWs480, custom intercooler, AEM Infinity, 2 speed powerglide, Fully built Ford 8.8, 4:56 gears/spool, 4 link suspension.


#14 JMortensen

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Posted 23 February 2007 - 05:10 PM

It's been a while since I sectioned mine, but that should be correct.

Jon Mortensen, owner/operator www.petdoorstore.com


#15 stony

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Posted 20 March 2007 - 09:16 PM

Well i finally got my vw struts. the body is 12.5 inches long and the strut total length is 19 inches or so.. This is perfect and will lower the car ALOT and gain some suspension travel.

They are larger in diameter then the konis i had which means they dont slip up into the the strut tube nut like the konis did. Is this bad? do i need to get a different upper strut gland nut? if so anyone have a part number or ideas?

5.3 truck motor, BTR stage 2 cam, BWs480, custom intercooler, AEM Infinity, 2 speed powerglide, Fully built Ford 8.8, 4:56 gears/spool, 4 link suspension.


#16 johnc

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Posted 21 March 2007 - 07:10 AM

Call Truechoice, push 2 for the Koni shop, ask for Craig, give him your shock part number, and he'll tell you what gland nut you need and that its on backorder back in Holland.
----- John Coffey, Fabricator at Benton Performance, LLC

#17 stony

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Posted 21 March 2007 - 07:55 AM

So i guess i will just get my current gland nut machined to fit:mrgreen:

Thanks for the info john as always..... helpful

5.3 truck motor, BTR stage 2 cam, BWs480, custom intercooler, AEM Infinity, 2 speed powerglide, Fully built Ford 8.8, 4:56 gears/spool, 4 link suspension.


#18 stony

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Posted 21 March 2007 - 08:38 PM

OBTW here are the struts I got fro my MOCC up. They were Cofap OEM Scirocco strut insert
Part number 30017
Fully extended 20 inches
Body length 12.5

The konis that I had installed were 21.5 fully extended and the body was 15 inches.

If I figured it right I will be able to section the struts 2.5 inches and this will put me right where I want to be as far as ride height

5.3 truck motor, BTR stage 2 cam, BWs480, custom intercooler, AEM Infinity, 2 speed powerglide, Fully built Ford 8.8, 4:56 gears/spool, 4 link suspension.


#19 Guest_d260z-turbo_*

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Posted 03 March 2008 - 09:01 PM

well i really like to be at stage 4 or stage 5 no more no less that is it for now. so i just like to get a really good coil over set up for it
so can you guys let me know what a good coil over set up that i can go with

#20 G.I.jonas

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Posted 03 March 2008 - 09:43 PM

well i really like to be at stage 4 or stage 5 no more no less that is it for now. so i just like to get a really good coil over set up for it
so can you guys let me know what a good coil over set up that i can go with


Ummm? dude? i read in another thread you posted in that your datsun is RB'ed with awd.Now i cant help but wonder how you accomplished this and still have an s30 based suspension to work with for upgrading.Do you have any pics of this alleged setup?
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