My Theoretical Suspension Setup

Canada Nissan Automotive
1

This is what I’ve been thinking about for suspension. I don’t know what stock settings are for some of these or how they will affect handling. So please chime in with some suggestions or if you know how they will affect handling!

Front:

Camber - -1
Caster - 4-4.5
Toe - -2

Rear:

Camber - -1.5-2
Caster -STOCK
Toe - STOCK

Reasoning:
Well, What I basically want is a stiff rear end, however basically stock. I want my handling to be mostly in the front, aiding driving feel and response.

Stock Caster on the front is about 6-6.5 and at 4.5 or so I would be experiencing slightly easier effort on turn-in and quicker response.

The negative camber on the front and rear I’m adjusting mostly for the drop correction, and grip. It’s not extreme so tire-wear is limited, but it’s enough to grip very efficiently on turn-in.

The Toe I’m not too sure about adjusting in the rear, because I want less drag in the rear end. I want it to more or less ‘follow’ the front.

In terms of sway bars. The front sway bar preload will be adjusted to the ‘hard’ setting on the 3 way adjustable endlinks, while the rear will be placed at the middle preload adjuster. This will hopefully generate a rock solid front end.

The spring rates I am running are SUPPOSED to be setup with the swaybars technically, but I have no specs on either. I believe the sways Im getting are 27mm front and 22mm rear. So hopefully an 8/6 spring rate is what I have on the coils (not sure) and that should match up well with the sways.

Aluminum subframe bushings finish off the rear end (might not be until next season that I press those into my new subframes) to eliminate slop and increase throttle response.

Since I REALLY don’t want to touch my lower control arms. I am not dropping the car past 2". Adjusting the roll center along with the rest of the multi-link is a task WAY beyond my (or anyone in the area’s) ability. Maybe one day I will get LCA’s and figure out howto adjust the roll center… that would be spectacular. Fine-tune the center of gravity :slight_smile:

Anyways, thats the end of my long winded write up. Enjoy and post up your thoughts :slight_smile:

2

Front toe seems like a lot… but then I normally use /16th of inch for measurement, not degree.

I agree with Pete, get more camber up front. I had 1.8 degree on both front for the Z and that was still not enough. Too much sidewall flex from tires under load. 2.5-3 seems optimal.

You’ll need more positive caster. Most people run max on their car. Better turn in, but not sure how that affects manual rack though.

You’d want a bit of toe in as well for the rear for stability considering it’s FR. Toeing out will make car kick out like no other.

Edit: Pulled this off another forum:

this should help anyone who want to setup there suspension not only for drifting but for autocross, road racing, etc…
Front spring rate increase:
More under steer; increase in proportional weight transfer to the front when rear wheel rate is not increased; reduces front traction when rear rate is not changed.
Usable adjustment: 150-600 lbs/in
Symptoms of too much adjustment: terminal under steer; front of car hops in corners; excessive wheel spin on inside front tire on FF cars.

Front spring rate decrease:
Less under steer; decreases proportional weight transfer to the front when rear wheel rate is not increased; increases front traction when rear rate is not changed.
Usable adjustment: 150-600 lbs/in
Symptoms of to much adjustment: Too much over steer; over steer then under steer if spring is so soft that the car bottoms out on lean, car bottoms out excessively with a jolting ride.

Rear spring rate increase:
More over steer; increase in proportional weight transfer to the rear when front wheel rate is not increased; increases rear traction when front rate is not changed.
Usable range: 100-600 lbs/in
Symptoms of too much adjustment: too much over steer; sidestep hop in corners; twitchy; pretty scary.

Rear spring rate decrease:
Less over steer: decreases proportional weight transfer to the rear when front wheel rate is not changed; increases rear traction when front rate is not changed
Usable range: 100-600 lbs/in
Symptoms of too much adjustment: car under steers; if way to soft car under steers then over steers as car bottoms out on lean; car bottoms out excessively with a jolting ride.

Front anti-roll bar stiffer: more under steer
Usable range: none to 1.25 inches in diameter
Symptoms of to much adjustment: terminal under steer; lifts inside front tire off the ground witch can cause massive wheel spin on FF cars; also not good for most effective tire usage as inside tire is now doing nothing.

Front anti-roll bar softer: less under steer
Usable range: none to 1.25 inches in diameter
Symptoms of to much adjustment: overstate scary; more like fun

Rear anti-roll bar stiffer: more over steer
Usable range: none to 1 inch in diameter
Symptoms of too much adjustment: Big-time over steer. Can cause inside rear tire to lift off the ground.

Rear anti-roll bar softer: less over steer
Usable range: none to 1 inch in diameter
Symptoms of to much adjustment: under steer; slow and boring

Front tire pressure higher: less under steer by reducing slip angels on most tires
Usable adjustment: up to 55psi hot
Symptoms of too much adjustment: no traction- tire crowned so more under steer; adds wheel spin in FF cars; jarring ride; center of tire wears out

Front tire pressure lower: more under steer by increasing slip angles on most tires
Usable adjustment: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up.

Rear tire pressure higher: less over steer by reducing slip angles on most tires
Usable range: up to 45psi hot
Symptoms of too much adjustment: no traction—tire is crowned so more over steer; bad wheel spin on FR cars; jarring ride; center of tire wears out.

Rear tire pressure lower: more over steer by incresing slip angles on most tires.
Usable range: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up

More negative camber front: less under steer because of better lateral traction as tread is flatter on the ground under side load.
Usable range: up to 3.5 degrees negative
Symptoms of too much adjustment: poor braking; car is road crown sensitive; twitchy; front tires wear on inside edge

More negative camber rear: less over steer because of better lateral traction as tread is flatter on the ground under side load. More rear grip
Usable range: up to 2.5 degrees negative
Symptoms of too much adjustment: more over steer; car feels twitchy in back; tires wear out on inside edge; less breakaway warning when limit is exceeded.

Ride height to low (typical beginner mistake): car is twitchy with unpredictable dynamics. Bump steer make you life miserable.
Usable range: usually 1.5-2.0 inches lower then stock unless car has been modified to go lower.
Symptoms of too much adjustment: everything that could possibly go wrong: sudden over/under steer; twitchy due to bump steer; very harsh ride; premature tire wear.

Toe in – front: car is stable going straight. Turn in is average
Usable range: 0-1/8th inch
Symptoms of too much adjustment: car has slow twitchiness under braking; feels odd; kills outside edge of tires

Toe out – front: Car turns in well; works pretty well on FF car as they tend to toe-in under load.
Usable range: 0-1/4 inch
Symptoms of too much adjustment: Car is really twitchy under braking; car wanders on straight road; kills inside edge of tire

Toe in – rear: car is less likely to over steer when the throttle is lifted
Usable range: 0-1/8th inch
Symptoms of too much adjustment: weird, slow, rocking movement in back; feels slow but still unstable; wears outside edge of tires.

Toe out – rear: Helps car rotate useful in low speed and slalom courses; very common on FF pro rally cars.
Usable range: 0-1/8th inch
Symptoms of too much adjustment: not to good for street driving; causes lift throttle over steer; makes violent side to side rocking motions in the rear; tie wears on inside more.

Positive front caster: helps stability; suspension will get more negative camber when turning; reducing positive caster reduces steering effort. (Negative caster is not usable)
Usable range: 4-9 degrees positive
Symptoms of too much adjustment: can increase under steer especially in cars with wide low-profile tires. Can increase steering effort.

Single adjustable shock stiffer: Better turn in; better transient response; causes slower onset of over/under steer by slowing weight transfer depending on what end of the car is adjusted.
Symptoms of too much adjustment: suspension becomes unresponsive; ride gets harsh; car skips over bumps, loosing traction; Causes a big delay in weight transfer resulting in strange handling like under steer then late corner stage over steer.

Single adjustable shock softer: slower transient response; quicker onset of over/under steer
Symptoms of too much adjustment: car oscillates due to under dampened spring motion, like a boat. Car gets twitchy in turns. Feels unstable.

3

Thanks guys! David thats for finding that, that’s gold. Is it meant for FR layout?

I was thinking of running more Toe in the rear actually this morning after re-reading this. More negative camber in the front will not be good for me, it will decrease steering ease ESPECIALLY with the manual rack. Same reason for the more evened out Caster spec. Basically just making the car grip better and easier to steer in the front.

David, btw this car isn’t being setup for drift. It’s being setup for grip. But any and all input is appreciated and welcome.

THANKS!

4

Read the first line “this should help anyone who want to setup there suspension not only for drifting but for autocross, road racing, etc…”

This is only a guide to help you decide what will create good response, good grip or just slide the **** out of everywhere.

5

I AM decreasing the caster on the front. That was one of my first points. Stock is around 6.5 I’m going for 4-4.5.

The front camber you may have a point about. I was thinking more of tire-wear than I was about lateral grip. I may revise that to run somewhere in the -2 range.

Sorry David, I went straight for the meat of the article! Thanks for the great input David!

Thanks so far guys, I’m just starting to get into the nitty gritty of this stuff and I could always use some corrections and/or advice.

6

I was doing some reading today and caster can also affect your compression camber levels, aswell as bump steer, and steering rack return (PS).

So I’m gonna put some more thought and try and figure out some calculations for the front Caster.

Suspension noobs this thread will be an EXCELLENT resource!