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Suspension Options and Setup for B Series Ts


Erko

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Mods - please sticky and I'll pull some stuff together from my previous threads and get input from other members with regards to what is available (in detail), approx pricing and some other info. This can act as a repository for info on ride height, different shocks, sway bar info, over/understeer, grip, wheel alignment etc.

*************UNDER CONSTRUCTION******************INFO NEEDS SOME CORRECTION**************

I have just been using a suspension design spreadsheet to have a look at different spring / sway bar configs and the effect they have on the front roll couple (FRC) which is a percentage of the weight transfered over the front wheels (divided by the total weight transfer).

In effect the lower the number, the more the car will oversteer. The higher the number the more the car will understeer.

I have used BA-F XR6T Sedan data as below

Weight 1780kg

Weight distribution (front / rear) 56%/44%

Stock sway bars (front rear) 24mm/19mm

Stock spring rates (front/rear) 450lb/250lb

above weights / distribution info is from my car when I had it corner weighted.

So stock FRC is 48.5% I have calculated below FRCs for commonly available upgrades.......

Sway bars only :

Front 27mm sway 52.8%

Front 30mm sway 57.8%

Front 27mm sway / rear 22mm sway 45.0%

Front 30mm sway / rear 22mm sway 50.0%

King Springs only (520lb/390lb) 44.5%

Tein Performance Coilovers only (670lb/436lb) 47.3%

With sway bars and King Springs (520lb/390lb)

Front 27mm sway 48.4%

Front 30mm sway 53.1%

Front 27mm sway / rear 22mm sway 42.2%

Front 30mm sway / rear 22mm sway 46.8%

With sway bars and Tein Performance coilovers (670lb/436lb)

Front 27mm sway 50.7%

Front 30mm sway 54.6%

Front 27mm sway / rear 22mm sway 44.8%

Front 30mm sway / rear 22mm sway 48.8%

So this gives you an idea of how changes in spring / sway bar will affect the front/rear balance. I have been playing different sway bar configs on my Tein equipped phoon....the above does line up with my experience, and I think I have almost settled on the 27mm front bar with stock rear bar, after trying 30mm only, 30mm +22mm and 27mm + 22mm. As I expected the numbers line up with what I was feeling, the Teins with 27mm front and 22mm rear were causing more oversteer than stock, not something I want to be dealing with at 180kmh+ on the circuit.

Edited by Erko
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argh fark it, will need to do it in word.......wont let me edit after a few mins

Edited by Erko
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Great post Erko well done.

Just a question, what happens with weights when you are excellerating hard around a corner? Should the car have a little more stationary weight over the front which will transfer to the rear when accelerating to allow a balanced car when accelerating around a corner? I just remember Nissan doing this with the 350Z to allow better handling.

Benny

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Great post Erko well done.

Just a question, what happens with weights when you are excellerating hard around a corner? Should the car have a little more stationary weight over the front which will transfer to the rear when accelerating to allow a balanced car when accelerating around a corner? I just remember Nissan doing this with the 350Z to allow better handling.

Benny

Gday Benny,

Its nowhere near done mate, I am going to put something together in word and the get a mod to edit original message and add in.

In answer to your question, the B series has plenty of static weight (too much really) over the front axle. Ideally a 50/50 front rear balance is what you are after, but not possible in a B Series unless you add weight to the rear which will only make it go, stop and corner worse.

We can play with "weights" if you like with spring rates and sway bars. Ie. in order to shift "weight" more rearwards we can use a heavier rear spring rate. This will however mean the breakaway will come from the rear (oversteer as opposed to understeer) and while fun, may not be the quickest way around the corner and is difficult to handle in the wet or at high speed.

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ok, I'll keep adding stuff and then we can tidy up later

Coilovers

Tein “Performance” Spec Part No. QSJ66-EZAS3

Spring Rate 670lb/in Front, 436lb/in Rear

Tein “Street” Spec Part No. QSJ24-EZAS3

Spring Rate 523lb/in Front, 340lb/in Rear

Both are available with “EDFC” (Electronic Damping Force Controller) which allows adjustment of rebound (soft-hard) from inside the cabin. Cost is about $400.00 on top of the normal installed price of around $2600.00 or so. Both of these coilovers are height adjustable on car with the Tein spanners. If you don’t get EDFC adjusting damping is quite easy via turning the knob on the end of the Shock via the strut towers (front) and from under the car on the shock body (rear).

As you can see the “Performance” Coilovers run heavier spring rates which gives better control and less body roll than the “street” spec at the expense of a little comfort. Neither are what you would call uncomfortable however.

Edited by Erko
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Springs

King Springs SL and SSL

King Springs do both SL and SSL for the B series. The normal King Springs are we believe 450lb/in front and 250lb/in rear. This is basically the same as the Ford OEM spring rates. The difference in these springs and stock is the Spring length, With the SL sitting about the same height as the stock XR6/FPV height, and the SSL about 20mm lower than that.

King Springs also make some uprated springs with rates of 520lb/in front and 310lb/in rear. These increased spring rates are preferred over the regular King Springs for better handling. Refer http://www.kingsprings.com/catalogue.htm to see what is available for your model. Note : BA-BF1 use different springs to BF2. The 520lb/in front and 310lb/in rear springs have these numbers in the part number so you can identify them.

******* appreciate feedback on this gents ********will add part numbers when I get around to it.

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Swaybars

Whiteline Front : 27mm and 30mm. Fixed and adjustable.

Rear : 22mm. Fixed and adjustable.

Fixed bars have one hole at each end to attached to the sway bar links. Adjustable have two holes at each end (the adjustment comes from using the different holes to connect to sway bar end link). All sway bars for Fords in Australia are solid bars, rather than hollow. Sway Bars will usually come with Polyurethane D links. These links can break down and get squeaky with age. Be sure to keep the well lubricated or source rubber replacement bushes.

Sway bars will control lateral movement of the vehicle (roll) without changing ride (comfort) as can happen with uprated springs. Use sway bars to minimise body roll, and to alter handling characteristics of the vehicle. From stock, adding a big rear sway bar only will add oversteer, while adding a big front sway bar only will cause the car to understeer more. Bigger is not always better however, as large bars can dull steering feel, cause very fast breakaway making the car difficult to control on the limit (particularly with street tyres) and loss of power down traction through lifting the rear inside wheel when cornering. Sway Bar sizing is often a matter of preference depending on the driving style of the driver and type of driving done.

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Bushings

In addition to the Ford OEM Parts, the Superpro and Nolathane make a number of replacement bushings in Polyurethane. Best bang for buck Bushing to change is the Front inner lower arm bush (Superpro Part No. SPF1838K) which controls forward and rear movement of the front control arm. The standard Ford part is fluid filled and has a lot of slop in it, sure its comfortable, but its rubbish for handling. The Ford part number is the same for FPV’s as it is for Taxis. This mod is particularly important for FPVs or cars with bigger brakes than standard as the additional weight makes the stock bushing even less effective. Changing this bushing will improve turn in and front end feel without any notable change in comfort.

When past the warranty period it is worth considering replacing stock bushings with something from Superpro of Nolathane if you have performance in mind. At the moment, not many cars have them fitted, these firmer bushings are great for handling though may get squeaky with age, time will tell how these hold up over the years. In addition to Bushings, shortened bump stops are available to suit lowered suspension and are worth getting to get the most of your suspension.

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