Track Setup Ba Xr8 Ute

[Apes]

Hi Guys,

I have read all the other posts in regard to these understeering BA XR utes. There is some very knowledgeable individuals on this topic so I thought I would post my personal issues with my vehicle to receive some guidance.

The car is a 2004 BA XR8 ute (turbo charged) making 520RWHP. I do sprints at QR and have had the suspension recently upgraded. Kym down at Mermaid suspension did my work and I went for 850LB front springs FG HD rear springs and revalved bilstein shockies all round. All the bushes in the front end have been replaced and upgraded.

I had a 30mm front sway bar fitted prior to the the suspension upgrade.

Prior to having the suspension upgraded I was running 1:01 on the sprint configuration. Since the upgrade I can only manage a 1:03 very disappointing.

Other changes I made since the previous sessions. I was running toyo 888's until they went off. The new tyres I purchased to replace those toyo's where pirelli p zero corsas off ebay for $150ea. They are garbage if anyone is considering to give them a go.

The understeer I was getting on the weekend was terrible. My thoughts are adjusting as much neg camber as possible and reducing the front bar back to 27mm adjustable. I was considering getting a bar at the rear however Kym and the previous info has made me reconsider. I was also considering going to a full stick at the front to aid turn in and cycle the pirelli's through the rear.

I will list the alignment values for you really switched on guys to look at;

Total toe 3.2mm

LH RH

Camber: -1.16 -1.62

Caster: 7.30 6.45

Any advice or guidance would be appreciated. Cheers

[Jman]

I've got Pzero's on my ute with a 19"/10.5" rear rim and have nothing but respect for them as a street tyre. Holds 3rd gear on the ground WAY better than my old Marangonis.You do realise a R888 is a track tire, if anything going to a Pzero is a step down for what your after. It's like comparing a MT slick to a high end street tyre (both have +'s and -'ves)

Did you go with Bilstein coilovers all round or the traditional shockers?

What size tyres/rims you running?

Also from what I've heard a 30mm front sway bar on a turbo is too hard, but for a 8.. it should be ok. 27mm seems to be the norm for us XRT boys

[Guest XR09]

I don't think any street tire is going to take that much scrubbing. Not for more than a lap.

[senna_T]

That toe figure seems extreme! Is it toeing in or out (+ in or - out)? I just did an alignment on my car tonight at the shop to get it back to where I like it. Before I went down to Jindy for the combined snowys cruise I set it up for highway cruising and protecting the tyre - now the car is back home I want it responsive.

Tonight the before toe settings were +1.80 (toe in) l&r so the car was super stable on the highway and kept the tyre wear even while running -1 deg camber.

Afterwards I left the camber the same, but changed the toe settings to +0.30 l&r. Rear toe was set at +0.20 l&r. Results are a much more responsive turn in, making the car feel like it pivots around the centre when thrown into corners rather than pushing against the front tyres. I have so much more feel mid corner and the car almost feels 200kg lighter - seems extreme from a simple alignment, but it can change the drivability of the car so much.

Maybe look into the alignment specs and get your own feel for what works - keeping an eye on the wear pattern when at the track (or having a little infra red temp gun to check variation on surface) can tell you what the car is doing in relation to alignment. Get the aligner to drop as much camber into it as possible, being an 8 it needs it

The ute has a major downside in that the wheelbase is so long, making it much harder to turn quickly - when we set up the race utes the alignment settings are very agressive (but so is the rest of the susp set-up) running over 4degrees neg camber and toe out (which can destroy tyres, but helps pull the nose in on initial turn in).

Hope this give you some ideas and good luck with your next outing

[Apes]

I don't think any street tire is going to take that much scrubbing. Not for more than a lap.

I have pirelli p zero (nero) tyres on my street rims in a 19 and I agree they are amazing, however I stated that I am using P zero (corsa) which is a semi slick tyre on my track rims which I dont rate after coming off the toyo 888's

[Apes]

That toe figure seems extreme! Is it toeing in or out (+ in or - out)? I just did an alignment on my car tonight at the shop to get it back to where I like it. Before I went down to Jindy for the combined snowys cruise I set it up for highway cruising and protecting the tyre - now the car is back home I want it responsive.

Tonight the before toe settings were +1.80 (toe in) l&r so the car was super stable on the highway and kept the tyre wear even while running -1 deg camber.

Afterwards I left the camber the same, but changed the toe settings to +0.30 l&r. Rear toe was set at +0.20 l&r. Results are a much more responsive turn in, making the car feel like it pivots around the centre when thrown into corners rather than pushing against the front tyres. I have so much more feel mid corner and the car almost feels 200kg lighter - seems extreme from a simple alignment, but it can change the drivability of the car so much.

Maybe look into the alignment specs and get your own feel for what works - keeping an eye on the wear pattern when at the track (or having a little infra red temp gun to check variation on surface) can tell you what the car is doing in relation to alignment. Get the aligner to drop as much camber into it as possible, being an 8 it needs it

The ute has a major downside in that the wheelbase is so long, making it much harder to turn quickly - when we set up the race utes the alignment settings are very agressive (but so is the rest of the susp set-up) running over 4degrees neg camber and toe out (which can destroy tyres, but helps pull the nose in on initial turn in).

Hope this give you some ideas and good luck with your next outing

Hi Senna_T,

Thanks for your info. The curret values are +3.2mm toe. (total) LH +1.8mm RH 1.4mm REAR LH -1.5mm RH +3.4mm.

Can you confirm if you own a ute also??

What do you think of my ideas to help with the understeer I.e change to a 27mm front bar or keep the 30mm and change the alignment??

What is the maximum camber adjustment I can make without the caster kit??

Just for your info my last set of track tyres wore perfectly on the old suspension setup.

Thanks again

[Guest XR09]

Sorry mate I was thinking more about the amount of toe. If you have that much + toe in your front then it will not want to turn in. I am presuming you had poly bushes put in. So it should stay more neutral under pressure. It would take a bomb to move it off line with that amount of toe in. But for the most it would be scrubbing the tire and putting a huge amount of heat through it.

With that much grunt your rears would naturally want to toe in under power.

I have tried it using a more soft front setting and going neg on the rear, and wore out a good set of tires in no time at all. I got the initial turn in but the mechanical grip was just not there. So it bit then felt like it was steering from the rear. And then pushed on the way out, making it slower in the long run.

But hey I hope you find the magic cure ha ha.

Is the understeer more so coming out of the corner and pushing under power. Or are you just not getting the initail bite ???

[Apes]

All good. Yes they are super pro poly bushes. The understeer is more the inital turn in.

Edited 03/12/10 12:16 PM by senna_T
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[senna_T]

Mine is a sedan bud, so I can adjust the rear, unfortunately the ute has no adjustment in the rear so you are stuck with some funny figures there.

Definitely need to change those alignment settings - not sure how much more you can get into the front camber wise, but they should be able to even it up by playing with shims (removing all the factory ones) to make the car more balanced.

The 30mm swaybar is usually ok on a V8, but it all varies with spring rates and tyre choice - do you know what spring rate they have used?

[Apes]

850LB front and heavy fg rear kings.

Do we know of any guru's that could set the car up in the brisbane area?