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Adjustable camber/caster


Guest Uncle Woja

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Guest Uncle Woja

I am looking to make a camber/caster adjustment kit for my lowered TR7 V8. The reason for this is I suspect I have too much negative camber and the passenger side has more negative than the drivers side.

 

The car stops woefully and I think a little less camber will help the matters.

 

The brakes are fine. uprated 4 spot calipers and vented discs. The problem I have with braking is that the left wheel locks up too easily and the car in general just does not inspire much confidence in stopping performance.

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Guest ajttriumph

K MAC make a kit that will fit, its so cheap that you wouldn't want to muck around making your own, it gives a large range of adjustments for both camber and caster.

 

However i haven't come across camber causing a braking problem in many years of racing 7v8's and 8's, i run 2.5 to 3 deg of negative camber on the lower speed tracks and up to 4.5degrees on high speed tracks (combined with adjustable spring platforms).

 

This has never been a problem, the engineer in me suggests that you look at some other areas as follows first.

 

Too much negative on one side could only be because of damage to the suspension, the most that you can get without modifying the strut towers or bending the strut is about 1.25 to 1.5 degrees, which BTW the most people find hard to pick with the eye.

 

What condition is the shock absorber in on the problem wheel?

 

Is the proportioning valve allowing fluid to pass to the rear brake shoes? This or seized pistons in the rear will give you the weak brake effect.

 

Is the booster working properly? Even if it is you wont get the firm brake pedal that you get with a modern car with the older style calipers and the branch pipe system to feed the extra pots that rimmer for example sell.

 

I run rear discs on my race 8 which is overkill for the street but makes the braking very effective.

 

Good luck but ask for some professional input before you spend time modifying the camber.

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I would also check (or get checked) the corner weights. This can have a large impact on braking performance as one wheel could have less load on it so will lock up more easily. Prior to doing this check for broken or obviously different springs, damper condition (both from a side load point of view and for damping ability), indeed make sure one is not seized up. Also check the general condition of the calipers, especially the one that doesn't lock first, can the pistons move freely? Finally make sure the tyres are consistent and at the right pressures.

Also, if the car is lowered more than an inch then i would definitely recommend not using an anti dive kit, these do you no favours once the car is lowered as they significantly reduce the castor available.

 

Cheers

Andy

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Guest Uncle Woja

Thankyou for your replies.

 

The springs are 280lbs and have been rated. They are both the same free length and same rate, although the drivers side spring is 5lbs stiffer than the passenger side. I'm told this is normal.

 

The shocks are Koni off car adjustable. They have been up to the Australian Koni importers (3 doors up the road from where I work) and have been dynoed there and adjusted to suit the spring rates. The shocks are in as new condition.

 

The rear brakes have recently been overhauled, but I suspect that one or both is pulling off too much. I have about 1/2 total pedal travel before I get any noticable braking. Pumping the brakes does not bring the pedal height up.

 

The front calipers are off a volvo and have 3 bleed screws per caliper. I also suspect that they haven't been bled properly because the mechanic who did it might not have known about the third bleed screw.

 

The tyres are the best I could get. 205/60/13. An upgrade is 15" rims will occur with the next tyre purchase. What pressure should I be running in these tyres?

 

Thankyou andrewt for that info about the inti dive kit. I am running the Rimmer Bros anti-dive kit. I hope I can get it off as I have ground away a fair bit of the bolt by bottoming out on overly high speed humps (at least the roll bar retainers scrape before the radiator does.... the car is quite low)

 

I also have done away with the TR7 front bump stops and replaced them with Koni pregressive bump stops. This has given me about 2" suspension travel as opposed to 1/2" with the old bump stops.

 

I will also be replacing all the bushed very soon. My car has a real mixture of bushes. Some new, some old, some poly, some rubber. The anti-roll bar on the passenger's side has one rubber bush on one side and a poly bush on the other  ???  How can worn bushes affect braking?

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Changing parts un-symmetrically can all upset the balance of a car, then when you change the load (braking/cornering or accelerating), one part moves fractionally more than another, but at the tyre rim the movement is magnified.   From what you say about pedal travel, it certainly sounds as though bleeding hasn't been completed.   I do notice on both our modern cars that the FN/S tends to slide first, and wonder if on our public roads it's the effect of the road camber pushing more gravel and dust to the N/S.
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Guest pilbaratr7

For your info-

 

 

 

 

Glen,

 

We manufactrue Uprated Front and Rear Anti Sway Bars at $245 each.

 

F/R Springs (any height) $330 (4).

 

Front Top of Strut Camber and Caster Kit $380 a pair.

 

Payment can be made by Visa/Mastercard by providing Card No. and Expiry Date

when confirming order.

 

 

Regards

 

Kevin McIntyre

Managing Director

 

 

----- Original Message -----

From: <go-cb@bigpond.net.au>

To: <sales@k-mac.com.au>

Sent: Saturday, June 19, 2004 3:39 PM

Subject: K-MAC Enquiry

 

> Your Inquiry: What products do you have for Triumph TR7/TR8? Can you

supply prices?

>

> Thanks

> Glen Ormiston.

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I agree that sorting out the bushes is the place to start. Once this is done, see if you can borrow a set of corner weight gauges. These will tell you the weight each wheel is actually carrying. Ideally each one should carry 25% of the cars weight, however in practical terms you want to see each side of both axles carrying half the weight of that axle within 10 to 20 pounds. Less than this for a circuit car. This is ideally adjusted using adjustable platform struts but can also be achieved using shims etc. Since you have had the springs etc checked off the car, any big differences seen on the car may be down to something on the body being in the wrong place. Has there been accident damage for instance? The 5% difference in rate is not outside what i would expect to see but 280lbs/in is high for a road car (at least on pot hole ridden British roads!) and of course the higher the spring rate, the more sensitive the corner weight adjustments have to be. If you start to see big differences in the weights, measure the suspension mount points in relation to each other and from the ground. i recently corner weighted a rally car with enough of a twist in the body to let you see it when you looked along the roof skin. (it has since been reshelled) However after set up the driver commented that the car handled better than ever after the corner weights were equalised. The cynic in me suggests that it was only a major improvement over what was a very tricky car to drive with a twisted shell! The twist (measured from the ground up to the subframes) was around 1/2in to 3/4in from one axle to the other. (Peugeot 205) but was counteracted by the adjustable spring platforms. it looked a bit odd on the floor but definitely drove better.

 

Cheers

Andy

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Guest Uncle Woja

Well, I've been trying different tyre pressures over the last few days. I'm currently running 24psi and it has made a distinct different in the braking. It's less likely to lock-up the wheels before the suspension starts to collapse.

 

Also, with the lower pressure, the turn-in understeer has dissapeared.

 

I have got a complete new set of bolts/screws/nuts/washers for the suspension from Rimmer Bros. i felt this was neccessary as a few weeks ago I heard the back bushes squeaking all the time. I did all the trailing arm bush nuts up about 3 turns. 3 days later, they were loose again. Bugger.

 

I'm going to get new bushes, although I'm at odds wether I should go standard rubber, uprated rubber or poly.

 

Maybe it's just the driver in me that wants to pound this thing through corners, but the 280lbs springs actually don't seem to transfer too many road imperfections to the occupants. I am sure this might have something to do with worn bushes though, the new Koni pregressive bump stops did make a difference.

 

One thing I do notice is that the car does seem to handle better through LH corners, but so does any car I drive. I think that's subconcious more that suspension related.

 

Thanks everyone for your help so far. I'll soon get this thing nutted out.

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