Having recently got my Indy on the road, I now need to do some suspension setting because on the power it's reasonably steady, but off the power it's all over the road which is somewhat scary. The tracking is parallel (Baz at MK says this how they set their's up), and the front wheels are pretty much vertical i.e. no camber. The rear wheels are on maximum negative camber after the SVA test so that the wheels were within the arches. The shocks are on the middle setting on the compression damping adjusters, and the spring seat adjusters are set so there is 25mm of thread showing. I've spoken to a couple of people who say that rear wheel drive cars should be toed in, would this help with straight line stability because it takes a hell of a lot of concentration to keep the thing in a straight line. Any thoughts will be greatly appreciated.

Cheers, Kurt

Suspension set up is not so straight forward as no two cars are the same.
Apart from toe in etc, did you get the castor sorted?
Many a 7 has lack of castor and this can cause the sort of poor handling you describe. That is why self centering is an issue for sva.
You really need someone with the proper tracking equipment to get your car right, but castor is a must do, first !
Have you measured any of the settings?Because if you can tell what suspension settings are just by looking, then you will make a fortune!


[Edited on 1/3/2007 by nitram38]

I know you've said that the tracking is parallel but the symptoms you describe ie, because it takes a hell of a lot of concentration to keep the thing in a straight line reminds me of how bad our Indy was after SVA (When we'd tracked it by eye). If it has been tracked correctly, the next place I would look is at the rack, to check for any bump steer.

Phil

Kurt

As a start, let some air out of the tyres. I am running 16 psi in the back and 18 in the fronts. You will find that the springs are pretty hard for a BEC, so a lot of the suspension is in the tyres (hence the 13" vs 17" debate).

Putting air in and taking it out is something you can do really quickly yourself. You should notice some improvement pretty quickly. (Mine had 30psi straight from the tyre fitters!!)

Then bring it too the trackday on 2nd April at Teesside. Bring some tools and go trial and error.

Go out, do a few laps, push on, come back in, monkey about underneath it, go out, do a few laps, push on.

Repeat until it gets better, once it's better then push on harder!



Cheers

Mike

Just going on what you've said, and where I'm up to with setting mine, here are a few bits that madea lot of difference to me.
Get the rear wheels back up at verticla, ie no camber.
Get your tyre pressures down to around 18 psi.
Set toe in to " ever so slight!" - a degreee or two.
15-20mm rake from front to back, measured at the body sides fromt and rear.
Front springs, two turns, rear 5 turns.
Dampers 5 clicks from full left.
This lot made a sum of a big difference to mine.
Self centering gets better as the steeering loosens up after a 1000 miles or so.
HTH for a start , in a not too scientific way.
I would still pay money for corner weighting and all that jazz at some time but for now it's perfectly driveable, which it was'nt post SVA, as you describe
Regards

My car (rwd) has:
0.5 degree toe in on each front wheel
0.25 degree toe in on the rear
0.25 negative camber all around on each wheel.
7 degrees of castor.
My tyre pressures are 28 psi rears and 26psi fronts (remember mine is rear engined though).
I bought a 5 wheel tracking machine off ebay. It is a palava to set up because I have to level the car on uneven ground first before I can start, but I got there.
I found that my front shocks were set too hard for the road so I had to back them off until I felt comfortable and the car did not take off over potholes.

you could allso make sure you havnt got the top front wishbones the wrong way round.

I had the same problem , it turned out to be the ride hight, mine was set to high, make sure your shock's are set at half travel distance, if there 14" fully extended, and 10" compresed, then they should be at 12" when car is on the ground, mine only had 1/2" of lift , hence dodgy road manners.
Hope this helps.

Thanks for the quick response chaps, that lot should give me plenty to work with for now. Looks like it could be an interesting weekend.

Cheers, Kurt

I would go for a conventional setting first; and then start playing:

- 1 to 2 mm toe-in at the front
- 0 to 1 mm toe-in at the back
- 0.5 to 1 degree negative camber at the front
- 0 to 0.5 degree negative camber at the back

Dampers at soft. I know that Nitron advises to keep the dampers at their softest lever for the first few 100 miles.

Three words of advice:
- Go to a garage with the best equipments you can find. Once it is set properly the first time you can adjust things you self by equally changes on both sides.
- Write down the effect of what they do: one turn means X degrees camber change, etc. This makes things much easier later.
- Buy some cheap mechanical scales (4euro at ikea). Two per wheel and a piece of wood should do it. For 32Euro you can balance the wheight per wheel. BIG BIG BIG impact on handling. Best investment I ever made.

Then; enjoy playing! I really enjoy changing one thing and then experience the effect it has. I find that as my trust in the car and myself increases my preffered set-up changes to. FUN!

If it's as bad as you are saying I would check the bumpsteer front and back, and check that nothing is moving under load. But my bet is bump steer, it's a killer to handling.
ATB
Phil

My settings are similar to Reman and I was surprised how stable the car was. It tracks dead straight and isn't upset by bumps.

My settings are:



16 psi front and rear tyre pressures

1 degree toe in at front [set up at home using a laser angle finder suiggested by someone else on the forum]

Neg camber at front [done by eye]

vertical at rear.

Ride height set so that wishbones are slightly lower at chassis pivot point than wheel pivot point [if that makes sense]

Dampers set as soft as poss.

ps. How can toe be set at back? - mine has no way of adjusting rear toe.

Stu

[Edited on 2/3/07 by whitestu]

quote:

---

Originally posted by whitestu
My settings are similar to Reman and I was surprised how stable the car was. It tracks dead straight and isn't upset by bumps.

My settings are:



16 psi front and rear tyre pressures

1 degree toe in at front [set up at home using a laser angle finder suiggested by someone else on the forum]

Neg camber at front [done by eye]

vertical at rear.

Ride height set so that wishbones are slightly lower at chassis pivot point than wheel pivot point [if that makes sense]

Dampers set as soft as poss.

ps. How can toe be set at back? - mine has no way of adjusting rear toe.

Stu

[Edited on 2/3/07 by whitestu]

---

if you have time and a couple of bob, go to procomp

Thanks for all the suggestions, I'm working my way through whatever I can but need to get everything measured and matched side to side. I've given it some toe in on the tie rods aswell as some negative front camber via the top ball joints. This has improved it but the back end still feels like it's bouncing around. I'm going to bring the rear wheels to somewhere near vertical as I think the rear tyres are kind of running on the corners there is so much negative camber. As has been suggested one thing at a time, but the changes so far have gone from 70mph feeling scary to just over the tonne now doable. Thanks for the help, and onwards and upwards or should that be onwards and faster?

Cheers, Kurt.

sounds like it could be toe'ing out on braking which indicates some form of bump steer..

Ie the car is getting toe out under front suspension compression!

Most cars have the steering rack behind the wheels so get toe in under braking but with the rack in front you get the opposite effect...

the lack of self centering makes it worse as well...

Sorry forgot to say, are the steering balljoints mounted to the arms under or over the steering arms?

If they can be mounted over the steering arms, this may decrease bump steer

the toe in/out is fixed on an indy though isnt it? mine handles like a penny farthing on a cobbled street when driven on country roads! was much better with the extra weight of the pinto, or if i have a passenger! ill have to get mine set up properly as ive not done it since sva!

Has anyone reamed out the top ball joint mount on their mk indy and fitted longer ball joints with nuts either side like at the rear so that camber can be adjusted without removing the ball joint and relying on it doing a full turn? I ask as its something i want to do!

My mk was a bit all over the place for a while, rear wishbone nuts had loosened off a bit and needed re-tightening, handles like on rails now ^__^