Some suspension handling issues NOVA

**CraigGreen** · 06-10-2008, 11:43

Just after some ideas & input regarding my Nova I have just put on the road.

Currently the rear is sitting quite a bit lower than the fr end. The rear spring rate is also much higher than the fr end I think (too stiff) not that the fr springs are soft. The rear beam has newly fitted GM bushes.

The car seems to have a vague feel & inspires no confidence in grip at all. The torque steer seems less since I had the tracking reset on Saturday but the car still pulls accross the road when the engine comes on song.
The beam also feels like it is moving around in aanother direction other than up & down. I have performed a nut & bolt check & all appears tight. Could the OE bushes have softened with the silicon grease I used to install them?

Naturally I want to address the fr to rear ride height issues & will probably have some fr coilovers to sample short term. But the road holding feels awfull & I just want some pointers or reassurance it will improve.

Tyres btw are Good Year Eagle F1's upfront (matching pair) & some Kumho KH11's on rear.

Gordo · 06-10-2008, 11:49

The grease 'shouldn't' be a problem, depending how it was used.
One thing that some manufacturers do is to use bushed that have voids - this gives good stability in one direction - fore and aft but allows more movement vertically - if this is the instance in your case, they may have been incorrectly aligned when fitted.
Other point is that the place may have toed in the front end whereas it's usual to have slight toe out on front driving wheels.

**CraigGreen** · 06-10-2008, 11:51

I did look for any markings on the bushes for orientation & didnt see anything. Didnt look like they were oval or anything.

As I say, the re-set tracking seems to have improved the feel & grip somewhat.

The Simps · 06-10-2008, 12:08

I'd say its the height difference.

I had to raise my front end up for an MOT last year and driving it there was scary! Front end was so light and all over the shop.

Are you on coilovers rear? (couldn't remember) if not just try some std height springs in and see if it makes any difference.

**CraigGreen** · 06-10-2008, 12:14

Yeah AVO coilovers on the rear, the tops of the turrets are a bit high really, so with the spring platforms wound up as high as I can get them, its still too low compared with the fr. I'll add some pics later, you'll see the rear is an acceptable height but the difference fr to rear is a bit much.

The rear beam feels like its flaotaing about all over the shop though. Most passengers thought it felt OK but my Mrs commented that something didnt feel right.

Paul · 06-10-2008, 13:27

Can you not just raise the rear then?

loggyboy · 06-10-2008, 14:13

Quote:

Originally Posted by CraigGreen

so with the spring platforms wound up as high as I can get them

Quote:

Originally Posted by Paul

Can you not just raise the rear then?

Meh?

Mine is handling like a dog at the mo. Im putting it down to front end geometry and joints that havent been (cant be) polybushed. Defo sort ride height out 1st, its just a process of elimination.

**CraigGreen** · 06-10-2008, 14:40

Yeah. I figured its mostly due to the ride height, though previous to the coilovers going on it had KONi fr setup with some Courtenay rear springs which were a tad too low, it never felt so poorly balanced or nervous as this. I guess the vast difference in spring rate is not helping.

Thanks for all the input so far.

Fow16v · 06-10-2008, 14:46

i know this isnt a great comparison as im only running gmax fixed rate shocks and springs but, the other day i replaced my rear springs from 90mm custom at the rear and 40mm at the front back to 60mm rear and 40mm front and the difference was so noticable straight away, the back end now feels astho its following the front were before it felt really light coming into bends quick. the car feels alot more controlable now through the corners at speed.

The Simps · 06-10-2008, 14:47

Quote:

Originally Posted by CraigGreen

my Mrs commented that something didnt feel right.

You sure she was commenting on your car?

baboom tish!

lee303 · 06-10-2008, 15:44

rake is quite important for a good setup, so that may well be the source of your problems, what did they set the tracking to? some people go paralell for some reason, 1mm toe out seems to be the way to go on the nova though
do i remember you played with the rear toe settings too craig?
are the rear bearings new? what tyre presssures are you at?

**CraigGreen** · 06-10-2008, 19:30

Simps.... You should get your own show, preferably very late at night.

Lee, I removed the rear camber shims as I initially thought the rear felt loose when driving it to & from the MOT back in July.
I've no idea what the tracking is set to tbh, book figures I'd imagine. Atleast I know your recomendation.
I'm unsure about rear bearings, one of the few things I havent replaced but the hubs spin smoothly & not loosely like you'd expect from a worn bearing.
Tyre pressures are usually 29psi though I have been using a bicycle track pump. Something else to check next time I attempt to get some fuel in it. (another problem)

lee303 · 06-10-2008, 21:48

hmm, 29 sounds ok, khumhos may like to be a bit less though as they tend to have very stiff sidewalls, and rely on the tread having some movement to generate some heat
what poundage are the springs? a stiff rear set is usually the way to go, as it gives a razor sharp turn in, vague front end usually can sometimes be traced to worn out dampers, or dampers without the rate to cope with the springs, a quick bounce test to see how they cope with the springs can be of use, just see if the car settles quickly after bouncing it.
are the top mounts new? as they are another source of vagueness, but tbh, as i know how freshly built the car is i would rule that out
sorry for all the q's but its hard to give advice over the interweb without knowing these things, i would be getting the car at least level first though, ideally a bit higher at the back, then see how that is, maybe a total bolt spanner check could be a plan too, let me know how you get on

oh, and seeing as you mention the fuel issue, make sure the breather isnt blocked in a away that its spewing a bit of fuel onto the rear tyres, been there, done that!!

The Simps · 06-10-2008, 22:31

Quote:

Originally Posted by CraigGreen

Simps.... You should get your own show, preferably very late at night.

**CraigGreen** · 07-10-2008, 08:56

Thanks Lee. Plenty to go on.
The KONI's upfront have seen less than 10k use, the top mounts, genuine GM the same.
The rear tyres do seem stiff on the sidewall so the pressure recomendation seems no surprise.

I might have some fr coilovers to try by the weekend, so should be able to get the fr down to match. I can't get the rear any higher though unless I have the tops cut off the rear turrets & the top mount dropped down, which is something I want done but is going to have to wait.

lee303 · 07-10-2008, 15:03

can you not get longer springs for the rear?

**CraigGreen** · 07-10-2008, 15:32

The piston would be topped out, I could wind the spring platform up about 1cm more, but its topped out now pretty much, so the coilovers need longer pistons & springs IMO in order to remain usefull with the current turret dimensions.

It isnt overly low at the rear, though I wish it would go a tad higher to give me a nice range in ride height, as opposed to low, lower & fecking low.

lee303 · 07-10-2008, 15:47

ah i see, fair enough then, you could revise the lower mount to raise the damper body, but its a fair bit of work if you dont have the facilities as it were

**CraigGreen** · 07-10-2008, 15:51

Yeah that has crossed my mind also, make some really sturdy lower damper mounts on the beam that stand taller. A lot of work for someone unlike yourself.

I will get the turret tops chopped out & remade an inch lower I reckon. Something for when the winter really sets in I reckon, unless I see how much AVO want to rebuild my shocks with longer pistons & some longer springs.

Thanks for the advice though Lee. Lots to think about now.

lee303 · 07-10-2008, 16:48

vxlgsi · 07-10-2008, 16:54

does the spring poundage match to your front and rear axel weights? and have you corner weighted it?

**CraigGreen** · 08-10-2008, 12:39

No I doubt it, I always intended to get some coilovers for the front, but funds dont allow just now.

Corner weighted, God no.

vxlgsi · 08-10-2008, 12:53

Quote:

Originally Posted by CraigGreen

No I doubt it, I always intended to get some coilovers for the front, but funds dont allow just now.

Corner weighted, God no.

Its a shame you dont live closer to me as a friend of mine has a set of scales he would let me borrow, you would be amazed the difference it makes..

if the turn in feels vauge id say your tyre pressures are to low, go up 2 psi and see how it helps.. when i got my corsa the rear was way to low but when i changed the springs i found the the weight i had shifted to the front mad the rear end less grippy.

if the car skips about on bumpy corners your spring poungade is probably to high.

vxlgsi · 08-10-2008, 13:10

Im hopeing by christmas our suspension units will be available, we have designed proper struts for corsas/novas fully adjustable that can run low without loosing the travel.. unlike gaz and koni etc. although gaz units seem to be popular on here they are not really right for the job if you use your car on the road.

lee303 · 08-10-2008, 15:51