111 replies to this topic

[A9X]

Thanks Andy,

I'll take it. It'll give my spannerman an excuse to catch up with you on your offer to look at your front end.

Welby

[dattoman]

So you paid market value for it.......... next to nuttin

I'm just waiting on a reply back from supplier on avail and I'll email you your prices

Wanna cut some bits off that wreck if I need them ?
You driving down ?

[A9X]

Andy - are we good on the Nolathane ?

Rory - What balljoints did you use ?

Welby

[Dangerous]

I just posted a few pics on the RTS and upper wishbone thread if anyone's interested. Maybe I should have posted in this thread instead?? I kinda got carried away and put a few in of A9X steering arms and stub axles too.

Rory, that's a nice front end setup - did you drill the upper arm holes at the same spot as A9X, or lower? The A9X front crossmembers also had a dirty big square section bump stop welded to them- you might be able to see it in my 'jigsaw' photo.

[slr5640]

The A9X front cross members also had a dirty big square section bump stop welded to them- you might be able to see it in my 'jigsaw' photo.

Hi there, Is this what you are referring to?

[dattoman]

They probably won't know themselves

I've seen many cars with these calipers legally registered so I don't see the issue really
Many production calipers don't have a proper dust boot and allow the piston to be exposed
Such as Range Rover , Mini , And alot of other british poo
Its not really an issue it just means the caliper required more regular maintenance
Infact many AP racing calipers that have ADR31 compliance don't have proper dust boots either

[Dangerous]

The A9X front cross members also had a dirty big square section bump stop welded to them- you might be able to see it in my 'jigsaw' photo.

Hi there, Is this what you are referring to?

Yep, that's it.

[Dangerous]

My stubs are also HZ so if HZ 1 tonner are the same as A9X part no, it stands to reason the sedans will be the same number...cant see why they would be different..it is GMH after all...they used the parts bin like everyone else.

Nope, the 1 tonners used a 'heavy duty' stub axle with a different part number to the rest of the models. The 1 tonner part number is the same as the A9X part number. It's probably overkill though, as I can't see how you'd break even an HQ stub axle short of running the car into something.

As for the measurements, I haven't measured to the top of the tower, but there are measurements to the bottom of the chassis rail in the "RTS thread" for LH, LX RTS, non RTS. Haven't got one yet for the lower ones on the A9X.

[Toranamat69]

Here is the bumpsteer curves for the HQ to HZ stubs fitted to a Torana using all 3 options of steering arms.
As the rumours say, the A9X arm is the one to use. These measurements were taken using 3 degrees positive castor.

Interrestingly, it would be even closer to ideal if I wound the castor up to about 4 degrees positive and the UC steering arm one would be the pic if I was running more like 1 to 1.5 degrees positive castor.



M@

[TerrA LX]

I am surprised the A9X one is so different considering it is the same length as the UC one bit is only slightly lower.
R

so would it right to say that keeping the rack as close as possible to horizontal reduces the amount of bump steer (that being the relation to the differences of higher or lower location) or does the length (away from the stub C/L) play a part too?

[dattoman]

Hi all , just registered and new to this computer world so forgive me if i stuff this up somehow. Read with interest all the front end mod's going on , having just done similar stuff myself. I used crs dropped stubs, hq. discs & hz alloy girlock calipers front mounted, 15+7 convo pros 225/15/50 on a UC front end . Didn't know about the harrop steering arms , wish i did because the bump steer is S@#T. After reading all the info iv'e got a couple of Q's.
1/. How did u get around the K.P.I.A. 2 DEGREE difference between torana & hq. stubs?

2/. Reason for lowering UCA mount ?

Any info would be appreciated, cheers craig.

Question 1 and 2 answer each other

[Toranamat69]

QUOTE (rorym @ Jan 23 2007, 11:22 AM)
I am surprised the A9X one is so different considering it is the same length as the UC one bit is only slightly lower.
R�


so would it right to say that keeping the rack as close as possible to horizontal reduces the amount of bump steer (that being the relation to the differences of higher or lower location) or does the length (away from the stub C/L) play a part too?

Have you checked out this link from the PS thread? Check the diagram right at the bottom it is really useful for working out where to line everything up.

http://www.longacrer...rt.asp?ARTID=13

If you check the curves I plotted above, they are each a fairly good approximation of a straight line. The curl on the top of all 3 is in my measuring device, not the bumpsteer so it shouldn't actually be there and the little wriggles are my inaccuracies in my measurements so if you ignore those couple of things, you have 3 straight lines. What that says is it doesn't matter how high or low your car is if you are using the same stub axle and steering arm, your bumpsteer is not going to change, you just operate further up the line but you rezero when you set your toe-in when you get a wheel alignment.

The reason the H series stubs make such a difference with bumpsteer is because the 2 holes that mount the steering arm are a lot higher above the lower balljoint than they are on a Torana stub.

It is the relationship between the Top and bottom balljoints and the steering tie rod end that make the Torana stubs different to the H series, not the fact they are 30mm lower ride height, nor the difference in KPI.

The distance away from the rack CL plays a part in your steering directness and will also effect the ackerman angles of your steering but not really your bumpsteer.

M@

Edited by Toranamat69, 19 February 2007 - 01:31 AM.