55 replies to this topic

[yel327]

Just use HK to WB stubs, UC steering arms and either HQ PBR calipers or HX PBR style with UC alloy bits. The best way to use HQ calipers is to put a plug in the hose inlet and get them machined to take a hose in the top, this is all GMH did for L34 calipers. Or find some L34 calipers, I sold a pair about a year ago on Ebay for about $500, but easy to modify HQ. Either fork put the $ for repro A9X steering arms or use UC ones, either work fine.

[Toranamat69]

http://www.gmh-toran...yline-calipers/

Here is some discussion about it on both Torana and H series stubs. Looks like you need an adapter bracket but the photos of the are gone now.

There is also mention that the caliper fouls lower control arm using Torana stubs and needs to be notched.

Torana stubs use UC steering arms if you go h series stubs you use Harrop A9X steering arms unless you like bumpsteer which you should be trying to avoid.

[yel327]

UC steering arms work fine with Holden/Statesman stubs. I drove an LX for years with UC front end, HK-WB stubs, HQ-WB discs, UC PBR calipers (with countersunk lower slide and Allen headed bolt) and HOLDEN pad carriers. It drove totally normally, line a dream in fact.
It had the upper control arms mounted up high in the standard UC location and ran 1” lower V8 Lovells springs but with it having a 6 in it only really sat lower by the amount you get by using Holden stubs. People who have issues may well be because they screw the geometry up by lowering the upper arms and/or lowering the car using springs rather than doing it properly with drop stubs and/or using wheel offsets way out from original? Not sure, but mine drove and steered perfectly. Mine ran 14x7 with 245/50/14, which were 4.25” backspace which means they were the identical 0.25” offset as the original L34/A9X 14x6 rims, so the track was identical to L34 and A9X.

Edited by yel327, 06 August 2020 - 07:48 PM.

[Toranamat69]

Sorry I disagree. I too have driven with h series stubs an UC steering arms for years. I used to spout there was no bumpsteer. Then I swapped to the Harrop steering arms and it made a huge difference.
I suspect you don't know what bumpsteer feels like.

I have also plotted the bumpsteer curve for every combo of steering arm and stub axle. The charts are probably somewhere on my old Car domain page if I cared to look.
The bumpsteer curves support exactly how they feel when tested on the road back to back

If you only ever pussy around the street, the only time you will likely feel the bumpsteer is when you hit a rut or pothole with 1 wheel.

If you drive in a spirited manner on a windy rough road like up to Mt Mee in Qld or out through the cotter road past Tidbinbilla in ACT, you will come back here and revise your conclusions.

[neglectedtorana]

Hi Daniel,

I havent fitted HQ discs to a Torana but from what i have read in the past i think the discs will fit on the LH stub.

I think both models use the same wheel bearings

Maybe try get a cheap HQ disc or second hand one to test fit

Good luck with the Nissan caliper conversion, hope it goes easy

Cheers, Tom

[76lxhatch]

From my own plotting and testing bump steer depends massively on how much caster. You can get away with the UC arms if you have minimal caster (like less than 2 degrees) but that's kind of pointless if you want it to handle, once you pile on a bit more caster the A9X arms compensate for the increased angle. There are other ways and means too of course.

 

As far as the brakes go, the rotors will bolt straight on to either hub. And for caliper mounting it doesn't matter which one you use if you're making custom brackets since you can make them to suit whatever you need, and the steering arm interference is not stub-specific since they still mount in the same spot relative to the spindle.

[claysummers]

You will have trouble setting enough camber due to less king pin inclination requiring you to offset the top arm inward.


Sent from my iPad using Tapatalk

[yel327]

Sorry I disagree. I too have driven with h series stubs an UC steering arms for years. I used to spout there was no bumpsteer. Then I swapped to the Harrop steering arms and it made a huge difference.
I suspect you don't know what bumpsteer feels like.

I have also plotted the bumpsteer curve for every combo of steering arm and stub axle. The charts are probably somewhere on my old Car domain page if I cared to look.
The bumpsteer curves support exactly how they feel when tested on the road back to back

If you only ever pussy around the street, the only time you will likely feel the bumpsteer is when you hit a rut or pothole with 1 wheel.

If you drive in a spirited manner on a windy rough road like up to Mt Mee in Qld or out through the cotter road past Tidbinbilla in ACT, you will come back here and revise your conclusions.

 

Yes I do know what it is. The first iteration of this car was the standard LH front end as used on a 2/76 LX. I fitted Holden stubs, HQ rotors and calipers with slightly lower springs and big sway bars. Also still had a banjo with L34 axles and HQ rear drums, running 14x7 fronts with 4.39" backspace (0.39" offset). It handled well but did have significant bump steer when driven hard.

 

When I fitted the UC front end I couldn't find a good UC 6cyl or Starfire crossmember but found a mint Opel one. So after close inspection the early LH one was the same design as the UC one, whereas the RTS LX one was different in the shock tower where the upper control arm mounts. So I grabbed a mint LH crossmember, stripped it and replicated the UC crossmember by drilling UCA mounting holes up in the same location as a UC, and welded on shock cups plus whatever those welded on round bar bits were. Then fitted it with all the UC gear with Holden stubs and the UC-HX caliper combo. This car was a daily driver, but on times I did drive it hard including a few track days at Amaroo Park. I never noticed any evidence of bump steer, as compared to how it was earlier. But as I said maybe it wasn't as exaggerated as it might have been in a lowered V8 car with wider track? In any case you could easily drive it with the throttle, the suspension and brakes were far better than the tyres I could afford in the day which were either TA's or Yokohama, basically how quick I could drive it was governed by the tyres not the steering or suspension. It was a budget low expense build car, used basically all off the shelf easy to obtain (in the late 80's and early 90's) bits other than the Celica 5spd and I had to shorten a HZ Salisbury welding on Torana mounts to make it the right width for A9X axles and rear brakes. I certainly did not find any compromises in how it drove, and there were never any wheel alignment issues, it used to align up with UC settings, I can remember it ran -0.5" camber with no shims, can't remember the caster. It was probably the most neutral handling and predictable driving car I ever drove until I git to drive modern high end cars this century. Unfortunately the only A9X I ever got to drive was modified a bit but pretty standard and not my car so I never got to thrash it. I did get to drive a few standard UC and drive them hard and it was driving those that pushed me towards the UC front end.

[yel327]

If it was me I’d fit Holden stubs, UC steering arms and the UC/HX caliper combo. It is the easiest way I reckon. As I said I didn’t notice any issues.

If you keep Torana stubs there is no affect on your geometry, you just have to sort out a caliper that will work and clear your wheels which may mean machining the discs too. You want calipers at the front too from my experience.

[76lxhatch]

Bump steer depends on the combination of steering arms and caster setting. The stub axle choice (Torana or Holden) has no direct effect other than the Holden one will limit the caster you can achieve without camber issues (due to the ~2 degrees less KPI). If you're just trundling around then 1 degree of caster and UC steering arms will work fine, but you don't need to be a racecar driver to appreciate the big improvement that 4+ degrees of caster will make to everyday handling and driving manners.

 

Otherwise its just a matter of actually fitting the calipers, once you commit you won't be able to change stub axles without at least changing the caliper bracket because they have a different mounting radius. Personally I wouldn't even consider the UC/HX caliper, if you want a bolt-on option then the cast iron HQ caliper is heavier but much better. If you go R32 calipers you're making custom brackets so no problems exist until/unless you create them. With a more capable caliper you may want to consider a larger and thicker rotor up front, you can usually squeeze a little bigger than HQ under a 15" wheel.

 

Also depends on your budget and skills. There's a big difference in cost and difficulty between the easy/good enough option that yel327 is suggesting and other options that will give vastly better results - you seem to be somewhere in the middle based on the R32 caliper suggestion.

[yel327]

Have you been quoted for Engineering yet? You have to do this with brakes other than what was optional. That is one factor why I used what I did.

The UC/HX calipers were fine. You just have to start with decent ones and rebuild them. Were trouble free for me, although I did pull them apart once again in the time I had the car and put a kit through them. If you can find some A9X calipers to copy the machining of the cast part onto HZ calipers that will work too.

[Toranamat69]

Omg I knew I would regret coming and looking back in here the BS still flow as solidly as ever.

[Toranamat69]

As much as I bag Holden about the design of Torana front suspension. They actually got it right with the A9X setup. You will struggle to improve on this setup especially if you lower the front end.

Uc was ok but was compromised on camber curve due to the high UCA mounts. Gets worse a lot quicker when lowered.

There are so many combos to go into the details of every one.

Torana stubs with Torana steering arms and H series stubs with Harrop steering arms for useful road alignment setting for Radial tires is the easy bolt up.

If I was engineering your cars, I would not approve unless a satisfactory bumpsteer curve could be provided.

Edited by Toranamat69, 07 August 2020 - 12:22 PM.

[yel327]

Did you ever plot the L34 setup compared to A9X?

[76lxhatch]

1) If I go with the torana stub, and other factory gear as I mentioned. If I wanted to get more than the 1 degree of caster as you mentioned, what changes will I need to make?

You can usually get around 4 degrees without exceeding the maximum shim stack (0.5") or excessive negative camber (say 1 degree negative) with a Torana stub and UC upper control arms, provided the front end is relatively straight. You should have UC steering rack and steering arms, don't use LH/LX.

My post above doesn't exactly read right now I look at it again, the height of the outer tie rod end relative to the control arms is what matters in this case. I've probably said too much on bump steer without lots more context so I think I'll just leave it at this for the simple version:

Torana stubs with Torana steering arms and H series stubs with Harrop steering arms

And measuring the bump steer on your actual setup with your actual alignment is definitely highly advisable if you make any significant changes.

2) If I'm running the 15" wheels, and can afford to go larger than a HQ rotor with an r32 caliper, what rotor would you recommend?

Sorry not particularly familiar with the R32 calipers but even a basic Hoppers kit uses a 290x28mm rotor under 15s where HQ is only 276x25.4mm. I would have thought the calipers were designed for a thicker rotor than 1", what was the factory size?

[rexy]

Why not just fit the Hoppers 290mm kit?

Simple bolt on and not too expensive.

 

Who is going to make your caliper brackets and brake hoses for you?

[Toranamat69]

Did you ever plot the L34 setup compared to A9X?

I have never had L34 steering arms to try or to see how they differ to the Harrop ones so no. I'm not sure where I would get any either. I was of the understanding they were like the Harrop ones but with the steering stop on them

Is that what you mean by L34 setup?
If you mean the rest of the setup as per which stubs, position of UCA, camber etc, I probably did as I checked many many combos. I didn't bother with some that I could see were going to be really undesirable.

I actually found all the ones I posted on Cardomain they are still there but they must have compacted all the photos as I can't read the legend on them now when I blow them up. I bought my work PC home as it has a DVD drive on it do I can check my archives from 4 PCs ago.
I should still have the .xls data if I'm lucky.

M@

[Toranamat69]

Perhaps a new thread on this would be good so we don't overrun Dan's brake question any more, even though it is all related.

The hoppers kits are hard to beat for value and simplicity. I'm tempted to get a set myself and then upgrade to better calipers later.