55 replies to this topic

[HDT166]

Just ordering some suspension for my lx does any body know if the macdonald bro racing tubular suspension is a legal fit? I am order the tubular front wishbone kit with coil overs and rear adjustable trailing arms. My car is regoed but gotta go through engineering for ls1 conversion. Any one else used their stuff? Thanks

[Struggler]

I have used their stuff before and been very happy with it and the advice they have given.

 

Is it a legal fit ???? I couldn't tell you.

[ls2lxhatch]

McDonald Bros have had their tubular front control arms engineered. You will still need to get an engineer to sign off on the arms but the engineer with not need to test the strength of the arms.

 

I bought the McDonald Bros tubular arms a couple of years ago and have found the following issues.

 

The arms I have do not have provision for the factory compression and rebound bump stops. Compression can be handled by fitting a bump stop on the shock. Rebound can be handled by shorting the shock. I did not buy shocks from McDonald Bros so don't know what they have done about compression and rebound bump stops.

 

The sway bar mounts on the McDonald Bros arms I have are in the wrong position for an off the shelf rear mount sway bar.

 

There is no provision on the lower control arm for steering stops so the steering arm could get caught in the suspension.

 

Ask them what springs they supply with the shocks. Last time I checked they were supplying 250 lb/in or 350 lb/in springs which you then cut to suit the Torana. The standard Lovell V8 springs are 650 lb/in, track cars run a minimum of 850 lb/in . Cutting the spring produces a pigtail top, the Torana spring tower is designed for a flat top spring. Fitting a pigtail top spring in a tower designed for a flat top springs should not pass engineering.

 

I have the part numbers for Moog Ball joints to suit the McDonald Bros tubular front control arms if you want better quality ball joints.

 

I have a set of McDonald Bros rear adjustable upper and lower trailing arms for sale.

Edited by ls2lxhatch, 09 February 2014 - 12:50 AM.

[ls2lxhatch]

Hopefully McDonald Bros have resolved all the above issue since I purchased my control arms.

Edited by ls2lxhatch, 09 February 2014 - 12:57 AM.

[madtoranajzedded]

pretty sure tubular is not legal,engineered sure but not approved,getting it approved from the big knobs is the problem,waddingtons would be the one to get ,go see an engineer and he will ring to find out for you

 

 

Maz

Edited by madtoranajzedded, 09 February 2014 - 01:17 AM.

[ls2lxhatch]

The engineers I spoke too a couple of years ago said that in principal they would be able approve tubular arms. The WA DPI does have the final say so it would be best to get approval in principal from the WA DPI first.

 

The NCOP does not rule out tubular replacement suspension arms.
http://www.infrastru...Jan_2011 v3.pdf

[HDT166]

Thanks for all the info. That's great. The guys at McDonald bros have been really helpfull. I'm going to use coilovers at the front with 350 pound springs. As far as sway bars I'm going to have to work out something there though

[myss427]

350lbs are too much for a Torana, I use them in mine and its on the lowest setting and its too high.

[ls2lxhatch]

The 350 lb/in supplied by McDonald Bros for the front suspension are too tall for the Torana as they have the wrong free height. McDonald Bros say to cut the springs down to the height you want but that is a bad idea.

The 350 lb/in springs are way too soft for a V8 Torana.

Lovells V8 springs HFL-14, HFS-14 and HFR-14 are all 760 lb/in with different free heights.
Lovells 6 cyl springs HFL-14/6 and HFS-14/6 are 590 lb/in with different free heights.

[madtoranajzedded]

gee i didnt read the question properly, thought it was complete front in tubular ,my bad

 

Maz

[HDT166]

So if I buy the coil overs I will have to change springs any way? Could I use the lovels and still have them height adjustable?

[myss427]

If you buy them through Jegs or Summit you order the same spring with a -2 at the end and you get a flat top with the spring, don't know why Macdonald bros dose not do this.

[ls2lxhatch]

If you buy them through Jegs or Summit you order the same spring with a -2 at the end and you get a flat top with the spring, don't know why Macdonald bros dose not do this.

 

The reason McDponald Bros don't buy the -2 is that they know they need to cut the spring. as the free height of the spring is still too tall for a Torana. The are too many coils to reset the spring lower without coil bind therefore the free height can only be altered by cutting the spring. Then you are back to a pigtail spring with too low spring rate.

 

Any decent spring manufacturer should be more than capable of making you up a set of springs to suit your specs.

 

That is what I thought, so I rang a couple of spring makers and they said that they don't have a jig to make a spring to suit the QA1 Pro-coil system. If you can give me the name of a spring manufacturer that does that would be great. The top and bottom are flat, the bottom id is 2.5" and the upper id is 3.5", free height is around 8".

 

I was considering paying to have a jig made but then I found that the QA1 Mustang Pro-Coil spring is close to what is required for a Torana. I am using the 600 lb/in as my baseline spring. According to my calculations it is close to being the correct height but I won't know for sure until the car is fully assembled and driven. I should be able to get the free height reset if required however one spring place was not that keen of resetting the spring without knowing the type of spring steel used. If I can't get the spring reset I at least now have a spring that can be used to make a jig and a baseline for the spring rate and free height.

Edited by ls2lxhatch, 11 February 2014 - 12:05 PM.

[TerrA LX]

Can't be too hard for a spring guy to cut the spring a bit longer than required, grind the pig tail flat then heat the thing till it sits flat, followed by the correct heat treatment...
I thought that was what part of resetting a spring was.

[myss427]

I have been using the -2 springs as is for over 2 years, and never felt coil bind, but they need to be about 1inch lower maybe more.

[ls2lxhatch]

I have been using the -2 springs as is for over 2 years, and never felt coil bind, but they need to be about 1inch lower maybe more.

 
I put the 8"  600 lb/in Mustang springs in a press and compressed the springs to the point of coil bind and measured the height. The compressed height of the 8" Mustang springs was only around 20 mm less than the space available in the Torana spring tower when the bump stops are compress on the suspension.
 
The 11GSF250-2 has a free height of 11" but will have thinner wire or less coils than the 600 lb/in spring. The chances are that it will bind before the bump stops but only way to know for sure is to measure the fully compressed spring height out of the car.

 

Can't be too hard for a spring guy to cut the spring a bit longer than required, grind the pig tail flat then heat the thing till it sits flat, followed by the correct heat treatment...
I thought that was what part of resetting a spring was.

 

That may be an option but you are still stuck with a maximum of 550 lb/in springs which is still a lower spring rate than the factory 6 cyl springs.

Resetting a spring is basically heating the spring and then stretching or compressing the spring to the required free height. You really need to know the type of spring steel used to heat treat it properly.

Edited by ls2lxhatch, 11 February 2014 - 04:38 PM.

[HDT166]

This is sounding very complicated! So much for the coilovers being direct replacement!

[ls2lxhatch]

The QA1 Pro-Coil shocks are not true coil over shocks. They are hybrid that uses the stock spring tower instead of the shock to seat the top of the spring and the bottom of the spring sits on the shock as per a true coil over shock. The result is that the QA1 Pro-Coil springs are unique to QA1.

 

I am not aware of a factory spring or a coil over spring that has an I.D of 2.5" at the bottom to suit the shock and the top of the spring has an I.D of 3.5" to suit the factory spring tower..

 

Now that I have a sample spring I can send it to a spring manufacturer who hopefully will be able to find a combination of their standard jigs that can be used to make the spring or make a suitable jig. However until my car is complete and weighed I won't know what free height I want so I haven't pursued it any further at this stage. I might get lucky and find that the Mustang spring is suitable.

 

Skip to 1:20

Edited by ls2lxhatch, 11 February 2014 - 11:37 PM.

[TerrA LX]

^ what would be the benefit of that?

All I see that doing is placing a lot of load on the bottom shock mount.

[HDT166]

Thank god for the internet. I'm not knew to working on cars but modifying them is relatively new to me so I'm learning. Have played with commodores more than toranas! Thought setting up suspension would be straight forward, but like the rest of the build, it ain't.

[ls2lxhatch]

^ what would be the benefit of that?

All I see that doing is placing a lot of load on the bottom shock mount.

 
The only benefit is that you get height adjustment. As to whether or not the stock suspension arms a strong enough to handle the load on the mount is anyone's guess. The McDonalds arms are intended to be used with air bags or the QA1 shocks and have been engineered so they should be strong enough for the job.

 

Not sure what weight myss427 has over his front end but your LS would have to be less? Isn't he is running QA-1's with 350lb fronts springs within the standard arms and mounting position. I have not read that he is unhappy with 350lbs and by looking at his car I doubt that a set of springs would stop him from changing to something else (if it was not performing right)?

 

The QA1 Pro Coil spring is essentially mounted in the same position as the stock spring just around 70 mm higher up the shock at the lowest adjustment position. The suspension ratio should basically be the same as the factory suspension ratio. Therefore it would appear that the QA1 setup should be using the same spring rate as you would have used with the factory setup, but with the free height reduced by around 70 mm plus maybe another 10 mm to allow for 10 mm or lowering adjustment.

 

The Lovells V8 springs I used to run with my 308 where 650 lb/in (measured by Malaga Suspensions) with a free height of 270 mm (10.63"). The equivalent QA1 spring should be 650 lb/in with a free height of around 270 mm - 70 mm - 10 mm = 190 mm (7.50").  I changed to HQ stub axles which drops the car around 20 mm and provides a bit more room for the spring on full compression. This increases the calculated free height to around 190 mm + 20 mm = 210 mm (8.2"). On paper the QA1 600 lb/in Mustang spring with 8" free height look like a reasonable starting point. If the car sits a little to low then I could try the QA1 700 lb/in Mustang spring.

I expect the weight on the front wheels with my LS will be more than the 6 cyl but less than a 308.  I have 17" rim with low profile tyres, the car will only be street driven mainly in the metro area.  I was thinking that I could run a spring rate springs closer to the 6 cyl than the V8 to compensate for the low profile 17" tyres.

 

According to Lovell's their standard 6 cyl spring range is 590 lb/in and their standard V8 spring range is 760 lb/in. Surely this means that the 350 lb/in springs are too light for a street car. It isn't that unusual to bottom out the Torana suspension with stock rate springs on the roads in WA.

Edited by ls2lxhatch, 12 February 2014 - 03:37 AM.