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Picking out rear springs for my hatch ?

Started by _LS1 Hatch_ , Jul 29 2012 09:50 AM

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33 replies to this topic

#1 _LS1 Hatch_

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Posted 29 July 2012 - 09:50 AM

I'm going to be doing a container back this way from there soon, so trying to work out a few things to buy for the car.. (stuff too big or heavy to normally get brought over in luggage, lol)

One thing I'd like is to get some new rear springs to lower the car somewhat. I don't know what springs are under the car to start with though, stock, or ? (they were on it in 2000 when I bought it) They were painted red it looked like (under layers of dirt) not to say that means much I suppose after the years.

I'd like to bring the rear of the car down 1/2" - 3/4" or so.
Here is how it sits now, with about 3/4 tank of gas in it. I realize with the drop tank the weight over the back can change a fair amount from empty to full...which makes it harder to know what springs to go with I suppose ? (the second pic in the driveway was probably with half a tank or so of petrol in it)

As well, I wouldn't mind buying a complete set of front and rear springs if that is a better way to go, so they are matched, but I do like where the front sits at least now. Again, hard to know what springs the front are. I am using HQ stubs, and some coils from a sub frame I had got ages ago there from a mate, that had the HQ stubs and these springs all done to it already. (so no idea if they were A9X length, standard LX, lowered, etc)

Any thoughts on springs to use to get the rear down somewhat without going too low ? I plan to use a wider tire as well, but will keep a similar height. (I am using a 265/35-18 now but plan on either 295/30 or 315/30's)

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#2 A9X

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Posted 29 July 2012 - 10:11 AM

I honestly reckon it looks fine Jeff

But if you are serious about lowering it, you should flick those ugly wheels,
in the spirit of us relations, I' could take them off you I guess.

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#3 _LS1 Hatch_

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Posted 29 July 2012 - 10:16 AM

I just sort of wanted to perhaps level off how it sits was my thoughts in the slightly lowered springs...

Have any side on pics of your's how it sits for comparison? Even though it has shopping trolly wheels, I'll still take a peek I suppose

Need to sort out some sway bars too for the car, Hmmmmmm.....

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#4 _judgelj_

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Posted 29 July 2012 - 12:31 PM

pedders springs perhaps? im sure you can find some lowered springs, king, lovells or pedders?

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#5 _LS1 Hatch_

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Posted 29 July 2012 - 12:53 PM

Was wondering if one brand was better than another, along with what drop if they come in different heights would probably be best to suit the approximate amount I want to go down... (since I don't know if what I have are lowered already, or ?)

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#6 dattoman

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Posted 29 July 2012 - 01:00 PM

Since you don't know what you have.... just get the ones you have reset

Cause if you buy some here and they are wrong... not much good
If you get some that are different spring rate... not so good

So just get yours sorted

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#7 _LS1 Hatch_

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Posted 29 July 2012 - 01:05 PM

Hmmm...hadn't thought about getting these reset, not a bad idea. Have to check around and see if there are even any spring places around any more.

I had "thought" if they were lowered ones already it might have been obvious by how the car sat, but from the sounds of it...not..

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#8 _judgelj_

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Posted 29 July 2012 - 01:28 PM

http://www.kingsprin...r_catalogue.pdf
ü Front Low: Lowers vehicle approximately 30mm below standard. ü Front STD: Standard Height. ü Front Raised: Raises vehicle approximately 20mm above standard (recommended for bull bar, country driving or whenever increased ground clearance is desired). ü Rear Low: Lowers vehicle approximately 30mm below standard. ü Rear STD +:Standard height to 20mm raised. ü Rear Raised: Raises vehicle approximately 30-40mm above standard (recommended for excessive towing, load-carrying or LPG tank etc)
NOTE: Super Low coils are generally 40-50 below standard.

this might be a reference point for you

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#9 dattoman

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Posted 29 July 2012 - 01:30 PM

Since the cars modified
The spring perches on the 9" might be in a different spot... so might be abit hard to get spot on.... reset

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#10 _LS1 Hatch_

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Posted 29 July 2012 - 01:58 PM

Thanks Jacob...

And...

Since the cars modified

It is ? No one told me...

And makes sense, yep....

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#11 _judgelj_

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Posted 29 July 2012 - 05:53 PM

Ohhh i didnt know it had a 9"

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#12 A9X

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Posted 29 July 2012 - 08:19 PM

These with Lovells inch low.

Posted Image

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#13 _LS1 Hatch_

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Posted 30 July 2012 - 09:14 AM

Great pictures

And it seems to have a sorta-kinda similar rake to mine ? Hmmmm....

Maybe I'll put something real heavy in the boot (along with a full tank of petrol) and see what I reckon about the look for a little bit.

I've got until early September to buy what ever I want for the container, so gives me a little time to play around with it I suppose.

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#14 _LXSS350_

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Posted 01 August 2012 - 07:04 AM

Jeff how is it handling/riding etc? If your not chasing handling and/or ride improvements resetting the rears (to the height you want) is the easiest safe method (as 18yo dumb kids we would have just cut them - LOL).

Remember when you upgrade to a wider and or taller tyre to allow for the reduced height (ie rubbing). Filling the fuel tanker like aluminium tank or having fat rear passengers obviously effects height and may dictate the need for a spring rate change on a lower ride height. Also remember the shorter spring changes your shockies stroke and might cause issues. From memory you run Bilsteins so they at least (if needed) are easy to modify to suit any changes. When resetting or selecting new height springs it is best to work backwards from your worse fully loaded minimum height to your normal load condition. We weigh the rear of the car both full of fuel and nearly empty, then remove the springs leaving the shockies connected (on a two post hoist). Then using our two sissor lift tables (under each tyre) we select ride height and run it through its full travel range taking notes of meaurements and shockie travel issues. You will notice one of the bug bears of the Torana's suspension setup with the binding up when the top arms try to centralise the diff. Thats why the racing Torana's had rock hard suspension to limit the travel handling issues with the standard suspension layout. Loaded with measurement info and personal needs give it to the suspension manufacturer for recommendations.

Are you running H series stub axles on the front?

As I have said dozens of times to make up for the poor 59/41 weight distribution and poor suspension control most Torana's who are chasing handling go for go-cart like rock hard suspension. 1200lbs/350lbs spring rate might be fine for smooth circuit racing but not LA potholes and speed-bumps (or for false teeth - LOL)

For a street car progressive rate springs are imo the only way to go. That way you can have say the first 1.5" of travel soaking up the minor bumps. Use your current springs as the baseline and by measuring their spring rate you can make decisions on what you want to achieve. Giving someone like Eibach your springs would be easier than generalising or guessing. They would build you what you want in a progressive or fixed rate locally.

Eibach Springs, Inc.
264 Mariah Circle
Corona, CA 92879
1-800-507-2338

We run so many different set-ups on standard Torana suspension points/parts that you can't generalise because of the different weight distribution, swaybars, spring rates, shockie rates and general suspension set-ups (changes in bushes, control arm lengths, stub axle heights, hub offsets, rim offsets, tyre compounds and sizes). Although more expensive than Kings, Lovell and Pedders we tend to get Kmac to build (to our specs) 95% of our standard fitting Torana aftermarket springs and sway bars. Remember as you come lower on your rear the balance between your rears pivot centre changes and may not be ideal for your front setup. Lowering any car (if you want to do it right) is a balancing act and should not just be done for a look issue.

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#15 Heath

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Posted 01 August 2012 - 08:46 AM

For a street car progressive rate springs are imo the only way to go. That way you can have say the first 1.5" of travel soaking up the minor bumps.

For anything with neat fitment, progressive rate springs are no good, because it either has to sit like a 4WD at ride height or has to be munching the guards by the time the springrate is actually holding back the bumps hahaha.

Just go IRS springs with the pigtails cut out, they are a winner

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#16 MRLXSS

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Posted 01 August 2012 - 09:35 AM

For anything with neat fitment, progressive rate springs are no good, because it either has to sit like a 4WD at ride height or has to be munching the guards by the time the springrate is actually holding back the bumps hahaha.

Just go IRS springs with the pigtails cut out, they are a winner

IRS springs are what I run in mine!

Posted Image

Not the best shot to show the rear...

In the front I run A9X King Springs Lowered Springs.

Looking at yours, I reckon the Commodore IRS springs would probably drop the rear 1 maybe 2 inches.

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#17 _LXSS350_

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Posted 01 August 2012 - 10:36 AM

Not true unless you don't know what you are doing? Or if you prefer to guess and buy off the self one size fits all?

On the last set of progressive Kmacs we custom made to suit the cars 550kg rear weight (297kg's rhr 253kgs lhr) at ride height the righthand rear runs at 200lbs, after first inch or so firms to about 235lbs then at about 1.75" travel runs at 280lbs. The left side runs slightly less spring and shock valving due to the extra 18kgs right hand side rear weight (fat driver). Its all about trying to keep max tyre pavement contact and not cracking the car or driver up when negotiating our not so good roads. We use the accurate Longacre racing scales for setting up the cars. It takes out a fair bit of the guesswork. If we run straight 280lbs on the street it rides too firm and its easy to damage tyres and rim and loose your false teeth. We can run 80litres of fuel but then we are carting weight we don't need. Nothings perfect but on our roads we find properly designed progressive works. The new car will run progressive multi setting coil over shocks much like the Monton 4 ways which along with progressive springs will allow us to tailor how we want the car to ride and re-act.

http://www.motonsuspension.com/
http://www.longacrer...sp?id=1&catid=1

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#18 _LS1 Hatch_

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Posted 01 August 2012 - 11:47 AM

Colin...

Handling seems decent so far, but I have not really pushed the car hard yet thought. Ride is somewhat firm but not bad at all. My daily driver is a 2011 Chev truck, so that is the main thing I have to compare with, lol. The car does ride somewhat firmer than it did over the years but I have much better shocks now and low profile tires of course.

The larger tire sizes should be similar in outside diameter to the ones on the car now (265/35 now versus 295/30 or maybe the 315s)

I can't remember the last time I ever had anyone in the back seat, and don't really have any fat mates who come along, ha ha.. But obviously the fuel weight is something I need to factor in with the drop tank.

Interesting to know about the spring rates and other issues you mentioned.. cycling the suspension is a good idea as well. From fuel tank of petrol with perhaps a passenger as well, versus a 1/4 tank of petrol for example with only me in it ? The majority of the time though it is only me in it and no passenger.

Those high spring rates would, as you said be pretty interesting on the normal roads around here ! ha ha.. I don't mind firm at all..but don't want stuff to rattle loose all the time ! Oh, and on the rear suspension design with binding or what not as it gets compressed....I could change things around there too...no laws to say other wise of course

(as to a 3 link/watts link, etc, etc) but hadn't really thought too much about that sorta stuff so far.

I am using HQ spindles

I hadn't even thought of seeing is Eibach would make springs. I've driven past them now and then when heading out to the Riverside area.

I need to sort out which sway bars I am going to run too as well actually and get them bought for the container.

Thanks for all the ideas and thoughts as well, I'm still taking it all in... was a long day loading a container today, lol.

Oh, and had not heard of the IRS spring idea...but 2" lower would be a tad much probably unless I never filled the tank up

I guess they would be cheap as something to try if nothing else. But I don't mind buying proper Torana springs too for that matter if need be. I do realize though it is a bit of trial and error on a car with variables like mine.

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#19 _LXSS350_

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Posted 01 August 2012 - 01:12 PM

For an off the self bar - I like and use the adj Kmac front and back bars.
You can get them in whatever size you need but 24mm front and 18/20mm rear is the standard. The std rear bar between the trailing arms is yet another worthless holden suspension piece.
Lots of threads about off the self bars. I must be becoming a fat biggot because they do weigh a bit and ideally I would do that style in hollow thin wall chrome moly tube and save a kg or two.
http://www.gmh-toran...nt-bar-arrived/
http://www.gmh-toran...e-rear-swaybar/

http://www.k-mac.com.../listofkits.htm

Going 3 link is best but you have to loose the centre of the rear seat (or the whole seat) as the link mount needs to be higher than the tunnel floor pan and of decent length. You could run a 3rd arm like some modified mustangs/camaro's run (mustangs have the same binding issue) but I am not a fan of that set-up. Also running a chassis watts link is best to keep the diff true centre and prevent walking. You can run it off the 9" housing but you don't then get an adjustable roll centre for matching your front roll centre to ride height differences in independent front and fix axle rear suspension.

A few pic's of different layouts discussed.

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#20 _LS1 Hatch_

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Posted 01 August 2012 - 01:28 PM

I've been reading a bunch of the sway bar threads actually....a fair bit to take in with them all and this-vs-that, etc. Have you used the front or rear mount style ones ? (both front and rear of the car)

And great pictures of the various suspension setups. The first couple look like a copy of the 90's - 2002 Camaro/Firebird factory setup. A somewhat simple design, if you get the center arm the right length and mounting point I suppose ?

When I built the '69 Camaro with the '00 floor pan and running gear, I had to lengthen the torque arm, and while looking around I noticed a company or two that design a shorter setup that moves the pivot and mounting points.

Some trick looking setups amoungst those (as a start obviously) , and I suppose it just depends on how much to go through on a car that mainly street driven (at this point at least) I don't mind modifying the car though of course, lol..

Hmmmmmm......

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#21 _LXSS350_

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Posted 02 August 2012 - 10:25 AM

When running a big watts link setup I can't get two 3" tailpipes over the diff so I dump exhaust just before the diff. Because I have no tailpipes I have tended to prefer to use the rear facing Kmac style bar. Nothing really trick about sway bars however having adjust-ability helps a lot on the dial in. Some torana's that I have seen don't run any rear bar. Personally that set-up has never worked for me but talking to some owners they seem to prefer the result.

The key with a three link is length. Most floor pans (aka hatch) don't allow for either the travel or mounting height needed. If you look at the orange torana race hatch (above) it uses the most ideal mount point. That length gives you about 3/4 of the bottom trailing arm length and keeps the diffs travel arc within reason. For the street we split the rear seat and hide it with an armrest type console. Not that anyone ever uses the back seat. On the race hatch like the orange hatch the workings and arm are all out in the open.

MSF do a very good watts link kit

Posted Image

http://msfracingcomp...andpanhardkits/

My latest fad is running very soft front springs and slightly harder rears with cockpit adjustable big bars,rebound valving and a lot of camber. Mainly trying to improve bump stability and get a touch of controllable over-steer so that mid corner speeds might improve. Its all trial and error till you find what works for you.

Edited by LXSS350, 02 August 2012 - 10:27 AM.

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#22 _LS1 Hatch_

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Posted 02 August 2012 - 12:11 PM

I have the exhaust in front of the wheels as well...having the side exit mufflers makes it easy

I would have room (going by the pictures) to have either a front or rear mounted one I'd think. Does the rear one interfere at all with wide wheels/tires or a drop tank? If so front mount would be easier obviously.

Nice looking setup on that link and thier watts setups. I suppose it would be overkill on a mainly street car ? Not that over kill has ever worried me before, ha ha.. (and be nice to have the potential to have a car that really could do the job on the track if so inclined as well.) or just hard running up in the mountains, etc out here.
And partially just for the sake of doing it to do it and show people out here something out of the norm !

Thanks for the info so far ! :spoton:

Oh, and should have mentioned...I've watched Welby on the track too on dvd...and his car obviously and him as a driver show even a more factory style setup can do the job obviously too ! But being open with any mods I wanted to do, just makes me wonder...what if.... more often than I should probably, lol..

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#23 _LXSS350_

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Posted 02 August 2012 - 12:31 PM

Jeff of course it comes into its own on the track and allows you to lap faster. 95% wouldn't drive their car as hard. Not to mention if you did you will see those flashing blue lights. Trouble with modifications or what I call hotrodding is its hard to justify on the surface. Not what you could validate unless you are racing. I just love trying different things (because I can) and I always wanted a Hatch to go, stop and handle as good looks. Suppose that's why monster hp and drag racing doesn't ring my bell but the corners do. Its a Bathurst thing LOL.

It fits with the big aluminium tank although on these hatch's I run a self modified standard tanks (80litres). Honestly the 24mm front and 18mm rear would cover you and because of your fuel tanker tank a 200lbs at ride height would be a good starting point. Hell throw a factory 500hp crate LS3 or LS7 and have some fast driving fun.

Edited by LXSS350, 02 August 2012 - 12:34 PM.

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#24 _LS1 Hatch_

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Posted 02 August 2012 - 12:36 PM

I always wanted a Hatch to go, stop and handle as good looks

I agree there. I figure getting the "go" side of things is pretty straight forward since the LS1 family is so easy to modify and responds so well to things. 500 hp is not out of the way and that is surely a good start for "go" on a daily driveable style of car.

As for the "stop" side of things...I have that pretty well under control at the moment I figure...

The handling side of things is just the one to work at now.

And good thoughts on the sway bar sizes, etc too, thanks !

(and speaking of drop tanks, that is one thing I really get a kick out of on the car when other people are looking at it, at a cruise night,etc since we never really had anything like that here in the States and really get people to look confused, ha ha..)