Jump to content
SAU Community

Recommended Posts

As many of you know. when you lower your nissan excessivly at the rear strange things happen to the geometrys.. also the driveshafts run at bad angles leaking to breakages and the handling of the car starts to go backwards. Most ppl will tell you to raise the car.. but wheres the fun in that! Anyway what you CAN do is correct the roll centre at the rear by raising the subframe up into the body by half an inch and effectibly flush mounting it. this way you can have a lowered car and correct the roll centre back to where nissan intended (somewhat).

If your running the traditional style alloy cradle bushes or pineapples on top of the subframe all round you have actually made things WORSE by lowering the subframe. sure in the case of alloy cradle locks its only 10mm but still.. its not an improvement.

I'll show you what i did by myself in my garage. pretty much done for a total cost of $120. that was to pay for the new bushes. everything else i did myself.

THE PROCESS

Start by ripping out the entire subframe.. with diff, arms and everything still attached.. all i took off was calipers and left them attached to brake lines to save bleeding brakes. i cable tied these in place.

Once the rear cradle is out... strip it down bare. remove everything til its just a bare cradle.. then go give it a wash with soapy water, degreaser and leave it in the sun to dry. then chuck it on the bench to start work,

Start with bracing the subframe... its a good idea to do this while its out as they are reknown for cracking the lower control arm mounts when tracked. I went a little over the top and bracked areas where i saw fit... do what you want in this area.

In this pic i braced the toe arm mounts together, cusco make a toe arm brace.. but why pay money when some steel and welding can do it for nothing. It has also created a new jacking point more rearward of the car for me. this is 50mmX6mm flat bar btw.

img0152b.jpg

middle re-enforcement

img0155ei.jpg

here i have used a small amount of flat and encased the mount for the rear LCA.

img0153l.jpg

and otherside

img0154fd.jpg

I chose to weld these triangle sections in... its not a known weak spot on the subframe but i had the materials, time and thought why not.

img0156c.jpg

Both sides

img0157zs.jpg

Next up is getting the stock rubber bushes out... this is a prick of a job and there are several ways to do it... the easiest and messiest way is to use an oxy and melt the rubber out and then an air saw to cut the sleve on the side to allow it to fall out after some taps... I chose to press them out using a simple garage 20t press and this still required the use of a hammer and chisel.

img0167ba.jpg

Next up... i threw some paint on it to stop exposed area's rusting. up to you

img0176z.jpg

Also got some new Cazman arms to replace my shitty china spec shit.

img0184ud.jpg

Got some Subframe bushes machined up. this is a design that me and a mate came up with and seems to be good so far. they will allow the subframe to travel up into the body by around 35-40mm.

img0190ro.jpg

They then install into the subframe.. designed to be a snug fit not a press fit. they will tap in with a block of wood to protect the alloy and a hammer.

img0194zg.jpg

they only go in one way :yes:

img0192yp.jpg

img0193ml.jpg

Now you can bolt it in. the shot here shows it test fitted but i find it easier to re-assy the cradle with all the diff/arms and hubs before refitting. Pics show bare cradle so you et the idea of clearances.

p5060209.jpg

p5060210.jpg

Watch the handbrake cables... they do have the potential to be crushed if your not routing them correctly. may have to bend a bracket here and there to make sure they clear

p5060211.jpg

Nice and close... can fit a sheet of paper between the pick up and mount haha

p5060212.jpg

So there you have it kids.. an easy mod you can do at home. Subframe bushes can be had for around $150 so if your handy its not an expensive exercise at all to stiffen up the rear end and increase the handling of your car.

this can be carried out on any Nissan IRS rear end.. for what its worth this is a S14 cradle.

Article by Simon Michelmore

2010

  • Replies 117
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

thats a great write up but useless, unless you are prepared to strip the whole rear of the car..well done anyway ,i am about to do alloy subframe bushes those ones you made look awesome

As many of you know. when you lower your nissan excessivly at the rear strange things happen to the geometrys.. also the driveshafts run at bad angles leaking to breakages and the handling of the car starts to go backwards. Most ppl will tell you to raise the car.. but wheres the fun in that! Anyway what you CAN do is correct the roll centre at the rear by raising the subframe up into the body by half an inch and effectibly flush mounting it. this way you can have a lowered car and correct the roll centre back to where nissan intended (somewhat).

Just a question. How are you correcting the roll centre of the car by lowering the bodies mass further down towards the ground in relation to the suspension geometry. Most people run their cars higher because you need the mass of the car higher to to apply the weight onto the wheels. Wouldn't you need to run massive roll centre adjusters/spacers on your lower ball joints to now correct your roll centre through suspension geomentry? It just goes against what I have been told.

Possibly you should have raised your lower and upper arm mountig points on the sub frame to correct for the lowering of the centre of gravity. I think I have read one of the track guys (Duncan?) did the same mod as you but rasied his sup mounting points to correct geomentry. Its about the cars mass centre and something to do with an angle through your susp arms to where they land on the ground. Your mod would have pushed it out way beyond the wheels?

Its a really good mod to keep your driveshafts in one piece and its also good to see people out there actually working on their own cars and having a go.

Let me know if I'm completely wrong?

yeah you've got slightly wrong.

Your actually raising the subframe further up into the body not lowering the car down onto it.. the difference is the ride height does not change since the strut length is still the same.

when you lower the car by a fair amount two things happen. the axles have a tendicy to break and the susp arms are all at bad angles. your roll centre is also lowered beyound the factory setting and you induce jacking of the car during cornering. there is more leverage acting on the arms and you end up with more body roll rather then less.

by moving the subframe up all the arms get a little more towards where they should be, as well as the axles. and your roll centre is further up towards where nissan intended.

guys who have pineapples sitting between subframe and chassis are just making things worse by again excessivly lowering the subframe and increasing angles.

cutting and relocating mounts is a painful to go about doing things. and even then wouldnt fully correct the problem.

simon post pics of how your LCA now sits with your car lower. mine are pretty well dead flat. also with the front have you re-drilled your LCA / Castor arm up higher to recorect the front?

ps: im not gona add a jacking point in, its all back in the car :blush:

on another note... hows ya lock situation. i designed a weld on knuckle (based on a jap brand) which corrects geomatry in the front end and also gives epic lock. im looking at getting some made (not sure on cost yet), if your keen :)

pics on 32. (17x9.5 + 15) lca lengthened 20mm so -5 offset effective

Image0188.jpg

Edited by 32_Dave
  • 5 weeks later...

after some extensive testing yesterday i can say this is the most awesome mod done to my susp yet.... so much better to drive now!!

and no i wouldnt recommend it for a street car... the NVH levels go through the roof.

It is possible however to raise the subframe but not go the alloy bush route.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • I know why it happened and I’m embarrassed to say but I was testing the polarity of one of the led bulb to see which side was positive with a 12v battery and that’s when it decided to fry hoping I didn’t damage anything else
    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
×
×
  • Create New...