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Post by Al Ramone on Jul 24, 2012 7:19:12 GMT 1
A few of us like to lower our cars, some more then others... so i thought I'd do a little write up on it. This is not a step by step, how too. Just thought I'd talk about the way to go about it and the problems that can arise... Firstly, your car needs some suspension travel. Driving around on the bump stops is not much fun and will either break stuff or just ruin the enjoyment of driving it. Bump stops are there for a reason! don't remove them! Don't cut them down either, or better yet, fitting shorter ones, without at least checking a few things first. The bump stops are a safety item, they stop parts bottoming out. If the dampers bottom out with no bump stop you'll be smashing metal on metal and they will break. Also constantly smashing into the bump stop will do damage, the suspension mounting points are not meant to take the abuse. Another thing the bump stops do, is limit the suspension travel. For a reason. Balljoints, bushes, suspension links, all have a limited range of movement. If you extend beyond there operating range you will bend/break stuff! Also, watch out for brake hoses. If you car is running at a height the factory didn't design it for you may be stretching hoses, which will obviously be very bad if/when the hose fails. Handbrake cables, again, could be stretched and this could lead to the handbrake coming on when you driving along. Not cool. There may be issues with parts getting squashed between suspension parts. The rear trailing arms on a mini for example, has the brake hose on top of the arm and will get squashed when lowering one of them a lot. So check where the hoses are. Steering angles. Wheel alignment. If lowering a lot, some suspension angles can be thrown out. Rear semi trailing arms on a lot of the IRS RWD datsuns will gain negative camber (not a problem) But will also give "toe out" to the rear wheels. This is a problem, as this will cause the car to over steer much more easily. Obviously tracking will need re setting once any suspension work has been carried out. There are ways to deal with all these problems and there are parts available to help too. Once you understand the issues you can deal with them. More to follow. For now have some pics.  This one is the front suspension on a typical RWD datsun. The car has been lowered but the lower suspension arm is still at the normal operating angle. This means the lower suspension links have not been put under any extra stress, which can cause the torsion link to snap..... It's at a correct angle because a spacer has been fitted between the steering arm and the strut body. These are aftermarket and can find them on eBay USA or AU normally. They call them RCA's or roll center adjusters, sometimes bump steer spacers. Rear suspension  A picture showing a rear semi trailing arm suspension setup.  Suspension crossmember showing the mounting points for the arms.  And the adjustable bolts i fitted to be able to adjust the rear camber and toe angles, you'd need to slot the mounting holes first. |
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Post by Al Ramone on Jul 28, 2012 18:52:11 GMT 1
Different ways of lowering. Cutting springs. This works ok if you only wanna lower it a little, say 1-2 inches. you can only do this to springs that are the same diameter their entire length and are not tapered off at the ends. Removing coils and shortening the sping does raise the spring rate a little, not as much as most aftermarket uprated springs thou. The reason you can't lower too much doing this is because the suspension will be to soft and will bottom out fairly easily. Also there may be issues with the springs falling out  when the car is jacked up (at MOT time for instance) or possibly when driving, like over a hump backed bridge maybe? With obviously very dangerous results... You can secure loose springs, either by limiting the amount the suspension drops, like using straps or fitting shortened dampers. Or you can secure the springs. I've done this with jubilee clamps in the past, you'd need to make a hole in the spring cup and run the clamp through the hole and around the spring. Depending on your setup, you might end up using up to 2 clamps top and bottom. Now there's no hard rule as to how much spring removal equals how much drop you get. But as a very rough guide, one complete coil is unlikely to make much difference, maybe half inch? This doesn't mean that removing another coil will drop it another half inch thou.... it could drop it another two inches, depending on the suspension design and the coil itself. Best bet is to go conservative and remove a half coil at a time, you can always remove another coil, but you can't weld bits back on  also it may settle and drop a bit more once it's been driven a bit. as ever, this is just from my experience and you may get different results.... Modifying is dangerous, working on cars is dangerous, getting out of bed is dangerous.... use your own judgment, if in doubt, get someone qualified to carry out any work! |
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rob99
forum Member
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Post by rob99 on Sept 9, 2012 15:24:56 GMT 1
I'm sure this is probably common knowledge but another option is to get Gaz shocks to make up some adjustable coilovers for you. If they've never made them for your model you can send off your shocks and they will make coilovers to suit. It's not a cheap option with my recent purchase costing about £700 but for the money you will get bespoke 'new' suspension that you can easily adjust to exactly the height you want. I hope it's ok to add this! Not meaning to step on any toes!  |
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Post by Al Ramone on Sept 9, 2012 15:34:06 GMT 1
yeh heard of a few people using GAZ with good results. even having shorter struts made up to replace the current ones.
all i'm really trying to do with this thread is give an idea of the problems and things you need to look out for when lowering any car.
but yeh always good to hear from other people, this isn't the alramone forum! ;D
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Post by dave120a on Sept 9, 2012 22:43:59 GMT 1
Cheers Al nice overview. i am looking to find a way of lowering mine a tad and getting some poke on the wheels prior to fitting some arches i bought (only time will tell if it ends up looking like a dogs dinner though). The GAZ option sounds cool but sadly the wallet does not run anywhere near that deep.
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Post by Al Ramone on Sept 10, 2012 18:24:43 GMT 1
RWD offset wheels should give you the poke you need.
them cherries have really long struts and the front arches are cut pretty high, so hard to get them looking low enough.
hope you pull it off. i reget not playing about with the 120A coupe i had as thats something i'd have liked to try.
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jakob
club Member
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Post by jakob on Sept 11, 2012 0:21:59 GMT 1
any ideas on springs that would fit a datsun sunny, probably with a bit of modification ? was hoping i could cut the cost a little..
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Post by Al Ramone on Sept 11, 2012 19:31:53 GMT 1
any ideas on springs that would fit a datsun sunny, probably with a bit of modification ? was hoping i could cut the cost a little.. datsun sunny springs? ;D |
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reece
club Member
Posts: 88
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Post by reece on Sept 11, 2012 22:27:11 GMT 1
any ideas on springs that would fit a datsun sunny, probably with a bit of modification ? was hoping i could cut the cost a little.. On my B310 I had cut down 180b 810 springs at the back and the 280zx front struts with coilover conversion. |
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jakob
club Member
Posts: 43
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Post by jakob on Sept 13, 2012 16:46:23 GMT 1
cheers guys, looked into the 280 conversion, seen it done a few times and its simple finding sunny springs, but its another matter finding them in stock  |
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Post by RatDat on Sept 13, 2012 18:44:14 GMT 1
One thing to bear in mind with 280ZX struts is they have seriously heavy brakes. If you don't NEED the big brakes there might not be much to gain from using them, as it's a hell of a lot of unsprung weight which is never good for ride or handling.
Personally, I've always built shortened front struts using Golf inserts and 2.25" ID coilover sleeves. That way you get full suspension travel and full adjustability to get it sitting right.
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Post by Al Ramone on Sept 13, 2012 20:50:26 GMT 1
One thing to bear in mind with 280ZX struts is they have seriously heavy brakes. If you don't NEED the big brakes there might not be much to gain from using them agreed. in fact i found the braking too front heavy when i had s130 brakes on the front of my 810 estate. So i swapped that over to C230/C210 struts/brakes instead and it felt much better balanced. |
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Post by RatDat on Sept 13, 2012 22:16:26 GMT 1
When I ran them on my 510 I changed both the master cylinder and the rear wheel cylinders for larger ones to get it all working nicely. Once that was sorted they worked well but limited choice of decent pads and the excessive weight means they won't be going back on it. I'll most likely build my own front brake set up (Maybe Brembos) and use the R31 conversion I have for the rear along with a bias pedal box. Not really a very practical solution for a road car, mind.
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Post by datsolow on Feb 7, 2013 21:22:18 GMT 1
On my B110 ive 280zx struts and brakes , changed the master cylinder for 310 for the extra fluid needed.the car stopped really well but rear brakes not so clever , i have excessive hand brake travel not sure whats up?
i will be changing rear axel for english as better ratios and lsd(ford) and 9" rear drums=better stopping
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Post by Al Ramone on Mar 20, 2013 20:37:55 GMT 1
had a few people asking me about lowering, and swaping struts and coilovers. guess it's the time of year when people are starting to think about getting there car out and making it look good. anyways. here's pretty much what i've said to everyone who's asked me. obviously if anyone has anything to add or thinks i'm talking rubbish, please reply here. lowering, and how you go about it... well it all comes down to what you want and how much you'd like to spend. if your happy with the stock brakes and don't want massive lows, then just cut the springs or get some proper ones made. You should be able to find a local company who could make lower/uprated springs for you. obviously make sure the sping doesn't fall out out when the suspension is not under tension. that could cause a big accident... if your happy with the stock brakes and want to lower more then the stock struts will allow, say over 50mm lower, then you'll need shorter struts front and rear (assuming you have struts on the rear). you could send the complete struts off to a company like GAZ, and they will use parts from your struts and return you a set to your spec. so shorter, longer, uprated, whatever. this is prob the easist method and the parts should just bolt back in, no messing about. i haven't done this myself, but have heard good things about them. if your not happy with the stock brakes, then now's the time to look to the larger Datsun/Nissans for differnt struts and the bigger brakes they are fitted with. 200L,240L,240K,280ZX,S12 etc. there are various issues with swapping the front struts about depending on what car you have and what your trying to achive. some are shorter then others but there are other things, like camber change and hub offset, that make each option suit some peoples goals, but not others. |
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