I just fitted a set of BC Coilovers BR series, and thought I would share my experiences of fitting and setting them up for anyone thinking of doing the same. The car may go out on track in the future, but for now, the focus is for fast road work, b-roads. Hoping the photos show up in the thread and apologies for its length! I’m a competent mechanic – always worked on my cars over the years (I’ve just hit 50) and like to do a neat job. For some reason, I thought the BC’s would be bolt on, a few quick settings, and good to go. I’ve had to learn all about suspension setup! The geometry (ride heights, camber, toe, potential corner balance) has taken longer to fine tune than the fitting tbh. It has been satisfying doing it though. Car is a 27k miles 275 Cup-S. Most nuts and bolts are still un-rusted and free moving, which is a relief. The Cup suspension feels good to drive, but sometimes goes ‘floaty’ over fast rises in the road, and a jiggly ride on rough roads. I couldn’t justify spending over 1k on new suspension, so BC’s offer lots of adjustability and control. I opted for the 4K rear/7K front spring rates - more comfortable ride, with changing the shock damping for control. Fitting Fitting was straightforward – only broke a Torx T-40 on the brake disc retaining bolt. Drained the gearbox oil, just in case the drive shaft popped out. Old front struts and rears out, and then cut the strut top mount with a 76mm hydraulic punch, for easy camber adjustment. I used a high torque Impact Driver to pull it through (The big black bolt and washers were bought separately), and it probably took about 30-seconds of winding in the lower punch part to make the cut, which sounded terrible – it thought I had knackered it, but it is just really noisy. The cut is really clean and after filing-off the sharp edge, it was easily touched-up with primer and paint on the cut area. The strut towers only have the base coat paint on them, no top lacquer coat. There’s another thread on here talking about this cut making the strut tower weaker – it’s your call and risk to take. I think it’s ok for the softer setup I’m going for. Minimal metal is removed which you can see from the pic below, and the strut tower still has its strengthening features from the shaped pressing around the top bolts. I also added a strut brace to add more strength, just to be sure. Interestingly, the strut brace was fitted a couple of months ago to the stock suspension setup, and it made an improvement. I know there are sceptics on this forum, but it made the suspension slightly less busy in feel – more controlled – and in particular tight turns, eg roundabouts, were tidier with more grip. Also fitted 10mm Pure Motorsport spacers to the rear hub (you can see them in the pic), and 10mm conventional wheel spacer to the front. Some weights: Front Strut (Renault Complete with rubber top mount): 9.8kg Front Strut (BC Complete with metal top mount): 5.7kg Wiechers GW387013 strut brace 1.65kg before underside strut tower: After top side: Driving it Initial ride heights set to -30mm front and -25mm rear, and roughly 1.5 degree camber. Had the front shocks set to 6 from soft and the rears 3 from soft. The drive home wasn’t great – dips in the road bucked the front of the car up at speed, and pot-holes/broken tarmac were really rough. It was really disappointing. I found a good post on line on Turborenault, where someone with a Mk2 has done a good writeup of suspension setup. So I used these settings the next day – same ride heights, but front camber -2-degrees, -10’ total toe out (discovered that it was on +30’ toe in due to fitting the BC’s), and front shocks set to 4 from soft and rears 8 from soft. This made a massive difference – I mean, really surprising compared to the first drive out. The ride comfort is better than stock Cup – and the control over rises and depressions is similar to stock, but the jiggly feel over rough roads has gone – you feel the bumps as before, but less busy. Cornering has less roll and seems to have more grip and more controlled, but it has been icy, so not pushed it. I hear no more road noise than before with the hard top mounts vs. the stock rubber mounts. I also don’t feel any additional harshness through the steering wheel. I didn’t change tyre pressures from recommended, so they are set to non-motorway pressures (29 rear, 32 front). Tyres are Goodyear F1 Supersport front and some older Pirelli P-Zero nero on the back (which don’t have as much grip as the Goodyears imo). Thing is, to get the ride height perfect, each corner has now ended up with slightly different spring/strut lengths, which I now know means the corner weights of the car are unbalanced. Best way to explain this I read, is like a four legged table, with one leg too short – it rocks about. So I’m going to go through the whole setup again, around the car, to try and balance the strut and spring lengths (no - I don’t have the funds for corner scales). I also had to invest in a better digital camber gauge and will probably replace the BC drop links with some adjustable ones, so there is no pre-load on the front roll bar, because that has got to help? I also think that I will set the ride heights this time by disconnecting the roll bar drop links and perhaps unbolt the rear shocks and set the front shocks to full soft, but would appreciate any view if that is necessary. And that’s where it ends up… I could take it down the road to Abbey for them to setup , but i’m being drawn into the wormhole that is suspension setup… and it’s really interesting! Would love to hear what settings anyone else is running for a Fast Road setup.
@BillyA Good write up there I had CGR fit and set my BC's up well over two years ago, i went full on 10kg front and rear, set up for track use, use the car to drive to and from track but i'm more interested in its track abilities. I saw them use a 76mm hole saw to cut the tops out, the punches look a lot cleaner and quicker. My turrets were never strengthened and i have never had any problems with them on the road or track, i must have done 30+ trackdays and 35+k miles on the road, trips to Spa, the Ring, Bilster Berg and loads of UK tracks, i also don't run strut braces either. I also run 255 tyres on track and have run full slicks as well. My car had 82k on it when i had the suspension fitted, it now has just under 120k miles on it, now fully forged and running 388hp, 390ftlb torque, only managed 6 trackdays last year at that power and the car still handles as it has since the fitting of the BC's. I had the 19 inch wheels fitted, i ran them at what was recommended in the hand book, so 38 front and 34 rear, even ran those pressures with the 18's and hot on track, i did run lower pressures 32 front and 30 rear but the fronts folded in and lost pressure. I drive on the road with a max 5 clicks front and rear, i think its very good on the road with that setup, i also run Goodyear's (all round) but they are Asymmetric 5's, they are great on the road and absolutely fantastic in the wet on track.
Thankyou both for your reassurance and advice - I appreciate it. I’ll tweek the heights and geo again this weekend. Helps to have a pit to work under it too! I also love Goodyear F1’s in all forms - they were the best handling tyre on my R26 and I really like the Supersports on the 275. Their big rim protector has also saved my alloys from curbs a couple of times parking. The biggest surprise for me has been the effort needed for setup and adjustment of the coilovers. I’m so used to bolting stuff on and off and it just working, but when a minor suspension adjustment changes another, it really needs some thought and iterations to get right. Just didn’t realise when I set out to fit them. Another thing is the ride quality of the BC’s - they are bad when the geo is out, but feel really good when the geo is correct. I have read such conflicting reviews about their comfort and ride, but everything I’ve experienced so far suggests they’re alright. Time driving it will tell. And for the price point, there’s not much else out there with the adjustability. btw - the strut brace gets properly hot on a motorway run! Acting as a perfect heat soak for turbo, Down pipe, & everything else. I don’t think it will be a problem, but I removed the rubber seal at the back of the engine for air flow, just to see. A bit of water and dust does get in to the engine bay and I don’t want that either, so I put it back...
have thought about fitting cross strut, but as gap between top mount and A pillar is small this suggests vehicle rigidity is already strong unlike say a beemer with a larger gap and a brace works well you feel it makes a noticeable difference @BillyA
Yes - a small but meaningful difference - on stock suspension. I haven’t had the BC’s on long enough to tell for them. I understand that the suspension turrets in the Meg are really close to the bulkhead, and this makes a rigid structure already. So I wasn’t expecting any change to the feel when I fitted the strut brace on the stock Cup suspension - it was just to see how it fitted for when I got around to doing the BCs. But as mentioned in the first post, it tidied up the handling - less busy in corners with more consistent grip on tighter stuff like roundabouts (better turn in feel). Is it worth £150? Not sure about that. But it increased my confidence and with tuning the Meg I think it is prob small improvements like this which can refine it further .
thanks for your input re the strut, if you're liking a tighter turn-in you thought about upping the front and rear bushes to harder compound ? makes huge improvement to turn in and general rigidity also replacing lower stabiliser bar and upper engine mount
Thanks Bobsan. I’ve already done lower and upper engine mounts - made a positive difference to gear change. Not done bushes yet though. Another great project to keep my sanity if Lockdown continues
This is the way to do a good job. Congratulations man! Thanks for share it whit so fine explanation. But I confess, I am one of those sceptic that you say about the strut bar, but comment like your make me doubt. Anyway, keep us informed about next experiences with that gray machine!
Some more info for anyone considering working on the front strut mounts, or fitting a front strut brace to stock suspension: With the car sat on level ground, if you need to remove the top mount nuts in the engine bay, perhaps to test fitting of a strut brace, they can be removed for investigation and the suspension strut will not move - it was just something which concerned me. Re-torque to recommended 21Nm when refitting. I did a fraction more torque and also used some medium threadlock compound, just for peace of mind, when I fitted the strut bar. Fixing bolts Photo shows the standard Renault top mount fixing bolt, with captive washer, on the left. The Wiechers supplied bolt and washer in the middle (+ badly deformed washer, due to the uneven top mounting surface on the brace). And on the right, a nice replacement cap-head option, with a thick washer, both sourced off ebay. The thick washer is excellent for use with either the Wiechers bolt or cap head bolt. I also used this thick washer over the BC Coilover mounting studs and strut brace, which allowed the BC top nuts to clamp-up really nicely. The mounting groove around the hole on the strut bar is pressed – it is not machined – so it is not a particularly good clamping face for a thin washer, which is why it deformed. The underside of the strut brace mounting is machined – so you get a good, even contact with the turret surface. Some dims: Renault stock fixing: Bolt: M8, L=22mm (13mm socket head). Washer: 2mm thick, d=38mm Wiechers supplied fixing: Bolt: M8, L=30mm (13mm socket head). Washer: 1.7mm thick, d=24mm Caphead & washer replacement: Bolt: M8, L=30mm (6mm hex head). Washer: 4.0mm thick, d=21.0mm Top Mount Photos show the top mount fixing hole for Cup suspension, from top, underside and side view: 5mm of threaded depth. The body turret metal thickness is 2mm. this means that with the Renault stock bolt, which has 20mm of exposed thread (i.e. not including the 2mm washer), there is approx. 13mm of exposed thread on the underside of the topmount. If you fit the strut bar, it has a mounting thickness of approx. 3mm, so any of the bolt options are fine when you consider the stack-up mounting depth. Hope this helps someone who is working on the front struts
What a superb, informative thread. Like every traditional forum this place has seen traffic decline but this is a great example of quality over quantity.
Glad you find it interesting and thanks for the encouragement just in case you were wondering what’s underneath the front strut tower, in case you never looked, here’s the Renault top mount in all its glory at 27k miles! and finally a side profile: The raised rubber section in the middle of the top face, where it meets the surrounding flat area, measures 81mm diameter. The highest point you can see is approx 65mm diameter, which is where it touches the underside of the body turret, around the turret centre hole (which is 47-48mm diameter). There is also some contact with the turret in the areas around the mounting holes (of course), which is shown by slightly different coloured/shine on the surface.
I think as it's suspension then i would have used at least 8.8's or 10.9's A2 is okay for decorative stuff it can still rust though, A4 is proper Stainless but its very soft compared to mild steel
Agree whit Ian, 8.8 would be fine to keep the whole shock in the strut, in the case you raise the wheel of the tarmac!
The tensile grade of the bolt will probably be stamped on the head - either 8.8, 10.9 or 12.9. Just replace like for like. There are far worse places you could have used those A2's, but they still need replacing. I'd personally use hex head bolts unless there is an issue with access - less prone to stripping and/or breaking the tool being used to undo them.
Makes complete sense. I just checked and the Renault bolts are stamped 8.8 and so are the Weichers. I never used the capheads in the end - They were just my backup option. It now has the BC nuts, because the coilovers have studs fitted in their top mounts, so all good.
Hey mate!! I've been looking for the MK2 post on Turborenalt you mention about but I can't find so far. Do you still have it around?. I would like to have a read to it
What bushes are these bobsan? Thought about doing bushes a while ago but thought might be to much work, you have me intrigued now.
there's few places that supply either Superpro or Powerflex bushes for lower front arm, ARB and rear swing arm heres one example tinyurl.com/4wuafmoy
Cheers will check out, think this will be my next alteration, I thought before would need to do every single suspension bush to make it worthwhile/do complete job.
Thought I would post a follow up. For the BC shock settings, I’ve settled on clicks from full soft: 7 front, 8 rear. Feels controlled but comfortable and I prefer it to stock cup. I also fitted some adjustable drop links, because I wanted to replicate the stock angle and loading on the ARB: Even though the rears and front coilovers are set identically Left to Right, I had to slightly lever-up the ARB on one side to get the drop link to go in. I think that put the ride height out slightly from left to right (I measured 8mm difference at the front). I think it also slightly pre-loads the ARB, which unbalances the suspension – I want the geo setup as good as I can do it. Because I’m learning as I go, I’ve shared it below for anyone else thinking about it, so I’m sorry if this is simple stuff for the experts out there!: I did a quick drawing to calculate the ideal ARB drop link length, after lowering 30mm: Stock on the left and BC coilover + 30mm drop on right. When the car is lowered, the drop link top mounting does not change height – it’s part of the shock body, attached to the hub, attached to the wheel. However, the other end of the drop link is attached to the ARB, which drops with the rest of the car (by 30mm). So this means you would need a longer drop link than original factory. What I didn’t consider, is that the drop link mounting point on the BC shock, is lower down the shock body than stock Renault shock, so it is already closer to the ARB and actually a shorter drop link length is needed. To match the original factory ARB geo, I calculated 259mm drop link for a 30mm drop. Here are some photos of the drop links, with OEM Renault compared to BC supplied (the black ones) and then to Superpro: The Superpro links are built like tanks and they also weigh more (if you’re interested): Renault OEM - 250g (274mm) BC link - 400g (250mm) Superpro Adjustable - 500g (254-305mm) I fitted the passenger side adjustable drop link at 260mm, then put the wheel back on, put shocks full soft, dropped the car back on the ground and got into the pit under the car to fit the driver’s side. Drivers side drop link went on at 265mm length with no load up or down on the ARB, so that’s close. I might even the drop link lengths at a later date, but probably not necessary. Does it make a difference driving it? I think there’s a bit more precision and predictability around corners and in general. Maybe it’s placebo, but I’m happy with that! Probably the engineering of the drop links too – I cannot see them flexing any time soon – they are rock solid. I also do the tracking each time I’ve changed a setting – it is surprising how far out it goes. I use the Trackace Laser Wheel Alignment Guage, which I think is the best £80 I’ve ever spent on DIY tools – such a great piece of kit, if you are careful setting it up. Next mod might be wider spacers from 10 to 20mm all round, to give a more aggressive stance. I’m running the stock Tibor alloys. But I am worried this will screw-up the cornering – be interested to know what anyone thinks. 10mm seems to have caused no handling probs with the coilovers on my current settings.
setting drop link is relatively easy with just few easy steps to follow -only need 1 adjustable link on any vehicle (either side doesn't matter) -when setting up geo only disconnect the 1 adjustable link (leave other connected) -only connect the link after absolutely everything else is adjusted (ride height, tracking etc) and road tested -finally make sure the vehicle contains the loading its most used for ie single driver, driver and pax, all the family etc then adjust the link so it fits loosely into the ARB with zero tension on bar, every vehicle is different there's no fixed length working on your own ?? B&Q sell 20kg bags of sand to replicate occupants weight
I love the bags of sand method - I was trying to think how to do that and couldn’t think of anything! I know dumbbell weights can be used for the driver weighting but I don’t do those.
Quick update on the BC’s - I’ve gone stiffer on the front springs. From 7kg to 8kg. Reason was that the front was bottoming out on rough B-roads just a bit too much - running out of spring travel. Running the shocks at 11 from soft felt comfortable, so didn’t want to adjust them any firmer to compensate. The 8kg only make a slight difference, a bit firmer ride, but it has reduced the bottoming out whilst remaining comfortable. Doing the job, I was really hoping I could just wind the springs down to avoid taking the whole hub off, but tbh once I looked at it, seemed just as quick to get the hubs off again. Anyone done it the other way to get the shocks/springs out?
nice work, you get the pre- load set correct on work bench before re-fitting the units ?? could you feel difference between 7nm and 8nm, lot folk go 10nm, i'm on 7nm and thinking going firmer
I had 10kg front and rear on mine, thought it was quite compliant on the road, way better than the 8kg setup on my R26
I set the preload one spanner thickness as recommended. Spring is nicely clamped in place. I really like that it is just £70 for a pair of springs (and add the nub nuts to that) which makes it easy on the wallet to try out different springs. It does make a difference to the ride - it is slightly firmer, but still comfortable. The best bit is less crashing around at the spring limit! my setup is for fast road, not track, so some comfort is important, which is why I didn’t go any higher on spring loading, but interesting to hear what Ian said above about a 10kg not being as bad as expected. I don’t want to go that far and 8kg solved the problem for me (i’m still running 4kg on the rear, set 10mm higher than the front, with slightly firmer shock)
