[RbBugBitMe]

LOL my dayjob computer shit the bed so I'm suddenly burdened with free time. Don't tell my wife.

Finally, all of my projects are into one assembly after CMM'ing the knuckle (red things). 18x9 ET32 shown, making good progress on sorting the wheel supply chain issues. Without the rendered colors it looks crappy but I'm pretty sure I've settled on a copper rim and as close to a superfinished wheel center (mirror-like polish) as I can get. The one major redesign I'm going to tackle before I order anything is hiding the wheel hardware.

Should have the shock dyno adapter for BC outer bodies on order by the end of today. As soon as that's delivered the whole kit is getting dropped off at a local short track shop to dyno through the full adjuster range, friction test, rod force test, and a high speed test to see when cavitation starts in the as-delivered spec.

[RbBugBitMe]

I've decided to take my projects to production and became a forum sponsor. I can continue speaking about this as long as its kept purely technical

[ryan@PdVmotorsports.com]

I'm ready for the next steps. I've found a shop on the east coast to work with that uses a CTW shock dyno. This has an added benefit over some other brands because I can create custom test plans like in the pic below and provide them to the dyno operator. Then I can receive the raw data and review it myself from home.

I'm going to be running the following test schedule for straight out of the box F30 BC coilovers:
1) 90F and 140F characterization (example test pic attached) - all 4 dampers
These both start with a rod force test, then two friction tests, and then mid-setting (15 clicks) runs at 0.5, 1, 2, 3, 4, 5, 7, 10, 15, 20, 30 in/sec. I'm looking for gas pressure and rod force, friction, consistency between both front and rear dampers from the factory, main piston high flow characteristics, and potentially the start of cavitation and shim durability issues.

2) Adjuster sweep - all 4 dampers
I'm looking for consistency everywhere. Between both front and rear dampers, amount of force changed per click, and dead spots where nothing changes near full stiff/soft. From previous testing I anticipate this sucking, I already have my own needle profile designed.

3) Cavitation search - 1 front and 1 rear
This is just my synical ass having no faith in the performance of these from the factory. I want to know when I can initiate cavitation.

4) Oil sensitivity - 1 front
This is for the most part a characterization of the oil viscosity change over temperature (called the viscosity index) which will be tested at 90, 120, 150, and 180 Fahrenheit. If you're not aware, the force generated drops as temperature increases and a good oil will be more consistent throughout all temps. There will be some effect due to thermal expansion of the piston but I'm not going to bother parsing that out, its minimal. I may also run into cavitation at 180F which would be an indication that the oil has little or no anti-foaming agents or it wasn't bled very well from the factory. My expectation at this price point is the oil will be some no name shitty non-synthetic and just an oil swap will dramatically improve feel and consistency the driver will feel. Attached graph shows a non-syn vs a synthetic designed specifically for a very high viscosity index (high VI is good, yellow line wins by a lot).

5) 1 front and 1 rear spring and bump stop
Self explanatory

When all this is done, as long as nothing is clearly wrong with any of the dampers I will install them without making any changes.

[RbBugBitMe]

Finally some progress. Data should start coming in soon.

[RbBugBitMe]

Data is flowing.


I'll do a more detailed write up later. All data right now is from untouched off the shelf BC Racing I-41 shocks for the F30 AWD. I'm not going to comment on the tune itself as I've not driven on these yet and don't know what the OEM damper tune is to compare.

at that friction. There should not be hydraulic effects at 0.13 in/sec and -31 clicks but we're doing more testing to try and confirm that.



This is at 15 of 31 clicks. Sweeps are coming.


Upcoming tests include
- Friction at 90F
- Clicker sweeps at 90F and 140F
- Figuring out speeds/clicks when cavitation starts
- Spring and bump rubber rate measurements

[RbBugBitMe]

Unfortunately I can't get a proper friction test due to the limitations of the CTW RD2 2hp crank dyno. It can't go slow enough and at its slowest speed it doesn't have the power to overcome the rod force to actually achieve its speed target so the data is a mess.

Overall thoughts without driving them yet:
- Gas pressures from BC are WAY high. We cut them in half and haven't seen cavitation yet at 30in/s but we're still trying. These are "racing" dampers right.
- Linked to high gas pressure is high rod force and high friction. After a period of initial driving I'll be dropping the charge pressure down a lot.
- I think there are a lot of benefits to be had with a change of oil so that'll happen later but I may buy a spare damper to keep this development work going while still being able to drive the car. Turds are cheap afterall!
- I hate the adjusters. I have a design already to put a check valve in the rod so it will only be rebound adjustable but I ultimately want independent 2-way adjustability at a minimum. Clicks 1-20 of 30 clicks control 87% of their entire range and is too non-linear throughout the range for my liking.
- I have the spring and bump rubber graphs so I'll be playing with both of those. Interestingly, I was told I was getting 12kg/mm front spring but you really have to focus your measurement over a very narrow band near max compression to get down to 12.3kg/mm. Most of the travel is averaging 12.7-13 kg/mm. It's never good when you don't actually have what you think you have. The rears were stated as 6kg/mm and are 6.1-6.2.

[RbBugBitMe]

I've finally gathered all the dyno data and made a video review of brand new BC Racing coilovers. TLDW, the set I got is hot garbage.

[RbBugBitMe]

I made another one cause I was so frustrated at how many positive YT videos there were on BC Racing.

[Jvac]

In my research for aftermarket suspension parts I found there's very little truth in advertising, and no real data from the manufacturers to help one make an informed decision. Vids like this expose the dirty secrets they aren't telling the customer

[RbBugBitMe]

More parts came in! I can't wait for this cars transformation, I am moving to a new house in July and then I can start installing everything.

Just received the new spherical rear shock mounts.


And the Wilwood caliper brackets. These will install on various rotors with custom spacers and Ti heat shields to get the correct piston offset for the pistons. I'll probably start with the 370mm rotors before testing my floating rotors.


I can start mocking up for custom brake lines and getting these bits anodized.

[mike082802]

any updates?

[RbBugBitMe]

Not yet beyond some more IG posts on inspection, anodizing, and laser marking. My day job is a startup has been crushing me as we approach our first PO so I haven't taken the time to just put the parts sitting next to me on the car. Very frustrating but I'm hoping I'll be able to breath the first week of December.

[RbBugBitMe]

I'm currently editing episode 3 where I finally get the shaft bearing off of my spare S60R damper and spend the rest of the video talking through my process of reverse engineering and CAD modeling. At this point I'm focused on getting new shaft bearings quoted that have a rod seal I've worked with in the past and has significantly lower friction. So ideally my first rebuild will include a new main shim stack tune, better shock oil, lower gas pressure, and improved bleed with a vacuum bleeder I'm creating. Depending on timelines and costs I may also have a check valve for the bleed circuit ready which will make this a proper 1-way rebound adjustable shock.



The very next step will be to adapt the shaft bearing and seal designs from the S60R to the F30 dampers while I'm driving around on the as-built kit and probably playing with spring rates.

[RbBugBitMe]

Hooooollyyy shit BC NotRacing is terrible. Absolutely terrible default setup front and rear but the front takes the cake.

So I'm still not driving on them yet, that'll come by this weekend after I overnight some new springs. Might as well start the review now though since I had to quit for the night and grabbed a whiskey to add color to my commentary.

If you don't know me and haven't read this thread, damper design has been my career for 10 years now and I popped my cherry in F1 and LMP1 back in 2014. A lot of my time with IMSA sportscar customers was spent spec'ing new dampers based on whatever the customer sent me that they weren't happy with. This is where I formed my opinions on various brands. Ohlins, Multimatic, Penske... spectacular. KW, Sachs, Moton, Koni, and some others all made it to the professional level but were garbage.

QA1, BC NotRacing, ST, Silvers, Fortune Auto, Taiwan garbage brand X, Y, Z... don't exist at that level so I had no experience with them until now. Obviously from the dyno graphs in this thread, BC shouldn't even be in business let alone the largest most recognized Taiwan brand there is.

Anyway, before rebuilding these turds into something that works I bought their "default" setup. Whatever lengths and strokes they deemed necessary TO GO WITH the springs they "suggest". That would be 6kg front and 12kg rear. Now, these rates really make no sense for the F30 but I needed to evaluate what I assume many of my future customers have ordered. Most people don't know what spring rates they want and why so they trust the manufacturer to do their homework. These rates are also the softest they offer in the drop down list on their website which makes sense for me because I do not want to go any lower than the damper design requires me to. That's a loaded statement, if you don't understand it just ask.

So the bits arrived and had the always exciting unboxing day. Where to start...

The first thing I did after shipping them off to get dyno'd was reverse engineer everything I could in CAD without physically opening up the dampers. Many red flags popped up, the shitty hydraulics were already covered on youtube. The mechanical design has become my hell now.

I focused on the rear first because the decoupled spring/damper was more complex to plan the setup for. Ultimately, I determined the least amount I could lower the rear and the spring preload required. My other recent thread links to my blog explaining how fucked everything is regarding preload. I currently have about 2 threads left on my rear spring adjuster which is not good. I don't feel safe with that and need a longer spring before I consider this my daily driver and would put my kids in it again. What BC NotRacing should have done was provide a longer spring for the 6kg rate ORRRRRR sold the kit as a required 1" minimum drop which they don't do.

The front. This effort was saved for last and damn I wish I didn't. They supplied a 6.7 inch (170mm) long spring for a damper that has over 4.1 inches of stroke. That means the spring has about as much but possibly less travel to coil bind than the damper. What the ever loving fuck??? To top it off, the damper body has about 8ft of unused thread for the spring perch so its not a packaging issue forcing them to provide short springs.

Just so I'm super friggin clear, if you bought these piles with 6kg springs you potentially could follow their shit install instructions and coil bind. If you did follow their shit instructions, you're less likely to coil bind but you'll have way less jounce travel than you'd really want. Way less. Might explain a lot of the front camber plate noise complaints on this forum...

Edit: I think at this point, the plan is going to be to complete the turd polishing project and sell these. I want to switch over to polishing STANDARD brand coilovers because they make inverted struts ( ) and the factory is willing to work with me directly unlike BC NotRacing.

Also, I forgot I had the springs rated when the dyno work was done. I wasn't there to see how much travel was left but he was able to measure force up to 100mm. So still not clear how much travel these springs have but at least its 4 inches. They are closer to 13kg/mm than 12kg though.

[erball]

Late to the party here, but I've been following this on YT. Is this project making any progress?

[RbBugBitMe]

None in the last couple months. Day job is beyond ridiculous lately.

Always trying to get back into it and need to finish my brake project too. Cool custom shit just lying around doing nothing.

[mapyn]

Following

[RbBugBitMe]

Happy new year! After 6 years and 18,000+ hours of my time, our first customer finally announced our product to the world. This is what keeps me from making all my cool stuff.

[mapyn]

looks good. General opinion is the lotus system from the 80s failed because they couldn't commercialise it, presumably you've beaten the cost issue now, modern electronics etc..

[Alpinadrachten]

I think you can be very happy with this when you are in the engineering part of in this case suspension.

Are you also happy with the result? End result is always cost driven.. so can always be better when more money is spend on that particular part..

[RbBugBitMe]

Originally Posted by mapyn

looks good. General opinion is the lotus system from the 80s failed because they couldn't commercialise it, presumably you've beaten the cost issue now, modern electronics etc..

The Lotus system is more aligned with what Mercedes is trying to do with their system today, one central pump feeding all 4 corners. It works for primary ride control (2-3Hz roll and pitch movements) so you'll never see a system like that (by our estimation) be able to do this wine glass stunt at the speeds we do it because it can't control the actuators fast enough with long squishy feed and return lines. Extremely high pressure though so they'll wow everyone with driving on 3 wheels and whatever else they do. Our goal, to be the best and adopted by the most OEMs, is to enable a smooth enough ride you can comfortably work on a laptop with the coming slate of self-driving cars. We're also at the forefront of automotive motion sickness mitigation research.

Originally Posted by Alpinadrachten

I think you can be very happy with this when you are in the engineering part of in this case suspension.

Are you also happy with the result? End result is always cost driven.. so can always be better when more money is spend on that particular part..

Well as with most new tech its certainly debuting on the most expensive car they make for a reason but it will be pretty reasonable in the future on higher volume platforms. I'm already working on the next gen design for that purpose.

Am I happy? Hell yes. I'll be happier when we IPO though

[RbBugBitMe]

I do have an update to share finally. Spent the entire week blowing off work to finally figure out how to eliminate spherical bearings from shock mounts. This is the rear design replacement and I'm really hoping I can get it to work on front struts too.

https://www.instagram.com/reel/C1xl6...cxMWMzOWQ1OA==

I am intentionally, for now, going nuts on the design and I'll try to take cost out later. Everything in orange is Titanium. Not sure yet which grade of Aluminum the teal will be yet. The silver jounce bumper piece may be stainless but depending on quotes I may go with a more typical heat treated steel. Instead of anodizing I'm going to give Cerakote a try and hopefully end up with the color combo I have in the video with the silver jounce bumper piece being something super shiny/polished.