Weekend/Track car build

[dmytro98]

April 2022 - LSD

Setup
I ended up going with an mfactory metal plate v2 (MF-TRS-10E90) lsd as It seemed like a good budget option and was curious about it since there was no information about it, and couldn't find anyone else running it. Since it's adjustable I took recommendations from mfactory for setting it up and ended up with 25/45 ramp angles, 100% lock and 120lbs of preload.

Installation
I had a shop install the LSD into a used auto diff to get the 3.73 ratio. I also got the solid bushings kit from turner when I installed the diff into the car. If I wasn't replacing the bushings it would have been a very quick job as I didn't have to remove anything to get it in or out.

Impressions
After following the break-in process and changing out the fluid I took it for a proper test drive on some back roads. It is very responsive and you can really mess with the engagements on long corners depending on how much throttle you input. The car feels like it's getting every drop of power it can to ground, and I do enjoy the additional stability under braking. One major downside is how obnoxious this diff is at slow speeds. It literally sounds broken and very jerky, but all that goes away once you get up to speed or just simply drive the car hard. Overall I'm very happy with how it feels at speed but would not recommend it to anyone that wants to daily their car.

diff noise:

Camber plates
I went with vorshlang plates as it seems like they give the most camber possible for this chassis and just seem like quality pieces. Install was very easy and even though I haven't had an alignment I can feel the additional camber. It feels like my car finally has some front-end grip. Before I felt like I had a good turn in but it would let go mid-corner, but that's all gone. The car finally feels balanced.

Brake Ducts
As there were no good off-the-shelf options for brake ducts except the ones that go into a lip I made my own. I started with a cardboard prototype to see if it actually fit, then recreated and improved it in Autodesk, and printed it out with PLA filament for the final product. I went with 2-inch high temp hose but I could have probably made it work with 2.5 inches. For getting it to the rotors I just used some 2-inch aluminum flanges that I bolted on the heat shield after a little bit of cutting with an angle grinder. I'm happy with the final product except for the tubing. I bought 1 ply hose which has the wire support exposed on the inside which makes it very fragile. Just kinking the hose has the wire get dislodged from it's supposed to be, making that section of the hose collapse. I'm going to replace it with 2 ply hose but for now, it's fine.

[Dieselboy]

Great work so far. Curious as to which ducting you bought, as I am working on a similar configuration. I got the 2" ducting from Amazon (https://www.amazon.com/dp/B0792QD7KC...roduct_details) but haven't messed with it yet (it was the only 2" brake ducting I could find). How did you mount the duct into the dust shield to the rotor?

[dmytro98]

That ducting you have attached looks like what I wanted to buy since it doesn't have the wires exposed, but I think 3 feet might be a little short for each side. I think I used 4-5 feet per side on mine.

For mounting it to the heatshield I bought some aluminum flanges (https://www.aircraftspruce.com/catal...uctflanges.php), cut out some of the heatshields with an angle grinder, and bolted them on. Then used a hose clamp to hold on to the ducting.

[dmytro98]

June 2022 - Seat Time
Finally took the car out on the track since the recent wave of changes and overall it feels great. I'm gonna break down the different areas that were improved or need improvement.

Fastest lap from today at Pueblo Motorsport Park

https://www.youtube.com/watch?v=I8vm...hannel=Slowe82

Braking
I can safely say the brakes are finally sorted and I was able to beat on them for the full 20-30 min sessions without any issues. With the combination of new pads (Ferodo DSUNNO), bimmerwold brass caliper bushings and my custom brake ducts the car has no issues stopping from 120mph to 70mph lap after without any vibration or fade. I forgot to bring my temp gun so I couldn't do any tests to see how effective they were.

Power
With all my local tracks being at about 5000 feet of elevation, power is always going to be a struggle. With the headers, milvs n54 intake manifold the car certainly still doesn't feel fast, but it is noticeably quicker than it was stock and I think closer to sea level it would feel just about right. Also I added the n2mb wotbox for no lift shift, and it just makes it that tiny bit quicker through shifts along with giving me the ocasional BANG on upshift which is very satisfying.

Drivetrain
The lsd is very noticeable, in a good way on track. I can really play with the throttle to make the diff lock and feels great on corner exit or going over rumble strips where before it would just spin the wheel on the strip. The 3.73 gearing also helps making the car feel that much quicker and letting me stay in 3rd for my local tracks. I would still like to add more solid bushings for the trans and engine to really dial in shift feel along with an rtd shifter, but that's a minor addition.

Handling
The only change I've made here since the last track day is swapping from dinan-fixed camber plates to vorshlang plates. I have both the camber and caster maxed out but I haven't had an alignment yet but my guess is somewhere around -3 to -3.5 degrees of negative camber from what other people have reported. The car always had good initial turn-in but mid-corner grip was always a struggle and the plates made it better but it's still lacking. Not too sure where to go from here. my alignment should be -3.5/-2.2 camber f/r and toe about 0 all around. Stock sport sway bars. Revalved Ohlins with 70/120nm/mm springs. Some options I was thinking of was taking out some camber from the rear down to about 1.7 or stiffening the rear with either stiffer springs or a stiffer rear bar. Open to suggestions on this. It could also be my diff setup too aggressively, but even under coasting or maintaining throttle where the diff feels open/slipping it still pushes so I don't think it's that but I also have no clue what I'm talking about.

[Mach3M3]

Your diff ramp angle is 45 on decel so that's going to be quite a bit of lock on decel which will result in more understeer on entry. You're going to have to adapt your spring rates to that reality. Also, 120 lbs of preload is pretty high and thats also going to worsen the situation. For reference, my setup is 30/90 with 60 lbs of pre-load.

In terms of more front camber, dont throw away your dinan camber plates. You can stack those with your vorshlag plates and attain more than 4 degrees of camber. My current setup is a dinan camber plate on top of a GC camber plate that I machined part of it off and I can get more than 5 degrees of camber this way (I mayyyy have cut a bit too much off haha). How tall is the top of your shaft sticking out of the camber plates? You may need to machine away some of the strut tower center hole for clearance.

[dmytro98]

August 2022 - Interior
This update primarily focuses on Installing my half cage along with some additional weight reduction.

Carbon Sunroof Delete Ordering
For weight reduction, my major weight savings was my sunroof delete which I got from nelson racing wheel. The wait time ended up being nearly 4 months from when I initially ordered and trying to get order updates were impossible. Since I was local to them I was able to pick up the sunroof delete in person and it reassured me it was worth the wait. It was a pretty small shop with only a couple of employees hard at work but were able to give me a quick tour and were super friendly.

Sunroof Delete Installation
Installation was very straightforward and fit nearly perfectly. Since I got the "street" version it came coated and had a foam seal so there was no need to apply any additional sealant and after an unexpected heavy rain I can report not a single drop made it in. Also just to clarify this product is full carbon fiber and not just fiberglass with a carbon skin on it.

Weight Reduction
I weighted my sunroof at 35lbs and the delete panel weighted basically nothing, maybe 2 or 3 lbs. I also cut the rear half of the carpet so it only covered around the door trim but everything behind the front bucket seats was cut out. I didn't get an exact weight but it was around 10lbs. I also removed the last of any sort of carpet/carpet liner that was behind the front seats. Also with the sunroof deleted I choose to not run the headliner so I ended up removing everything from the roof and a-pillars including the curtain airbags. In total I removed about 65lbs give or take. The last time I weighted the car it was 2980lbs with a full tank and all other fluid but no driver, bringing me down 2915lbs, which I think is pretty good since I still have all of the speakers, ac, heat and basically a full interior from the seats forward.

Autopower Race 4 Point Roll Bar
When it got delivered it came pretty banged up and the paint was pretty terrible, but not a big deal since I didn't pay any extra to paint it but it wasn't good enough. I ended up sanding it down to basically bare metal and painting it a gloss black to match the calipers and paint. After painting, it was a pretty simple, but scary install since I'd have to drill a bunch of holes in the chassis. Fitment was pretty decent however without the headliner, it leaves a couple of inches of clearance between the top of the bar and the roof. Also, I weight the cage before installation and with all the hardware it weighed about 60lbs.

Conclusion
Removing that last bit of carpet did make it noticeably louder on the interior, but since this is primarily a track car it doesn't bother me. Also not sure if it's a placebo but it almost feels as if the car is a little stiffer from the cage but I have no way to really figure that out. And with my weight reduction, the car is 5lbs lighter and now has a rollbar. The next step is to install the harnesses. I mounted the anchors for the 6 point, I'm just waiting on paint to fully install them.

[Dieselboy]

Nice work! I've been pursuing weight reduction with my build as well. Have you looked into the lightweight batteries yet? You could shave 50lbs right there, and more with the trunk tray delete cover.

[dmytro98]

Definitely planning on doing some sort of lightweight battery, just waiting for either the one in the one series to crap out or for the one in my x5 to crap out so I'm not wasting a good battery. I haven't looked much into the battery tray delete, but that sounds pretty simple. Do you know how much weight that would save? I also remember someone talking about relocating a lightweight battery into the engine bay since then you could remove the heavy power wires from the rear to the front of the car but wiring sounds scary. Wiring in general would be a good way to save some weight since at this point I'm probably not even using half of the wiring, but again wiring is spooky.

The only other weight reduction I really have planned is carbon or fiberglass hood and trunk along with cowl filter delete. Also a lightweight flywheel but that would mostly be to make the engine more responsive on downshifts since I didn't realize I would like it until I bought my 350z that has one and being able to just breathe on the throttle is nice. I plan on still keeping the car somewhat streetable, so I want to keep creature comforts like heat/ac, speakers, door cards, and center armrest, and a little bit of carpet for front seat footwells

[amg6975]

2915 lbs? Damn. I have a very similar amount of weight reduction but went even farther with harness trimming, rear speakers, subs, AC and couldn't get below 3200. The S65 is around 40 lbs heavier than an N52 but we're still 200lbs off...

Do you have your F/R weights?

EDIT: I also have a DCT vs Manual so that's a bit of it there. Still curious about cross weights of your car.

[dmytro98]

I just used a truck scale to weight the car so I don't have any cross weights or anything. Also 2980 should be the total weight of the car. The 2915 number is the weight after I stripped it, but just without the cage, which weighs about 65lbs. It could be that one of our scales are off, but I was planning on going to reweigh the car to verify my guestimate, since the last time I actually weighted it was before the additional weight reduction and cage. It could also be that the full drivetrain of the s65 aka engine, trans, driveshaft, clutch/flywheel, diff axels, and brakes if you went with the m3 ones make up that difference.

[Ab28]

Great thread...I believe I reached out to you via IG regarding the sunroof delete. Still waiting on mine!

As far as weight goes: I'm pretty sure you are SPOT ON.

I put my 128 on race scales at Watkins Glen back in May.

Before installing the same Autopower cage I was at 2858 lbs. If you add the 60lbs in for the cage I would be at 2918.

This was also just after filling up the tank completely, both race seats, and the larger stock battery.

With half tank, one seat, and the race battery I'm at 2793 before I get in.

Not sure how much gas you had in the tank. I'm guessing less because you have a full front interior still (carpets/doorcards/radio/center console)

[dmytro98]

So when I weighed my car I had about a 1/3 of a tank, and I just did the math on roughly how much weight I would add from filling it up and that is where I got my 2980 number before the cage and further weight reduction. The additional weight reduction and installation of the cage was me just weighing things I took out and weighing things I put in, but the current weight should be 2980 with a full tank.

[amg6975]

I'm thinking the V8 DCT is probably a large source of my extra weight. The diff, axels and stuff probably add marginally more but I doubt more than 10-20lbs. I'd still like to get to 3000lbs flat at some point but that's going to be a full track car build and I still like to drive it around every now and then. It's plenty fast as is. :P

[dmytro98]

I also still like to drive mine around town from time to time, hence why I still have heat, ac, some carpet, speakers, and other luxuries I definitely don't need if it was strictly track only.

[dmytro98]

There's going to be a slight change in path for this car than what I originally had planned. The original end goal for power was to simply get the most I can NA until I can afford to properly swap an s65 into it, but a good deal changed that or at least added a detour.

Now I originally didn't want a supercharger as it just didn't seem worth it. About 5k for the kit itself, and another couple hundred for a tune that would work with headers and other mods, to just squeeze out 300whp. But I've been watching the development of upgrade paths that have made as much as 450whp (or about 400whp if you don't run a custom water-to-air intercooler) which got me rethinking my options.

So then I started looking for used kits until I found a v2 ess supercharger kit someone was selling for less than half the price of what it costs new, and couldn't pass up the deal. Next is buying the parts for it to make real power, which I'm planning on getting 22rpd's "stage 3" kit which provides a couple of goodies, with the important ones being, a smaller pulley to make 12-14 psi of boost instead of the original 6 along with a water methanol kit to keep all that air cool, and a tune to make it all work. All that should be put me at 400whp and still be able to keep that relatively high revving (7500rpm), and have a linear power band. I would be making more power, and weigh less than having an s65, all I would be missing is that sweet, sweet sound.

Additionally, to get the power to the ground I ordered the "Turner Motorsport Performance Lightweight Flywheel N52/N55" along with a 550i clutch since apparently, the stock clutch will slip at those power levels, and it gives me an excuse to install a lightweight flywheel. And got some solid engine and trans mounts just to make sure I never want to drive my car.

It might be a while before I actually install anything, but I figured I'd post an update as it's been a while.

[Dieselboy]

I am using solid: engine, trans, diff, and subframe mounts with a dual plate clutch and I honestly don't think the NVH is that bad. I don't daily my car though.

Are you going to run into fueling issues with the added boost?

[dmytro98]

The only change that needs to be made to fueling is larger injectors, but the ones that come with the supercharger are big enough. If wanted to go to e85 though I would need even larger injectors and a bigger fuel pump, but on 91 it’s not an issue.

[dmytro98]

December 2022 - Drivetrain
Installed 550i/335is Pressure plate, turner lightweight flywheel, solid motor and trans mounts.

Clutch/Flywheel
Since I'm going to be boosted, the stock clutch combination is supposedly not enough so I wanted to change that out before I had to worry about my clutch failing. I ended up going with the turner lightweight flywheel (17lbs) and the 550i/335is pressure plate.

I wasn't too sure what all I had to do to make this setup work since I had only heard that it could be done, but it all fit together without issue. The complete setup is either a stock flywheel or a lightweight one made for the n52, a stock or stock style clutch (550i clutch has a larger output shaft on the trans so it can't be used), and the 550i pressure plate. I'm not exactly sure of the power this setup holds since with the complete 550i setup (clutch and pressure plate) is good for over 500lb tq and I'll be making nowhere near that. The only other person I know running this setup makes about 330lb wtq and has had no issues.

This setup gives aa much stiffer clutch pedal compared to stock, but it is still light enough that it isn't an issue in traffic, and still has a stock-like engagement. Additionally going from the stock dual-mass flywheel to a lightweight single-mass makes the car far more eager to rev, and gets rid of that slight delay when shifting. It does chatter at idle, so if that bothers you stay away from it.

Solid Mounts
Install was super easy for both and could be done in under an hour with minimal tools.

Since I installed just the solid trans mounts first I can say they are a night and day difference in terms of nvh. From idle to about 3500-4000 rpm it's not too noticeable except it makes a cool whine, but above 4k it's a whole different animal. It feels as if the whole car is vibrating to the point that you can barely see out of the rearview mirrors. For a daily, this would be terrible, but for a track car it makes the car feel angrier and more raw and I love it. It also makes the shifter feel more precise, but that's hard to tell since I still have the stock shifter which has a lot of play in it.

The motor mounts combined with the trans mount are honestly a minor change. Not much more nvh compared to just solid trans mount, but again just makes the drivetrain feel that much tighter.

Conclusion
If this is a daily I probably wouldn't recommend any of these modifications except for the pressure plate. All the other mods do make the car feel tighter and more responsive which is great for a track car, but for a daily I don't it's a worthwhile trade-off.

[bbnks2]

Originally Posted by Ab28

Great thread...I believe I reached out to you via IG regarding the sunroof delete. Still waiting on mine!

As far as weight goes: I'm pretty sure you are SPOT ON.

I put my 128 on race scales at Watkins Glen back in May.

Before installing the same Autopower cage I was at 2858 lbs. If you add the 60lbs in for the cage I would be at 2918.

This was also just after filling up the tank completely, both race seats, and the larger stock battery.

With half tank, one seat, and the race battery I'm at 2793 before I get in.

Not sure how much gas you had in the tank. I'm guessing less because you have a full front interior still (carpets/doorcards/radio/center console)

I might've missed it in the thread but what radio delete is that?

[Yvrbmw]

Curious if you did anything with the battery ?

[dmytro98]

I'm still running my stock battery and just waiting for the one in my x5 to die so I can swap the one from my 128i into it and then put a lightweight one in the 128i. I was planning on going with just a smaller AGM battery from braille which weighs 17 lbs and is only like $200. Supposedly still big enough that you don't need to constantly have it on a trickle charger and saves more than 30lbs compared to the stock one.

[amg6975]

Originally Posted by dmytro98

I'm still running my stock battery and just waiting for the one in my x5 to die so I can swap the one from my 128i into it and then put a lightweight one in the 128i. I was planning on going with just a smaller AGM battery from braille which weighs 17 lbs and is only like $200. Supposedly still big enough that you don't need to constantly have it on a trickle charger and saves more than 30lbs compared to the stock one.

Yeah especially with a lot of the electronics gone a smaller lead battery is best option, in my opinion. I made a bracket that extends the H8/7/6 bolt down points to also accept an H4 and I run that with no issues.