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Thread: car weight loss advice and interesting learning yesterday! (worth reading)

  1. #1
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    car weight loss advice and interesting learning yesterday! (worth reading)

    Hi all - 2 things

    #1) LOSING WEIGHT IN THE CAR: I'm interested in finding the definitive E46 330 weight-loss guide to removing stock parts and/or replacing them w/ lighter aftermarket. My car is weighing in a 3105 [w/ about 1/2 tank of gas]; just weighed it at the track yesterday. My car is far from stock now, but I would like to remove some more weight. I'm looking at doing the sunroof delete, maybe the back seat, trunk carpet, etc. I still want to retain a decent appearing street car, even though it is not my daily.

    Question: Where is the list of weight-loss items for the E46 330? I can't seem to find a good guide (like the E36 list). I'd like to lose 200lbs, if I could.

    #2) WHY LOSING WEIGHT IS KEY: The learning of the day, yesterday... I was running laps at NHMS with PCA and .... basically after feeling like I was plateauing I asked for an instructor to hop in. The instructor was only to give me some pointers, which he did (and he was great) but the unexpected learning was my lap time impact. BEFORE he rode w/ me I was running 1:25-1:26s. I did 2 sessions and 30+ laps at this pace. AFTER he rode w/ me, same result and for 15 laps. DURING the session where he rode with me, I was a full 5 seconds slower, over the course of 14 laps. HIS WEIGHT: Yah, he is 275 lbs .. a big, big dude. (+ a very cool dude, no judging pls)

    So with some level of significance and certainty, I think shedding 300 lbs in my car will make a huge difference. So, that in mind, I'd like to shave some weight if I could.

    Any advice for me?
    Anyone have similar experience?
    Any good recommendations on weight savings (that I haven't already done; my car is here: www.e46bmw.com)

    Please share any insight. Thanks.

    BryDog

    - - - Updated - - -

    FYI - my laps yesterday:

    https://youtu.be/tnyizzdiQss

  2. #2
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    The sunroof cassette alone is 76 (or 78?) lbs, and positioned in the worst place in the car. Get rid of that thing first!

  3. #3
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    Yup, the sunroof delete is first on the list. I might get rid of the hood sound deadening and the trunk carpets; seem like easy quick wins. With someone sold a lightweight backseat to replace stock 80lbs backseat assembly.

  4. #4
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    The quickest/easiest ways to lose weight are:

    1. Sunroof cassette
    2. Rear seats/seat back
    3. Battery

    If you remove the speakers/woofer from the rear deck - you'll be surprised how much they weigh.

  5. #5
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    Not to dissuade you from lightening the car, because lighter is better for many reasons, but I have always been multiple seconds slower with an instructor than without because I'm engaged in listening to their advice and thinking about what I am doing and how to improve. Without the instructor in the car I am able to focus much more on just driving and improvement, not on driving + real-time analysis + communication + discussing options for improvement + implementing change + ohcrapnext corner. My laptimes may be slower with an instructor but the instruction and advice is far more valuable to me.

    This last weekend I was running about a half second slower with a 200lb passenger than without, with the difference being primarily driver error and not passenger weight. No communication due to car loudness; just focusing on driving the car. Less multitasking going on.
    "Fear disturbs your concentration" -Sabine Schmit

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  6. #6
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    I hear you! That said, the data and video proved I was slower on the uphills, with the weight. I was also really, really trying to go faster and was 5-6 seconds slower. Instructor was mostly observing. I think also w/ the weight, depending on the track, it makes a bigger or smaller difference. Mostly going downhill w/ the added weight is fine, but going uphill is much slower. I knew something was up when my shift points were all later than normal. I have 40 days at NHMS.

    Onward we go .. weight loss program for my car .. and maybe for me, too

  7. #7
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    Quote Originally Posted by Novablue454 View Post
    The sunroof cassette alone is 76 (or 78?) lbs, and positioned in the worst place in the car. Get rid of that thing first!
    The sunroof cassette from an E46 M3 is 37 lbs.

  8. #8
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    Quote Originally Posted by lmtfi View Post
    The sunroof cassette from an E46 M3 is 37 lbs.
    OPs car is a 330i

    Hmm, I have a note in my build thread that I weighed mine from my 328i at 34lbs. but than the below quote is from the other active thread going on about sunroof deletes.

    The BMW E46 sunroof cassette weighs a staggering 72.0 pounds, which was more than I remembered from doing a roof swap on an E46 before.
    - Vorshlag.

    I honestly don't remember how I weighed mine, if it was just the glass or the complete everything included assembly.

  9. #9
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    Quote Originally Posted by Novablue454 View Post
    OPs car is a 330i

    Hmm, I have a note in my build thread that I weighed mine from my 328i at 34lbs. but than the below quote is from the other active thread going on about sunroof deletes.

    - Vorshlag.

    I honestly don't remember how I weighed mine, if it was just the glass or the complete everything included assembly.
    I put my cassette on a scale and it is 37 lbs.

    I assume that its the same E46 sunroof cassette between the 330 and the M3 (don't know why they would be different). If anyone cares they can look up the part numbers - but the E46 330 sunroof cassette can't weigh twice that of the E46 M3.
    Last edited by lmtfi; 08-23-2017 at 12:37 AM.

  10. #10
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    I'll weigh mine and report back.
    Last edited by BryDog; 08-22-2017 at 11:54 PM.

  11. #11
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    Are you saying 275lb added 5 seconds over 14 laps (believable), or 5 secs PER lap (highly unlikely).

  12. #12
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    Sorry I am not adding much to your question, but I had some thoughts that might be useful.

    I will say though that it looks like the 911 was slowing you down in places. Are you running better than 1:25s/26s on clear laps?

    I'm not sure what you are running for tires or setup, but unless you are running bologna skins or slippery street tires I'd spend more time on carrying more speed than removing weight. With race tires or fast street tires I'd *think* you should be in the 23s or 22s in a 330i; your line looks really good, but I think you can probably just go faster in a couple spots given the 25s/26s you mention.

    From your video, the only real thing that stands out is that you are getting into 4th going into 1, then shifting down again into 3rd as you slow. I would stay on the gas longer (on the brakes at or after the 2 marker), hit the brakes a little harder, and go from 5th to 3rd, skipping 4th. Why waste the time letting the clutch out, easing off the brakes, then back on them when you get into 3rd? A higher entry line into 1 might also work if you have less grip. In my F80 M3 (stock), Civic (not stock but FWD) and Cayenne(Le Yacht) I take a higher line, but I see the higher grip BMW guys go lower to shorten the track. Again, not sure on your tires, but I think you have a half second just in T1 with small changes. I used to take the low line before they redid 1 a few years ago, but I find the high line to be overall faster for many cars with the new line.

    I'm also curious why you aren't in 2nd for T3. That's a mid to high 40mph turn best case, and I would think 3rd would be slower than 2nd. You are probably leaving a tenth or two on the table.

    If you want to take out weight, that's great, but I think you have a bunch of time left in the car as it is. Maybe some advanced coaching can unlock it? We (COMSCC) are at NHMS 10/14-15, and we do an advanced coaching program for drivers like you, who have a bunch of seat time but want to go faster. Availability is limited, but I would be happy to go out with you to try and find a few tenths here and there if all the spots are full. Not trying to push the club or downplay the mods (losing weight is always a good idea), but I think you can pick up a few seconds with a couple small changes to your driving.
    '91 Civic DX race car
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  13. #13
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    RyanC: spot on & yup, my driving still has room for optimization. Turn 1 feedback is similar to what instructor guy said. Turn 3, I maintain 3rd because I have a 3.46 LSD and carry mucho speed through the corner and have plenty of power to go up the hill. FWIW, my personal best is a 1:23 and change, but given temp/humidity on Sunday, could only do 1:25-1:26. I'd like to attend the COM events but they never seem to fit my schedule .. one of these days.

    aeronaut: yes, exactly what I'm saying. Does it sound crazy? Well, I have done ~40 days at NHMS, in 4 different BMWs, and last Sunday I did ~60 laps. 45 laps without the instructor, I was 1:26. The 15 laps with the 275lb instructor, I could only muster a 1:31 -- and I was trying, really trying, to get into the 20s. Believable or not, that is what happened. For me, the learning was that 275lbs is significant ... at least at this track where we have 2 very steep uphills that required torque/hp to climb.

  14. #14
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    take everything apart and put it back together.
    Ponder at the pile of left over bolts and brackets you have no idea where they went
    Enjoy

  15. #15
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    I would sooner think you suffered from "instructor syndrome". Which means you were analyzing your technique every corner which resulted in the deficit. Simply put, in 1/4 mile drag racing, 100lbs makes about a .08/second difference and that's from a standing start with a full-weight stock car....even less of an effect on a race-prepped effort.

    Be careful with weight reduction too....e36/46's can get really light from the drivers seat back. Obviously, this upsets the balance of the car making it more difficult to drive and requiring suspension/driving adjustments. Most guys that get serious with weight reduction that are running hard and timing themselves at DE's are doing roll cages and rear aero which help get that fr/rr bias back to stock. I'd continue as your are, sunroof, rear seats, etc etc. Throw a bolt-in cage to offset some of weight bias differences and improve safety. Concentrate a bit on the front end; AC pump/brackets/filter/lines/condenser/fan. You running stock headers? There's some weight to be had there. Also, stock air intake/filter system? Few lbs's there. It's tough from the firewall forward!!

    Don

  16. #16
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    A 23 is pretty good;weather can be a drag for sure. Last time there I saw a second between morning and afternoon. What tires are you running?

    I wouldn't worry too much about weight balance at this level; less weight = better. If you have coilovers, you can always mitigate some f/r balance with a good corner balancing. Most of us aren't good enough to notice a few % points different front to rear, whereas a pro would.

    At least taking weight out is free(-ish). I'm kind of in the same boat as you with my race car; I'm 100lbs too light for a class I could dominate, but I am not that competitive in my class (but I could lose 200lbs and be way better off). I've got the sawzall, angle grinder and dremel out every free weekend, hoping to close the gap. Because who wants to lose HP or add weight, amirite? At fast tracks I'll never be king in a civic, but at medium places like NHMS or Thompson, I can do alright, which is what I'm building towards.

    I am not sure on the E46, but I took about 4 lbs off the nose of my car by peeling some steel off the front bumper beam. It's in the right spot, and free... if you can get the bumper apart.

    nice driving, btw. If you do make it to a COM event, look for the blue Civic hatchback and hit me up!
    '91 Civic DX race car
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  17. #17
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    There's no way in heck that weight costs that much time. The difference between my car without ballast at 3120 and with ballast at 3340 isn't as huge as i thought it'd be. I'm not consistent enough to put an exact time on it, but less than a second for sure. The fast COMSCC T70 E36s (not me, I Fin hate NHMS) run at over 3300lbs and have basically stock power and run sub 1:20s on NT01s. I'm in the 1:21s on NT01s.

    Weight loss is good and fun, but that's not where your lost time is. If its not your daily driver, the A/C system is a ton of weight up front. Like 42lbs on an E36. My car with ballast is actually 51% rear heavy.

    Also, agreed with RyanC, run COMSCC events!

  18. #18
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    My this is turning out to be an interesting thread. At least for me it is Thanks for all the thoughtful replies and offers to help. Makes this forum great.

    I am running bfg r1 tires. Started the day at 31 and when hot they are 38. My car is corner balanced and nearly 50/50.

    Back to the weight issue. With the big-instructor in the car, I could not get out of turn 3 and up the hill. I could not even get going enough after 6 to shift to 4th. Normally I'm in 4th before the first apex there. I'm pretty convinced 275lbs is significant given the disparity in lap times and how many laps (and consistent laps) I achieved on the day both with and without the big guy.

    Maaaaybe it was only costing me 3 or 4 seconds, but it was most certainly muuuuch more difficult to explode up those steep hills like usual.

    I'm gonna delete the sunroof and few other minor items -- and that will get me to a little over 3,000 lbs. If I decide to make it a more serious track car, I'll add the roll bar and lose the a/c and everything else unnecessary

  19. #19
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    Post 14. Do it. You KNOW you're going to keep seeing that fat guy in the copilots seat every time you have to stick your arm out the window

    Don

  20. #20
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    A heavy car is harder on brakes. Mine is a pig (with power) and the local track is a series of hairpins after straights. I can't get my brakes cool enough to do a track day without burning halfway though a set of PFC01's and boiling the SRF fluid.
    '97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.

  21. #21
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    Actually, a faster car is harder on brakes. PFC01's are a pretty good pad. You sure you're not on the brakes too early and dragging them? You'll overheat pads real quick if you're not threshold braking when working with a car with as much HP as yours. Also, what rear pads? How do they look? Are you changing back to street pads and using the same rotors? Some things to consider.

    Don

  22. #22
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    Quote Originally Posted by dcvee View Post
    Actually, a faster car is harder on brakes. PFC01's are a pretty good pad. You sure you're not on the brakes too early and dragging them? You'll overheat pads real quick if you're not threshold braking when working with a car with as much HP as yours. Also, what rear pads? How do they look? Are you changing back to street pads and using the same rotors? Some things to consider. Don
    I use PFC01's front and back, I don't change rotors for track days, just the pads. I have 3" ducting to the center of the front 332 Stoptechs, no venting to the stock M3 rear brakes but I have trimmed the rear heat shields to see if it would help. I do my best to brake late into the hairpin at the end of the straight, going 130 mph down to 30 mph, but I'm sure there can always be some driver improvement.
    '97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.

  23. #23
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    As a test, try swapping the rotors with the pads. Just do the front...see if keeping the same pad material imbedded in the same rotor makes a difference. I used to burn up brakes all the time in my turbo e36. Bigger rotors. Bigger brakes. More cooling. Helped but didn't solve it. I'd cook brake fluid in 1 session. It was me. Dragging brakes. Braking too early. I had an experienced driver with me and he said, "why you braking so early"? I said because I want to make the corner? I cut my brake marker in half and no more overheated brakes. Sure, they wore out, but no more smeared, cracked pad material and no more boiling fluid.

    Now I run a stock S50 and never have an issue...except getting passed on straights

    Don

    Quote Originally Posted by chikinhed View Post
    I use PFC01's front and back, I don't change rotors for track days, just the pads. I have 3" ducting to the center of the front 332 Stoptechs, no venting to the stock M3 rear brakes but I have trimmed the rear heat shields to see if it would help. I do my best to brake late into the hairpin at the end of the straight, going 130 mph down to 30 mph, but I'm sure there can always be some driver improvement.

  24. #24
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    I was hoping not to spend the large dollars on an extra set of rotors and hats, especially for testing.

    Solution:
    Sign up for a bunch of track days and be an instructor hog and spend thousands on brake pads, rotors and fluid until I can reduce time on the brakes....... Amiright?

    I might still try my Arduino based DIY brake water cooling system that I want to do, even if it's just a placebo to get me back out on the track.
    '97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.

  25. #25
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    PFC01s are nice. I wish I could afford to use them but they wear off too fast. If you're taking 100MPH off your car at the end of the front straight, that's going to eat a lot off a high-traction pad. The PFC 08s last me a good bit longer, at the cost of some stopping distance but not an unreasonable amount.
    If God meant for man to motor-swap LS engines into track cars, He wouldn't have created Corvettes.

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