Fast Driver writes:
I used to be a major hooligan, taking cloverleaf offramps every morning at speed in my E46 3 Series with tires squealing and occasional stability control intervention. I also enjoyed revving the German machinery to about 3500 rpms and dropping the clutch for a warp speed launch. After 20 or so launches like that with the car, nothing broke, fell off, or otherwise malfunctioned. It’s like the car was made for that kind of abuse.
My latest question related to my 2009 335i sedan with auto trans. When I give it full throttle from a dead stop, the stability light goes crazy and the car seems to be moving slowly. Is this because if it were to unleash 300 ft.. lbs. to the tires the car would be sitting there spinning its wheels mercilessly and for an eternity? Theoretically, what would happen if I activated the DTC (first level) and tried this?
Would it allow the tires to spin freely before launch or would it give me a nice “chirp” and faster launch compared to when all stability/traction controls are active as described above? I know the simple answer is “try it” but these runflats are something like $1,200 a set and my wife would not approve.
Another question is what would likely happen if I turned off all stability/traction controls (second level; everything off) and floored it from a dead stop. Would the tires spin until RPMs reached 3500 and then the tires would hook up (in a cloud of very expensive tire smoke)? Maybe the answer again is “try it” but with no kind of safety net and the risk of getting arrested along with serious mechanical abuse, I am not inclined to.
My final question relates to the real power of the twin turbo motor. Automobile magazine and others have dynoed this engine and surmise that it is making more than the rated 300 hp and 300 ft lbs given that it can get to 60 mph in 4.8 (3560 lbs. curb weight) and do the quarter mile in 13.5. I know that the engine is tremendously powerful. I can spin the tires (as indicated by the blinking stability control light on the dash) in first, second, and sometimes when downshifting into third, which makes me assume that there’s more than the rated horsepower or torque there.
What do you think? Thanks!
Sajeev Replies:
Just in case it isn’t common knowledge, we’re talking about holeshot techniques this time ‘round on Piston Slap. Question is, do you want to make a scene and hear the noise Hollywood style, or beat the clock by pushing your skills to the limit? Because launching is a technique best served with 20+ practice runs in a race setting where you can monitor your 60-foot elapsed times.
Which is a real nice way of saying that you need to get your car on a drag strip. So do it already!
You won’t waste your tires once you learn that spinning wheels equals slow elapsed times. Get the lead out of your shoes and start practicing your launch technique without traction control assists. You are better than the electronic nannies, unless you own a SL65 Black Series with insane torque on a tight suspension. With practice, it will come.
To your second question, yes the 335i’s are underrated from the factory. And they respond quite well to ECU modifications, just like any other modern vehicle with hairdryers in the exhaust (i.e. Turbocharger). If you go the tuning route, the stock runflat tires will be even more of a joke: you’ll need summer tires with normal sidewalls. Not only are they faster and quieter, I suspect you and your wife will appreciate the price advantage too.
(Send your queries to mehta@ttac.com)
Hate to say it, but if you have to ask…
Not asking takes food off my plate. Just sayin’!
That picture, at that angle, slightly blurry, that looks like one of the last of the GTOs. Or as I like to say, “How’s your Holden treating you?”
This gentleman’s question makes me think TTAC needs to compile a list of “Fun cars that you can beat on and nothing is likely to break…” (Example, Toyota’s might take a beating but how much fun are they?)
Without snapping axles, transmissions and what not? For years of track use? I’d probably give it to LT-1/LS-1 F-bodies and Mustang V8s that don’t run T-5 transmissions.
Most everything else will make you pay big time for this particular vice.
My 06 Civic Si is fun to beat on, and I haven’t really broken anything yet. There’s not enough power to make stoplight racing much fun, but throw the car on a curvy back road and I get plenty of smiles per mile. The K20 loves to rev, so if you want to keep it in at 5000 rpm or above to maximize power and throttle response, it won’t really mind. The ECU reflash I got lowers the VTEC point from 6000 to 4500, and having some actual midrange makes all the difference in that car.
When I read the headline, I just couldn’t help but hear “Two turntables and a microphone”
That was by design. Mission Accomplished!
Step 1: Get rid of the run flat tires.
Step 2: Get an extended warranty.
Step 3: Go out and have fun.
Twotone
Is this because if it were to unleash 300 ft.. lbs. to the tires
300 ft-lbs to the tires? A ’60 Volkswagen could probably beat this!
The engine torque is multiplied by the transmission’s gear ratio plus the final drive ratio plus the torque converter in the case of a girlie (i.e. automatic) transmission. So you’re probably looking at 3000 to 6000 or so ft-lbs at the tires.
Sajeev, can you clarify the torque statement?
TR4 is right, but nit-picky. (No offense intended.)
Using the OEM’s flywheel power ratings in our vernacular is fine, just like saying “sway bars” or “pounds of boost.” Nobody wants to add bigger sway bars or cram 10 pounds of air in their engines, but we still say that.
And since we’re going there, a NUGGET OF WISDOM:
The BMW does NOT make 300 lb-ft at the wheels because of parasitic drag from the torque convertor, transmission, U-joints, differential, bearings, etc. Automatic cars (in general) lose 18%-20% by the time you get there, not accounting for gear multiplication.
Awww cmon d00d. This almost reads like a troll. The obviously answer is – if you’re really concerned with saving your runflats, then buy yourself a cheap pair of rims/tires or perhaps a whole set (go with steelies if your super cheap) and slap em on. Now turn off all your nannies and go practice. I recommend wide open spaces (like an empty parking lot at 3am) to really learn the limits of your car with no stability control. Personally I would just run the runflats until they were done then when it was time to get new tires, go with regular tires which will be far less than $1200 a set. Worried about flats? Get AAA.
IME, modern electronic stability controls, on their full settings can be too aggressive. I haven’t tried the Beemer, but “Fast Driver’s” comment “When I give it full throttle from a dead stop, the stability light goes crazy and the car seems to be moving slowly” is my experience with both a Hyundai Genesis and my neighbor’s Mercedes E-series. If you nail the gas while making a left turn the car practically crawwwwlllls around the corner…making for a tense moment if you did it in front of an oncoming car. I can get through the intersection MUCH faster with the ESC turned off (or to a lesser position as it isn’t totally off) albeit with a bit of wheel spinning and tail end wagging antics.
Did you also put a bigger gas tank in so it can go more than 300 miles between refueling? Seriously, what’s up with BMW owners?
They’ve got enough laws out there, why there isn’t one to demand 300mi+ out of a gas tank, I have no clue.
Honda, Subaru, I’m looking at YOU.
Hey – my Honda routinely goes 330 miles between refuels… GRIN!
From experience, I can tell you that the 335i (coupe) doesn’t launch very well. Apparently they don’t drag race much in Germany.
My advice: don’t try to power-brake the car. It just confuses the ESC and traction control.
Put the selector lever in DS, and drive around agressively for a few days. The car learns that you want to accelerate fast. Practice 20 times so the car knows you really mean it. Don’t let anyone else drive the car unless they are a leadfoot also. Then the car will be ready for drag racing.
Thus conditioned, it will leave the line with 2 nice even streaks of rubber on the pavement about 20 ft long.
Turning off the ESC can produce more wheelspin, briefly, and only from 1 wheel. There is no locking diff on these cars (unless you get an M3) If you spin 1 wheel too much, the engine will dial back the turbo boost, and the car will lurch like an amateur driver leaning a stick shift.
My wife can concsistently launch her Mustang better than my BMW. In a 60 foot race, she wins every time. By the time we’re at 60, we are even, and then the BMW pulls away smartly.
This seems to work equally well with both the original run-flat all season tieres and the winter tires.
Bob
Fast Driver,
As a fellow owner of a 335 (coupe in my case) here is my 2c worth
1. Plan for new tires now. The run-flats struggle with traction, are noisy and will only get noisier as they wear. Get an M3 style tire repair kit which should be able to cope with most puncture situations.
2. Practice. You will need to figure out the best technique to launch without traction control as well as account for the throttle delay that all German cars seem to have.
3. Careful with the mods as some are better than others. I would only recommend ECU re-flashes and not piggyback units that alter the sensor signals to the ECU. There are some reputable companies that make them but don’t go overboard as about 400lb is about all your automatic transmission can handle safely.
BTW, total torque
engine torque ~300 ft-lb
torque convertor is pretty tight, about 2:1 multiplication
loqw gear ~3.7:1
rear axle ~3.2
total torque at wheels =~7100 ft-lb
By comparison, 70 Eldo with 500 CID engine, makes ~8000 ft-lb at wheels. Which is why the BMW axles look about as stout as the Eldos.
Bob
Thank you all for the “new tires” posts . . . my head was going to asplode while reading that :o
Every now and again I think “I need more power” or “frickin’ traction control!” but in reality, if I’m running on OE tires (2009 Mazda6 GTi 6MT), I really don’t care about getting going :/
I *am* surprised you all were so kind on the slushbox ;) Also Carguy’s #2 FTW :D
I also own a 335i sedan auto, so I figured I would chime in. My car has the sport package (wider rear tires) and the Michelin Pilot Sport run flats. If I want the car to break traction in the dry, I have to brake torque to do it to get the turbos spooled up (with all the electronic nannies fully turned off of course). Once it breaks traction, it will spin for a couple of seconds before the tires start to grab and you take off.
I only did it once just to see what would happen, since as you already know tires for these cars are insanely expensive. It sounds like you might have a non-sport package car with the Bridgestones. I am sure your car could spin the tires all day if you are already losing traction in second and third gear.
FYI… do a Google search for “bmw rear subframe tear” after you do your 20 runs dropping the clutch @ 3.5K rpm…. just sayin…..
That was mainly the e36 and e46 generation which didn’t respond well to suspension modifications or third party anti-sway bars. Like any car, abuse and ill conceived modifications will cause damage but the odd burnout is no problem – particularly in an automatic.
I doubt the automatic will allow you to induce significant tire spin, even with the traction control off.
Oh yes it does.
Can I point out how silly it is to “train” a car to your acceleration patterns? Why shouldn’t you want to drive like a chauffeur on the street and like a maniac on the track? Why doesn’t BMW just make a “track mode” and “comfort mode” and let you switch between them?
Get new wheels and tires and hoon the crap out of it! I’d recommend the DFORCE LTW5 wheels, forged, 17lbs & like $250 each. For the cost of a set of crappy run flats you can have wheels and Dirrezza Star Spec summer tires. My GF just got a 335i aut0 (it was better than not getting a 335i) and I don’t imagine I will ever drive it with the traction control on or without burning out on my set of summer wheels and tires.
I’m also a 335i driver. Any dirty road surface or bump will send the stability control (DSC) on, killing your power. It’s very sensitive. At the strip, I was able to get a 13.6 @ 105 mph quarter mile (at high altitude- about one mile) by going from DSC to DTC, which allows for quite a bit of spin. That was my first ever time at a drag strip. I also have a JB+ piggyback, which normally I keep turned down pretty far or remove altogether for durability reasons, but turn it up at the strip. Great device- I recommend it as the best bang for buck and easiest to remove mod out there. I think I could shave more time off by practicing an unassisted launch, and by getting rid of those terrible RFTs. I think I’ll get some Hankook Ventus Evos when I get the snow tires off.
For a good launch, make sure it’s clean, smooth pavement. Put it in DS, go to DTC or no traction control at all, brake torque to about 1800-2000 rpm (depends on traction), and let off the brake and floor it, possibly easing into flooring it if traction is weak.
The 335i automatic makes about 3,700 lb ft at the wheels in first gear from 2000-5000 rpm, making assumptions for driveline loss, but NOT considering torque amplification from the torque converter, or considering that the power is likely underated.