[F22santiago]

So I took my 1300 mile just broken in m240i 6 speed to the track today. Car was only running JB4 map 1. Conditions were TERRIBLE but I was already there so . It was 86 degrees and 95% humidity (there was condensation on top of every car!) I have plenty of track experience but this was the first time with this car so I spun alot more than I'd like to in 1st. 2nd and 3rd were fine. I was prett dissapointed with the overall ET's however I did find the MPH in my first run (111mph) to be promising. I also noticed the humidity and hotness started to take its toll after the 1st run. I did 6 but only saved the best 3. Any opinions on what the car should run on a dry cold night?

I am car #6223

[XutvJet]

111mph in hot and humid weather is promising. As you know, that type of weather hurts performance, even a turbo car. Your 60 foots are killing you. My experience with street cars has been that every .1 of second in 60 foot equates to about .15 seconds at the 1/4 finish. I would think upper 1.9 to 2.0 60 foots should be possible in this car on the OEM tires and decent track prep. That means you could shed about .5 to .9 seconds from those slips. Cooler, dryer air should help too with ET and MPH. I would think in 50 to 60 degree temps and dry air, the car could go 12.6-12.8@113-114mph with a 2.0 60 foot the way it sits currently.

On slicks, you should easily be able to pull a 1.7 60 foot and get into the low 12s. Easy.

[bowhun2r]

Originally Posted by XutvJet

111mph in hot and humid weather is promising. As you know, that type of weather hurts performance, even a turbo car. Your 60 foots are killing you. My experience with street cars has been that every .1 of second in 60 foot equates to about .15 seconds at the 1/4 finish. I would think upper 1.9 to 2.0 60 foots should be possible in this car on the OEM tires and decent track prep. That means you could shed about .5 to .9 seconds from those slips. Cooler, dryer air should help too with ET and MPH. I would think in 50 to 60 degree temps and dry air, the car could go 12.6-12.8@113-114mph with a 2.0 60 foot the way it sits currently.

On slicks, you should easily be able to pull a 1.7 60 foot and get into the low 12s. Easy.

I have the auto and xdrive.

Here is my slip total stock.

Link to post....

http://www.2addicts.com/forums/showthread.php?t=1416357

[amw896]

95% humidity is your answer! I am FBO with upgraded IC and mine struggles big time with humidity. If it's hot but the humidity is low, then it will still run strong but the humidity is brutal. Also the 60' is probably dragging your times down.

[F22santiago]

Originally Posted by XutvJet

111mph in hot and humid weather is promising. As you know, that type of weather hurts performance, even a turbo car. Your 60 foots are killing you. My experience with street cars has been that every .1 of second in 60 foot equates to about .15 seconds at the 1/4 finish. I would think upper 1.9 to 2.0 60 foots should be possible in this car on the OEM tires and decent track prep. That means you could shed about .5 to .9 seconds from those slips. Cooler, dryer air should help too with ET and MPH. I would think in 50 to 60 degree temps and dry air, the car could go 12.6-12.8@113-114mph with a 2.0 60 foot the way it sits currently.

On slicks, you should easily be able to pull a 1.7 60 foot and get into the low 12s. Easy.

I honestly hope I can atleast dip into the high 12's. I will go hopefully in two weeks once its colder. As far as slicks, I do not care or go often enough to justify the price or work of having to switch them on etc. That and I believe my stock clutch, axles could give away.

[F22santiago]

Originally Posted by bowhun2r

I have the auto and xdrive.

Here is my slip total stock.

Link to post....

http://www.2addicts.com/forums/showthread.php?t=1416357

I had seen your thread before, ridiculous times. I always knew that auto and xdrive make them monsters at the 1/4 I just can't wrap my head around how much of a big difference it makes. I did notice your trap was a bit lower and you're deep in the 12's so I hope I can atleast do 12.7-12.8 on a good day.

[XutvJet]

Originally Posted by F22santiago

I had seen your thread before, ridiculous times. I always knew that auto and xdrive make them monsters at the 1/4 I just can't wrap my head around how much of a big difference it makes. I did notice your trap was a bit lower and you're deep in the 12's so I hope I can atleast do 12.7-12.8 on a good day.

60 foot and 60 degree temps are key. He too is tuned and is essentially running the same boost as you.

I'm with you on slicks, this isn't a drag car. No sense in beating the car to get a killer 60 foot and ET. Your trap speed is very telling though. From a roll, the 6MT is what you want.

Most of us 6MT owners know we can't hang with the X and/or autos from a stop or even at speeds below 50mph, BUT that's really not the point to getting the 6MT

[TajoMan]

http://wahiduddin.net/calc/calc_hp.htm

does humidity matter that much?
It does a bit but not as much as temperature.

[B58togo]

I went a best of 12.39 @ 110.7 mph on a 1.98 sixty. 60 degree day @ ~400' elevation. Conditions were good and the corrected numbers were about the same. Around 2k miles on the car. Sport + with the lever in drive. That was with intake and JB4 with +4 PSI. I'm now at +6 PSI. Next time I go I'll also run with DSC off and the lever in M/S. Sport + keeps nannys on and cuts power. I think I'll probably hit 12.20's if I'm lucky, but the trap should go up to 113 or so with the extra 2lbs boost and DSC off. It's hard for the 6MT to compete with the ZF8, but man, I do miss driving manual.

[F22santiago]

Originally Posted by B58togo

I went a best of 12.39 @ 110.7 mph on a 1.98 sixty. 60 degree day @ ~400' elevation. Conditions were good and the corrected numbers were about the same. Around 2k miles on the car. Sport + with the lever in drive. That was with intake and JB4 with +4 PSI. I'm now at +6 PSI. Next time I go I'll also run with DSC off and the lever in M/S. Sport + keeps nannys on and cuts power. I think I'll probably hit 12.20's if I'm lucky, but the trap should go up to 113 or so with the extra 2lbs boost and DSC off. It's hard for the 6MT to compete with the ZF8, but man, I do miss driving manual.

Yes driving manual on this car is very engaging since I daily it. I almost came close to buying a ZF but I absolutely loved my basic 228i 6 speed so I knew I was in for a good time with the M240. Also, 60 ft times must be critical since I got 2.1-2.5 and on my JB4'ed 228i basic line and with crappy 17" runflats I was always between 1.8-2.

[F22santiago]

Also for those 6 speed people here: Do you guys reccommend dumping or slipping the clutch out of the hole?

[Dylan86]

Originally Posted by F22santiago

Also for those 6 speed people here: Do you guys reccommend dumping or slipping the clutch out of the hole?

I've experimented with Sport+ Launch Control and it actually works really well, imo. You pin the accelerator and slightly slip the clutch, then drop it so you don't smoke it out. Hardest launch I can achieve is with the factory launch feature. Only tried it a couple of times, here and there as I'm not intending to master this feature at the expense of a premature clutch job

I've launched on DSC off and I find I got more wheelspin and sometimes bad wheel hop with the soft OEM rear bushings..

[cxp213]

Yeah, your short time definitely needs work. Your trap is good for at least high 12s just with a better launch but your back half seems a little slow, also.

[XutvJet]

Originally Posted by F22santiago

Also for those 6 speed people here: Do you guys reccommend dumping or slipping the clutch out of the hole?

You've got to slip the clutch. Every manual FWD/RWD/AWD car I've raced at the strip on street tires requires a decent amount of slip or else you'll either:

1) Smoke the tires
2) Bog
3) Snap an axle or input shaft

My M235 6MT is stock and I find launching at ~3500rpms with a decent amount of slip and throttle modulation results is decent launches on the street. On a decently prepped track, I could leaving at 4,000rpms.

[XutvJet]

Originally Posted by cxp213

Yeah, your short time definitely needs work. Your trap is good for at least high 12s just with a better launch but your back half seems a little slow, also.

Hmmm....he's gaining over 24mph in the last 1/8th mile. That's pretty dang strong topend pull. In cooler weather, I bet he'll see 25mph, maybe even close to 26mph on the back end. The M240 8ATs that have posted seem to only be doing 22-23mph on the back half.

[jmwilson125]

Originally Posted by Dylan86

I've experimented with Sport+ Launch Control and it actually works really well, imo. You pin the accelerator and slightly slip the clutch, then drop it so you don't smoke it out. Hardest launch I can achieve is with the factory launch feature. Only tried it a couple of times, here and there as I'm not intending to master this feature at the expense of a premature clutch job

I've launched on DSC off and I find I got more wheelspin and sometimes bad wheel hop with the soft OEM rear bushings..

Zf auto here, but I still can't get launch control to do any for me other than smoke the tires. Running 265 PSS in the rear too.

[cxp213]

Originally Posted by XutvJet

Hmmm....he's gaining over 24mph in the last 1/8th mile. That's pretty dang strong topend pull. In cooler weather, I bet he'll see 25mph, maybe even close to 26mph on the back end. The M240 8ATs that have posted seem to only be doing 22-23mph on the back half.

Not sure why I said back, but I meant the front half. In addition to his obvious weak launch, his shifts probably needs a bit of work considering his 330m and 1/8 mi times.

[F22santiago]

Originally Posted by Dylan86

I've experimented with Sport+ Launch Control and it actually works really well, imo. You pin the accelerator and slightly slip the clutch, then drop it so you don't smoke it out. Hardest launch I can achieve is with the factory launch feature. Only tried it a couple of times, here and there as I'm not intending to master this feature at the expense of a premature clutch job

I've launched on DSC off and I find I got more wheelspin and sometimes bad wheel hop with the soft OEM rear bushings..

Launch control on a 6 speed? Am I missing something? No idea that was a feature. I agree with you on the slip, I always do that to get best times even on my miata

[F22santiago]

Originally Posted by XutvJet

You've got to slip the clutch. Every manual FWD/RWD/AWD car I've raced at the strip on street tires requires a decent amount of slip or else you'll either:

1) Smoke the tires
2) Bog
3) Snap an axle or input shaft

My M235 6MT is stock and I find launching at ~3500rpms with a decent amount of slip and throttle modulation results is decent launches on the street. On a decently prepped track, I could leaving at 4,000rpms.

To be honest I was terrify to slip the clutch (or dump it for that matter) at anything above 2800. But I will definitely keep this in mind next time I go and update with new slips.

[F22santiago]

Originally Posted by XutvJet

Hmmm....he's gaining over 24mph in the last 1/8th mile. That's pretty dang strong topend pull. In cooler weather, I bet he'll see 25mph, maybe even close to 26mph on the back end. The M240 8ATs that have posted seem to only be doing 22-23mph on the back half.

Yes the top end is very strong. Only thing is at the VERY end right before the line with the 6MT you need to either ride out the redline ALL the way through at which point you aren't really making power, or lose time and shift to 4th for that last few feet which doesnt seem to be smart either. 6MT problems

[XutvJet]

Originally Posted by F22santiago

Yes the top end is very strong. Only thing is at the VERY end right before the line with the 6MT you need to either ride out the redline ALL the way through at which point you aren't really making power, or lose time and shift to 4th for that last few feet which doesnt seem to be smart either. 6MT problems

Maybe grab the 3-4 at 6500rpms and see what happens? A stock B58 achieves peak power near 6000rpms and holds it basically flat and steady near fuel cut. I would imagine the ideal shift points for all gears would be ~7000rpms on a stock B58. The N55 is basically the same way except the 3-4 which should happen around 6300-6500rpms according my calcs.

I'm not sure how it would play out with a piggyback though because most piggybacks push the turbo harder, creating a lot of low and midrange power and make the powerband more hill shaped, with peak power occurring around the same rpm as stock, but a more dramatic power fall off in the upper rpms. Basically all piggybacks wreck that naturally aspirated, more linear power delivery BMW tries so hard to do with the N55 and B58.

[XutvJet]

Originally Posted by F22santiago

To be honest I was terrify to slip the clutch (or dump it for that matter) at anything above 2800. But I will definitely keep this in mind next time I go and update with new slips.

I'd try 3500rpms and modulate the clutch and throttle a bit. When you hear and feel the rear tires tramp about rather than fully spin, you'll know you got it right. I'd try this:

1) Shallow stage (i.e., roll up just enough to trip the light). Shallow staging will give you about 6" of roll-out before the timers trip. That untimed roll out can help lower ET and improve MPH. It's basically a running start.
2) Rev to 3500rpms, but bounce the rpms a bit.
3) Let the clutch out to the point that it's just about to catch.
4) On the last set of ambers, let the clutch out barely to the point you feel the car start to roll. This will help plant the tires and reduce tire shock. Then let the clutch out somewhat quickly while feeding the gas and keeping it above 3000rpms. At that point, it's a matter of feel with respect to slip, gas, and when to fully let out the clutch.

With my manual cars, I've learned that launching at higher rpms and with more slip got me the best 60 foots rather than launching lower and with less clutch slip. The clutch slip will also help quell some of that turbo torque surge that tends to blow of the tires when trying to leave rapidly in 1st or 2nd at 2000-3000rpms from a stop light.

Of course, sometimes at the strip no matter how hard you try, the traction just isn't there.