[olehead]

As promised here is the best time slip from todays run - The track was pretty slick as it was very cold but never the less the car did well as you can see -12.73 at almost 109 -- there are at least 3 or 4 10ths that we can cut the time by with a stickier track and higher launch rpm which would give us a better 60ft time (a 1.6 60 ft would put us in the low 12 sec range)
- The run was made in sport plus launching at 2200 rpm (which is conservative) using paddle shifters and trying to shift at about 6000K- Still a driver mod learning curve regarding launch and shift points but it was the fastest bmw today over a M3 and a heavily modified 335i coupe and some older models -
This car has a auto 8 tune and a AFE cold air intake running on 93 octane with staggered Pilot SS tires

[ORIGIN M.]

Originally Posted by olehead

As promised here is the best time slip from todays run - The track was pretty slick as it was very cold but never the less the car did well as you can see -12.73 at almost 109 -- there are at least 3 or 4 10ths that we can cut the time by with a stickier track and higher launch rpm which would give us a better 60ft time (a 1.6 60 ft would put us in the low 12 sec range)
- The run was made in sport plus launching at 2200 rpm (which is conservative) using paddle shifters and trying to shift at about 6000K- Still a driver mod learning curve regarding launch and shift points but it was the fastest bmw today over a M3 and a heavily modified 335i coupe and some older models -
This car has a auto 8 tune and a AFE cold air intake running on 93 octane with staggered Pilot SS tires

Fast car.

Running staggered tires on xDrive... Interesting.

[Zooks527]

Originally Posted by red-sauerkraut

Running staggered tires on xDrive... Interesting.

Why? BMW's been selling staggered tires on xDrive models for years.

[M235iguy]

nice work! looking forward to getting my car on a track at some point.

[chattanooga240]

Extremely impressive time given the track condition.

[casper83]

Good work! Times sound about right for the given conditions.
Out of curiosity why are you manually shifting at 6000rpm? I've thought about short shifting in the past because of how bad the boost tapers down at high rpm, but never tried it. Thinking better power under the curve that way?

[olehead]

Shift points are very hard to determine on a turbo car that is automatic - As the summer goes along we will try various combinations - Short shifting I am sure will produce a higher trap mph but not sure about the ET which is what wins the race - Still a learning curve with this car. We are used to manual NA car like my mustang - so maintaining max boost is something new for me and the wife to work on - Also we never used launch control as the track was slick so that will be a big help with 60ft times

[Transfer]

Awww I thought you meant a road course track day. Drag strips aren't real tracks.
At least you beat the Motor Trend M2 1/4 mile ET and trap.

[mike@x-ph.com]

Nice numbers

[olehead]

Does anyone know how much the car is effected by outside temp - I ran it last night and it was about 85 to 90 degrees with some humidity - I am aware of heat soak issues so I let the car rest 20 minutes at least between runs - It seemed the car was shifting into the higher gears earlier especially at the top end - also it was considerably slower 3 for 4 tenths - Knowing BMW and the over engineering I was so wondering if do to heat the car was automatically compensating and not let the car rev as high - only think I could think of and I did not want to run it hard with paddle shifters also due to the heat Comments???

[casper83]

Use this calculator to play around with numbers and you can see how temperature (and other things like barometric pressure) potentially effects performance.

http://www.dragtimes.com/da-density-...calculator.php

As a data point, my fastest time for a given day has almost always come hot lapping the car.

[olehead]

I went to the experts i.e. bmw racing - as intake air temp increases the ecu senses that and it pulls timing and reduces boost - this is for safety reasons - most of the guys who race both 1/4 and track on a regular basis replace the stock intercooler with a performance one - so that explains it as you I could feel the car losing power - I race a mustang also and it does the same thing but not near as bad -

[casper83]

If your question was simply does the engine pull timing if the intake temperature exceeds the optimal engineered design conditions, the answer is obviously yes. It will pull timing to prevent detonation.

I understood your question to be two fold 1) “does anyone know how much the car is effected by outside temp” in which case the link I shared would help you understand this. You’ll also note there are more factors than just ambient temp (ie. Barometric pressure and humidity) 2) Due to heat does the car compensate and short shift. Based on over a dozen visits to the drag strip and multiple track days my answer would be no, but I don’t know this for a fact.

Our cars will generate more heat because of the turbo charger versus a natural aspirated Mustang.

[olehead]

according to bmw the ecu will actually not let not let you rev as high as normal thus shift earlier - this occurs as stated in hot and humid conditions - guess it is a good thing!!
I do use the DA calculator and actually have a hand held one that I use at the track - as well as track surface temp gauge and tire temp gauge - as I race a lot I am very familiar with DA etc my question was related to BMW specific and the M235