[Tom Droze]

I went back to the drag strip tonight for the fourth time to see how my car has progressed with the mods that I have done. As a recap, I have an e92 automatic N51 which that has a weight of 3580 pounds with a driver and a full tank of gas. The drag strip has an elevation of 1,250 feet above sea level. The comparison below is an average of at least four passes that I made each time at the track.

Stock with PE and Dinan Ram Air Intake:

60 foot time: 2.33
ET: 15.40
MPH: 92.33

Same as above but with AA tune:
60 foot time: 2.59
ET: 15.49
MPH: 94.13
Note: my ET was off because of additional wheel spin as a result of the AA tune, which I did not experience prior, but please note the increase in MPH.

Same as above but with MFactory LSD:
60 foot time: 2.33
ET: 15.17
MPH: 92.85
Note: While my 60 foot time improved, as well as my ET, there was a fall off in MPH.

Same as above but with AFE catted headers:
60 foot time: 2.39
ET: 14.95
MPH: 94.38
Note: I made seven runs but this is the average of my four best, as I had a huge issue with tire spin and had to adjust my launch. three of the four runs were in DS manual mode, which means I launched in first gear, with the exception of one run, tire spin was through first and second gear. DS mode in automatic mode proved to be the best option, which means I was launching in second gear. The tire spin was excessive, even with the LSD, and was difficult to manage.

For those of you that are drag strip savvy, you will recognize that my 60 foot times suck. Anyway, I hope you find my analysis somewhat entertaining and interesting. Oh, I think my drag strip days are done and my focus will be on HPDE's, which I enjoy a lot more.

[cdgatti]

interesting Tom, but I think these cars are made for long curvy roads and bombing down freeways at hight rates of speed! Not for 1/4 mile bursts, that is an American car thing.

[Taskmaster]

Nice data, but I feel like a good/better set of tires (or less PSI in your current) would do you more justice. With that MPH, you should be mid 14's...

[bimmerquick43321]

so if I understand correctly the MFactory LSD makes you lose some power? Because more whp is loss considering power is distributed more evenly between wheels? Just assuming trying to understand why you lost power going lsd.

[Tom Droze]

Originally Posted by mecbain

so if I understand correctly the MFactory LSD makes you lose some power? Because more whp is loss considering power is distributed more evenly between wheels? Just assuming trying to understand why you lost power going lsd.

The data would suggest a power loss to the rear wheels with the fall off in MPH as a result of the LSD. I suppose it is plausible in a lower horsepower car. Other than that, I don't have an explanation.

[Tom Droze]

Originally Posted by cdgatti

interesting Tom, but I think these cars are made for long curvy roads and bombing down freeways at hight rates of speed! Not for 1/4 mile bursts, that is an American car thing.

Agreed!

[Taskmaster]

Originally Posted by Tom Droze

The data would suggest a power loss to the rear wheels with the fall off in MPH as a result of the LSD. I suppose it is plausible in a lower horsepower car. Other than that, I don't have an explanation.

Did it change the final drive?

[refugeeofwar]

I find it interesting that you did a 15.40 with the PE and dinan intake. I did my first 1/4 mile drag day this summer and averaged 15.50 with my best being 15.43 completely stock.

[Tom Droze]

Originally Posted by TheAxiom

Did it change the final drive?

No.

[Tom Droze]

Originally Posted by refugeeofwar

I find it interesting that you did a 15.40 with the PE and dinan intake. I did my first 1/4 mile drag day this summer and averaged 15.50 with my best being 15.43 completely stock.

A lot of variables play into 1/4 mile times. Do you have a N51 or a N52?

[refugeeofwar]

Originally Posted by Tom Droze

A lot of variables play into 1/4 mile times. Do you have a N51 or a N52?

Yeah I know. I think I was closer to sea level. Otherwise I'm not sure.

I have the N52. Canadian (US) 328xi.

I should find my slips and see what my 600s were. Just wondering if the fact that I was so close to your times had anything to do with my launch in the x-drive. It's possible I just got off the line faster. I think my speed was sub-90mph

[refugeeofwar]

Found my slips. Best run was as follows:

Reaction: 0.765
60 foot: 2.369
330 foot: 6.567
660 foot: 10.025 MPH1: 70.81
990 foot: 12.892
Finish: 15.445 MPH2: 88.89

Wasn't worrying about reaction time, as I was not competing for anything.

Edit: mine is x-drive and I have the 6spd manual.

Edit 2: I also think my car is closer to 4k pounds with driver and fuel. I think empty weight is like 38-something

[Taskmaster]

Originally Posted by Tom Droze

A lot of variables play into 1/4 mile times. Do you have a N51 or a N52?

Tom, do you ahift at 7000RPM every gear? Did you try to ease it off the line? What gear were you in crossing the line?


This reminds me In need to get some baseline numbers myself

[rjahl]

[QUOTE= exception of one run, tire spin was through first and second gear.

[/QUOTE]

Wait a minute here, Let me get this straight. You have a 3,600 LB car with an automatic, LSD rear end and a three liter motor. I don't understand how you can have that much wheel spin.

I can see launch control being important but once you get rolling, these cars don't have enough power to break the tires loose all the way into and through second.

Something does does not sound right, What type of tires are you running? Were the tires Cold and or over inflated?

[Taskmaster]

Originally Posted by rjahl

Wait a minute here, Let me get this straight. You have a 3,600 LB car with an automatic, LSD rear end and a three liter motor. I don't understand how you can have that much wheel spin.

I can see launch control being important but once you get rolling, these cars don't have enough power to break the tires loose all the way into and through second.

Something does does not sound right, What type of tires are you running? Where the tires Cold and or over inflated?

They must be! Or it could just be track prep.

[refugeeofwar]

I only get a squeek out of mine, being awd.

[refugeeofwar]

Originally Posted by rjahl

Wait a minute here, Let me get this straight. You have a 3,600 LB car with an automatic, LSD rear end and a three liter motor. I don't understand how you can have that much wheel spin.

I can see launch control being important but once you get rolling, these cars don't have enough power to break the tires loose all the way into and through second.

Something does does not sound right, What type of tires are you running? Where the tires Cold and or over inflated?

I wonder if he drove through the water before the line and then tried to launch with wet tires. I was able to drive around the burnout section when I pulled up to the line.

[hassmaschine]

Originally Posted by refugeeofwar

Found my slips. Best run was as follows:

Reaction: 0.765
60 foot: 2.369
330 foot: 6.567
660 foot: 10.025 MPH1: 70.81
990 foot: 12.892
Finish: 15.445 MPH2: 88.89

Wasn't worrying about reaction time, as I was not competing for anything.

Edit: mine is x-drive and I have the 6spd manual.

Edit 2: I also think my car is closer to 4k pounds with driver and fuel. I think empty weight is like 38-something

your trap speed is lower by quite a bit - that's a better comparison than the times, which are more variable.

[Tom Droze]

Originally Posted by TheAxiom

Tom, do you ahift at 7000RPM every gear? Did you try to ease it off the line? What gear were you in crossing the line

Yes, I let the car shif itself so it was shifting at the redline. I did ease it off the line a few times, which eliminated the tire spin but the result was a slighty slower 60-foot time. I think 5th gear, but honestly I wasnt paying attention to the gear selector indicator. However, the last shif twas just prior to the finish line. If I had a manual transmission I would have held in that gear without shifting because I am so close to the finish line.

[Tom Droze]

Originally Posted by rjahl

Wait a minute here, Let me get this straight. You have a 3,600 LB car with an automatic, LSD rear end and a three liter motor. I don't understand how you can have that much wheel spin.

I can see launch control being important but once you get rolling, these cars don't have enough power to break the tires loose all the way into and through second.

Something does does not sound right, What type of tires are you running? Were the tires Cold and or over inflated?

First off, my tires won't spin like this on the street. I have experienced this before where street tires just don't hook up on the drag strip. I am running Michelin PSS and the rear tire pressure was set at 32 PSI. And no the tires were not wet as I was very careful to drive around the water box. The first few passes the track was cold and most everyone was having traction issues. The lack of traction I was experiencing was a function of track conditions and not too much power--but it was still something I had to deal with. As an example, on my first pass, with a significant amount of wheel spin, my 60-foot time was 3.201 and my ET was 16.843. Also, I didn't spin the tires through first and second gear on every pass, but for the first few passes traction was an issue and I had to adjust my launch technique.

Another potential issue with my tires is that I have done two HPDE's with them for a total of 10 sessions so they have heat cycled quite a bit, which can affect their traction.

[jan31]

My e92 328i 1/4 mile best time was 15:39, completely stock!

[jan31]

Originally Posted by jan31

My e92 328i 1/4 mile best time was 15:39, completely stock!