[ParadigmDawg]

Originally Posted by Max Well

Good to know. I also have the Michelin Pilot Sport 4S, but Front: 255/40 ZR 21 and Rear: 265/40 ZR 21.

Suspect your traction (0-60 foot) should be better based on the tires alone?

With your background in Drag Racing, can you comment on my experience with the tires I (and the Hellcat Driver) described earlier using LC? Even if I get the LC timing down to full boost at launch, I'm still not sure I'm going to be able to put all of it down in the 0-60 foot interval, at least based on my experience Saturday. Not sure if a modified DSC-on launch would grab better?

Hard to say on the tire size making any difference. It could be the bigger tires and wheels weigh more and could actually slow it down.

I have no idea on what would make your 0-60 or 60 ft better. I have never had a street car on a drag strip. My "Outlaw Street car"1700+ hp and was either on 10.5" slicks or 14.5" slicks depending on what class we were running. I was about as far from a street car as you could get.

My Pro-Mod was North of 2,000 hp and was on 16" slicks.

The difference off the line would be all over the place based on tire pressure being even 0.2 psi off. We normally ran between 5 and 7 psi.

My guess would be to find the correct tire pressure, lean on the 2-step and get your rpms to 5500 before you even think about letting go of the transbrake and make certain the 4 link is setup properly and that it's not unloading when it hits the wheelie-bars.... Maybe even lower stage one of NOS to 250 hp and have the timer for stage two come on at the shift point with another 200. try not to ever hit the skatter unless its a big money race and you are behind at the very end. It has put me into the wall to many times.

Also once on the big end, pull the chute at any sign of the car crossing the centerline.

[MrItaly]

Originally Posted by Max Well

While you're still over there with access to high speed roads, do you have a Dragy to test the differences on the road? Dyno results are helpful but nothing beats real world testing. Looking forward to your thoughts on the mods when installed.

Unfortunately, I don't have a draggy. It should just be an app and not require seperate gow hardware, right? If so, I might get it. Also, is launch control locked under 5k km (3k miles)? I tried doing my first one the other day with this car and couldn't get the flag. I had no problems with my M40i.

[MrItaly]

Originally Posted by Max Well

Thanks, IND, and appreciate your first run data back in July! A Photographer at the track took this one so thought I'd share. Will definitely be going back for another round - was a lot of fun and enjoyed meeting such a great group of Enthusiasts.

I love this photo.

[Max Well]

Originally Posted by ParadigmDawg

Hard to say on the tire size making any difference. It could be the bigger tires and wheels weigh more and could actually slow it down. I have no idea on what would make your 0-60 or 60 ft better. I have never had a street car on a drag strip. My "Outlaw Street car"1700+ hp and was either on 10.5" slicks or 14.5" slicks depending on what class we were running. I was about as far from a street car as you could get. My Pro-Mod was North of 2,000 hp and was on 16" slicks.

The difference off the line would be all over the place based on tire pressure being even 0.2 psi off. We normally ran between 5 and 7 psi. My guess would be to find the correct tire pressure, lean on the 2-step and get your rpms to 5500 before you even think about letting go of the transbrake and make certain the 4 link is setup properly and that it's not unloading when it hits the wheelie-bars.... Maybe even lower stage one of NOS to 250 hp and have the timer for stage two come on at the shift point with another 200. try not to ever hit the skatter unless its a big money race and you are behind at the very end. It has put me into the wall to many times. Also once on the big end, pull the chute at any sign of the car crossing the centerline.

Ha! But your point about psi is a good one. I had them at 33 front/38 rear as rec by BMW. Next time I’ll lower to 32/34 and see how that goes.

Originally Posted by MrItaly

Unfortunately, I don't have a draggy. It should just be an app and not require seperate gow hardware, right? If so, I might get it. Also, is launch control locked under 5k km (3k miles)? I tried doing my first one the other day with this car and couldn't get the flag. I had no problems with my M40i.

Dragy is a 3” x 1” x 0.5” lightweight unit with a USB charger that Bluetooth’s to your phone via Dragy’s app available at the App Store. Although I bought a mobile phone holder to place on the dash/windshield, I ended up not using that, opting just for painter’s tape to secure it on the dash when in use. Helpful to evaluate your performance if you don’t have access to a Strip.

LC is available right away although BMW doesn’t rec using it until the 3,100 mile (5K km) point. Re LC set-up, would just check to see if you have the settings arranged as onfireX5 recommended in doberzus’ thread. I shared the iDrive screen images after following his suggestions in post #14, 4 Nov 2019 https://x3.xbimmers.com/forums/showp...9&postcount=14 . His idea was great, as it was easy to quickly push ‘M2’ twice when the stage light showed, push hard on the left brake and hard on the accelerator, and LC began. Honestly I never even looked down to check to see if the flag appeared in the cluster as it is fool-proof at that point.

[ParadigmDawg]

Originally Posted by MrItaly

Unfortunately, I don't have a draggy. It should just be an app and not require seperate gow hardware, right? If so, I might get it. Also, is launch control locked under 5k km (3k miles)? I tried doing my first one the other day with this car and couldn't get the flag. I had no problems with my M40i.

I think Dragy has a right to make money off of the device. It should be more accurate than just the GPS on a phone.

High-performance GPS and GLONASS accurately measures your performance within 1/100th of a second.

[ParadigmDawg]

Originally Posted by Max Well

Although I bought a mobile phone holder to place on the dash/windshield, I ended up not using that, opting just for painter’s tape to secure it on the dash when in use. Helpful to evaluate your performance if you don’t have access to a Strip.
.

I just put mine in the passenger seat where the gap is when you extend the thigh extension a tad and open the sunroof.

You may like sticky things more than I do. What was cool about my M40 was the center speaker grill was metal so the Dragy would just stick to it with its magnet and it was in perfect position. I left it there 100% of the time as you couldn't even tell it wasn't part of the speaker. Did they change to plastic on the M?

[Max Well]

Originally Posted by ParadigmDawg

I just put mine in the passenger seat where the gap is when you extend the thigh extension a tad and open the sunroof.

You may like sticky things more than I do. What was cool about my M40 was the center speaker grill was metal so the Dragy would just stick to it with its magnet and it was in perfect position. I left it there 100% of the time as you couldn't even tell it wasn't part of the speaker. Did they change to plastic on the M?

Didn't even think to try the speaker cover - just assumed it was plastic. But you're right - the magnetic base sticks great to the center speaker and a perfect location for satellite viewing. No more temporary painter's tape.

[kingmonkeyjr]

I'm surprised times weren't a little better since running 100 octane. Also seeing everyone's dragy results.

60' could get some help from lowering tire pressure to 32 all around.

Hey but what I always say... time slip or nothing🙃😁

[Max Well]

Originally Posted by kingmonkeyjr

I'm surprised times weren't a little better since running 100 octane. Also seeing everyone's dragy results.

60' could get some help from lowering tire pressure to 32 all around.

Hey but what I always say... time slip or nothing🙃😁

Not sure if you're referencing my time slips and results, kingmonkeyjr? As mentioned, I was using Shell 93 Octane, not 100.

Re: psi, I agree that lowering the tire pressure from BMW's recommended 33/38 may make a significant difference, certainly in the 0-60 foot interval. I plan on making that change next time out. I wanted to at least get some baseline numbers as this was my first time taking the X3MC to the Strip.

[kingmonkeyjr]

Originally Posted by Max Well

Not sure if you're referencing my time slips and results, kingmonkeyjr? As mentioned, I was using Shell 93 Octane, not 100.

Re: psi, I agree that lowering the tire pressure from BMW's recommended 33/38 may make a significant difference, certainly in the 0-60 foot interval. I plan on making that change next time out. I wanted to at least get some baseline numbers as this was my first time taking the X3MC to the Strip.

Okay I went back and read it again. The IND car had the 100 octane. Regardless your best 60 ft with perfect launch and grip should put you around 1.7x-1.8x

[sly1types]

nice results, great pics and documentation

[Max Well]

Originally Posted by kingmonkeyjr

Okay I went back and read it again. The IND car had the 100 octane. Regardless your best 60 ft with perfect launch and grip should put you around 1.7x-1.8x

That’s the goal, and I think with a psi around 32 as you mentioned it should land in that range. Even with the high psi I ran (38 on the rears), Round 82 had a 0-60 ft time of 1.897, and we know the fronts tried all day to help with traction given the embedded gravel and frayed edges they also showed.

Looking back at Nate’s IND run on 100 Octane and a bit higher DA, he was able to get 1.812 but I don’t recall his tire psi (maybe he can comment). Comparing his vs my best interval times over all my runs, his 0-60 foot was better. Pretty consistent otherwise.

Nate’s/my: 1.812/1.897, 3.184/3.179, 2.626/2.625, 2.270/2.256, 1.939/1.913

Originally Posted by sly1types

nice results, great pics and documentation

Thanks, sly1types. For completeness of documentation, here’s a chart I placed over in the F97/98 ¼ mile Reference thread looking at ‘Time Slip vs Dragy’ data from that day (in case others don’t frequent that Forum).

[kingmonkeyjr]

Originally Posted by Max Well

That’s the goal, and I think with a psi around 32 as you mentioned it should land in that range. Even with the high psi I ran (38 on the rears), Round 82 had a 0-60 ft time of 1.897, and we know the fronts tried all day to help with traction given the embedded gravel and frayed edges they also showed.

Looking back at Nate’s IND run on 100 Octane and a bit higher DA, he was able to get 1.812 but I don’t recall his tire psi (maybe he can comment). Comparing his vs my best interval times over all my runs, his 0-60 foot was better. Pretty consistent otherwise.

Nate’s/my: 1.812/1.897, 3.184/3.179, 2.626/2.625, 2.270/2.256, 1.939/1.913

Thanks, sly1types. For completeness of documentation, here’s a chart I placed over in the F97/98 ¼ mile Reference thread looking at ‘Time Slip vs Dragy’ data from that day (in case others don’t frequent that Forum).

The 60' is similar to my wife's X3m40i. I'm waiting for my GLC axles to go as I'm grabbing mid 1.5x 🥰🙃

[Max Well]

Originally Posted by kingmonkeyjr

The 60' is similar to my wife's X3m40i. I'm waiting for my GLC axles to go as I'm grabbing mid 1.5x 🥰🙃

Don't recall your Wt/HP with your mods (? 4,650 lbs./800 HP) or your tire info?

Here's the documentation of my Dragy data:

[kingmonkeyjr]

Originally Posted by Max Well

Don't recall your Wt/HP with your mods (? 4,650 lbs./800 HP) or your tire info?

Here's the documentation of my Dragy data:

4700lbs, 760 crank hp, Michelin PS4 that are shot on the rear😂

[Max Well]

Originally Posted by kingmonkeyjr

4700lbs, 760 crank hp, Michelin PS4 that are shot on the rear😂

With that power I'll bet the tires aren't the only items showing wear.

So next time at the Strip I'll plan on running 32/32 psi fronts/rears and will repeat the stoplight starts as reference for that tire pressure, then try Sport and Sport + stoplight runs in comfort suspension as well to see if gblansten's theory can be supported, and then some LC runs with hopefully with a better DA and less fuel.

[Max Well]

Just getting back from another day at the Raceway. I'll try to put everything together tomorrow so I can post a formal update with spreadsheets and slips, but with a better DA and lowered tire PSI she didn't disappoint. I think we should have a solid reference series now for bone stock, formal 1/4 mile drag slip runs to compare with all of the mods coming out now, so looking forward to slips from those with performance upgrades for comparison.

[AlexFL]

Originally Posted by Max Well

Just getting back from another day at the Raceway. I'll try to put everything together tomorrow so I can post a formal update with spreadsheets and slips, but with a better DA and lowered tire PSI she didn't disappoint. I think we should have a solid reference series now for bone stock, formal 1/4 mile drag slip runs to compare with all of the mods coming out now, so looking forward to slips from those with performance upgrades for comparison.

Great, Max! Look forward to your data.

[AlexFL]

Btw, what do they ask for to do gainesville test & tune? just helmet or engine diaper, too?

[GT500R]

Originally Posted by Max Well

Just getting back from another day at the Raceway. I'll try to put everything together tomorrow so I can post a formal update with spreadsheets and slips, but with a better DA and lowered tire PSI she didn't disappoint. I think we should have a solid reference series now for bone stock, formal 1/4 mile drag slip runs to compare with all of the mods coming out now, so looking forward to slips from those with performance upgrades for comparison.

If you could advise changes in your report that would be appreciated!

[Max Well]

Intro: First, I wish to give a round of applause to the Staff of the Raceway and all of the Volunteers who worked so hard to get it open for Saturday morning’s Event, considering the severe weather that rolled through just 36 hours previous. There was still some work to be done Saturday morning, so the start was delayed from 10AM until 11AM, and there was an occ glitch in which an interval time didn’t measure on some runs (two of mine), but really great work by them.

It was a perfect day for performance engines, and I knew as soon as I left home with frost on the roof and crystal blue skies overhead. Because of the large turnout and the delayed starting time, I also knew I wouldn’t be able to run as many attempts as I did my first time out (11 that time), so that altered the strategy I had previously planned. I wasn’t sure if I was even going to be able to get four runs in, so I started with one Sport+/D3/Sport+ run, then figured I needed to hit LC every chance I got.

The differences from Round 1 mainly centered on a much better DA, beginning at -361 and ending at +14. We don’t have many opportunities to run in such pristine conditions at this Raceway as it is used throughout the year for professional runs and serious hobbyists with slick and drag radials only, so I definitely wanted to run max out on each attempt. As I noticed a lack of grip the last time out using BMW’s rec tire pressures of 33 front/38 rear, which definitely hampered my 0-60 foot times, I ran 32 Front/35 Rear this time. I know kingmonkeyjr had suggested 32 psi all around, but I didn’t want to make such a big jump down with this being only my second visit to the Raceway. Surely there is a sweet spot with our X3MC, so I wanted an intermediate data point for this series, and then next time figured I can try lowering the rears to 32 psi as well.

Gas was the same, just Shell 93 Octane, and this time tank volume was down to 5/8 for a starting point ending up at 3/8 tank at the end.

Results: What a difference with LC this time around – I had no trouble whatsoever setting the launch. Obviously if one were racing to see who gets across the finish line first as opposed to time slip results that would create a problem, since one only has 1.5 sec when the lights start and it has been suggested in previous discussions, we need roughly 3 sec for max boost build. Because you never know the abilities of the competition in the next lane or the timing start sequence (at least here I couldn’t judge that), hard to start building boost until you see the first yellow. So forget the R/Ts as I was totally ignoring that aspect.

Best ET for the ¼ mile was 11.671 s @ 117.81 (in which Dragy showed the 0-60mph time was 3.60 s, with the 1’ rollout like C&D and others use as 3.40 s). Best Speed for the ¼ mile was final round with ET 11.744 s @ 118.80. And to stress again, this is just bone stock, with a half tank of pump gas Shell 93 Octane.

Can’t count the number of folks who came up to me in the pre-staging lanes to remark they couldn’t believe what our X3MC is capable of laying down. Quite a sleeper visually (which personally I prefer but I understand others wish for the more aggressive aesthetic), but don’t mess with it when serious performance is desired.

Next time out, I would like to lower the rears to 32 psi as mentioned and begin with less fuel in the tank. Unfortunately, it appears that ‘All Welcome test-n-tune’ Events like this one which allow street tires may not be available again at this high echelon Raceway until early December (if I'm reading the printed year's schedule provided on Saturday correctly), so I'm not holding my breath on when I can get those trials done. And I heard for the first time around 1215PM the Announcer mentioning the ‘Sunoco Race Gas station was closing in 15 minutes, so if you need race gas you need to head right over.’ The fourth try would be to add race gas to raise the octane. Those incremental steps in slightly changing parameters should allow a better idea as to how much effect each change produces.

And one other point – it seems everyone always looks at the ET, but if you look at my final run, all of the interval times except for the 0-60 foot were essentially won in that last race (ignoring the .003 difference in the 60’-330’). So, the difference was totally in the 0-60’ interval (0.161 s). Subtract that 0.161 from the ET of that run of 11.744 yields 11.583 s for a very realistic and objectively documented ¼ mile time. Bone Stock. Shell 93 Octane, half a tank of gas, and DA +14.

Really liking this X3MC – once again thanks to BMW for their design and engineering on this model.

[GT500R]

Thanks for all of the info! I wonder if any other settings like changing suspension to comfort would have helped or not.

You have 21’s right? I see you removed spare and have to moonroof, did you get a weight?