05-12-2020, 04:35 PM | #133 | |
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There doesn't seem to be much data discussing 'tire psi vs performance' at drag strips that I could find online. Some links are available but aren't vetted analyses and seem to be written mainly for upper echelon Drivers, which discuss making only 1/2 psi adjustments at a time for drag slicks and radials. Kingmonkey mentioned he runs 32/32 if I recall correctly in his modified GLC63? I think one of our UK colleagues also runs lower than OEM psi? Would be interested in reading what others have found with their F97/98 runs. |
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05-12-2020, 07:11 PM | #134 |
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Correct, not much behind street tires and pressure changes, but the concept extensions the same, lower the pressure for more contact patch. I doubt even 3 psi provided a 1/2” extra patch (I’m sure there are calcs out there). Point is you have better runs And that’s awesome but I wouldn’t say it’s all due to tire pressure.
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05-12-2020, 08:09 PM | #135 |
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Both of you are correct. Several factors have contributed to those improved times, with lower tire pressure being a significant contributor.
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05-14-2020, 04:33 PM | #136 | |
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Last edited by Max Well; 05-20-2020 at 08:35 AM.. Reason: Updated to now include 21 and 24 psi data points |
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05-24-2020, 09:17 AM | #137 |
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Did a quick interval comparison between a few stock X3MC formal slips and the Meth injection Dragy run bmw_romy shared at: https://x3.xbimmers.com/forums/showthread.php?t=1723080
Maximum time difference found in the 60'-330' with a slight downward trend thereafter. Wonder if a lower tire psi would've allowed an even faster 0-60 foot as the power increase is definitely there? Don't know if he has spare (looks like moon roof is there) or tank volume. |
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05-26-2020, 08:54 AM | #138 | |
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This is just 93 octane OTS tune with a near 0 DA. You can see where the HP starts to really take over and that MPH is crushed with downpipes, E blended gas and Meth.
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05-26-2020, 12:34 PM | #139 | |
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05-26-2020, 01:49 PM | #141 | |
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So just regular X3M for me
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05-26-2020, 02:54 PM | #142 | |
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Sorry . Here' a corrected version, and I've added interval analysis of your St1 X3M vs my stock X3MC (Dragy vs slip). Once the Strip opens and you get the chance, can you revert back to Stock for a few runs like you did with your G01 so we can get some formal stock X3M data as well? Last edited by Max Well; 05-26-2020 at 02:59 PM.. Reason: Had to correct 'X3MC' to 'X3M' in the interval analysis |
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06-15-2020, 06:27 AM | #143 |
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Added forza1976 fastest run to the X3MC Stock page. His thread at: https://x3.xbimmers.com/forums/showthread.php?t=1728438 . Remarkably close agreement to the interval times between 330'-1320' despite the wide variation in octane, DA, and overall weight. Was Lemongrease planning on submitting his slips from Bandimere as well?
Last edited by Max Well; 06-15-2020 at 06:50 AM.. Reason: Forgot to add link to forza1976's thread |
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07-02-2020, 04:22 PM | #144 |
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For those with tunes, it would seem the ideal evaluation would be running pure stock at a sanctioned Strip followed by variations of tune settings within a time-frame where DA, tires, engine temps are similar. We've all seen how conditions change throughout the course of a day, so making runs close together would control the conditions.
Would be interested in seeing those slips for apples-apples comparisons. And to see what the X3MCS will be capable of... |
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07-13-2020, 12:34 PM | #145 |
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Max Well I might get to the track today. Can you refresh how to do launch control. I got it to work a couple times back when I first got Draggy. Now I can't get it.
I thought it was all settings to max, Manual shifting in 1, and then brake & gas to the floor and let go? I tried that the other day and it wasn't working. Am I missing a step? |
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07-13-2020, 12:43 PM | #146 | |
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07-13-2020, 02:12 PM | #147 |
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07-13-2020, 02:32 PM | #148 | |
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It really is best, at least for me, to set my M2 button with these parameters, then when I pull up to the line and Staged lights up, I simply push it twice (you have to push it the second time to confirm you want to disable DSC) and you are all set. Push down hard on the brake with left foot, push accelerator quickly to the floor, count to three sec and let loose of the brake. Really is flawless if everything is set up in M2 correctly. Looking forward to some slips! Last edited by Max Well; 07-13-2020 at 02:42 PM.. |
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07-13-2020, 03:05 PM | #149 | |
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Also found out track is closed today. Maybe tomorrow if the weather holds out. |
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07-14-2020, 04:13 PM | #150 |
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Didn't get to the track yesterday and today isn't looking good for getting out of the office. I managed to get one decent run yesterday with Draggy. However, shifting into 4th it felt like boost dropped. Turns out it tripped a boost safety and went into safety mode. Still managed to click off a 11.52 with limited boost into 4th. It was approx 72 degrees out and I was running Map 2 on a JB4. Now I raised the limit a couple PSI hopefully I can get a full pass clean soon. Unfortunately it's hard to find a clean 1/2-1 mile road by me to make some passes..
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07-15-2020, 03:40 PM | #151 |
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Heading to the track in NH tonight with some of my RS3 buddies and a buddy with a C8. I CANNOT wait! I'll post slips later tonight
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07-15-2020, 09:37 PM | #152 |
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Didn't get a chance to mess with tire pressures, but put down a respectable time for only getting in three runs. DA was 600, tire pressures 35 all around, and 3/4 of a tank. Car 222
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07-16-2020, 12:15 PM | #153 | |
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Also, it'll be important to know if stock or tune (and if tuned, which brand and which setting for each slip's run), octane of fuel (and Brand), and whether you have moon roof and spare? Trying to provide as much data as we can to allow comparison of tunes and what role octane, weight, etc. play in final results. |
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07-16-2020, 12:21 PM | #154 | ||
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