Season 1 Of 1/4 Mile Testing

10-27-2025

Hi all... so I am summarizing this seasons findings for my 2025 X5M and days at the drag strip. I posted in the X5M/X6M sub forum but probably should have posted here....

The start.... June 13th 2025....
Stock vehicle (21''/22'' wheels) | 0 lbs reduction in weight | 617 HP | Gas Tank ~ 56%
Best Run: 11.953 @ 114.09 MPH
DA: +771 (using airdensityonline.com)

The middle.... August 6th 2025....
Modified vehicle (21''/21'' lightweight wheels) | -28 lbs reduction in weight | 617 hp | Gas Tank ~ 66%
Best Run: 11.975 @ 114.44 MPH
DA: +750 (using airdensityonline.com)

The end.... October 26th 2025....
Modified vehicle (21''/21'' lightweight wheels, 2ndary ER Downpipes, Titanium X Pipe - Mid Pipe) | -43 lbs reduction in weight | 627 hp? | Gas Tank ~ 60%
Best Run: 11.805 @ 115.80 MPH
DA: -490 (using airdensityonline.com)

My takeaways:
Wheels
1. I would have sworn lighter wheels, especially 7lbs less per corner would have helped a bit on the 1/4 but not even a bit. Car does feel a bit nimbler and does help with braking but nothing really on the acceleration.
2. Happy overall with the "Vossen EVO4" forged wheels and how they have held up.

Exhaust
1. Stock exhaust right after the secondary downpipe is not uniform in size, it goes from approx. 2.75'' ID to 3'' ID after the resonator.
2. Stock resonator IS an H pipe (didn't think it would be).
3. Downpipe + X pipe did help with sound, not obnoxious, not too loud and helped with responsiveness of the engine.
4. The "Allen" / "China" titanium exhaust fit very well to the stock exhaust, no issues.

Track Time
1. So did the exhaust help overall? I think so, even when you take the 2nd and the 3rd tests and use SAEJ1349 Style Air Density Normalization it still comes out to 11.923 vs. 11.840 (-.08) and 114.97 vs. 115.46 (+.5 MPH) gains. So the downpipe and X pipe is worth almost 1 tenth in the quarter if you look at it like this... not bad!
2. 0-60 was 3.59 (3.40 with 1 foot roll out)
3. Best times achieved were holding the LC for right around 2 seconds.
4. Track Mode vs. Pure M2 Mode with everything dialed up yielded no difference in times.
5. This ///M is consistent AF... like super consistent with ET and MPH, great bracket car

Weight Savings
1. Every component taken off and put back on the car was weighed... picture attached.

Thanks for the long read and next season I am going to look at JB4, possibly more weight reduction, Race Gas and that's probably enough for me.

-GT500R

An image attached to this post, provided by the poster

10-31-2025

GT500R wrote
My takeaways:
Wheels
1. I would have sworn lighter wheels, especially 7lbs less per corner would have helped a bit on the 1/4 but not even a bit. Car does feel a bit nimbler and does help with braking but nothing really on the acceleration.
2

-GT500R

Yeah, I’ve read the legends about reducing unsprung mass/wheel weight too. Some people even mention a 6:1 ratio.
About a week ago I swapped my summer wheels for the winter set on my 45e, which meant roughly a 20 kg weight reduction.
In the 100–200 km/h measurement, that gave me a 0.16 s advantage (corrected 8.00 s vs. 8.16 s), so it was roughly equivalent to about a 40–50 kg overall weight reduction ( about 2:1 ratio) .
I’ll also do a 1/4-mile test, since the difference should show up there as well ( I hope).
In your case - based on my experience - a 28 lbs (~12 kg) less on the wheels could mean about equivalent to about 25 kg overall weight reduction, which would be equivalent to a third of a tank of fuel. This would be barely noticeable.

As for the 1/4-mile time, with the MHD Stage 2 software the 45e runs about the same time (~590 BHP, but with slightly more torque than the stock X5M).
What’s interesting (at least to me) is, how different the split times are. The 3.6-second 0–60 mph is insanely good compared to mine, so the X5M easily pulls ahead at the start.
However, above 100 km/h, aerodynamics start to play a bigger role (and that’s where the X5M is much worse), so from that point the 45e slowly starts catching up.
By the finish line, we’d probably cross almost at the same time, however the 45e has about 3mph higher trap speed.

11-02-2025

The difference is the 45e should launch harder or at least if it did you would have a 11.5-11.6 capability.

Also the 45e must have more ho than the M as they weigh pretty much the same but the MPH indicates you have more power than me.

12-16-2025

Great post, thanks for sharing your results!

01-02-2026

6SPDG82 wrote
Great post, thanks for sharing your results!

NP! Season 2 coming up this year… figuring out what’s next..

JB4
100 octane
Lower weight

03-07-2026

GT500R wrote
NP! Season 2 coming up this year… figuring out what’s next..

JB4
100 octane
Lower weight

Do you plan on tuning the car?

Garage

1 Series

2 Series

3/4 Series

5 Series

6/M6 Series

7 Series

8/M8 Series

M2

M3/M4

M5

X1/X2

X3/X4

X5/X6

X7/XM

Z4

BMWi

Season 1 Of 1/4 Mile Testing