Quote:
Originally Posted by BulkBen
Hey Brock, given the challenge of launching with the extra power, have you considered an M5 / X5M caliper upgrade?
A few of us on here have done it. If you get the right calipers (X5M) it's a bolt on job which can be done in an hour, you can swing it for less than $2000 USD too.
I bought slightly used calipers with virtually new pads and its worked a treat.
I track my X3M at the race circuit so also added ducts. The combination has worked brilliantly here (where I have to brake from 220kph to around 80kph) and it def helps hold the car when launching too.
If you do some searches the various posts on the subject will come up.
Just a note on tyre pressures too.
I have only done 3 x 1/4 mile runs with my car after the PJ tune and managed 60ft times of 1.62, 1.61 and 1.66.
All runs were done on the street using between 30 and 32 psi with the same tyre combo as you - MP4S 265 front and 295 rear.
Just some food for thought given the higher pressures you ran.
|
I actually did look into the X5M brake upgrade! I saw
Kevin_The_Clean1 created a thread about it but I didn't realize people had them up and running already. It is certainly something I have my eye on at some point. I don't have immediate plans on pulling the trigger so I figured just a pad upgrade would serve me well for now. I love that I don't have to fork over $4k for Brembo's like I did on my S4 haha!
As for tire pressures, I do agree with you. As you mentioned, those work great on the street and I always air down to achieve my best runs. I haven't had a chance to launch the 265/295 combo on the street just yet so I'll report back when I can.
The same tire pressures don't really translate to a prepped track though. Nearly every time I dropped that low in an AWD car with a "brake boost" style launch control it never can hold the car back. Which is what led me to experimenting with upping the PSI. It may work for some instances but most of the time, from my personal experiences, I always have to air up with street tires at the track.