[4.8 E70]

So today I went with a few buddies of mine to Englishtown. I finally got a chance to test out the JB4 to its full potential.

JB4 Map 7
97 Octane - Had a 1/4 tank of 93 and mixed it with 5 gallons of 100 Octane
DCI
Muffler + Resonator Delete
Stock RFT tires, btw.
(Downpipes will be arriving this tuesday )

I had 3 runs in total but my 2nd one was the best.

First Run = 12.98 @ 107.93 with R/T .352 & 60' 1.985

As this was the first time I ever took my car to the track I did not know the time you had to get ready. ie. set the right launch RPM. So I was in the middle of building boost and getting ready to take off, the light just turned green. At that point, I knew I was screwed so I just gave it WOT and still managed the 12.98.

Second Run (Best run) - 12.56 @ 108.97 with R/T .360 & 60' 1.748




Sorry for the crappy iphone 4 quality


Third Run (Worst run) - 12.86 @ 108.43 with R/T .079 & 60' 1.912
This would have been the perfect one had I not spun out all 4 of my tires. I held the RPMs at 4K until the light hit green, let the brake go, my 335XI went sideways while all 4 tires spun for about a second. Finally grabbed traction and just sling shotted away.

What do you guys think for my first time at a track ever.

[Clap135]

Your trap speed seems really slow for what it is. Also how did you manage to brake torque to 4k? What kind of boost were you running?

[idrift4wd]

you do know that the time starts when you actually leave the line right? meaning it can turn green and you can wait there and take off and still get the correct 1/4 time.

[4.8 E70]

Originally Posted by Clap135

Your trap speed seems really slow for what it is. Also how did you manage to brake torque to 4k? What kind of boost were you running?

Jammed on the brake with my left foot and smashed the gas pedal with the right lol. Maybe it wasnt exactly 4k but def around there. Map 7 (light race map - 97 OCT and above) max's the boost out at 17.5 psi. Having a 6AT def helped out launching it a lot !!

[4.8 E70]

Originally Posted by idrift4wd

you do know that the time starts when you actually leave the line right? meaning it can turn green and you can wait there and take off and still get the correct 1/4 time.

lol I didnt know. Like I said, this was my first time ever at a track.

[Clap135]

if you actually ran 17.5psi, then your trap speed is REALLY slow for that boost pressure.

[4.8 E70]

Originally Posted by Clap135

if you actually ran 17.5psi, then your trap speed is REALLY slow for that boost pressure.

How does that work ? I saw the top 20 times and the 20th spot is Jim Messina, which ran a 11.959 @ 116 mph. .6 seconds quicker with only a 7 mph higher trap speed. Do 7mph really make that much of a difference ? Sorry, i'm kinda new to this track thing.

Edit: Just realized Map 7 is max of 16.5 PSI not 17.5. Does the weather have anything to do with this ?

58 F
58 Relative Humidity
Absolute Baro 2986

Does that help a bit ?

[RambleJ]

Originally Posted by Clap135

Your trap speed seems really slow for what it is. Also how did you manage to brake torque to 4k? What kind of boost were you running?

Brakeboost to 4k does seem extremely high. I usually sit at around 1800, to minimize wheel spin. Hell @ 4k, I would sit there burning my tires for way too long.

[roninsoldier83]

Originally Posted by Clap135

Your trap speed seems really slow for what it is. Also how did you manage to brake torque to 4k? What kind of boost were you running?

I don't know, he's running stock downpipes & stock intercooler, pushing 16.5psi in a 335xi trapping just a hair away from ~109mph, not too far off from what I would have guessed. Mostly considering that it's an AWD 335xi, I would imagine the extra 200-300 lbs of weight (vs. RWD) and larger drivetrain loss (via 2 extra drive-wheels & AT) would bump his trap speed down 2-3+mph vs a RWD 335i. Sounded about right to me.

Just my $.02

[themyst]

Originally Posted by 4.8 E70

How does that work ? I saw the top 20 times and the 20th spot is Jim Messina, which ran a 11.959 @ 116 mph. .6 seconds quicker with only a 7 mph higher trap speed. Do 7mph really make that much of a difference ? Sorry, i'm kinda new to this track thing.

Edit: Just realized Map 7 is max of 16.5 PSI not 17.5. Does the weather have anything to do with this ?

58 F
58 Relative Humidity
Absolute Baro 2986

Does that help a bit ?

A 7mph difference is like 7 car lengths on a highway roll, so yes it's a lot.

[Bagelfast]

Nice runs, 12.5 it a good ET.. Trap speeds can get better.

[themyst]

For 16.5 psi on an xi, your trap speeds are still low. A comparable I model would trap 112-113 at that boost with the proper fuel.

Next time out, try launching in 2nd gear.