Slow 1/4 times for tuned 135i's?

[BMW86]

I'm well aware of what sort of gains you would expect from a JB3 or similar tune and I've seen the dynos before but I'm finding it hard to understand how the power has been translating to the track. I keep hearing of people going to the track with a tuned 135i and running a quartermile time of 13.10-13.50 at best. I also hear of people acheiving this with a stock 135i as well?

I thought a tune or reflash on an otherwise stock 135i would put you in the mid to high 12s for sure considering the massive gains you get - 60kw at wheel for jb3 etc.

I know there are many variables - driver ability, temperature, gas, tyres, launching and so forth but I still imagined the times would be alot better considering the official quarter mile time is 13.3 for the 135i. Am I missing something or do certain variables have a big influence in what times people are achieving? I've never tracked my car before so i'm lead to believe that launching the 135i is alot harder with added extra power and the quarter mile times reflect this.

Can anyone with a tuned 135i chime in on why people are getting these times?

[eunosracr]

Driver skills, or lack there of.

[Citizen Z]

Originally Posted by eunosracr

Driver skills, or lack there of.

+1

If you suck and don't know where the proper launch/shift points are, you're gonna be slow.

[themyst]

Originally Posted by BMW86

I'm well aware of what sort of gains you would expect from a JB3 or similar tune and I've seen the dynos before but I'm finding it hard to understand how the power has been translating to the track. I keep hearing of people going to the track with a tuned 135i and running a quartermile time of 13.10-13.50 at best. I also hear of people acheiving this with a stock 135i as well?

I thought a tune or reflash on an otherwise stock 135i would put you in the mid to high 12s for sure considering the massive gains you get - 60kw at wheel for jb3 etc.

I know there are many variables - driver ability, temperature, gas, tyres, launching and so forth but I still imagined the times would be alot better considering the official quarter mile time is 13.3 for the 135i. Am I missing something or do certain variables have a big influence in what times people are achieving? I've never tracked my car before so i'm lead to believe that launching the 135i is alot harder with added extra power and the quarter mile times reflect this.

Can anyone with a tuned 135i chime in on why people are getting these times?

If you lose boost, you're going to be slow. The MT drivers are almost always going to be slower than an equivalent AT, because the ATs do not lose as much boost between shifts as the MT. There are a few exceptions to the rule, such as Citizen Z. Your best ET was sick!

Another factor is most JB3/PROcede tunes are netting 350-355+ whp. The stock 245 rears just aren't wide enough to get the power down! I believe the stock RFTs are pretty sticky, just makes the launch tricky to get down pat consistently, AT and MT alike. The best 1/4 mile runs were done with DRs. I need to get some Kosei K1s with Nitto 555Rs!

[Citizen Z]

Originally Posted by themyst

If you lose boost, you're going to be slow. The MT drivers are almost always going to be slower than an equivalent AT, because the ATs do not lose as much boost between shifts as the MT. There are a few exceptions to the rule, such as Citizen Z. Your best ET was sick!

So true and thanks for the complement. I ran several mid 13's that day by virtue of mis-shifting 2nd or 3rd. If you can get high octane fuel in a tuned car with better tires, hit your shift points and get the power down on a warm but not greasy track, you're gonna have insane times.

[themyst]

Originally Posted by Citizen Z

So true and thanks for the complement. I ran several mid 13's that day by virtue of mis-shifting 2nd or 3rd. If you can get high octane fuel in a tuned car with better tires, hit your shift points and get the power down on a warm but not greasy track, you're gonna have insane times.

I noticed my best results are by riding out the clutch for a half second between shifts. I was experimenting a few days ago, and I peak at 14.7lbs of boost, and noticed if I shift at 6000 RPMs while riding out the clutch between shifts slightly, you drop down to around 7lbs of boost, which is a hell of a lot better than starting at zero. The launch on RFTs is an acquired skill though, YMMV. I like slipping the clutch really aggressively from idle - 1.2k because then there is no question in reference to your tires hooking up.

I may take the Map 7 settings (1.3 8D4) and bump the Pedal Input / Boost Gain (PD) on my BMS Tuning Gauge to build boost faster between shifts... will need to check with Terry to see what bad may come of this, but I would imagine this would increase the margin of error for MT owners.

Shifting even earlier in 1st gear helps too... around 5.5-5.8k. Spinning 2nd gear is a real ET killer.

Citizen Z, does this sound accurate?

[blklacker]

Sounds like you need a steptronic and you will pull 12's all day and night

Originally Posted by BMW86

I'm well aware of what sort of gains you would expect from a JB3 or similar tune and I've seen the dynos before but I'm finding it hard to understand how the power has been translating to the track. I keep hearing of people going to the track with a tuned 135i and running a quartermile time of 13.10-13.50 at best. I also hear of people acheiving this with a stock 135i as well?

I thought a tune or reflash on an otherwise stock 135i would put you in the mid to high 12s for sure considering the massive gains you get - 60kw at wheel for jb3 etc.

I know there are many variables - driver ability, temperature, gas, tyres, launching and so forth but I still imagined the times would be alot better considering the official quarter mile time is 13.3 for the 135i. Am I missing something or do certain variables have a big influence in what times people are achieving? I've never tracked my car before so i'm lead to believe that launching the 135i is alot harder with added extra power and the quarter mile times reflect this.

Can anyone with a tuned 135i chime in on why people are getting these times?

[BMW86]

From what I understand it comes down to driver skills and some other variables. I have steptronic 135i and it is completely stock and I have been practicing launching my car. I have found with everything off (DTC and DSC) it is best to rev launch at 1600-1700rpm. I get minimal wheelspin. I let 1st and 2nd gear redline but I have heard it's best to shift early in 3rd?

[AlBel1214]

Yeah shift at 6500 in 3rd and a little bit less in 4th....

And no matter what tune you have if you cant get traction your screwed...Until you figure out how to launch your times will not be good (even with an AT)... Rev to high and you spin big time off the line, don't rev enough and you get a slow ass 60 foot, which is what its all about...

[infinitekidM2C]

I've seen a lot of people getting 12's with tunes...so i disagree with this post

[Citizen Z]

Originally Posted by infinitekid2002

I've seen a lot of people getting 12's with tunes...so i disagree with this post

Which post?

Oh, and 6500 rpm is a horrible place to shift; nearly 750 rpm too high.

[Chicago1]

Well, I had my very first virgin experience at the track last night and I have to agree with this post. Slow (relatively speaking) times, and poor driver skills (me). Best was 13.5 @ 106. I have intake, exhaust, and Dinan S2, and was hoping to get high 12's. There was a 2003 AMG Benz squeezing 23psi out of his supercharger and pulling 12.8 all night. Track conditions were decent, but could have been a tad warmer (it was about 60 degrees). I think the key here is to master the launch. With approx 435lb-ft of torque at the crank with my mods, I should be able to get a sick launch, but to my own fault, and partially b/c of these run-crap tires, I didn't get 1 single good launch in 7 runs. The one time I really tried to launch, I spun insanely through first gear and had to shift to 2nd before I was even out of the box (worst run all night). The guy with the Benz recommended letting some air out of the tires, so I dropped to about 25psi, but even trying to launch at 2,000RPM caused mad wheelspin.

Further, I love everything about this car, but I absolutely hate our transmissions - more specifically our ambiguous shift gates. This is my 3rd manual transmission that I've owned (formerly a Saab, and a Nissan), and I never missed or crunched a gear (until this car). Hard shifts at 7,000RPM in this car make it easy to miss a gear (only did it once last night), or grind them, even with full clutch engagement. My damn shift knob also pulls off VERY easily, and made me miss 3rd on another run as well.

Also, before someone comments, yes, I know I need to shift before 7k, as the Dinan software starts to taper off boost in the upper RPM band. (A pain in the a$$ for 1/4 mile because I have to shift to 4th right at the end of the track... it would be nice to roll across the line while still in 3rd with 1 less shift).

All-in-all, I think these tunes will yield some quick track times, but it'll take some good tires, and a lot of practice to find the sweet-spot for putting all that torque to the ground. I personally have a lot to learn in this area.

[AlBel1214]

Citizen is right.. ignore my post.. I saw the dyno where around 5800 RPM the power goes down hill...

[SpeedballTrix]

My best on my bone stock car was 13.26.
That's with not very much practice and no track prep.
I'm convinced that with practice and prep I can hit 12.99 on a bone stock car. Turns out Im not going to be able to find out cuz my RFTs are on their way out, and will be replaced with proper tires soon.
Although I would still technically consider the car stock and the numbers wont get much better... they will get better.

[BMW86]

If I run 235 in the front and 265 in the back do you think this will help with any potential wheelspin problems with a tune? In stock form I have minimal wheelspin and I get off the line very easily.

[john08135i]

Originally Posted by infinitekid2002

I've seen a lot of people getting 12's with tunes...so i disagree with this post

Yep..first time out with SSTT i ran 12.7 in the 1/4 rest was all stock

[BMW86]

Originally Posted by john08135i

Yep..first time out with SSTT i ran 12.7 in the 1/4 rest was all stock

Nice work!

[jeremyc74]

I think the reason you're not seeing great times is that a lot of people discount how difficult it is to turn a great 1/4 mile time. You don't just roll out there and put your foot on the floor and match the magazine times.

Also the weather, and time between runs has a HUGE effect on the times. On my GTO (which I had done about 150 passes in by the time I sold it) the times would vary as much as half a second from the first run to the last run, depending on how much cooldown time it had.

There are tons of variables.

[Bdh821]

My first time out with JB3 when it first came out, I ran a 13.6 @ 108 best... could not get traction in first or second tho on stock RFTs.

[FORCED AIR]

Originally Posted by Bdh821

My first time out with JB3 when it first came out, I ran a 13.6 @ 108 best... could not get traction in first or second tho on stock RFTs.

ouch.....gotta love the performance of those awesome tires we get to have because so many buyers wouldn't want to change or fix a flat.

[Alext]

If you relax a little, your MT shifting will actually improve. I find that the BMW MT likes to be carassed a little rather than banged violently into position.

[Citizen Z]

Originally Posted by Alext

If you relax a little, your MT shifting will actually improve. I find that the BMW MT likes to be carassed a little rather than banged violently into position.

+1; this was a big factor for my fast times. I slowed down when I got too anxious.