[amclint]

Originally Posted by themyst

No way, my first 60-130 of 9.81 was done on a 0.8 slope, when I pulled on level ground after 2 hours cool down I ran a 10.57 with a 0.01% slope. slope can influence 60-130 by well over a second.

Buddy with the C63 went from high 9s low 10s on level ground to 8.7 on a 2.5% slope.

Maybe you coincidentally bogged during those downhill slope pulls? That'll hurt you a ton.

I had no idea it was that much of a difference, no wonder you guys hunt so much for those grades just under 3% !

No I'm really going to have to start driving around with my vbox and watch the elevation, I wonder if there is some website that lists elevations for highways and such ? Google Earth maybe?

[themyst]

Well yeah, physics. Less rolling resistance when you're accelerating down a hill.

[39nas-t]

I am going to run my wifes 335xi again soon! I have the Vbox back from my brother and we are going to check out what she can run in the weather with my tune that Terry helped me with!

[amclint]

Originally Posted by themyst

Well yeah, physics. Less rolling resistance when you're accelerating down a hill.

Yes I understand all that, ask me about my 3.1s to 60 run down a 7% grade by my house I don't publish those #s because it's more just for fun, I did that on map 7 full weight so I may try it again and see if I can hit a 2.9x run on the vbox

I just had figured a slope would gain maybe .5s, hadn't imagined it would be potentially 1 to 1.25s on a 0% run compared to a 2.5% run.

The 60-130 is still pretty new to me, I'm learning and once I find a 2.5-2.9% slope I will come back with a time in the low 10s

[jpsimon]

the 2% i use is pretty much the only safe place to do it on my way home, plus i used that before i had meth so i had to continue to see accurate changes

[DefactoM6]

Originally Posted by themyst

No way, my first 60-130 of 9.81 was done on a 0.8 slope, when I pulled on level ground after 2 hours cool down I ran a 10.57 with a 0.01% slope. slope can influence 60-130 by well over a second.

Buddy with the C63 went from high 9s low 10s on level ground to 8.7 on a 2.5% slope.

Maybe you coincidentally bogged during those downhill slope pulls? That'll hurt you a ton.

Oh I totally understand the physics behind it, and in theory it should be the case, but that was simply my observation. I have spent tons of time doing Vbox runs, and for some odd reason, my times have always been better with less slope (within reason). I have never run on a net incline. I am fully aware that bog makes a huge difference. That said, my 8.84 was run on a 0.8% decline, IIRC...meanwhile, I've run an 8.87 on a 2.4% decline with 150 lbs taken out of the car, with a slightly taller tire, which should help, since the car's slowest spot is the 120-130mph run. Bottom line, yes, decline should help in theory. I just find it strange that with the sheer number of runs under my belt, I have never found that to be the case with my 335. Other cars...I totally agree.

[themyst]

Originally Posted by DefactoM6

Oh I totally understand the physics behind it, and in theory it should be the case, but that was simply my observation. I have spent tons of time doing Vbox runs, and for some odd reason, my times have always been better with less slope (within reason). I have never run on a net incline. I am fully aware that bog makes a huge difference. That said, my 8.84 was run on a 0.8% decline, IIRC...meanwhile, I've run an 8.87 on a 2.4% decline with 150 lbs taken out of the car, with a slightly taller tire, which should help, since the car's slowest spot is the 120-130mph run. Bottom line, yes, decline should help in theory. I just find it strange that with the sheer number of runs under my belt, I have never found that to be the case with my 335. Other cars...I totally agree.

doesn't apply to me it seems. I've cracked 8.9 with two shifts on my 6AT on a 3.2 slope full weight. I need to get that slope as close to 2.99% as possible and I think I could do 8.9 again in proper conditions. Actually, I have a compressor upgrade now, if I don't crack 8.9 with a proper tune I'd actually be pretty upset

[DefactoM6]

With the compressor upgrade, I would imagine that breaking 8.9 shouldn't be hard. Do it sooner rather than later, the temps really seem to make a huge difference...yes, including meth. Humidity also makes a big difference, I always got faster times when it is 5 or even 10 degrees hotter but 20-30% lower RH.

[themyst]

Originally Posted by DefactoM6

With the compressor upgrade, I would imagine that breaking 8.9 shouldn't be hard. Do it sooner rather than later, the temps really seem to make a huge difference...yes, including meth. Humidity also makes a big difference, I always got faster times when it is 5 or even 10 degrees hotter but 20-30% lower RH.

+1 on the humidity. Also gotta have a day with calm winds as headwinds and cross winds near Mexico wreak havoc on results.

For reference, my 9.39 was done with the compressor upgrade but with an OTS map running 18.5 psi mid tapering to 13.5 at redline (which was more like 17 mid, 11 at redline if I didn't add boost with a JB4). Need to run far less taper or no taper to wake these things up. Cobb is working on it for me.

[jpsimon]

Originally Posted by themyst

+1 on the humidity. Also gotta have a day with calm winds as headwinds and cross winds near Mexico wreak havoc on results.

For reference, my 9.39 was done with the compressor upgrade but with an OTS map running 18.5 psi mid tapering to 13.5 at redline (which was more like 17 mid, 11 at redline if I didn't add boost with a JB4). Need to run far less taper or no taper to wake these things up. Cobb is working on it for me.

seeing the same thing i do pretty much, compressor only begin to shine when you have enough octane and can bump the boost up and reduce taper a bunch. That being said, i haven't pushed mine yet that hard since i got the new meth setup: I need to make my own meth mixture, the boost juice just doesn't cut it for octane

[themyst]

You need to find some VP M1 and run that stuff straight 100% or at the most, splash it with 10% water to make the mixture less flammable.

[jpsimon]

Originally Posted by themyst

You need to find some VP M1 and run that stuff straight 100% or at the most, splash it with 10% water to make the mixture less flammable.

I have a source on the way to work that i just recently found out about (thanks defacto), don't feel comfortable with a 100% mix in my engine bay though. I'll do a 70/30 or so.

[themyst]

There's A noticeable difference between 50/50 and 100% I think even a 70/30 mix might help you a good bit. Thing is you're already pretty much maxed out on boost it seems, 19 psi no taper? Only thing you can really do is push timing for power it looks like unless I missed something.

[Mike@N54Tuning.com]

Here is a new one for the list:

8.57--Terry (135i AT, JB4, 2 shifts)

[jpsimon]

I wish my car weighed 400-500lbs less

[SIKH335]

Nce run looks like a perfect night.

[hotrod182]

And on the vbox, the car trapped 125.4 mph in 85% humidity, level qtr mile run. Not too shabby at all!

[SIKH335]

Originally Posted by hotrod182

And on the vbox, the car trapped 125.4 mph in 85% humidity, level qtr mile run. Not too shabby at all!

That's 123.4 at Sacramento right Hotrod.!!!!!!

[hotrod182]

Originally Posted by SIKH335

That's 123.4 at Sacramento right Hotrod.!!!!!!

Yup, or 128 mph there a couple years ago! And its amazing to think that this is only about 15-16psi above 6000rpm. Much more turbo friendly boost curve, than high boost, low timing alternatives.

You should do a few runs at Sacramento to compare against a Vbox. Still curious if it is 2mph off. Please vbox log for us with the time slip if you can. Or better yet, just find a level road, and see if you are getting 125mph+ on the Vbox. Sacramento is kind of like the twilight zone. How did I set a stock turbo N54 335i world record in the 1/8 mile of 98mph, when my car wasn't even running very strong last visit there??? They are having the 2012 opening test and tune at Famoso this weekend. Let me know if you can come!

[jpsimon]

9.74 seconds tonight, little better

[amclint]

Originally Posted by jpsimon

9.74 seconds tonight, little better

Nice, one of these times you should run a 1/4 on the vbox just to see what you trap

[jpsimon]

Originally Posted by mykal335xi

Nice, one of these times you should run a 1/4 on the vbox just to see what you trap

i know i know, one of these days!! the 60-130 is easier since i have a pretty good spot for it. finding somewhere to do the 1/4 mile is a bit tougher