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First 1/4 Mile Results and Questions

11K views 54 replies 13 participants last post by  BohlDiesel 
#1 ·
Took the vehicle to a dragstrip this weekend for their last test-n-tune day of the season. Never been to a dragstrip before and didn't know what to expect. Must say it was a fascinating experience. As a complete newbie didn't do anything special to prep the vehicle: Fuel tank was 2/3 full, tires were normal air pressures, didn't remove any items (except the jumper cables) to reduce weight. Also, there was an 18mph NNW wind with gusts into the mid 20's and the track has the cars racing straight North . . . right into the wind. And man was the place packed with racers!

The best run was the first one before many people had made passes (and started dragging water into the main lanes). Was able to mostly bypass the water pit, but the pits were nearly as wide as the lanes. I had read about starting in 2nd and brake boosting to ~2k, but for my first 1/4 pass ever and I tried to start conservatively. Didn't really do any brake boosting and left the traction control on. I did start in 2nd gear. It was obvious the vehicle had too much torque for the track surface as the traction control kicked in quite a bit in 2nd gear even without brake boosting. The Michelin Pilot Super Sport's were not up to the task. Also, my reaction time sucked and the 60' was a horrible 2.24sec, but ended up with a 13.1 sec 1/4 mile at 107.2mph. That was fun.

Next pass still had the traction control on but tried to brake boost a little and had bigger traction issues. Much better reaction time on my 2nd pass, but an even worse 60' at 2.6 sec. Still ended up with a 107.1mph at the end into that headwind.

Tried once with traction control completely off and it was a fricken' clown show. Car nearly went sideways before I took my foot off the pedal. And water was becoming a problem as the big boys were heavily using the water pit (that's kinda cool to see) and dragging water everywhere. I didn't see any reason to continue trying without drag slicks.

Calculating the difference in wind drag at 107 mph vs 125 (107 + the ~18 mph headwind) shows an extra ~35hp sucked up by the headwind. Too bad it wasn't a strong tailwind :)

So, you guys with drag strip experience, what do you think proper tires that could hook up with brake boosting, and a calm day, would do for the 1/4 ml time? And any suggestions on a good drag wheel/tire setup?
 

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#2 · (Edited)
Were you running stacked?

Get yourself a set of BF Goodrich DR's. Forget going to the track with street tires - been there done that. Like you all I did was spin-out no matter how I feathered the accelerator. The drag strip is fun though... OH, and next time go with a max 1/4 tank. All of that weight you were carrying drug you down. I bet you could have broken 13 on your one pass had you had less fuel in your tank.

BTW, that is an outstanding time/trap for not brake boosting, traction control on and on street tires. **** that is an outstanding time period, but esp so considering the aforementioned.
 
#3 ·
Were you running stacked?

Get yourself a set of BF Goodrich DR's. Forget going to the track with street tires - been there done that. Like you all I did was spin-out no matter how I feathered the accelerator. The drag strip is fun though... OH, and next time go with a max 1/4 tank. All of that weight you were carrying drug you down. I bet you could have broken 13 on your one pass had you had less fuel in your tank.

BTW, that is an outstanding time/trap for not brake boosting, traction control on and on street tires. **** that is an outstanding time period, but esp so considering the aforementioned.
Thnx.

Yes, Evolve with custom progressive controlled JBD with 600cc/min 70/30 H2O/methanol injection.

Maybe next year I can find some DR's and be smarter about the weight and find a test-n-tune event with less wind. Today the weather is calm winds and would have been a much better experience, just took too long for the front to move through.

Question on the 4th/5th gear shift. Watched a couple youtube videos before going from hotrod and others and it seemed like the shift point for 4/5 was right at the 1/4 mile point. On that first run I did I short shifted 4th early (~4000 rpm) thinking it might help. Anyone have experience with how best to manage that shift? Should you just leave it in 4th longer and hit the 1/4 ml while it's shifting in 5th? Almost wonder if larger tire diameter would help so that shift occurred at a higher speed?
 
#5 ·
That is interesting that they were sloshing water onto the track. Usually the more cars with sticky tires going through there the more sticky the track becomes as they are laying rubber down onto it. I have not been to a stip in many, many years, I am pretty confident I'd embarrass myself greatly at this point in time. We used to go all the time though, lots of fun times except when you break something and are a hundred miles from home and trying to figure out how to either a) fix the car there or b) somehow get the car home.
 
#7 ·
TDI, do you have the capability to log the 'performance' of the i/c over these multiple runs? I'm curious about how well the i/c performs in cooling the air for the initial run, and then how well it performs in terms of heat soak on multiple runs. Does the BT have the capability to log ambient versus intake air temps?
 
#8 ·
Yes it can and yes I have, but I didn't for this event as when reading their rules online before the event it appeared they didn't allow any type of recording devices, computers, etc. However it appears that was more for the $ competitions and not the test-n-tunes. Heck, I was so clueless I forgot to put my helmet on the first 2 passes. I did capture the first run on the android torque app's "track recorder" which is pretty neat to watch. But the GPS was still on from routing to the strip and appears to have messed up the times recorded as it argued with itself wether or not to use OBD or GPS speed data (it said 11.9 1/4 mile time and failed to register 0-60, 40-60, etc).

There's some data here that gets really interesting starting pg 3 (http://www.bimmerfest.com/forums/showthread.php?t=598240&page=3). Has BT data on IC temps during full fueling runs in hot weather. The water/methanol injection does a tremendous job of holding temps down run after run. Eliminates heat soak conditions on multiple back to back runs in hot/humid weather.

Looks like there's another test-n-tune Friday night. Not sure I can get drag radials and clear my schedule for that event or not but I'm tempted...
 
#9 ·
I love the work you've done with injection, but I fear I'm not technically savvy enough to attempt such a thing on my car. OTOH, I'm interested in the possibility of improving IAT and heat soak issues via an improved i/c. I can't imagine a better i/c can approach the improvements you are generating, but I hope it will provide improvement from where I am today (Evolve tune, but no JBD).
 
#10 ·
Thanks.

There's more than one way to skin a cat so an improved intercooler would be a good option.

I should mention that after the 3rd pull in 14 mins time the engine coolant was elevated and the car needed to rest.
 
#11 ·
Well . . . ordered a dedicated drag wheelset. Kosei k1's with Hoosier's. Anyone know the easiest way to drain excess fuel from the tank? Can it be syphoned or is there an anti-syphon device in the filler neck?
 
#15 ·
Anyone know the easiest way to drain excess fuel from the tank? Can it be syphoned or is there an anti-syphon device in the filler neck?
Just an FYI . . . If you use the supplied nozzle adapter to open the filler neck, and have a long enough tube, it's possible to syphon the fuel tank.
 
#17 ·
Yes, but there's a problem with one of the tires not holding air. Loses ~1psi/hr. Waiting for replacement but that particular size is on backorder . . .

Last Friday would've been perfect (no winds, 70F) but the track was setup for 1/8th mile only.
 
#23 ·
Yes, but there's a problem with one of the tires not holding air. Loses ~1psi/hr. Waiting for replacement but that particular size is on backorder . . .
Replacement tire showed up yesterday. Mounted and balanced and holding air. Did some testing this afternoon and they provide significantly more launch capability based on GTech measured data than the street tires used previously. A major storm front is supposed to hit Saturday, but the weather for this Friday is looking promising for the last Test-n-Tune opportunity of the season in this area. We shall see . . .
 
#18 ·
Back when I used to be a track junkie I'd routinely use the 1/8th mile tracks for testing new things. Especially suspension and tire changes. Guess I was more concerned with 60' testing when I was going to the 1/8th. You can at least though look at an 1/8th mile slip and get a good idea of what the 1/4 would probably be.
 
#19 ·
Good point. However, I'm actually more interested in the trap speed at the 1/4 ml point as it seems to correlate a lot closer to horsepower, so don't want to make the trip and take the time if it's not going to be the 1/4 mile.
 
#20 ·
Hopefully that bad tire can get sorted out quickly. I'd imagine weather conditions are becoming great for a boosted car at the track. I'd be very curious to see how much improvement is seen in the trap speed due to a more real launch from the tires. My experience never was much of a gain but it was in cars with suspension more purposely built for drag racing and never on an RFT but instead real tires(with some give in the sidewalls) v. usually drag slicks but sometimes cheater slicks. Probably a whole other world in these cars.
 
#21 ·
I'd be very curious to see how much improvement is seen in the trap speed due to a more real launch from the tires.
I don't expect much if any due to improved launch (got within 0.07mph trap speeds with the 2 runs even with a significantly worse 60' on one), but the 18mph headwind had a quantifiable impact (significantly more wind drag sucking up ~30+ hp).
 
#24 ·
Launch data comparison of the street tires vs drag radials: http://www.bimmerfest.com/forums/showpost.php?p=7126837&postcount=83

The dragstrip cancelled this Friday's track event. That sucks. They have a season ending race the following Saturday and are supposedly opening up a test-n-tune in the afternoon for a few hours before the evenings races.
 
#25 ·
What track are you going to? Would love to come out and watch.

Cordova is open for a test n tune tonight if you want to make the 1- 1 1/2 hour drive east. Its a decent track.

Jay
 
#26 ·
Thanks for the tip.

Since the local track event was canceled (the race director had a heart attack which is why the weekend events got canceled... hopefully he's recovery rapidly and his family is doing well) I spent the beautiful Fall day lumberjacking and cutting/loading/hauling/unloading a massive oak tree from our family timber and I'm whooped. Must say I like loading up that big'ol inline 6 Cummins Diesel with a fully loaded tandem axle trailer and letting it growl :) Plus I've started imbibing so any possibility of making it to the strip tonight are long gone . . .

When looking for local strips I didn't see that one you mentioned. Google says it's a 2hr 15 min drive, which means a 4.5 hr round trip. That's 2.5 hrs more driving than the one in Cedar Falls. But I'll keep in mind. Thanks.
 

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#27 ·
Nice saw :)

You are in Cedar Rapids right? I wouldn't trust google on that calc... unless you are are 30 mins from IA City, then maybe...

Let me know when you are headed up to Cedar Falls, I would make the drive. I'm trying to sell my V and would love to get into a 335d to polish out my garage full of diesels.

Jay
 
#30 ·
Let me know when you are headed up to Cedar Falls, I would make the drive. I'm trying to sell my V and would love to get into a 335d to polish out my garage full of diesels.

Jay
I'll consider that.

Been very pleased with the 335d (still can't believe they brought that to the US). Hope you find a nice one!
 
#35 ·
It's definitely higher than what a lot of others run them at. Had read best results come from using the most psi as possible while still getting good grip (more psi gives less rolling resistance). From the previous Gtech testing it seemed a ~2 sec 60' time was achievable with 25-30psi in the Hoosiers, and that time point was what it looked like would be needed to get into the mid 12's. The slush box tranny really reduces the violent start compared to dumping a clutch in a stick so ... used more psi.

Could probably break boost higher rpm's and run lower psi's to improve the 60' and improve the ET. But dang, that's a lot of stress on things.
 
#36 ·
It's definitely higher than what a lot of others run them at. Had read best results come from using the most psi as possible while still getting good grip (more psi gives less rolling resistance). From the previous Gtech testing it seemed a ~2 sec 60' time was achievable with 25-30psi in the Hoosiers, and that time point was what it looked like would be needed to get into the mid 12's. The slush box tranny really reduces the violent start compared to dumping a clutch in a stick so ... used more psi.

Could probably break boost higher rpm's and run lower psi's to improve the 60' and improve the ET. But dang, that's a lot of stress on things.
Yeah drag racing can be pretty brutal on parts if you get overly serious about your times.
 
#41 ·
Well, last years 1/4 mile performance wasn't a fluke...

Improved just a tad today from last years 12.69 to a 12.65 today, with less favorable conditions.

Today was opening day at the nearest 1/4 mile track. Wasn't planning on going until the night before when an obligation got canceled. So, I was able to try some of the new things, but the car wasn't optimally prepared. It had too much fuel (2/3 full of fuel) and the temps were a little warmer than last year. Oh well, it was still a chance to learn.

The car was heavier by 50-60 lbs from last year due to more fuel and more urea. More urea in the tank than last year (last years run was very close to the yearly maintenance and today was less 1/2 way to the yearly service). The temps were pretty good at ~65F, but that was ~18F warmer than last years run.

Also used slightly smaller diameter drag radial. Last years run was larger than stock diamter 245/44/R17 drag radials. Todays was with 225/45R17's which are close to stock diamater.

So, a recap of differences from last year include:
1.) 225/45R17 drag radials vs last years 245/45R17
2.) Customized the water/methanol injection. I made a circuit modification to the Snow boost based controller that creates
a 2D controller ... It now works based on boost AND rpm. Our cars make max boost happens at the lower rpm's and then taper off slighter at higher rpm's. This causes a problem with a boost only controller as you can bog down at the lower rpm's
if you have things setup for optimum higher rpm performance. So now it has an additional rpm component. It will
turn on if enough boost is present (adjustable level) AND based on a minimum rpm (adjustable). If those are satisfied
the output is proportional to rpm's. At full fueling the water/methanol starts at ~2000 rpm's at ~350ml/min and maxes out
at ~4500 rpm at 700 ml/min. Both last and this year used 50/50 mix.
3.) 65F this year vs 47F last year.
4.) ~60 lbs heavier than last year.
5.) Stock intake, stock intercooler, stock exhaust, stock differential... same as last year.

The smaller diameter tires helped the times, even with the heavier vehicle. But I'm at a frustrating point where the 4-5 shift is occurring right at the 1/4 mile point. The top speed is a tad slower this year even though the time is quicker. The smaller tire caused the 4-5 shift to occur before the 1/4 mile point. The shift point causes a loss of application of power as during the shift the power output is cut to help the transmission's longevity ... Last year the larger diameter tire caused the shift to occur right as I was crossing the line. This year with smaller tire it happened right before ... Not sure how to optimize this problem any further. Basically I can trade off a faster 1/4 mile ET with the larger tires, but a faster 1/4 mile time with the smaller tires. Think for real world/street application the smaller diameter tire is the way to go.

Had a great time chatting with the former BMW tech I met during last fall's run. He was there with his car, but broke something in his drivetrain on his 2nd run. He had a co-worker who was the diesel calibration technician at a major heavy duty ag company ... we went over the car, what mods it had, and what he's seen in real world applications for his companies modern diesels (EGR, SCR, DPF, Carbon buildup, how to work around emission components ...). Was fantastic to have a face to face with someone who knows their modern diesel technology.

So basically what I'm seeing is that to significantly increase capability will get really, really expensive and make the car less user friendly and emission clean. I'm not keen on removing the DPF due to the smoke/stink. And at this point it doesn't seem to be causing any performance issues. Think I'm probably at the end of my tweaking on this vehicle as its my main ride now and having something I can daily drive in all conditions (except deep snow) is a priority. I may go back again to the track if the weather is perfect and I have time to get the car in the proper condition (~1/8 tank of fuel, lower urea capacity, cooler temps... strong tail wind :)).

Happy dieseling everyone.
 

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#42 ·
@TDI, I've been pondering the meth/water injection. Did your Snow setup come made for the 335D or can you please elaborate about your setup please. Tank in trunk? Did you drill your intercooler pipe fpr the bung or get another pipe with bung already installed? I assume you are injecting in the intercooler pipe. I had read Stugots was runing JBM with meth but the JBM was taking into account that he was meth/water injecting.

Any guidance or pointers would be much appreciated? thanks
 
#44 ·
I'm using the windshield washer tank for the fluid.

Drilled and taped the intake pipe before the IAT (see below).

The Snow controller I'm using is a simple progressive "boost" operated unit. It came with the option to use either a hose barb connection (if you're routing a line from the boosted air intake) or a DC voltage from a MAF input. You could set a starting and ending value and it would progressively increase injection across that range. I was using the 335d's MAP (not MAF) sensor, which is the boosted air reading, for the DC level for quite some time and it worked pretty decently if you didn't get too aggressive with the setting.

The 335d can make full boost at really low rpm's (http://www.bimmerfest.com/forums/showpost.php?p=6875655&postcount=56) where you can quench the combustion if you inject too much at lower rpm's. So it was a fine balance of injecting too much for a given boost at low rpm's vs not quite getting enough at high rpm's.

I was injecting before the IAT (Intake Air Temp) sensor so the DDE could take advantage of the cooler combustion air and adapt the injection parameters (it changes injection timing/duration based on the IAT data). The location of the H2O injector and the impact to IAT's is shown here for some open road 3rd gear pulls: http://www.bimmerfest.com/forums/showpost.php?p=6940121&postcount=62

This configuration is what I was using when I did the 1/4 mile run last October in 12.69 sec at 109.7 mph. Actually found the Torque Track Recorder video and posted it on youtube today. This was at a Test-n-Tune and I was lined up with a real drag car who CRUSHED me :)



I wasn't happy with this setup, as an issue I noticed was that during the DPF cycle, boost response changes a bit for a given amount of power output. As the DPF regen approached the engine would make more boost for moderate accelerations than with a freshly regenerated DPF. This caused some issues with optimizing the H2O injection settings. Also, I didn't want to be injecting methanol during regens for obvious reasons. See my response on this thread for why starting at post 14: http://www.e90post.com/forums/showthread.php?t=841543

So... I customized things a bit. I was already using a circuit I created to progressively add in the JBD fuel rail distortion based on rpm, so I modified it some more and created an rpm aspect to the H2O injection control. Now the controller sees a DC input that is based on boost and rpm. This way I can minimize the injection quantity at low rpm's so I don't quench the combustion, but still be able to inject full amounts at high rpm's. This setup helped me do an even quicker 1/4 mile at 12.65 with warmer temps and a heavier car than the video above.

I took a quick video today showing the flow rate vs rpm response for a moderate accelerating (enough boost to trigger the H2O, but not so much as to make it too short to see the relationship) 3rd gear pull. You can see the H2O start to be injected at ~2300 rpm (the start level is adjustable on my circuit via a potentiometer) at ~400 ml/min on the AEM guage and rise to full ~650+ ml/min at 4000+ rpm's. This is a much more optimized approach.



Another interesting comparison of the impact of the H2O injection on IAT's and EGT's is shown from the dyno data I posted recently. Even with substantially more output torque and power than the Evolve remap alone provides, the EGT's are similar with the help of the H2O injection. Without the H2O injection, the EGT's would be at dangerous levels...

http://www.bimmerfest.com/forums/showthread.php?t=699265

Hope you find this helpful.
 
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