# First 1/4 Mile Results and Questions



## TDIwyse (Sep 17, 2010)

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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## cssnms (Jan 24, 2011)

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.


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## TDIwyse (Sep 17, 2010)

cssnms said:


> 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?


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## cssnms (Jan 24, 2011)

TDIwyse said:


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


Larger diameter tire will be counter-productive to your effort.

Fastest times thus far have come by letting the car shift itself in manual mode, brake boosting.


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## Snipe656 (Oct 22, 2009)

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.


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## TDIwyse (Sep 17, 2010)

Not finding much online to quantify wind impact on results. Some qualitative info here for newbies indicating 0.2-0.3 tenths potential impacts:

http://www.8thcivic.com/forums/auto...ect-your-1-4-mile-time-newbies-must-read.html


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## 62Lincoln (Sep 26, 2004)

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?


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## TDIwyse (Sep 17, 2010)

62Lincoln said:


> 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?


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...


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## 62Lincoln (Sep 26, 2004)

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).


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## TDIwyse (Sep 17, 2010)

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.


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## TDIwyse (Sep 17, 2010)

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?


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## Snipe656 (Oct 22, 2009)

How much does a gallon of DEF weigh? I'd imagine between that and the fuel these cars must have a lot of backend weight.


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## GreekboyD (Jan 25, 2012)

Think I've read that a full passive and active tank of DEF on our cars will add about 50 pounds of extra weight.


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## floydarogers (Oct 11, 2010)

GreekboyD said:


> Think I've read that a full passive and active tank of DEF on our cars will add about 50 pounds of extra weight.


Let's see: it's basically the same weight as water, 5 gallons is 20 liters (or thereabouts), a liter of water is 1 kg, so it's 20 kg or 2.2*20 = 44 lbs.


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## TDIwyse (Sep 17, 2010)

TDIwyse said:


> 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.


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## 62Lincoln (Sep 26, 2004)

TDIwyse said:


> Well . . . ordered a dedicated drag wheelset. Kosei k1's with Hoosier's.


Did the wheels/tires show up yet?


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## TDIwyse (Sep 17, 2010)

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.


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## Snipe656 (Oct 22, 2009)

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.


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## TDIwyse (Sep 17, 2010)

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.


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## Snipe656 (Oct 22, 2009)

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.


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