First Drag Race Log

[oztracktuning]

I raced yesterday for the first time since tuning the car myself and had great fun collecting data.

It was however the hottest conditions i have ever raced in. :bash: The first race was in 99 F (37deg C) and at Track side it was hotter than that.

The second race was still 93 F (34 deg C)

Here is the log - the car spun both times at the start although less in this run. It was a 1.684 60 footer 12.045/112.5mph at a density altitude of about 2200 feet. The first run was a 12.051/113.2 with a 1.708 60 footer at a density altitude of 2688 feet.

I am interested in comments about anything to do with the log. I think i may have some interference on the wideband signal - so i am going to fit a filter capacitor today. It seems to jump around a bit too much.


http://www.oztrack.com/clubsport/dragrace12045.jpg

[joecar]

A few comments:
You get premptive [burst] knock just when wheelspin starts.
You get a degree of knock just about when wheelspin ends, sticky tyres, must be loading.
I wonder why the g-force and power_rw curves are so wiggly...?
Torque tracks airflow.
Spark mirrors airflow.
It was a quite a hot day, IAT is high, you may go quicker on a cold day... :rockon:
TFT looks very good.
How much time was each shift (RPM drop)...?
Which track were you at...?

Good work, mate, 12.0 is quick.
:cheers:

[MN C5]

Burst Knock:help2: Joe you snuck in, guess I took to long to post.

Hey nice runs Flyer ! We could use some of that heat up here in Minnesota...lol just MINUS -11c here...

[turboberserker]

I'll mail you some sunshine if you mail me some cool wind :)

[MN C5]

Erik you Fricker:muahaha: had to rub it in didn't ya

[turboberserker]

hehe lots of folks had jackets on today. It was 73F after all lol

[oztracktuning]

I wanted the Burst knock so that it prevented actual knock. It was planned - at least that is the philosophy . My previous run had 3.0 KR at the same point (max is set at 3.0) so it seemed to have worked.

It has a Yank SS3600 and that the shift extension. It slips up high at the start of the gear and doesnt drop below around 4800. But by the top of the gear is only logging less than 100rpm TCC slip. ( I dont have it set to lock at all )

The car weight about 3655lb with me in it. 1657kg.

Best is 11.765 on a cool day. But has gained about 0.2s since then - but its our summer now - which is almost over. Hope in the winter to run under 11.50 - need a real good air day.

[MN C5]

Are you sure its engine knock? Try turning the fuel up and see if you can make it go away by adding fuel. I'd do that before I'd start pulling timing. Whats your PE threshold at?

You might be on to something using Burst Knock for traction control:banana:

[oztracktuning]

I did add fuel a bit after the first run down low. Can i tell if its actual knock somehow by looking at the wideband values?? What will knock do to the wideband numbers??

Burst is preventitive of real knock so i was hoping to have burst knock prevent knocking and maybe have a better performance effect than just pulling out timing.

I extended its duration by a factor of 2. Note the flat top. It seems to have impacted on the knock. But i am not sure its real knock - maybe its vibration from wheelspin causing the KR???

[oztracktuning]

Qualifier 3
Reaction 0.111
60 footer 1.630
660 was 7.496 at 91.990
ET 11.768
115.10mph
DA zero 11.58/116.75
25C 55.00% RH pressure 30.040 Track Temp 37.00 1655kg

Pleased with the run - tyres were swapped left to right on the rims and it helped with better 60 footers for the rest of the meet. Changed the tune to richen it up a little down low in 1st.

http://www.oztrack.com/clubsport/drag3.jpg


Elimination Run 1 - won against a highly regarded racer - i knew it would be hard so I had to cut a good light.

Reaction 0.007
60 footer 1.645
Half Track 7.518 at 91.93mph
ET 11.801 at 114.670
DA zero correction 11.62/116.75
27 C 45.00 % RH 30.000 pressure 59C Track Temp
1655 Kg

http://www.oztrack.com/clubsport/drag4.jpg


Elimination 2
Had a some wheelspin after the launch


Reaction 0.021
60 footer 1.664
Half Track 7.542 at 91.81mph
ET 11.820 at 115.130 mph
DA zero correction 11.65/116.62
26 C 59% RH 30.000 pressure 45C Track Temp

http://www.oztrack.com/clubsport/drag5.jpg


Elimination 3 - a win in this race would put me straight into the final.

The logs showed some KR at both changes probably had cost me the win. Lost by 0.0206s in this race. The other guy did 11.025 on a 11.000 dial in with a 0.059 reaction


Reaction 0.009
60 footer 1.640
Half Track 7.529 at 91.680
ET 11.815 at 114.860
DA zero correction 11.71/115.70
23 C 75% RH 30.010 pressure 40C TT

http://www.oztrack.com/clubsport/drag6a.jpg



I am interested in suggestions on what strategy is best to use to improve the tune. Especially to get rid of the in change knock. ??

[MN C5]

Try some race gas and see what it does

[joecar]

Hmmm, thinking out loud...
The knock events seem to occur when the airflow starts to increase, after the RPM has dropped (on the tail of each shift).
Your actual AFR doesn't seem to lean out, ECT is low, so maybe you have upto 2 degrees too much advance at those airflow values.
IAT seems warm on first 1 or 2 knock events, but then cools down.
Can you prevent heat soak on the intake plumbing...?

[oztracktuning]

Thanks for the insight i will be looking into it.

The intake is an over radiator cai. It works good but the IAT sensor is near the hottest part of the intake. Its almost certainly not an accurate position. I wonder how it would work if i put it much earlier like in the start of the intake away from the soak. It shows high 40s but in truth the air entering the TB is probably much cooler. This would mean the higher than real intake temps would function to do what to the mixture??

Colder air than the IAT indicates would mean my VE table is corrected by IAT to add fuel when hot. Is this what happens or is there more to the story??

I wonder if it would be advisable to use torque reduction tables to pull timing out of only the shifts. Just the minimum timing of 3 degrees - rather than take it out of the main timing table??

[oztracktuning]

Here is one of the log files of my best run. It may be of value to someone.

It is of the burnout , 11.768 run and back to the pits.

Steve

[oztracktuning]

Here is a video of the last race for anyone who is interested.

http://www.oztrack.com/clubsport/summernationalsoztrack.wmv