Bracket racing a Nissan Leaf - Current Attraction.

[1932highboy]

If you have torque steer, you need to measure the rollout of the front tires. One way to do this is jack up the car to get the tire up in the air and measure the circumference. Do this on all four tires and place the two closest on the front. Before you do this make sure all tires are at the same air pressure as differences in air pressure will cause torque steer.

 

[garsh]

I measured the rollout:
front left: 6' 10 1/4"
front right: 6' 9 7/8"
So that's a 3/8" difference.

I also tried swapping my front & rear tires, and I still noticed torque steer.
rear left: 6' 10 1/2"
rear right: 6' 10 5/8"

That's nearly identical. I think the torque steer is most likely due to something else. But I do wonder if my stability control issues are due to the circumference difference. I didn't try to reproduce that particular issue with the rear tires on front.

 

[etracing]

10/12/2014 Carolina Dragway.
Test and tune. Time to get Tammy back in the swing of Bracket racing. This was her day to play and see if we can get her launch times back in the .05 second range.
I got to do the first two test passes since we had not been to the track in several years. That way I could possibly give her some feedback on anything I saw that would help. Since we have a radio in this car we tuned it to the track announcer. They loved the car and their comments like “real race car” and that car is going to “make some bracket racing money” made me smile. I ran one pass in the right and left lane running a 17.51 and 17.50 sec. pass with a .060 and .061 reaction time. Not too shabby.

Tammy’s turn. Since this track forces you to use the water box it was also a good time to practice what I thought was going to be some boring burnouts. Even though they were not the cant see, lung choking smoke like from the pro cars it was cool to see smoke from the “4 door family car” tires even without any type of line lock.

Her first few passes were OK reaction times with a .11 and .21. She has been racing for years and I knew we could do better. I asked her to shoot for a red light. That would be able to give her the limits to work with to start cutting consistent lights. Her next light was a -114 red. Perfect! After that the reaction times got much better with the last 5 passes all in the .05 range and even a .009 light. Looks like I need to tighten up my lights now…

She is ready… next time… Bracket money?

Another fun day at the race track! We even made some passes for a NEDRA Record in the SP division!

EV Ed

 

[LeftieBiker]

I've never switched off the traction control to try, but I assumed this was the case. Not many engines produce that much torque right off the line. As I think I've already mentioned, my father used to do burnouts with his Volvo, to get the competition to heat their engines up too much before the race.

 

[etracing]

Tammy at Carolina Dragway testing her reaction time. She cut a .08 light.


[youtube]http://www.youtube.com/watch?v=LkLAe7P_8NE[/youtube]

 

[asimba2]

I'm not sure what your experience has been, but when I switch off the traction control on my 2013 SV, the electronics resort to a "soft start." In other words, it won't feed as much torque from 0 to say 5 mph as it would if I had traction control on. On dry pavement, it means I get a slower start with traction control on.

 

[LeftieBiker]

You mean with it off?

BTW, looking at the times posted earlier, if that's a quarter mile track, the times are almost identical to what my father's first "Violent Volvo" ran in V stock in the late Sixties.

 

[etracing]

You mean with it off?

BTW, looking at the times posted earlier, if that's a quarter mile track, the times are almost identical to what my father's first "Violent Volvo" ran in V stock in the late Sixties.

That is 1/4 mile.


We found the start with the traction on or off were about the same. With it off kept the car more consistent for racing.

 

[LeftieBiker]

They reprogrammed the power delivery curve of the 2013, so if you have an older Leaf, it may well be faster with the TC off.

 

[asimba2]

You mean with it off?

I'm sorry, yes, I meant to say turning off the traction control results in a soft start.

 

[etracing]

Our pre-race info. Looks harder than you think. We made it to the Quarter finals....
Ran ON the number, had a .08 RT and still lost by 13 thousands of a second. Still had a great time!!

 

[garsh]

Another issue I'm having - I have to disable the stability control. Otherwise it kicks in whenever I take a high-speed curve (40mph+). Quite unsettling.

If I could get confirmation that both of these problems are due to the larger circumference rather than the tire width, I'd feel a bit better about keeping these wheels - I'd just get different size tires for them.

That was with 235/50R17 tires. When the tires were about thread-bare, I no longer had the problem with the stability control.

I replaced those tires on the front with a set of 215/50R17. I no longer have the problem. So my problem appears to have been due to the added diameter of the larger tires.