Dan's NC track toy

[oztrackdays]

This is in the NA8 Racecar with Daniel driving tyres were pretty old.

7th-July-2013 1-08-55.zip

[Regie]

Shoot us a PM with your email dan. I'll shoot you the pbox files.

I have some videos in my garage thread from yesterday also

[Dan]

Subject: Dan's NC track toy

Shoot us a PM with your email dan. I'll shoot you the pbox files.

I have some videos in my garage thread from yesterday also

Done, thanks mate.

Watched your videos, looks good. A bit hairy a couple of time on that wet lap but some nice driving

This is in the NA8 Racecar with Daniel driving tyres were pretty old.

7th-July-2013 1-08-55.zip

Thanks very much for that, will check it out

[Dan]

Got a video from the day, my girlfriend took it from the top of the hill, it wasn't a hot lap since I was following an Integra around but it's cool to see another angle.


I've uploaded some photos onto flickr too which she took of the day, there are a few other cars in the photo's, mainly from group 3 though:
https://www.flickr.com/photos/55844227@N08/sets/72157644965194052/

Here are a few (more on the flickr page):

[cwto24]

Thanks for the video and the pics.

Rather interesting seeing myself driving.... Too bad i never put my gopro into any good use...

[Dan]

So, after starting talking about getting a 4.1 Diff on Thursday, Daniel Deckers got me one installed for me on Sunday ready for the Circuit Club track day today (he swapped my old pumpkin with a JDM one) and I brought a set of BC coilovers with uprated springs off him second hand, I wouldn't normally buy coilovers second hand but the price was right and for the moment it's me not the car holding me back so I'll wait until I'm closer to getting to the cars limits before I upgrade.

I'm not going to say the exact way Dan set the car up but he set the ride height to a level that's more street than track and the other settings are a middle ground between a street and track. Given his experience with this setup I let him do his thing. My impressions on the coilovers on the road is that they are more than livable, even if this car was a daily driver I wouldn't have a problem driving it, given they are uprated spring rates on a cheap coilover I'm pretty impressed.

It was a wet and greasy day today and even the dry laps were still a bit wet so I was letting off for the S bend between T5 and the fish hook and T9 but I could feel the speed difference in a few places, it was definitely a combination of the 4.1 and coilovers though since I was carrying a little more corner speed due to the coilovers which allowed me to come out of corners with more revs anyway, down the end of the back straight I had a fair bit more speed which is pretty impressive given I was letting off a bit at T9.

The most clearly noticeable section of the course the coilovers made a difference on was at T3, the stock springs with the same tyres/sways had the car plowing too far over to the outside when I took T3 at speed but this setup let's the car point in and follow the line like it should.

In the wet it was definitely more challenging to control the car with the stiffer setup and I took a dive into the outfield after getting in a line of water next to the ripple strip on T3 and onto the infield after using a bit top much throttle exiting the fish hook. Given I had no spins last Sunday at the club day I definitely need to get used to the setup.

As for times I got my PB down by .5 seconds to 1:14.7 which I was pretty happy about given the conditions, I did a 1:15.5 on the official Timing but I only had one dry timed season and my fastest time was during the 45 minute open session at the end of the day after I had some time to practice on the new setup.

Here are a couple of pics of my car after taking those two off track excursions, it was a bit of a job cleaning it when I got home!

[Dan]

I compiled some information to look at different FGR and Tyre Sizes to see if downsizing the wheels to 16x8 like Charlie Brown and others have done would be close to going with a 4.1.

I have since gone with a 4.1 but since I’ve got the information I thought I’d post it since it might be helpful to others assessing if they should go to a different Final Drive or if you are looking at different tyre sizes.

Basically what the numbers are the speed you will be at @7000RPM with different FGR and Tyre Sizes and in the final column is the speed you will actually be doing when your speedo says you're doing 100 (obviously this depends on the accuracy of the speedo).

It is interesting to note that running 215/45/16 @ 3.73 is the equivalent to having a 3.94 FGR with the size of tyres I’m currently running (215/45/17) and 215/45/16 with a 4.1 FGR is equivalent to 215/45/17 with a 4.28 FGR.

I did the calculation out of my own spreadsheet but if you want to look at speeds for specific RPM’s you can go here http://www.flyinmiata.com/tech/gearing.php

[Magpie]

Seems to be a popular topic at the moment, ratio decisions. Whilst speed is important you should consider ratios by looking at your torque curve at the same time. Good post though as we did not address tyre size in the thread an this subject

[Dan]

Seems to be a popular topic at the moment, ratio decisions. Whilst speed is important you should consider ratios by looking at your torque curve at the same time. Good post though as we did not address tyre size in the thread an this subject

Definitely a popular topic and it's interesting hearing others opinions.

That's true about the torque curve. I guess the speeds I gave probably aren't the best ones to have since knowing what speed you will be doing at the start of your torque curve is probably more important than the top end of the gear, it does show the range of speeds within the gears though which hopefully helps.

Also a size that isn't noted in the table for those who want to run stock wheels is 205/40/17, seems like a good choice since:
- V70A's are available in this size.
- They are a slightly smaller diameter than 215/45/16.
- They will fit perfectly onto the stock rims.

I still am pretty much convinced that I should run 215/45/16 on FD 16x8's but I'll consider these when I wear down my current NT01's since I don't think I'm fast enough to really take advantage of the extra inch of width, 10mm of tyre and 800 grams of unsprung weight at the moment.

[Charlie Brown]

Dan,

Kumho don't make a 215x45x16 V70a.

I run 225x45x16 V70a on the 8" RX7 rims. They weigh in 0.5kg less than the stock wheel with 215x45x17 Michelins.
As you have a 4.1, the 245x45 is another option on the 8" rim, though you'd need some guard rolling and a few extra $$$ to buy them.

I like your link and table above. I went through the same exercise 6 months ago, before the 4.1 was fitted, to work out what revs/gears I'd be in at the critical points in Turns 2, 8 & 10 at Wakefield. I could then work out if I needed to bump my cut off point back up to 7,500rpm. Still to find out how the 4.1 will go on the track as I missed last Sundays meeting.

[Magpie]

Here is an update version of my excel file, gives acceleration, speed and torque for a 5 speed, 6 speed and custom gearbox with the same dif ratio. Just change the tyre radius and other cells in pink.

Again the file does require a known torque curve.

[Dan]

Dan,

Kumho don't make a 215x45x16 V70a.

I run 225x45x16 V70a on the 8" RX7 rims. They weigh in 0.5kg less than the stock wheel with 215x45x17 Michelins.
As you have a 4.1, the 245x45 is another option on the 8" rim, though you'd need some guard rolling and a few extra $$$ to buy them.

I like your link and table above. I went through the same exercise 6 months ago, before the 4.1 was fitted, to work out what revs/gears I'd be in at the critical points in Turns 2, 8 & 10 at Wakefield. I could then work out if I needed to bump my cut off point back up to 7,500rpm. Still to find out how the 4.1 will go on the track as I missed last Sundays meeting.

Good call, I got mixed up with the V710 for that size.

What do you think about wider tyres? Are you thinking about moving up with the addition of the 4.1?

Hope your eyes are better, looking forward to seeing you out there at the next one!

Here is an update version of my excel file, gives acceleration, speed and torque for a 5 speed, 6 speed and custom gearbox with the same dif ratio. Just change the tyre radius and other cells in pink.

Again the file does require a known torque curve.

I like the spreadsheet Unfortunately I don't have a torque curve for my specific car, I just know mine's dead below 3200 and dies up top

[Magpie]

The blue line from Danny's NC (not really a stock NC). The red line will make you cry


From the states

http://forum.miata.net/vb/showthread.php?t=421422


The speed part will work as it does not require torque information.

[Dan]

Yeh that Torque curve looks much better than an N/A NC one, it looks like it's choked up top though.

Looking at the graph 3200RPM still seems ike a pretty good number to make sure it doesn't go below.

Not trying to E-Peen it too much but here's the red line from my other car on 98 fuel ;)

[Dan]

Had another fun day out at the track today at the Track School day today.

With only 12 participants they just ran open pits all day which resulted in an empty track at some points of the day but lots of fun for all involved. Some mechanical dramas saw me off for some of the day, but to get me back on the track I need to give a huge thanks to the Deckspeed team for going WAY above and beyond to help me out! I also now need some new rear pads as they are down to the wear indicator and are screeching so I'll take it into Deckspeed and get some pads and rotors sorted out next week.

In the end I managed to shave nearly a second off my PB which now stands at 1:13.81 and consistency is improving with most laps being Low 14's.