Feature: Koyorad x NDF Street ISF V.2 – Team NDF Testing

Back in June, after several months of owning the car, I introduced the new ISF project and sort of explained the direction I’d be taking the car.  After a short Summer hiatus, I’ve accumulated a little more data, or what I’d think is at least is enough, to post an update.

In the first post, which you can check out here if you’re interested, I went over the general ethos behind the purpose of the car, and also covered the initial modifications I did to help negate some of its shortcomings.  I got a lot of feedback and questions regarding the car, so I figured that I’d do my best to keep a log of what’s been going on with it.

I suppose to make this a chronologically correct post, we’d have to go back to August.  After the Nitto event at CVR in May, I naturally took off June and July from the track due to no other reason other than really disliking Summer track days.  I did make one exception, however, with the RS Future and Friends invite only track event at Buttonwillow at the end of August. Amir and Muoi organized a really fun day with a good group of people, and it gave me an opportunity to try CW13 in the ISF.  Admittedly I don’t have much seat time at Buttonwillow, and actually hadn’t driven it for 2 years – so I went in without expectation.  It ended up being a great lesson in weight management and controlling the car under braking and corner exit.  As I wasn’t able to order a thicker, adjustable rear sway bar in time (my previous order was cancelled due to backorder), the car was understeering quite a bit coming around On Ramp, Cotton Corners, and the Sweeper.  I was in traffic most of the morning, but was able to get some clear laps  later in the hot afternoon (100+ temps) – you can see one of my 2’06 laps here.  As the day progressed and track temps got hotter, it became increasingly more difficult to put power down and I was having to counter out of many corners as I learned the need for more throttle modulation and being a but more smooth with my steering inputs.  Full disclosure, it’s a boring video – I’m fighting the urge to get an exhaust to make the in-car footage more exciting, but it cuts against the nature of the project.

There were no changes done to the car since the last event at CVR and I was on the same set of NT01s which were, by now, getting pretty clapped out.  The alignment specs were the same, with only natural camber in the front.

Here’s a shot of Will and I in the garage at Button.

So, as I mentioned in the first article, I wanted to baseline the car as it stood at SOW because that’s my go-to track and the one I have the most experience on, as well as the laps turned with the ISF.  After the Club Racer weekend at CVR in October (which I didn’t drive because I was working it), Team NDF driver Justin Yoo and I, had mapped out a couple of events to keep his momentum going with the practice S2000.  The first up was an On Grid event at SOW on November 14th; which was perfect because these same tires were probably on their last leg.

It would have been great to have Justin, Kristian, and Will there for testing (I don’t think we’ve ever had all our team drivers together at one event), but Kristian was contracted for support of Amir’s NSX at Super Lap Battle, and Will was contracted to drive the WRD Racing Prelude the same weekend (both of which were quite successful I should note!).

The night before Justin and I got the S2000 and ISF prepped with fluid changes and brake bleeds.  I had also previously ripped the bushing on one of my front sway bar end-links, so I replaced them with spherical units from FIGS (more on that later).  I adjusted them to match the OE units, so essentially nothing was changed.

We departed the shop around 0530 and made our way up the 14 to WSIR.  I had a crazy two weeks leading up to this event between work and other work, that it felt nice to just be cruising to the track with only driving to focus on.

We were both hoping that because it was Super Lap weekend, the event would be pretty mild in attendance; boy were we wrong.  For SOW being such a small track, it looked like a fucking parking lot most sessions.  There was also a strange incident in which a driver somehow spun on the front straight after the flag tower, and kicked a bunch of rocks onto the track right on the race line.  For whatever reason the track officials/host didn’t clean it until several sessions, and ran each run group with the debris flag out; we couldn’t understand why because it would have been such an easy clean.

Two generations of Advans.  It’s worth nothing that the drilled rotors that were already on the car when I bought it started to crack during this event. I will be replacing with blanks or slotted.

I was stuck in bad traffic all day, and never actually got a clean lap in.  Not great for what I was trying to do, but that’s the way it goes sometimes!  Overall it was still a really fun day.

So, here’s some notes for my personal documentation on how the car handled.  Obviously the main, and only, difference was tire compound.  Even on the worn NT01 I was able to carry much more speed into turn 1. Giving the brakes some slight pressure to help with rotation, I for sure cut off a few tenths on this turn alone.  Turn 2 was sort of a crap shoot all day.  The track was uncharacteristically slippery for a cooler day, so I eventually learned leaving the car in 3rd gear for the tight right hander was much better for powering out.  It was very difficult to put power down out of this turn.  Through what we call ‘Omega’, the downhill/uphill left handers that came  next, the car expectedly understeered during the camber change.  I figured out sacrificing mid-corner speed helped the car not push as much.  Turn 5 is a semi-tight right hander that sets you up for the S’s going towards the bowl.  I’m never quite certain how to take this complex, so in the ISF I just tried not to over throttle through it, which proved to be difficult for me.  Several occasions the rear would give on the final left headed to the bowl.  In fact, on one such occasion, I had a scare where I went from full lock right to full lock left, as the car pushed off to the right of the track.  I went two off and powered out safely without spinning, but the curbing on the outside of the track in that section is massive; I nicked Will’s Advan and put a hole in the side of my front lip haha – could have been a lot worse though. Again, this section was especially slippery that day.

The bowl was as expected; from outside turn in, apex at the dip, and let the throttle pull me out.  Not many issues here save for a bit of understeer that was corrected by going slower.  The blind, downhill chicane after the back straight is my favorite section of SOW; it’s technical, scary, and super satisfying when you get it right. The NT01s gave me a bit more confidence here and noticed after the first session I was over braking after the crest straightened.  This is another section of the track that can kill your time as it has the potential to either carry a higher average speed longer, or dramatically reduce it.  The tight left after the chicane was another corner that I had to take in 3rd instead of 2nd; I just couldn’t put power down otherwise.  As it was for the remaining corners to the skid-pad as well.  2nd gear was basically unusable for how the car is set up.  Mind you, all this was in heavy traffic.  Despite the setback, I was able to put down several 1’27 flat laps, and on the second session actually dipped into a 26’9.  I went in with the assumption that I would be able to get a mid to low 26, so while still half a second off, I attribute traffic to at least a second.  If you remember the last time, on the Apex, I was only able to get a 28’7, and imagined a 26 with a better compound.  So I wasn’t too far off.  I think ideal conditions, new tread, and no traffic I’m confident with my limited skill I could find 25’s.

I have sort of been using Will’s ISF as a metric to where I should be.  Back in July 2019, he clocked a 25.8 on RE71R at SOW CCW with his ISF with I/H/E, rear sway, full FIGS arms, and a bunch of weight reduction.  With all the gives and takes, and after some funny math, I’ve determined I’m fairly on pace…maybe, to be honest I have no idea.

With all that being said, I absolutely need to address the car’s alignment and balance.  I was getting pretty bad front tire rollover and it just felt like either the car was understeering or oversteering, and never just balanced through a corner.  Which is all good and fun figuring it all out, but if I’m truly going to maximize the platform I need to sort out the balance.  I’m stoked on documenting the small changes though; it’s something I should have been doing, and will being to, the Civic once it’s running again.

For Justin, it was the first time driving SOW in almost 5 years!  Having been held back with school and work, the past few years of seat time for Justin have been off and on. 2020 saw a sort of resurgence in dialing in the practice car and with it much more consistent event days.

Despite the aforementioned conditions, Justin was able to turn a 1’23 flat on the used AR1’s.  While he wanted a 22, and most likely would have had it if not for traffic, a 23 is definitely notable.  A bent rear knuckle disallowed the car from having accurate alignment, and the lack of LSD all sort of attributed to a tough day on a slippery track.

The development of the S2000 will continue with a OS Giken rear differential, new exhaust, and some small adjustments as we shoot to overtake the current NA S2000 record at SOW of 1’21.4.

I’ll get his lap up on our YouTube channel this weekend.  Unfortunately, I don’t have video of my lap as my GoPro Hero 3 decided to finally die after years of servitude.  RIP little guy.

 

 

Headed out for the morning session.

 

Ouch…

Justin modeling almost the entire 2019 lineup.

After the third or fourth session, I forget, we decided to call it and head home early.  We drove up to Horsethief Mile real quick and snapped a few photos of the two cars together, which turned out to be more difficult than expected haha

I should just let Justin shoot everything with these angles.

Here’s a good look at the amount of rollover I was getting on the front tires.  I couldn’t figure out why, other than just the immense weight of the car, but the next day when I got the car up in the air for a post-race inspection, I noticed that the driver side end link had completely backed out.

Which would explain a lot, not having a front stabilizer bar on this car is wild.  I found another washer and retightened to spec, and will keep an eye on it in the future.

On the to-do list now is to get the new arms ordered, as well as new front and rear rotors, and probably new front pads while I’m at it.  The Project Mu pads I got for the CVR event in May are almost done after the three events. Once that’s done I will be looking forward to heading back to SOW!