DarkSunrise FR-S

[DarkSunrise]

Also placed on order:

- JDL UEL titanium coated header + OP
- Magnaflow catted/resonated FP

And close to ordering:

- Perrin Oil Cooler
- Open Flash Tablet

[DarkSunrise]

Had the diff cradle and outrigger inserts (KDT925) put in today. First impressions:

- Reduces, but does not eliminate, drivetrain lash. Before when I would let off the gas, especially going downhill at lower speeds, I could feel moderate drivetrain shock. Almost a double jerk, as if the drivetrain was bouncing off the stock bushings on decel. Now it is a single jerk.

- There is a more immediate reaction from the rear end to throttle input. This is particularly noticeable when applying gas mid-corner. Before, the soft bushings seemed to absorb some of the initial application of throttle. Now the rear end will step out more immediately because of the stiffer inserts.

- There is some gear noise when letting off the gas, especially under 2000 rpm. Sounds like a faint, medium-pitched whir.

- There is also a faint, hollow noise when letting out the clutch in 1st and 2nd.

Overall, I'm really happy with this upgrade, particularly the way it stiffens up the drivetrain lash. The car feels more connected. I don't notice any additional vibration, just some new mechanical noises, which aren't annoying at all.

Next track day is this weekend. I'll update if I notice any differences with these inserts.

[DarkSunrise]

Another track weekend (9/6-9/7)

Had a great time trying the recently-extended Summit Point Jefferson Circuit for the first time. You can see the extension (black pavement) in this aerial photo:




Couple of notes:

1st Day
- Started on my old Sumitomo HTR ZIII tires to see what difference the camber bolts and whiteline diff inserts make.

- Camber bolts add a little more front grip mid-corner. More rotation (with throttle/lift) and more neutral balance. The rotation you get is still gentle, but now you can coax it out more easily.

- The diff inserts make the car react slightly more abruptly to changes in throttle position. You have to be a bit more careful when initially applying throttle at apex, as I later found out when it rained.

Overall, I liked both low-cost mods at the track. Neither makes a huge difference, but both are noticeable and positive.

Unfortunately the camber bolts weren't enough to stop the Sumitomo's from chunking badly. Trail-braking through T1, then immediately diving into a series of esses really wears out the shoulders of the front tires. So that led to another change before day 2.

After cutting my last session due to chunking tires, I spent a few hours at night mounting the Nitto NT05's. Sorry, crappy phone photo, but I was tired after a long track day and turning wrenches:



In case anyone was curious, here are the weights I measured for the TC105's bare, and then wrapped:

TC105N (17x8) - 15.3 lbs.
TC105N (17x8) and Nitto NTO5 (235/40/17) - 38.4 lbs.

That's about 2-3 lbs lighter than stock.

2nd Day

I was really excited to see what these Nitto's could do at the track. In the drive out to the track at 6 am, I could feel how much stiffer the ride was.

Well, the first session was disappointing. Even after putting heat in the tires, I couldn't help but think they had similar levels of grip to the old Sumitomos. My hunch was right that the sidewalls were MUCH stiffer and at least they weren't chunking or overheating, but I wasn't blown away by the grip.

Over the course of the day, I started taking air out of them and ended up with 40 psi hot, and grip seemed to be more inline with my expectation. Still not stellar, but about what I'd expect for extreme performance tires. I will play around with tire pressures more during my next track day and see if I can find an optimal pressure.

Lastly, I got a chance to try tracking with the traction control on. Hated it. Not surprisingly, it cuts in too conservatively and inhibits rotation. Great for the street, not so good on the track. Will not be trying that again.

[DarkSunrise]

Past weeks have been busy, so haven't had time to snap a proper picture (or even wash the car) after mounting the TC105N's. Here's another grainy cell phone picture I took after getting to work at 7:30 AM. At least it's better than the last night picture I took in my garage!



OFT came in the mail the other day. Been too busy to flash to stage 1, but hopefully will have time in a week or so just before my next track weekend. I'm expecting to get my JDL UEL header/OP and Magnaflow FP before then as well, but looking doubtful I'll be able to get all that installed in time.

[ZionsWrath]

Pics of your chuncked ziii?

[DarkSunrise]

Originally Posted by ZionsWrath

Pics of your chuncked ziii?

Sorry don't have any on me, but will see if I can take some pictures before my next track day.

[DarkSunrise]

Here's what my front right pads looked like, so decided to replace them based on advice from this forum.

Ranged from 4/32 - 6/32" (3.2mm - 4.8mm) -- left to right in this shot.








Small chunk missing here:



Shot of the rotor:

[DarkSunrise]

Originally Posted by ZionsWrath

Pics of your chuncked ziii?

@ZionsWrath while swapping pads, I took pics of the chunking Sumis:

[Pete156]

Nice wheels, sh1t tires.
No wonder they chunk like that

[DarkSunrise]

Originally Posted by Pete156

Nice wheels, sh1t tires.
No wonder they chunk like that

Haha yeah I can't complain for $85/tire though.

I think they might have held up with more negative camber up front.

[DarkSunrise]

Just reporting the results of some dyno testing.

Runs 1 & 2 were with:
- stock tune
- Perrin non-resonated CBE

Runs 4 & 5 were with:
- OFT Stage 2
- JDL catless UEL header
- JDL overpipe
- Magnaflow catted/resonated FP
- Perrin resonated CBE
- K&N drop-in



The baseline runs were really promising, making 177 whp with just an exhaust. (I was told stock cars usually dyno around 165 whp on this dyno, so maybe all the track days broke in the engine well.) But the stage 2 runs were disappointing, making only 178 whp.

One thing to note: We literally installed the parts and put it straight on the dyno, so not sure if the ECU needs time to adapt maybe?

Or the exhaust components need time to break in, not sure. Or perhaps the coolant temps dropped out of optimal. There's a lot of possible explanations, so probably best not to jump to conclusions yet.

The good thing is it sounds amazing. I was worried about how loud it would be, but it's actually pretty tame. Slightly louder than before, but with a muted rumble to the sound. I've been driving around the past few days just listening to the exhaust purr.

I'm going to take the car to the track this weekend and properly put it through its paces.

[Tcoat]

Originally Posted by DarkSunrise

Just reporting the results of some dyno testing.


One thing to note: We literally installed the parts and put it straight on the dyno, so not sure if the ECU needs time to adapt maybe?


I'm going to take the car to the track this weekend and properly put it through its paces.

ECU will certainly have to learn.
Will you dyno again after track?

[DarkSunrise]

Originally Posted by Tcoat

ECU will certainly have to learn.
Will you dyno again after track?

Yeah I probably will. Not looking forward to spending the money for another dyno session, but I should figure out if something's up with this tune.

[DarkSunrise]

I had my car aligned on stock suspension + whiteline front camber bolts before my last track weekend of the year.

Front: Camber -1.4L -1.5R
Rear Camber -1.0L -1.4R

I asked for 0 toe all around.

After doing a set of track days, the car is slightly more neutral compared with stock. There's still some residual push, but easily controlled with the throttle or brake. I don't think I'd want it any looser than this.

My Sumitomo HTRZIII tires had chunked at the track before the alignment. I rotated the chunked tires to the rear and ran them again. No more chunking issues at the front. In fact, now the rear tires chunked slightly, so all four tires are getting worked pretty well now I'd guess.