Honda K24 Swapped 2015 BRZ Ship of Thesus (NASA TT5)

[RedReplicant]

Few quick updates, been prepping to go up to High Plains Raceway for Aug 11-13. Finally signed up a couple of days ago to commit myself.

Put five new load range D tires on the trailer, regreased hubs, bought two spare hubs, and a few other things. I really, really don't want to have towing issues - especially since I intend to do the 14hr there in one shot.

Trip back I don't really have a choice on stopping at some point, so I'm trying to work out how to do that safely. Kinda thinking about doing an AirBNB in northern New Mexico.

I put on the RacerX rear upper control arms that I'd been sitting on since I sold the Hyperblue - set them to -2.8* rear camber for now. I can get another half a degree out of them but I need to buy thinner jamb nuts. It is a ~1 degree improvement for now though.

String aligned the car and found I'd been running like 3/8" front toe out. Set it to 0 toe front and rear.



Just in case it rains I picked up a set of stock second gen 18" wheels with the PS4 tires.




I'm about as prepped as I can be in terms of spares, should be fun.

I also drove the car around the street for about twenty minutes with the Xidas on full soft.... felt great, can't wait to get some track time in.

[grippgoat]

Are those SmartStrings?

-Mike

[RedReplicant]

Originally Posted by grippgoat

Are those SmartStrings?

-Mike

Yeah, I tried the usual 3d printed string kit some people talk about but got really frustrated by all of the pieces being round tube -- made it impossible to get everything square. If you mark the SmartString stuff and make a note of expected distance from string to hubs it is pretty easy to deal with.

[justinco]

Originally Posted by RedReplicant

....

Trip back I don't really have a choice on stopping at some point, so I'm trying to work out how to do that safely. Kinda thinking about doing an AirBNB in northern New Mexico.

Nice, glad to hear you're making the trip too!

I got a hotel in Las Vegas, NM on the way back, Sunday night. I'll let you sleep in the bathtub, lmk.

[RedReplicant]

Originally Posted by justinco

Nice, glad to hear you're making the trip too!

I got a hotel in Las Vegas, NM on the way back, Sunday night. I'll let you sleep in the bathtub, lmk.

LOL, will I wake up with all of my organs intact? Where are you staying that is safe for a trailer? I know you've got an enclosed so it isn't as big of a deal.

edit: I'll just message you on FB

[autoracer86]

Your wet tires are what I run in the dry haha. I need to get some better tires

[justinco]

Originally Posted by autoracer86

Your wet tires are what I run in the dry haha. I need to get some better tires

They are great dry tires too, just not as fast as some others is all. They just happen to be really good in the wet, where the faster dry tires are not.

[Irace86.2.0]

Originally Posted by autoracer86

Your wet tires are what I run in the dry haha. I need to get some better tires

You are probably joking around but…

The Gordon Murray T50 uses the PS4S and not even the Cup 2s. It is probably one of the best street summer tires for traction and longevity. There are not too many situations where a true track tire is needed on the street. It is the tire I use for my K24 turbo swap. There are definitely stickier tires, but many are dangerous in the rain or on unprepared surfaces.

https://www.roadandtrack.com/new-car...ice-interview/

[autoracer86]

Originally Posted by Irace86.2.0

You are probably joking around but…

The Gordon Murray T50 uses the PS4S and not even the Cup 2s. It is probably one of the best street summer tires for traction and longevity. There are not too many situations where a true track tire is needed on the street. It is the tire I use for my K24 turbo swap. There are definitely stickier tires, but many are dangerous in the rain or on unprepared surfaces.

https://www.roadandtrack.com/new-car...ice-interview/

Ps4s and ps4 are not the same thing. Also I’m talking about track driving. Been looking at something like a052. Anyway no need to highjack the thread was just a fun comment. PS most euro spec oem sport cars use the ps4s. Heck even the Tesla model 3 here comes standard with a ps4. It’s a good tire but most test show it to be around 4-5 seconds slower than a proper 200tw tire.

[RedReplicant]

Hah, I just didn't want to end up spending a bunch of money to do all this and get rained out on RC1s.

I've heard good things about the Conti ECS 02 for rain events but it came out far cheaper and easier to just find a used set of Gen 2 wheels. Given the current forecast it looks like I'll be bringing them along.

Last minute helicoil of valve cover #1 plug tie down and I'm all ready to go short of loading up.



I am really dreading this tow, planning to leave at 2AM Arizona time on Thursday morning.

[Pat]

Ugh. Well Abe and I should be out there Friday afternoon. Maybe even morning. Let me know if you need a place to crash. I got a hotel room and no one has claimed the other queen bed yet.

[RedReplicant]

Originally Posted by Pat

Ugh. Well Abe and I should be out there Friday afternoon. Maybe even morning. Let me know if you need a place to crash. I got a hotel room and no one has claimed the other queen bed yet.

Thank you, I should be good. I also got a hotel... first time doing that in almost ten years of trackdays between cars and motorcycles, must be getting old.

I'm signed up for the full Friday test day, see yall there.

[RedReplicant]

Alright, that was a long weekend. It is pretty rare for me to say, but I actually had a ton of fun - everyone I met was super nice and helpful, the track was absolutely insane, and the weather was polar opposite from Arizona. I got out of my truck yesterday to unload and I was like why tf do I live in Arizona?

I can't thank Abe, Pat, and Patrick M enough for their help on getting the track figured out. Suggestions like turn into the corkscrew when the pylon comes across the A pillar, the weird curbing change in turn 11, short shifting to 4th up 7, staying in 5th through 4, etc were all really a lot of help.

Track map for context:



On my end of things, I made a lot of mistakes.

I figured out that with my wheels, camber choice, and tires I need to run a small spacer to prevent rubbing on the spring. Fortunately, I had 5mm ones in my track box but I'll find some 3mm for the future.



The car felt fantastic on entry but was mildly pushy mid corner, on throttle, and exit. I didn't realize how bad it was until I noticed I basically corded the outside front in six 30 minute sessions on Friday (plus 4 prior HC from a previous event). The car would not rotate anywhere no matter what, but it also didn't have terminal understeer so I kind of left everything alone while I figured out the track. Tire wear on the other 3 was perfect.
Mistake.




I had to swap to the second set of new RC1s I'd brought with me for Sat/Sun.

On Saturday I threw everything I possibly could at the car to loosen it up. I realized I hadn't paid attention to the actual Perrin bar and that there had been a revision or something so I'd accidentally set it to full stiff into full soft as I'd expected.

Note soft hole alignment with bar in instruction image versus actual bar. This is on me for not taking two seconds to think with my own brain.





Set the front bar to full soft, rear bar to full stiff, wacked in all the camber, raised the rear of the car a few turns, took all of the wing out, and rotated the front tires side to side every two sessions for the rest of the weekend but it was still pushy in the same corners but I was out of options.

Context:
TT5 lap record - 1:59.3
86Cup Unlimited record - 2:01.996
I think there were 8 or 10? cars in class both days

On Saturday the quickest I went was 2:04:365. I think I finished 4th in TT5, there are no official results posted and I don't know everyones name to sort it all out.

Sunday I got help from Pat and Abe and was able to follow Patrick in his TT4 FRS on Hoosiers, dropped down to a 2:03:226 but based on how it was trending I should have been able to run a 2:02 without dumb mistakes or if I ran the 3rd session properly.

Instead of running session 3 like normal, I ended up taking the wing off the car for science / to see how it'd change the balance. I noticed it most in turn 1, tiptoed through 4 to not die just in case, felt it in 5, felt less push in 7, and felt the car be a bit more loose through 10. I went 2:03:6 without a wing.

I think I finished 4th on Sunday too, missed third by 0.01.

Anyway, here is a video of my quickest lap. Other than almost dying in turn 7 I see a few spots to carry more speed (1, 4, 10). It also has my quickest no wing lap, always happy to take input or more hints for figuring this place out.

All in all, I'd hoped to be a bit more competitive lap time wise but that is just how it goes. It is actually kinda rare to drive with cars closely locally so I actually had an absolute blast being around a pack of similar pace cars. I'll for sure be back for the event next year.

Where does that leave me for fixing the balance?

Another major factor that I hadn't mentioned yet was that I got the front ride height horribly wrong. My front pinch welds are too mangled to measure so I guestimated based on how I thought pinch weld height correlated to hub center to fender. Turns out I was running the front way too low so a lot of the push was probably coming from hammering the bump stops.

I'm going to be adjusting the spring rates, currently working out what those rates will be right now. It was my mistake as far as getting these things wrong, fortunately it is an easy fix.

I leave you with a weeee picture and a congratulations to Justin for winning TT4 and getting his 1:59. Also a congratulations to my other region friend, Cameron with the LS RX8, who won TT3.

[justinco]

Originally Posted by RedReplicant

...I got out of my truck yesterday to unload and I was like why tf do I live in Arizona?
...

This is me literally every day in the summer To be fair, our race season in AZ is much cooler than majority of the CO race season, which I like (except for early/late season of course!)

Your lines look good, I'm sure with more seat time you would become more comfortable with the track and faster. I can't believe the TT5 record is a low 1:59 Best I ever did there in TT5 trim was 2:02.5, I was underpowered a good bit but still, that's faster than my current TT4 times