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

[DocWalt]

Originally Posted by gt5759

Curious as to your reasoning on that?

I found the CR-S to not have the same lateral grip as the RE-71S. The CR I felt put the power down better oddly enough. They both ran pretty much the same times for me. The RE also had more grip first out the gate, CR needed some heat to come on. Just my worthless two cents on any of this. Also, the Yoko A052 was faster for me than either of those, but I am not a tester and did not do all of this on the same day.

Mostly because of his hot climate, I agree with your assessment on the tires

[RedReplicant]

Originally Posted by gt5759

Curious as to your reasoning on that?

I found the CR-S to not have the same lateral grip as the RE-71S. The CR I felt put the power down better oddly enough. They both ran pretty much the same times for me. The RE also had more grip first out the gate, CR needed some heat to come on. Just my worthless two cents on any of this. Also, the Yoko A052 was faster for me than either of those, but I am not a tester and did not do all of this on the same day.

How did you feel about the CRS in terms of feedback? I've been mildly scared of them because of the handful of AR1 sets I ran through - they felt numb and they seemed to fall off a cliff after 8-10 HC in terms of balance and pace. Curious if the CRS is similar in those respects.

Originally Posted by DocWalt

Going to consider the new Toyos too?


I'd do the CR-S before the RE-71RS for your use, I think.

They're on my list to try too, but I don't think they're out until April.

An over-arching issue is that I've been going through a set of RC1s every ~3-4 days if I run full sessions. On the S2000 and Miata it wasn't an issue and I'd see 6-8 days out of an RC1 or Toyo RR; I'm guessing a lot of it comes down to the additional weight, struts versus double wishbone, and a little bit more pace.

I assume the 200TW tires will last less time, but I'm curious and they're supposed to be a bit faster than the 100TW anyway. Still undecided on which, and now I'll add the Yok to the consideration list too. I will end up on a contingency tire again though, the 8 Maxxis a year and whatever Toyo bucks help.

[gt5759]

Originally Posted by RedReplicant

How did you feel about the CRS in terms of feedback? I've been mildly scared of them because of the handful of AR1 sets I ran through - they felt numb and they seemed to fall off a cliff after 8-10 HC in terms of balance and pace. Curious if the CRS is similar in those respects.



They're on my list to try too, but I don't think they're out until April.

An over-arching issue is that I've been going through a set of RC1s every ~3-4 days if I run full sessions. On the S2000 and Miata it wasn't an issue and I'd see 6-8 days out of an RC1 or Toyo RR; I'm guessing a lot of it comes down to the additional weight, struts versus double wishbone, and a little bit more pace.

I assume the 200TW tires will last less time, but I'm curious and they're supposed to be a bit faster than the 100TW anyway. Still undecided on which, and now I'll add the Yok to the consideration list too. I will end up on a contingency tire again though, the 8 Maxxis a year and whatever Toyo bucks help.

Vague feeling. Heat cycle wise I don't know as I never made it beyond 8 but the speed was consistent.

[RedReplicant]

RE71RS on a 9.5 is pretty much the exact limit for a 257 tire template.





It very likely is a case of won't pass as it wears, which goes back to the "supply new tire on same size wheel if you fail" part of the rule.

This is the same template on an RC1 pushed all the way left to show the extra space.

[gt5759]

Originally Posted by RedReplicant

RE71RS on a 9.5 is pretty much the exact limit for a 257 tire template.





It very likely is a case of won't pass as it wears, which goes back to the "supply new tire on same size wheel if you fail" part of the rule.

This is the same template on an RC1 pushed all the way left to show the extra space.

I would say that's all the tire for the rule, I look forward to your review! 255/40r17 correct?

[RedReplicant]

Originally Posted by gt5759

I would say that's all the tire for the rule, I look forward to your review! 255/40r17 correct?

Yup, 255/40/17 - we will find out how they do for me in a couple of weeks.

[RedReplicant]

Few things -

Put together a quick harness for my CanChecked MCE18 expander. Pretty neat, you can plug it in to USB with the car off and it'll let you configure it as a Haltech Expander, as well as see live sensor data. Popped a hole behind the battery where some stock harness usually mounts on the inside of the car. Now I've got fuel temp and fuel pressure working, I plan on wiring in transmission temp too.




Also, the RE71RS squeezed up a bit on the car.



I finally got around to getting the rear camber up to the -3.2 area from -2.8 by lightly sanding one of the jamb nuts. Checked corner weights, adjusted a little bit, and string aligned the car back to 0 toe all around afterwards.

This is with 3/4 tank indicated and me in it.



Alright, so I went and did the math on the new motor dyno:



199whp NASA average. For the next event (AMP 1/13 and 1/14) I'm classing as follows:

201whp avg
2895lb
+1.0 tire - Bridgestone RE71RS
+0.3 for <=257mm tire size
-0.5 for double wishbone rear
-0.2 for spherical bushings - roll center correcting FLCA ball joint
-0.5 for splitter

I plan to adjust based on how AMP goes.

Current state of the car mod wise:

2015 Subaru BRZ - 37266 miles on chassis

Engine
JDM Honda K24A
OEM K20A2 50* VTC gear
Drag Cartel drop-in cams
Supertech H1021D valve springs, retainers, and valve stem seals
KPower intake manifold and intake
KPower header, ceramic coated
Bosch 74mm DBW throttle body
Winning Formula Buzzyboi throttle body adapter
Perrin 3” catback exhaust
Injector Dynamics ID1050x injectors
Haltech Elite 1500 ECU
OEM K24Z upper timing chain guide
OEM K24Z side timing chain guides
Generic aluminum lower timing chain guide
Generic aluminum timing chain tensioner cover
Doryoku shortened and baffled valve cover with top vent
Radium BRZ CCV catch can
Radium surge tank
Radium fuel pump hanger
Radium fuel filter
Radium fuel pulse damper
Verus radiator w/ Spal fans
Verus radiator duct
Deatschwerks DW300c fuel pump
Lowdoller fuel pressure / temp sensor

Drivetrain
OEM Exedy clutch and pressure plate
KPower aluminum flywheel
Verus clutch pivot
Verus clutch fork
Shortened OEM BRZ 2pc driveshaft
OSGiken 1.5 way LSD
Cusco diff cover

Suspension
949Racing Xida 500lb / 600lb
RacerX rear upper control arms
Perrin 22mm front bar
OEM 13mm rear bar
RacerX rear sway bar end links
Whiteline roll center correction kit
Superpro FLCA bushings w/ caster offset
Perrin steering rack stays
Salasko Racing solid rear subframe and diff mounts

Brakes
2020 BRZ ABS Unit
BRZ OEM PP Brembo brake calipers
Centric PP blank rotors
Stoptech braided lines
CSG C2 brake pads

Wheels
6x Apex EC7R 17x9.5 +40
2x Apex VS5RS 17x9.5 +40
4x OEM GR86 18x7.5 +48

Exterior
Verus Engineering hood vents
Verus Engineering high efficiency wing
4” flat Home Depot Racing splitter
Verus Engineering air dam
JDL front crash bar
Tom’s tail lights
OLM wide mirrors
Shark fin removed

Interior and Electronics
Cage built by TC Design
Sparco Pro Adv w/ PCI racing slider seat mount
Sparco Evo 2 w/ PCI racing slider seat mount
Schroth Profi 2 6 point harnesses
Rennscot belt wraps
Lifeline 2.25kg FIA fire suppression system
Beastronix Nanny hard wired to vehicle CAN
NMSTec EPS controller hard wired to vehicle CAN
OMP WRC steering wheel
Works Bell quick release
Cartek battery isolator
CanChecked MCE18 CAN expander

Alignment and Ride Height
132mm / 138mm
-5* front camber / -3.2* rear camber
0 toe front and rear

[TylerLieberman]

Was cool seeing this thing rip around AMP this weekend. K series really is the jam for these cars.

[RedReplicant]

Originally Posted by TylerLieberman

Was cool seeing this thing rip around AMP this weekend. K series really is the jam for these cars.

Thank you, it seems to work alright most of the time . Hard to miss your Hakone out there too, god, I love that color.


General weekend summary

Saturday was CW, I was about half a second off pace from the last event - 1:46:843, but still got the TT5 win. I ran the RE71RS and the car started out super loose, so I ended up swapping to my Mann 13mm rear bar, dropping the rear, and pulling out some damping to settle it down. Unfortunately, I think I did like 5 laps the entire day due to an issue I'll mention later.

Sunday was CCW, I managed to drop the TT5 record by half a second on the RE71RS on a lap with a handful of big mistakes. 1:47:2, I feel like it should be a high 1:45 done right. Car still felt a bit loose. For sure threw away a 1:46 multiple times over this lap.

Coolant Temp Issue

I had a fairly annoying issue to deal with all weekend - on Saturday morning at first session warm up grid the car popped a check engine light, which is extremely abnormal. I proceeded to give the RE71RS a good single lap scrub in. I checked the data and it said the coolant temp was 235f, normally it rarely goes over 185f.

I decided to go out for the first real session, do a single lap for points, and come in. Temp was again 230.

I replaced a blown thermo fan fuse, did some IR temp gunning, decided that the temp was probably wrong, ran a lap or two for the second and third sessions, and bought a new coolant temperature sensor on the way home for the day.

On Sunday morning I tried to swap the coolant temperature sensor and it instead decided to break off in the coolant neck on the back of the head against the firewall. I heated the car up until the thermostat opened and didn't see the signs of the sensor leaking so I ziptied the new sensor against one of the radiator hoses, set the electric fans to always run below 10mph, and decided to finish out the day like normal.




Looking at the Haltech, the car was pulling 5* of timing at WOT on Saturday due to it being over 230f. Who knows what it was doing on Sunday with the coolant temps reading 85-125f on track. Sucks, probably a decent chunk of power both days.

RE71RS

General thoughts on the RE71RS are kinda limited right now since it was super cold and I the car issues. Generally speaking though...

They seem to want a fair bit more heat than the RC1 to start working. RC1 I generally try to do a very soft out lap with no scrubbing, the RE71RS seemed to want a hard scrub and it still wasn't fully ready on the first lap.

Pyrometer had me at 36-39psi for proper gradient, obviously there are a lot of variables here, but the gradients looked better than RC1s. I assume they have a stiffer sidewall.

They seem to be more quiet than the RC1 during breakaway.

The most noticeable thing I felt is that the RE71RS feels like they have a lot more grip under braking.

All in all, they have me wishing the RC1 and the RR get an upgrade since the main draw (other than contingency) of them in the first place was that they were supposed to handle heat better than the fast 200TW. I guess we will see as I get more time on them.

I'm happy with them, I'd buy them again.

Other random stuff

Turns out PCI is making some sphericals for the FLCA - they've got replaceable Aurora bearings in them and they're really cheap ($165 total). Grabbed a set, as well as a set of Hardrace sphericals for the FLCA rear bushing, to replace the poly SuperPros. This is an effort to help tire wear.



Techno Toys Tuning is also making some stuff for our chassis now too. I bought a set of rear toe links since they're no points, easier to adjust than what I have now, have heims, and the price is right.



Anyway, on to Chuckwalla on Feb 17 - 18.

[redlined600]

Originally Posted by RedReplicant

Other random stuff

Turns out PCI is making some sphericals for the FLCA - they've got replaceable Aurora bearings in them and they're really cheap ($165 total). Grabbed a set, as well as a set of Hardrace sphericals for the FLCA rear bushing, to replace the poly SuperPros. This is an effort to help tire wear.



.

This is nice, I've been planning on making a set for quite a while. Do they just press in or is there also a snap ring to retain them? Nvm, I see they press in

On another note I saw gk tech offers a spherical for the upright where is connects to the rear trailing arm. After some.digging, as far as I can tell, it looks like the bushings for rear trailer arm are the same, 1 in the arm and the other in the upright. I've been meaning to order a couple sets and try it.

[RedReplicant]

Originally Posted by redlined600

This is nice, I've been planning on making a set for quite a while. Do they just press in or is there also a snap ring to retain them? Nvm, I see they press in

On another note I saw gk tech offers a spherical for the upright where is connects to the rear trailing arm. After some.digging, as far as I can tell, it looks like the bushings for rear trailer arm are the same, 1 in the arm and the other in the upright. I've been meaning to order a couple sets and try it.

Eh, yeah, I'd also kinda like a snap ring for ease, but I guess this is fine too.

I did see the GKTech spherical bushings but I don't really want to give them any of my money. Cusco and I think Hardrace also sell sphericals for those spots; I emailed PCI and he said that he is working on a set too.

I'll dig around, I wish we had someone like Keisler for our platform. Let me know how the GKTech do if you go that route.

https://www.keislerautomation.com/rx...semblies-m2r3e
https://www.keislerautomation.com/mi...h-installation

[redlined600]

Originally Posted by RedReplicant

I did see the GKTech spherical bushings but I don't really want to give them any of my money. Cusco and I think Hardrace also sell sphericals for those spots; I emailed PCI and he said that he is working on a set too.

I forgot you had an issue with them in the past. The part that interested me was they also claim they are rebuildable with off the shelf sphericals. Maybe I'll sit tight for a bit.

[RedReplicant]

TechnoToys rear toe links in






SuperPro front lower control arm bushings out, PCI spherical compliance bushing and Hardrace rear spherical in. PCIs look great, the Hardrace are ehhh - they don't seem to be serviceable and everything is glued/compounded together.






The compliance bushings were an absolute breeze to swap, the rear was a slightly different story. Removing the SuperPro was super easy but the Hardrace were press fit tight and there is no way to get it fixtured on my HF press since the bushing is inline with the LCA.

I ended up with an absolute mess of stacked stuff, a balljoint C clamp tool, and old faithful Milwaukee 1/2 impact.

I grabbed a set of RC1s for Chuckwalla, I haven't decided which setup I'm running yet (RE71RS or RC1). Going to string align the car tomorrow, but I think I'm going to try a small amount of rear toe in.

[RedReplicant]

While doing an oil change today (Rotella T6 5w40 bayyybee) I realized the oil pan was resting on the steering rack, I figured this was a result of the motor mounts being worn and sagging. The car has had more vibration than normal the past few events for whatever reason, I assume this is related.

I've had some IAG mounts sitting around since I put the motor in originally so I decided now was the time. I had to do a bit of trimming on one side to clear the block and I ended up having to shim the motor up with pieces of a destroyed Miata wing since the IAGs sit even lower than compressed WRX mounts.






I just started the car with the new mounts and I'm headed to RockAuto to order some replacement WRX mounts now.



Also, I noticed there is a lot of room to feed some 2" intercooler pipes for a Treadstone TRV125 intercooler if one were so inclined to use a MDP or TTS Rotrex bracket that mounts a C30 or C38 in the stock K24 ac compressor location. A conservative setup might make something like 275whp NASA avg, about 200lb could be pulled out of the car, and the thing magically fits into TT4. Hm, imagine that.