Project rebirth, FRS - STX and trackday/TTD log

[autoracer86]

Originally Posted by redlined600

The overall front brake temps are concerning for sure.

In regards to the caliper paint, it's possible I'm getting bad data. I can try again with stickers and see if there is a difference, however given the temp of the pads and rotors, as well as the difference in rear paint color, I'm inclined to believe it.

Once the swap is up and running I'm leaning toward going with the performance package Brembos. The disks are larger/thicker, pads are cheap and the bias is correct. I just wish the pads were thicker.

I also have some ideas to modify the heat shield to allow more air into the center of the disk without going to a full ducted setup.

Maybe bad data I would think at those temps the seals would be toast but I can't say for sure.

Would you not look into something like the AP racing kit ?

[redlined600]

Originally Posted by autoracer86

Maybe bad data I would think at those temps the seals would be toast but I can't say for sure.

Would you not look into something like the AP racing kit ?

The dust seals are totally torched, I have a rebuild kit sitting on my workbench but haven't gotten to it yet so I can't comment on the inner seal condition other than they aren't leaking.

I think the AP kit is a decent option but I'm leaning toward the factory Brembo kit for a few reasons;
OEM design, no brackets
Larger rotor dia. F/R should lead to cooler brake temps
Pads are relatively inexpensive
Rotors are inexpensive, especially compared to AP (or any 2pc) rings

[redlined600]

Originally Posted by RedReplicant

.....

Curious what you come up with for a brace

Here is what I ended up with. In terms of effort for value, we'll see...
There are several OEM 4 cylinders that use manifold braces so I think it's probably a good idea, especially with the counter balancer removed.

[RedReplicant]

Damn. Nice work, that looks great.

[redlined600]

Engine out. Don't mind the oil slick, I forgot to drain the trans.
Lots of cleaning to do.


Mating the trans the to K24 and one bolt didn't make it to spec.
I measured the bolts and they are indeed 70mm


Now it's just waiting on the helicoil kit. In the mean time I can do all the engine bay mods.

[redlined600]

Small update before the engine goes in.

Tunnel modified, I decided to cut and weld rather than just bash it in.
grinder and paint...... I've since cleaned and painted it.


I opted to move the harness a bit by cutting and modifying the plastic guide. This moved the harness where it moves up the firewall by a few inches. Hopefully away from the exhaust heat. Where I have the ground bolted to right now is where the plastic guide used to attach.


3d printed a cover for the AC. It's petg/CF so I'm hoping it will hold up to the heat


I'm really just waiting on some rivnuts and a tool to put in some wire holders and clamps and I'm ready to drop the engine in.

[redlined600]

I should have a few updates coming as things move along.

Engine is in!


Since I damaged the oem zip ties for the main harness I have been unsuccessful in finding replacements. I finally gave up and put rivnuts in the holes and had these made to secure the main harness. M6 button head secures the bracket to the firewall and then zipties on either side secure the wire harness.


On the topic of the wiring harness, I really didn't like how the engine harness plug just hangs out. I had this bracket made to secure the plug to the engine, The plug snaps onto the left tab and the injector harness is secured by the right tab. I'll post the final setup once installed.


Going through this really gives one an appreciation of how much effort oems go though to ensure robust designs.

Another item that's been on my mind is the driveshaft. I originally planned to shorten the oem driveshaft, and that is still on the table. However, I also picked up the Kpower aluminum unit from Irace to experiment with. It's 12lbs lighter which would be nice but there are numerous complaints about vibration.
My theory was that the repositioning of the engine screwed up the trans output to diff input angle.
I was able to measure both and the difference was about 1*. Not as bad as I thought it might be, but a few driveshaft sources claim less than 0.5* is optimal for least vibration. My plan is to shim the front of the diff down to get the difference between the diff and output close to zero.
I'll probably still have the oem one shortened over the winter as a back up.

[RedReplicant]

I see you've got rivnuts ready to go for a header heat shield or similar. I ended up ordering some of this https://www.pegasusautoracing.com/pr...asp?RecID=7267 but haven't installed it yet.

The passenger floor area seems to get really burned up.

[redlined600]

Originally Posted by RedReplicant

I see you've got rivnuts ready to go for a header heat shield or similar. I ended up ordering some of this https://www.pegasusautoracing.com/pr...asp?RecID=7267 but haven't installed it yet.

The passenger floor area seems to get really burned up.

I put them in while the engine was out just in case. I'm planning on using the stock heat shields from the S2000 header as well (as much as I can).

I think you pointed the floor area out to me in the past, I put some gold foil tape in that area but am not expecting a whole lot from that. Since the S2000 header will require more work than I anticipated I have the option of placing the exhaust where I want it. Hopefully I can leave enough room for some sort of shielding.

[blsfrs]

FWIW: You might want to read this post. Aluminum driveshafts have a low critical speed which accounts for the extra vibration and can cause sudden failure. https://www.ft86club.com/forums/show...=148537&page=4

[redlined600]

Originally Posted by blsfrs

FWIW: You might want to read this post. Aluminum driveshafts have a low critical speed which accounts for the extra vibration and can cause sudden failure. https://www.ft86club.com/forums/show...=148537&page=4

I do sort of remember your thread, however at the time it didn’t apply to me so thanks for the reminder.

Here is what I actually know:
1. Multiple people have had vibration issues related to the Kpower AL driveshaft
2. Kpower stated that they later adjusted their balancing procedure
3. On my car there is a 1* mis-alignment between the Trans output axis and diff. input axis.

When I calculate the max driveshaft speed based on a 130mph top speed (this is estimated based on the tracks I frequent) I get the following.


Buckle up for a lots of speculation.

I really tried to find a critical speed calculation but didn’t have any luck, however, based on extrapolating (dashed lines) this chart (https://pstds.com/critical-speed-chart), I’m making some assumptions for the 46” kpower unit

If the aluminum driveshaft follows a similar trajectory as the steel driveshaft that would put the critical speed around 8000 rpm for a 3” (as is the Kpower DS)

Based on the comment that DSS made to Blsfrs that their critical speed was indicated at 110mph, that calculates to about 6000 rpm, which roughly matches up with the extrapolation based on a 52” long 3” AL driveshaft.


All this is to say I’m not still not sure if the critical speed of the Kpower unit is the issue. Shimming the front of the diff to match the angle is cheap and easy so I’ll start there. If there is still an issue I’ll swap to the shortened OEM unit. Maybe I’ll end up there either way as an extra margin of safety.

In other news here is the engine harness plug bracket installed, it’s a bit hard to see among everything, but if you look at it for a bit you can figure out what’s going on.

[redlined600]

Radiator is back in and the plumbing is done. Fuel pump relay, injectors and fuel rail are in. Lots of other little stuff completed.

The biggies left are modifying the S2000 header, pumping the remaining E85 out, finishing up the fuel lines and hooking up the ECU and wideband.

Unfortunately the car has to go into storage Sunday and I'm busy today so this is the end of the road for this year.
I probably win the award for slowest swap.

[cmiovino]

@redlined600, do you remember generally what alignment you were running with the +35 Apex Arc-8's a few years ago? I was snooping through your thread for my STX build. Probably close to -4 degrees.

[redlined600]

Originally Posted by cmiovino

@redlined600, do you remember generally what alignment you were running with the +35 Apex Arc-8's a few years ago? I was snooping through your thread for my STX build. Probably close to -4 degrees.

I only ran STX for a few events before I transitioned out of autox. According to my notes, when I ran STX, I ran about -3 front and -1.9 in the rear, zero toe f/r, however I ran STX for such a short time there wasn't any real development toward that goal. Also I'm pretty sure I only used the RPF1s (17x9 +35) and not the Arc-8s (17x9 +42) in STX. There are threads in the racing section that talk about STX setup, that would probably be a better resource.