John's JDM Honda K24A 818R Rebuild

[Hobby Racer]

Changes I made to the front end to increase downforce worked too well! I generated so much pressure on the splitter that it ripped itself off the car.

This pic was taken during the first session of the day. After coming in I noticed the damage and removed the front splitter completely and ran the rest of the event without it. The car was still amazingly fast and planted. It did have noticeably less front grip but I just altered my driving style and still had a great time.




2025-09-20-12-33-31-955.jpg 2025-09-20-12-33-25-765.jpg 2025-09-20-12-33-09-326.jpg

New splitter is in the works. It will be mounted much better.

[kabacj]

Awesome setup!

One idea you may consider as you redesign your splitter. Although its illegal in most racing organizations, you can make a venturi under the front axle. channel the air under the car and squeeze it under the front axle. this rush of air will make down force.

you will notice that some cars have a splitter that is slightly higher in the center and even canted upward to push air under the car. Seems counter intuitive but it works.

[driveslikejehu]

Interesting! I wondered if you had it supported out at the wings, but you did and it pulled thru the fasteners. Nothing against your splitter, but I wouldn't have thought it produced that much force in that area. I would guess the few hundred lbs front downforce was developed by the whole system; dam, splitter, hood, vents, etc.. Maybe the load cycling?
Having the same thought about potential damage, I also made mine with a few plys of woven glass on plywood. I'll keep an eye on it now.

[Hobby Racer]

The splitter I had before this one did have a few plys of woven glass on the bottom for strength and abrasion resistance and it held up better. It also did not generate the amount of down force that this one does.

I'm beefing up the mount points and laminating in large fender washers to distribute the load this time.

Heading back the Watkins Glen in early October for more testing.

[Hobby Racer]

Well the last event of my racing season ended with a broken driver side axle.

After the first day I destroyed the driver side rear wheel bearing. Loaded everything up in the trailer, drove home to my shop, located a replacement bearing and fixed that. Headed back to the track the next day and ran three sessions before snapping the driver side rear axle shaft. Broke it at 138 mph while in 6th gear. I was able to get off track safely and get towed back to the paddock.

Now I have a few more winter projects...

[Hobby Racer]

Started disassembling the whole back of the car to make it easier to work on. I need to take the drive-train out anyway to check and service it for next season. When I got the driver side spindle/knuckle off and CV axle out, to my surprise the axle shaft was intact and in good condition. The outer CV joint was completely destroyed. All the balls were missing and the cage and spider gear were trashed.

My theory is that the failing wheel bearing generated so much heat (and it really did, rainbow of colors) that it cooked the CV joint grease which lead to a metal on metal condition. The joint can only take so much of that before something seized and it spit out it's bearings. This felt like a snapped axle as the car does not have a posi unit so all the power went to the driver side which spun freely in the CV cup.

Now I have to decide if I want to still go for DSS axles or try and scrounge up a new inner and outer CV joints and guts.

2025-10-11-09-55-54-859.jpg 2025-10-13-17-33-40-890.jpg 2025-10-13-17-33-50-690.jpg

[jcarcustom]

Your project is really cool! I've seen a lot of people using this Honda engine in their projects.

[Bicyclops]

Wow! That must have made a lot of noise! Might be worth giving DSS a call to talk about CV joints and the strength thereof. The guy I've been dealing with is Tad.

Ed

[Hobby Racer]

Wow! That must have made a lot of noise!

Funny you said that. The tow truck driver said he could hear it over the sound of his diesel tow rig while towing me back to the pits!

[Bicyclops]

I bet. Mine was clanking pretty loud as I drove home on the other shaft at about 20mph.

Ed

[Hobby Racer]

Well it's that time of year again ... repair time!



Two different junk yards and 13 cars later, I have rebuilt my axle shafts. I got two serviceable outer CV joints and one really nice inner joint. So I damaged a total of three. Also put new bearings and seals in the rear spindles/knuckles and bought 2 new hubs.

2025-11-07-10-18-15-209.jpg

With the transmission out I was able to get a closer look and noticed I also damaged the differential. If you look at the 2nd pic below you can see the passenger side has a nice smooth surface. In the 3rd pic you can see the rough, gouged up surface of the driver side. So I decided this would be a great time to upgrade to and LSD (had an open diff previously). Trolled e-Bay for a while and found a nice, low mileage factory helical LSD out of a 2017 STI.

2025-11-07-10-17-59-865.jpg 2025-11-07-10-20-34-892.jpg 2025-11-07-10-19-49-829.jpg 2025-11-07-10-18-07-416.jpg

And finally I found a serious crack in the aluminum bracket that holds the supercharger on. Time to break out the TIG welder.

2025-11-07-10-49-17-840.jpg

I swear, if there is ever an off season where I don't have to take the car completely apart, I'm throwing a party and your all invited!

[Bicyclops]

Off season? You gotta be kidding. It's 88* outside.

You're running the Caddy Bremboes, right? Had any trouble with the pins? I was hearing a noise from the right rear and when I looked:

20250805_162700[1].jpg 20250805_162717[1].jpg

Maybe I didn't get them seated right in the first place, but when I pulled wheels to start disassembly for axle replacement one of them had moved a little and it's only been a few hundred miles since I made damn sure they were driven in. I'm going to make it part of my preflight to look for the pins all the way seated.

Ed

[Hobby Racer]

Off season? You gotta be kidding. It's 88* outside.

You're running the Caddy Bremboes, right? Had any trouble with the pins? ...

Funny you should mention that. I lost a pin on the driver rear. Same side I lost the wheel bearing and CV joint on track. Not sure if one thing caused or contributed to the other but it happened.

I have been running them for 4 years now and haven't had any trouble up till now. But with all the other issues with that corner, I can't fault the brakes.

I have thought about modifying them to accept a different bolt/pin that is more secure. I never liked the way they pop in / out.

[Bicyclops]

I wonder if some red loctite on the pin would help it stay in there.

Ed

[Hobby Racer]

I wonder if some red loctite on the pin would help it stay in there.

Ed

I don't think so. The fit is too lose for loctite to be effective. I'm thinking of drilling out the small end on the caliper so a same sized pin/bolt can fit through and either using a nyloc nut or safety wire to ensure the pin/bolt stays put.

[driveslikejehu]

The STi Brembos have a lock pin. You could probably drill thru to use those, or source them from a brake parts supplier.
Let me know if you need a measurement to compare
brake pins.jpg

[J R Jones]

I don't think so. The fit is too lose for loctite to be effective. I'm thinking of drilling out the small end on the caliper so a same sized pin/bolt can fit through and either using a nyloc nut or safety wire to ensure the pin/bolt stays put.

Two points:
* My 2004 Acura TL Brembo calipers have retainer pins wih reduced diameter at the leaf spring, so the pin is trapped by the spring. Not as secure as other methods, but it works.
* Red (and blue) Loctite is low viscosity for threads, not slip fit. To retain sliding cylindrical fit Loctite Green 680 is used. (with high viscosity) Actually it is stronger than red Loctite and I have used it for loose threads with great success.
https://next.henkel-adhesives.com/us...n/1835201.html
jim

[Bicyclops]

The Delco pins for the Caddy Bremboes have a split spring sleeve on the inboard end that's supposed to hold in the cavity. It isn't effective. If it's not too much trouble, I would like to have dimensions on the STI pins and lock pins and maybe a part number. One of these days it's probably going to bite me if I don't do something about it. Drilling for a cotter pin or equivalent might work.

These are the RockAuto Carlson version:

https://www.rockauto.com/en/moreinfo...8C%2FQyw%3D%3D

I'm just using the Delco brake pads, front and rear, and it stops. Anybody using more aggressive pads on the Caddy Bremboes?

Sorry to hijack the thread.

Ed

[driveslikejehu]

When I looked at it again, I realized the problem with my suggestion. There are cavities in the caliper to allow clearance for the pins. Here's the dims anyway, tho it looks like your calipers are wider.
The parts are just stock '06 STi
PXL_20251108_201621669.jpgPXL_20251108_205041170~2.jpg

[Hobby Racer]

I'm just using the Delco brake pads, front and rear, and it stops. Anybody using more aggressive pads on the Caddy Bremboes?

My car is strictly a track car so I can only speak to racing type pads. I have used two different pads. Both are sintered and both are amazing. The EBC pads are slightly better in my opinion and are easier to obtain as they are made in USA.

I really like the sintered type pads as they require no real bed in procedure, are good in the wet, can handle really high temps, and are are reasonably easy on the rotors (compared to a semi metallic race pad).

• EBC SR21 front & SR11 rear
• CL RC6 front and rear

[Hobby Racer]

When I looked at it again, I realized the problem with my suggestion. There are cavities in the caliper to allow clearance for the pins. Here's the dims anyway, tho it looks like your calipers are wider.
The parts are just stock '06 STi
PXL_20251108_201621669.jpgPXL_20251108_205041170~2.jpg

I think something like that will totally work. Instead of using a cotter pin I'm going to use safety wire. By safety wiring the two pins together, it will prevent either from backing out, plus the safety wire is only 0.030" diameter so it should fit even without the cavities. Just going to drill the stock pins and I'm good to go.

[Bicyclops]

I think the Caddy calipers are wider than we need inside. My guess is that the CTS rotors are wider than the STI front rotors we're using. That leaves some space between the caliper wall and the pad to drill and safety. I'm going to try that the next time I pull my wheels off. Having too much fun right now.

Just so you know, I think that this is endemic to the Caddy Brembo when used with the STI rotor. When I first looked at the one making all the noise, I found all of them slightly backing out on all four corners.

Ed

[Hobby Racer]

Drilled and safety wired the Caddy Brembo pins this morning. Worked really well. One less thing to worry about while out on track!

Drilling a 0.050" hole in the center of a round pin is never easy. To help I made a simple jig to hold the pin and guide the drill bit while drilling.

2025-11-09-11-35-48-728.jpg 2025-11-09-11-51-25-247.jpg


Here is how they look when installed. In the first pic I compressed the pucks all the way on the side with the safety wire to show that there is still plenty of room.

2025-11-09-12-19-50-613.jpg 2025-11-09-12-04-22-355.jpg

Best part is I did not have to alter the calipers so if I needed, I could still put a stock pin back in.

[Bicyclops]

That's great! Perfect. I was thinking last night about AN4 bolts all the way through with nuts on them. As you say, the safety wire trick leaves the calipers unmodded. I ordered Carlson hardware and that has the machined step in the middle of the pins which might help hold also.

Ed

[longislandwrx]

really enjoyed reading through this thread. its like all the 818 lore is coming back to me.