I did just end up making a 3D table of a pulse width multiplier

Works great, though needs some fine tuning at different temps/ethanol levels but not really a huge deal.



I definitely need to do some "post start" fueling additon to keep the flame front propagated once the engine is deemed running, but I am still trying to find a good angle to add a table into the open loop fueling. Low priority, but is fun work in the winter months.

 

Updated saved post with trackday stuffs (finally)...

 

Professional Awesome Splitter Rods + Rub Pucks

Because my splitter took a massive beating at Grattan, I decided to add some front rub pucks, and get new rods as the old rods were really stretched out too far for their length. I had more rub pucks to add, but I am happy with this.

We will see how long the carbon rods last.. I am a bit worried about them taking a beating.

 

Splitters are unfortunately there for sacrifice.... nothing you do will save them other than not running one.

I have a 4x8 sheet of Birch that I use and can make 2 from one sheet. Surprisingly after 14hrs and several times running out of talent it's still in good shape. Is it car show worth heck no, but I don't have a show car. It's a racecar and they get beat up. Not saying it shouldn't represent you, but expect it to take lumps along the way. That's just racing.

Oh, I sprayed the birch with bed liner paint and good lord that stuff is amazing! Dries hard as nails and takes quite a bit of abuse and still looks great.

 

with them attached to solid structure, some small diameter chromoly tubing likely makes more sense for the splitter struts. It would just take some basic fab skills to adapt them, and the weight difference is fairly minimal compared to longevity.

https://www.stockcarsteel.com/4130-C...y-Round-Tubing
.

 

AP Caliper Rebuild

Tossing into the maintenance log. The dust boost were a little worse for wear and I wanted to understand the rebuild process of the caliper. So I got myself a rebuild kit from Demon Tweeks for the AP caliper, $50 per side, and off we go.

Piston seals were totally fine, but replaced them anyways and noted down the part numbers for the dust boots as I can just buy those in the future. Saved the old piston seals as spares just in case I find myself in a bit of a pinch, or is the UK decides to not ship stuff to the US anymore

Easy peasy.

 

Putting this information down here in an attempt to solve a problem that I can't quite wrap my head around: ECU Resetting at 10k RPM at the rev limiter.

At first I thought that it had something to do with my FlexFuel patch, which I suppose is still possible, but after some testing I did this afternoon I am left with a few more questions.

For those that aren't familiar with this issue, which is probably everyone, it's basically exactly what I said above. If you hit the rev limiter (Mine is set to 10k RPM, though it still seems to happen at lower limit settings), the ECU will reset, the cluster will drop down and back up, and then the ECU will continue as normal.

Trace of this happening:


You can also see it happen at the end of this video (1:44):


The issue I am seeing seems to be exactly as described in this thread here: https://www.rx8club.com/rx-8-racing-...-track-269957/

This is what obviously led my down the rabbit hole of where in software I went wrong. I cannot find anything in my software that would cause this to happen.. though additional engine control calculations could be creating a situation where the ECU is unable to perform all of the calculations it needs to do in a given engine cycle.

This afternoon I tested a new software with a few fixes on my end (G-ROM FlexFuel v1.5.1), as well as a slightly modified stock ROM. Modifications were to delete the immobilizer as I do not have an immo unit in my car, fueling base set to what it needs to be for my current ethanol content (65%), and the rev limit set to 10k RPM.

In my testing I tried these 2 softwares, 2 different ESS sensors (both cleaned, though not a single one is KNOWN to be good), and 2 ECUs.

The ECU reset at the rev limit at 10k RPM with every combination of those 3 variables.

The test was conducted with the car on my lift in the air, in 2nd gear simulating in gear driving at the resets seem to happen MUCH more frequency while in gear with vehicle speed.

Other things I tested were:

• ECU Overvoltage, alternator controller kept the voltage at 14.3-14.4V through redline, ECU still reset. ECU Still reset when removing the alternator from the circuit entirely running at 12.8V on a battery charge
• Unplugging my CAN sensors so the ECU would not need to parse extra CAN messages (OEM and G-ROM FlexFuel v1.5.1), ECU reset in both condition

My next steps are:

• Put the car back on to pump gas and test a MORE stock ECU to see if some fueling situation is getting me into trouble with an overflow or >100% DC requested. The software at the injector driver level is very hard to understand through reverse engineering, so I don't have 100% confidence nothing is being weird there
• Investigate immobilizer delete software and see if that could be causing something weird to happen. Low confidence this is the issue as the immobilizer patch literally just satisfies the condional of "is the immo data we got good? If it's good, it's good... if it's bad, IT'S GOOD!" so the software should still run through the proper immo procedure.
• Get a new OEM ESS to confirm that sensor is good. I did get a P0336 code during my testing, though I am not sure if this was set because I swapped sensors with the key on. I didn't look at freeze frame data (doh), and could not recreate the issue with more testing, so this seems like a low probability issue.

Anyone ever deal with this on a STOCK car or know of this issue happening with stock hardware? I know the Versatuner stuff had this issue, but this seems to transcend software, so I am super lost. I may make a thread dedicated to this issue, though because I am in deep with my own engine control software I figured I'd keep it in this thread for now.

 

Not worth a standalone post for, but I do have a few things I've been working on that should wrap up JUST in the nick of time that I'll but updating this on.. but just swapped my post MAF hoses as they had some cracking in them.

I thought I had a bit of a vacuum leak towards the end of the season last year, so I figured maybe these were it.. Turns out that when I went to take the upper intake manifold of to get to the OMP air line, I was missing a bolt on a 2 bolt flange. Whoopsies.. that'll probably do it.

Swapped lines, added back in a bolt, happy days.

 

Racing Beat Header w/ Swain Tech "White Lightning" Aluma-Ceramic Coating

After trying to design my own header and balance realistic timelines of completion vs gains to be had.. I decided it was just easier to grab an off the shelf header, and that header being the Racing Beat header. After getting beat up by cheap ones not fitting, I decided it was best to just give this a shot.

On the note of designing my own header, I did 3D scan a busted engine I had on a stand, and you can find that 3D scan for download here: https://grabcad.com/library/mazda-rx...engine-mount-1

I don't particularly feel like discussing any benefits of a header on an MSP engine, as that's been beat to death.. but I do still think there is some power (ounces at best) to be gained with a different design from the Racing Beat, and we can leave it there.

As far as the header I tossed on goes.. It fits greats. I drilled holes and welded in my EGT bungs and off we went!

I had some trouble TIGing the stainless bungs.. I'm not entirely sure what was up, but the machine was acting like it had 0 argon running through it, even though the regulator was showing proper flow. I tried much longer than I should have to make it work, and after messing up one bung on an expensive header and cutting it out.. I just grabbed the trusty MIG, went over the scungy welds and sent it home. The ugly welds are ugly, but they will hold.







Upon turning the car on for about 25 seconds, it's very clear to me that the lack of double wall steel as compared to the OEM header was going to cause much more heat than I really wanted to deal with, so I popped the header off and sent it out to Swain Tech for their ceramic coating. Will it make a lick of difference as far as keeping the heat in the header? I have no clue. They charged me $370 including return shipping, and 3 weeks later it was back.





I kinda kicked myself in the face for not taking some (static) bay temps near the intake pre coating, so I won't take any post coating.. but anecdotally, the header can be touched slightly at idle without a blistering burn happening.. which was not the case before (and I have a new scar on my forearm to prove it!). I still think the under hood temperatures will be too much, so I am going to try out an LRB heatshield. When that doesn't work, because everything I have worked with with from LRB has been pretty poor fitting and basically a tier up from a DIY backyard fix, I'll just use it as some design inspiration for making my own.

For those curious as well, I can't really hear any engine sound change, aside from a small change ~6200-6500 RPM.. this is likely the 2nd order resonance at that RPM and EGT as the header lengths are pretty close to what that would be.

Who knows! More coming soon!

 

Rear AP Racing CP5316 + Willwood MC4 Caliper + Paragon 332x26mm 2 Piece Rotor + XP12 Brake Pads

Holy hell, it's finally in an on the car. I've had this project going since I did the front AP kit, and just now was able to get it off the ground.

I had an initial design that popped on the CP5316 Caliper for quite some time now, however the fact that there was no handbrake always never sat well with me. Because of this, it sat for 2 years.

One day this past winter I woke up and happened to find a CAD model of the 1in MC4 cable park brake from Willwood... and after looking around for literally ANY OTHER CALIPER FROM ANY OTHER COMPANY I chose to accept my fate and use the Willwood part. I HATE Willwood and their products, but when the market doesn't seem to exist for sake of one product.. you get what you get.

I printed out the model just so I could hold it up to the back of an upright and see if there was any chance in hell it would fit alongside the AP caliper... and to my surprise, there was! It was going to be super tight, but there was a chance! The first feasibility study had passed!






With my being able to toss the caliper in CAD, and make some quick parametric models I started to see if I could make it fit up. The MC4 out of the box comes with this bulgy steel bracket which basically has 2 sets of threads on it, one for the slides, and one intended for the bolts you mount it with. Using this bracket, it was very clear to me that there was basically no way to fit it in the mess of ball joint mounts the rear RX8 upright has... but then I thought "hey we don't really need this bracket, I am the bracket"... so in the model, I got rid of the steel Willwood bracket, and made my own ears to mount up the sliders with the same width as the old bracket. This unlocked some much needed space for the caliper.

While the MC4 still needed to be offset from the AP caliper, meaning there would be unique parts left to right, I was able to get it to mount up in an orientation that would possibly work.

The next challenge was to get it to mount radially such that the caliper and cable line wouldn't hit any ball joint, while also being able to be serviced. I didn't have all of the ball joints in the 3D scan I did, as I never intended to add this park brake, I needed to just be a little bit iterative until it fit.Through some constraints in my CAD model, I just moved the caliper around at various degrees, had the bracket "build itself" and just printed out parts until we had it cleared, or bashing into the AP caliper and we went back to square 1.



I think I did 4 or 5 iterations until I got an angle correct, and we were ready to spend some money and buy a real caliper!




The next step was to then completely redo the caliper bracket in CAD as my fitment test model, and the model I needed to actually get machined were a bit goofy in the assembly, and I needed to modify a couple things to make it a (seemingly) stronger part. I did all of that work, printed some stuff out and then ran into my next issue that I somehow missed years ago.

After getting a loaded AP caliper and testing the hat and rotor section out... I noticed the pads were going to wear into the hat mounting hardware. Oops.



To combat this fitment issue, I needed to go to a smaller hat PCD, but AP Racing did not offer me any rotors with this option. I looked at some Paragon rotors that were slightly oversized, but would clear without issue. So this rear kit has 2mm larger rotors than the front, but a smaller PCD and less width. It joins the small list of cars with this sort of setup! Either way, time to print more parts and double check.



Plenty of room now!

The next step was to make some drawings for the thread taps and depths and then send them off to Xometry so they could send off the machine work.

I had the rotor hats made from 7075-T6 Aluminum with a Type3 hardcoat. I think you could get away with non annodized 6061-T6, but I went extra. I also don't think the shop in Bangalore did a great hardcoating job either.. but.. it'll work. The brackets were just 6061-T6 and black annodized, and while the parts went to 2 different shops.. the quality of one vs the other definitely left room for discussion. It was also odd that the one shop actually machined in my lettering, vs the other laser etching it. Kinda odd.. but I never specified anything on the drawing, so that's what ya get!







Going back in time a little bit, I ran the Willwood parking brakecables using the OEM mounting hardware, as well as the mounting holes at the handle just by popping on some washers to the cable ends. I also grabbed some just screw in 3/8in cable ends to use the factory handbrake balance bar. I was pretty damn happy with how it all came out, minus the shitty clearance Willwood gives you for the shitty nylock on the shitty caliper adjuster. Shitty.





At the same time I also popped in some brake line AN adapters from Pegasus and measured out a hose length that would work.. when I put it all together and hoped it would all fit up, this is what we got:









I had to bring down the little hex seat for the OEM hoses to be able to get a clip into the adapters, but I am super happy with how it all has turned out. To get the rotors to fit, I just had to cut the backing plates basically at the section where they were bent over to cover the OEM rotors, and just a little bit to get the bracket in place. I think this will be enough cooling protection for the ball joints.

As far as total weight goes, the photos on my scale got messed up as the rolling shutter on the camera missed some digits but, it did end up heavier than the OEM setup:

AP Kit w/ Willwood Park Brake:21.4lbs.
OEM brakes: 20.8lbs
Both rotors came in at 13lbs each.

These were with full pads on the AP kit, and worn pads on the rear OEM.

I think if I didn't have to move to a larger rotor we could have saved some weight.. albeit not very much. You could also choose not to populate the parking brake and obviously would be better off. You could also remove the cables/etc which I would be partial to someday once the handbrake stops being useful.

As usual, I have put my BOM and CAD up on the internet for anyone to use for free which can be found here: https://github.com/equinox311/RX8_AP_Kit

I haven't driven the car with the brakes just yet, but them being basically the same size as OEM rear pistons, I expect nothing but great performance. Hopefully the brackets hold up!

 

Cool brake project. Eager to hear how it works out. Curious - why did you use a rear hand brake? I removed mine from my Spec Miata and mostly don't miss it.

Which class are you running? Still TT?

 

Running Gridlife ClubTR even though the title is borked.

I decided to keep the handbrake for the total purpose of the precarious trailer loading situations that tend to come up where the handbrake is useful. It was also not meant to add weight per my initial mass calc, however the larger rotor I ended up using is what I think sent it over OEM.

 

This looks great, awesome job. This is the reason I have not upgraded to the big break kit, just worries about the brake bias. Do you intend on selling the bracket?
Let us know how it performs. Have you made any other modifications to the brake system?

 

I have no intentions on selling stuff, but all of the files are online for free + the BOM for someone to get them made the same way I would.

As far as bias goes, I'd have to get the numbers I ran in front of me to confirm 100%, but I made it such the bias made sense for my corner weights and CG which was basically stock. It's not way out of whack like I have seen a lot of people run with just front brake kits, and with the ABS unit involved, the dynamic proportioning is still left to be determined. I'll instrument up 4 corner pressures when I get a second to do so, which was my intent from the start.. I just need some more IO on the module I have in the vehicle currently and I've been lazy on re-drawing that up lol

I am using a G35 larger master cylinder, there's a post on that you can find in the thread, and that's simply to improve the braking force required for the larger fluid amount to my liking. I also am running an AP 4 pot up front as well.

 

I did a quick google search and could not find the files one that you speak of. Can you lead me in the right direction? What site specifically can I find the files for the bracket?

 

They are on my github, with a link that is posted in the forum post above for the brake install.

 

Here was some of my VERY ROUGH math on the AP vs OEM setups I was running at the times.

The other irrelevant (now) data point I didn't include was the AP kit front with OEM rear, which statically was balanced ~ 71% front.. little heavy.



Like I said these are ROUGH calcs, but should trend correctly. So while I was wrong that the bias is a bit more rearward than stock, It should bias a bit more rearward than my last setup (duh)

 

I had looked into a brake kit aswell with the plan of going to 19in rims and larger diameter rotors. (didnt wanna drop another 10k on the car just yet though)

Spoiler to hide bloat. Good sanity check though. I had roughly estimated braking done for my assetto corsa car mod.

 

Few things worth noting that I got done that aren't gonna be a standalone post:

-Removed some more weight from the car, all in all was about 10lbs

• Popped off the rear exhaust heatshield and welded up the rivet holes
• Cut out the steel surge tank mount that had been put in years ago
• Got rid of the giant steel heatshield mount on the PPF
• Got rid of the MFD display on the front with a little carbon fiber panel

-Swapped the ESS for a new OEM one
-Replaced the cracked windshield
-Corner balanced the car without a passenger seat (will be removed for racing sessions) and race amount of fuel, car came in at 2643lbs without driver
-Mounted up two new sets of RT660+ tires
-Checked alignment, but made no setting change
-Printed out some new rear bumper brackets and installed
-Changed the oil
-Put in a NOCO Lithium Battery (I don't think it'll stay in)
-Reflashed the ECU with a few cal changes for a larger/more consistent timing split + few other small changes

Drove the car on the new brake setup, and I am VERY happy with it just with some street driving and pad bedding.



Getting the thing loaded up for Gridlife Midwest this weekend!

 

Nice collection of continued development. I've been plugging away at my car too so I can appreciate the effort.

Regarding the heat shield in the trans tunnel, i'm afraid to delete that in case the tunnel heat affects the integrity of the carbon fiber drive shaft. Unless I misunderstood the heat shield you are referring to....