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Play around with this Gearing Calculator - Graf Garage. I also have it in spreadsheet form if you prefer. Look at where you'll be at min and max speeds on tracks you plan on attending (I've started taking notes using other GLTC race videos with data). If you like the power band you have, then you can swap to a 5spd/4.77 and pretty much have the same gearing as your 6spd/3.9 minus the OD. There are also some odd ball final drives out there (4.44 and 4.57) that will fit the diff to fill in between the 4.77 and 4.30
Play around with this Gearing Calculator - Graf Garage. I also have it in spreadsheet form if you prefer. Look at where you'll be at min and max speeds on tracks you plan on attending (I've started taking notes using other GLTC race videos with data). If you like the power band you have, then you can swap to a 5spd/4.77 and pretty much have the same gearing as your 6spd/3.9 minus the OD. There are also some odd ball final drives out there (4.44 and 4.57) that will fit the diff to fill in between the 4.77 and 4.30
What is that 4.77 out of? Does it come in a miata diff or would it need built?
What is that 4.77 out of? Does it come in a miata diff or would it need built?
The 4.77 gear set is from the front diff out of a Kia 4WD SUV (Sportage IIRC), so usually very low wear and be had for cheap from pull yourself yards. You would have to swap the final into a Miata carrier, but it is a direct fit.
Started mounting the passenger seat back in. Pretty sure I need it to run SCCA TT and NASA requires a ride along before I can do ST. Had to move it real far forward.
I don’t want to ride on this side, but the seat is in. Can't see anything, way too far forward, way too close to the bars, and no padding. But most importantly, SCCA M4 legal. Prep for TT Nationals has started.
Man, I cannot get over this pad upgrade. My last set of stock size pads lasted 3.5 track hours (1.5 days). These pads have like 11 hours and still plenty of life left.
Installed a catch can so my breathers stop dripping oil everywhere. Only place I could find was the far frame rail.
Impressed myself with all the new space in the garage. Was able to do an oil change on the truck with the car in there too.
Apparently I need to clean out behind my headlights occasionally...
I needed to make a new undertray, but decided to leave the splitter on since TT Nats allows it. Added side support this time. Car is ready for NCM next weekend.
Also, I started an Instagram if you want to follow. Autofreak057 on there.
Last edited by AutoFreak57; 06-07-2021 at 05:25 PM.
Man, I cannot get over this pad upgrade. My last set of stock size pads lasted 1.5 track hours. These pads have like 7 hours and still plenty of life left.
Just for my understanding, what compound were you on before with OEM pad size? And what track? 1.5hrs seems really fast to be burning through a set of pads unless I'm just slow which is entirely feasible LOL
As point of reference, I was out at Miata Meetup (Gingerman) on OEM size Hawk DTC60/30's and after 3 hours of track time, they still seem fine. I need to check them formally yet. Superlites are my prime upgrade path if pad life becomes an issue
Just for my understanding, what compound were you on before with OEM pad size? And what track? 1.5hrs seems really fast to be burning through a set of pads unless I'm just slow which is entirely feasible LOL
As point of reference, I was out at Miata Meetup (Gingerman) on OEM size Hawk DTC60/30's and after 3 hours of track time, they still seem fine. I need to check them formally yet. Superlites are my prime upgrade path if pad life becomes an issue
Wait... my bad, it was 1.5 days at NCM. Which was ~3.5hours of track time. Killed a set of Carbotech XP10s. This was street tires, no aero, 250whp, and slow driver. So I was excessively using brakes. Also, the XPs are riveted in sport caliper size so you lose a lot of pad thickness.
I'll go back and edit my last post to clear up the time confusion. But either way, I've gone from needing to change pads every day to make sure they last to barely inspecting them.
Edit: Actually back checked my math, and the current pads have ~11 hours on them (mostly at NCM).
Well TT Nats is over without even setting a tire onto the track.
This was me about 30 minutes into the day:
Clutch is jamming about 75% extended, but only when the engine is running. Will return when you turn the engine off. Works perfect with engine not running. Not sure what is going on yet.
From 0:36-0:39 in the first video, it looks like the piston is rocking side to side in the bore while you're cranking. Looks like something in the clutch/flywheel assembly isn't square to the block. Do you have a dial indicator to check runout?
Instead of tearing it apart again, ended up dropping it off at KPower today. Now we'll get to the bottom of my clutch issues once and for all. Pretty easy tow up there, but of course it started pouring down as soon as we went to unload the car.
Kpower got it all sorted. Primary issue was a lack of space in the bellhousing. My engine and trans must be at extreme ends of tolerance and it just didn't work. They machined down the slave cylinder piston 0.200" to give more clearance (all 6 speed kits will now have shorter piston). They also found a missing engine dowel and added the trans dowels in for me. The missing dowels was causing a misalignment that got everything stuck. On top of all of it, the issues trashed my clutch disk, so they replaced it.
I can't thank Kpower enough for helping me out. Now time to prep for GLTC at Mid Ohio!
My splitter had a run in with the trailer when I loaded the car with a bad clutch. The trailer won. Oh well, cut the damage off and went back to air dam only for GLTC trim. Also had to straighten the Sturdy Bois.
Also pulled a bunch of angle out of the wing. I was running 4 degrees, apparently 0 is more normal.
Car is ready for Mid Ohio. Going to pick up some S80s for my fun day and need to load up the truck/trailer this week. Between personal and work trips, I need to be packed before this weekend.
Also, if anyone is wondering about the random MGB that appeared in my garage, it is a new project. 79 MGB that has been in my mother in law bought new. As all good MG's, it hasn't really run the entire time I've known my wife. After tinkering with it off and on, they finally convinced me to take it. Now its getting a 302 swap for "reliability".
Well... What a weekend. Went to Gridlife at Mid Ohio. Let's break this down by day.
Thursday
Arrived around 9 for a lapping day with the school program so I could learn the track before I was in a race.
Ran a lead/follow session followed by a full lapping session. Car was running great, no clutch issues. Until suddenly it started missing a ton and ran like garbage.
My tuner removed in and we tested everything. Coils, injectors, settings. Nothing changed anything. At this point, just kinda stuck until more of the Gridlife crew got there. Once Emile from Winning Formula took a look, he diagnosed it as lost compression. Then immediately confirmed on a borrowed bore scope. This is inside piston 4.
Tore off valve cover and found the culprit. Lost a valve lock nut.
At this point, it was getting pretty dark, but luckily I made a new friend who let me use his garage for the night. Pulled it in and started some more tear down to prep for a head swap. Got lifters tied together and a lot of components out of the way, then called it quits for the night.
Friday
Junkyards opened at 8. Called the closest one with an engine and found a 24k mile engine ready to go in Cleveland. About 1.5 later...
Also had to make an O'Reilly's stop for fluids and gaskets and a Harbor Freight stop for an engine hoist. Got back around 1:30. With the low miles of the engine, decided that a full swap was better than dealing with changing heads. Had everything out and could see the damage around dinner time. Swapped all the parts over to the new engine and got her mounted back into the chassis around midnight. At this point, we were oily and tired and had stopped taking photos. But felt very nice to get it back in.
Saturday
Got up relatively early and started hooking stuff back up. Got it ready to start around 940. Started up first try and sounded great! Bled the coolant, buttoned up the rest and gave the garage bay back.
Got the rest of the car together in my paddock spot. Took her for a quick entry road spin and it felt good. Ready for a hardship lap at 1p and excited to take green for race 3!
On warmup for race 3, the car started missing up top and shutting off. Had to power cycle the car a bunch and ended up way behind when the threw green. Figured out I could short shift at 2 green lights and have no issues. Finished the whole race like that and never saw anyone until I got lapped. Ran 1:43 short shifting on essentially my first session ever.
Looked at logs after the race and I had no TPS signal. Sure enough, TPS was unhooked. Plugged it back in, added zip tie for good measure, and tested on the road. Everything felt good and my tuner said the tune looks perfect still. Ready for race 4.
Unfortunately, rain came in. Everyone warned me about rain at Mid Ohio, but I didn't fully understand. Went out and it was a mess. Spun entering the track. Almost spun 3 or 4 more times by turn 4. An ASM car decided to form up next to me there and we went through 4, 5, 6 2 wide on the formation lap. In 6, with him on the outside, I was forced on the no grip inside and at like 20mph, lost control and spun. I hit his door and my wing hit the roof. Called it quits then, waved everyone by and putted in. Damage was a broken taillight, cracked bumper, and a bent wing end plate. Not a terrible cost for discovering how bad it is out there.
We had an exhibition race at 1130. I gridded at the back of the cars that completed the race, but a ton of people still gridded behind me. Including most of the front guys. The start ended up being insane. We were at least 3 wide from turn 4 until Thunder Valley. Definitely 4 wide through 7.
Once that all got sorted out, I had a ton of fun. Started learning the track some. Ended up passing 5 or 6 people. Real proud of a couple passes I setup. Got excited in the last lap. Finally got to look at my dash and saw that I was running 1:40s. I managed to push and get a 1:40.05. I was hoping to get into 39s by the weekend, so it was almost harder being that close 🤣.
The last trick was to get everything packed up. Fortunately, the guy I borrowed the garage from wanted the engine hoist, so that was one less thing to drag home.
Overall, still a fun weekend. I hate that I lost most of my track time, but making that last race Sunday made the engine swap worth it. And now I don't need to do it at home! And by all accounts, it looks like this motor is better than my last one.
The Gridlife community is the best and there was so much help from everyone. I'll get some more pics up when I get them and try to get Sunday's video up soon.
Super cool you got the engine swapped that weekend and got it back out there! Sorry I didn't help more, but I was distracted and probably would have gotten in the way more than helped lol.
05-05-2021, 09:26 AM
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