Thanks man! The 2560, especially in the upper RPMs, rarely leaves me waiting for it to spool. This is still open loop boost control as well, so hopefully once I get closed loop dialed in it'll be even better.

 

I pulled my damper when doing the 3.636 gears, and have SuperMiata poly bushings in the diff, and have poly engine mounts.
I don't get anything like that grinding noise. I'd think it's coming from somewhere else.

 

Must be the 6 speed then. I remember it was significantly worse when I first installed the transmission and didn't have the shift boot. I did grab some more MT90 today to top off the fluid, since I think it's a tad bit low. I do get a humming at 55 mph as well that I'm pretty confident is the pinion damper. IIRC I heard that when the 5 speed was installed with the 3.6.

The 6 speeds history is unknown. It drives fine enough, but it's noisy as hell. I adjusted the PPF after I first installed it to try and help, but maybe I'll revisit that.
PS, the speedo gear seems to be working fine so far.

Good work out in Las Vegas btw. I saw you were pretty close to one of our locals who's usually pretty close to top PAX.

 

I forgot to mention, but the car was handling and rotating super well this weekend. On Sunday, entering the "wall-oms" I was able to snap off the throttle to get the rear to come around just a bit to setup a better entry angle. The car felt pretty slippery all weekend, but very controllable.

 

Low profile adhesive balance weights FTW

 

That's what they had installed previously on the tire, and when I get new tires put on these wheels that's what I'll request. Either that or just leave the wheels unbalanced since they see a pretty minor amount of street miles.

 

Damn dude, makin' 'er dance out there! Nice work this weekend. All the changes don't look like they messed with your ability to drive the car. You looked confident and clean out there.

This. I didn't know anyone used clip on weights on our cars haha.

That coolant temp graph makes me happy, too. You're measuring/reading AFR entirely in lambda though? I guess that's actually the right way, but my pea brain is still calibrated to read stoich haha.

 

Yeah, I swapped over to Lambda a while back. Still getting used to it but I figure it's the way most people seem to be heading and if/when I get flex fuel installed it should simplify that a bit. My gauge still reads AFR and I usually have to convert Lambda to AFR to comprehend what I'm looking at, but I figure that's how you learn it.

 

Yo, check this out. Just ran over to my favorite custom parts supplier, aka the public library's makerspace. I sent these ones in a week ago and they finished up over the weekend.




I found the files on Thingiverse here. The design calls for a softer outer filament and a stiffer inner filament to get the best of both worlds. I printed the outer part in TPU and the inner in PETG. Blue filament since my door jambs are still painted blue.

Fitement is perfect. The two parts slotted together with no sanding or trimming.

Best part? It was $1.95 for the pair. We'll see how they perform. I'm hoping they help a bit with NVH going over train tracks and such. Bonus, they're quite a bit lighter than the bushings I had on the car. We're talking grams here, and it's not offsetting the sound deadening I just added, but I'll take it.

 

Damn, and I thought my $9.95 China door bushings were a steal. Noice.

 

This has been on my list for a while now. My car sees a good deal of high RPM, and ideally I'd like to raise the limiter a bit further to eek out another couple MPH in second gear.

A while back I bought a used Skunk2 unit, which I ended up stripping the threads on the throttle shaft where the cable guide attaches. I was able to clean up the threads well enough, and I've tried to pull the cable guide off without success. I feel pretty comfortable about it at this point.
The idle set screw is also missing the O-ring. I grabbed an assortment from Harbor Freight but unfortunately none have fit and I haven't gotten the size from Skunk2.
On that note, I did reach out about buying a new throttle shaft and o-ring, but they don't seem to sell any parts, only the full assembly.

So, enter eBay. A clone of the skunk2 unit pops up for $20 that's only missing the IACV adapter plate. My original plan was to cobble together these two throttle bodies into a single good unit. Well, the throttle plates have different spacing on the holes, so I can't simply swap the throttle shafts around. I might be able to swap the shaft and plate from the eBay unit to the Skunk2, but I didn't want to pull the staked screws from the Skunk2 unit. The throttle shaft also seemed to be pressed into the bearings, as I couldn't get it loose with some whacks from a dead blow.




My current thoughts are that I can either find an o-ring and run the real skunk2 unit, or (assuming it fits) take the IACV plate from the skunk2 and move it over to the ebay unit and run that. If i run the Skunk2 unit I might give it a test run for a week and then JB weld the nut onto the end of the throttle shaft for some peace of mind, but like I said I have tried to pull it off and there's enough thread engagement to prevent me from doing so. The PO already drilled extra holes for the spring tension, so I'd get that dialed in before sealing it up.

I could probably draw up an adapter plate and 3d print something to get the IACV working on the eBay unit as well. I know someone else who's running one of the ebay clones and it seems to work fine for him. Hell, who knows, maybe I could 3d print the o-ring in TPU as well and have 2 complete, semi-jank throttle bodies.

 

Box name checks out lol.

I remember being baffled emailing S2 about buying a spare throttle cable bracket (an epicly common failure point) for their intake manifold on my NA. "Those are not available, they can only be purchased with the intake manifold assembly". Bro, what?

One of our local tuners actually swears by the eBay S2 throttle bodies. The ones he purchases have return springs that are actually able to close the throttle plate fully without modification. Not sure if that's all of the eBay version throttle bodies or if there's a couple different manufacturers/versions.

 

Well that's good to hear. Running the ebay unit seems more and more appealing, especially if that IACV plate swaps over from the Skunk unit. The joys of trying to save some money with used parts

 

Well, I got the eBay throttle body on. I hardly took any pictures since I wasn't really enjoying the job.

Things I learned
- Aftermarket throttle bodies require cap screws and not the stock hardware
- If you mess with the throttle plate make sure you get it put back together with as little gap between the butterfly and the housing
- If you need to remove small screws that you recently used red Loctite on, you can use a soldering iron to heat up the screws and break the bond
- The IACV adapter is the same for the Skunk2 and eBay manifolds
- Paper gasket material is really handy to have on hand to prevent a parts store run/order

It's on there at least. Still not sure about how happy I am. I rushed the job and probably made a few mistakes, so I'll likely have to pull it back apart... again.

I thought I was pretty smart when I realized I could replace the stock bolts with some leftover turbo manifold studs. This was before I struggled for far too long trying to get the nuts onto them. I couldn't understand how a design could be so dumb and leave no room for a socket. That was before I realized I was supposed to be using cap screws instead of studs/bolts.



On a similar note, I picked this trick up a while back. Spray some WD40 on a gasket to transfer it to the gasket paper. Why I didn't just trace it with a Sharpie is beyond me... And that's what I ended up doing when I remade this gasket a second time.




On the upside, the Chevy was one of the few parts of the job that didn't involve the struggle bus. This things been sitting since I moved into my new place almost 6 months ago and it fired up like I'd driven it last week. Hopefully it'll get a bit of a build thread in the future.




Originally I got the TB on and couldn't idle lower than 1050. Pulled it apart today and got the throttle plate resituated to seal up a bit better, which worked way better. Unfortunately I'm pretty confident it's leaking from somewhere. Could it be the IACV gasket I decided to reuse for some reason? Definitely not... Boost doesn't seem to be building as quickly and manifold pressure is down, confirmed by logs. Maybe I'll just say the new TB is so much less of a restriction that the engine is breathing that much better now. Oh well. I've gotten pretty good at pulling that bit apart now, so I'm sure I'll get it sorted in the next week or so.

Oh yeah, one other thing. When I pulled the throttle body coolant lines off there wasn't really any coolant in them. A bit leaked out onto the floor, but not very much at all. Not sure what to make of that, but I guess I'll do a more thorough than normal bleed on the coolant system now.

 

Dude, that truck is rad. Good taste.

Did you spray around the throttle body with carb cleaner to test for leaks? That usually helps me pinpoint them.

 

Thanks Fire, I can't take complete credit for the truck. My grandpa bought it back in '74 and it's been passed around the family ever since. I got tired of it rotting up at my parents place so I decided it was time for it to live with me and rot a little bit less. Really it needs a full restoration at this point, but I have no idea when or if I'll ever get around to that.

I didn't have time to spray around and check for leaks. I figured that was the next step. It'll be a new one for me. I also have a small stick of wood that is used like incense, so I might get that smoking and see if I can find any spots it's pulling in air.

 

Few things are cooler than a truck that's unrestored, but still on the road and plenty functional. As long as whatever damage there is, isn't actively making the thing fall apart (like a leaky windshield rotting out your floors), I say let it run as-is and keep being useful.

I've seen loads of comments about the eBay TB's actually being better than the Junk2s. Mine has been pretty much problem free for 35k miles, but I'm all stock other than that and a cold air intake. No high redline, no boost. I've seen other people say they broke the S2 TB in as few as two laps on track.

 

Ooh, the incense/smoke idea isn't half bad. I wound up with a vacuum leak from my S2 TB after running it for about 4-5 months. The two bolts holding the IAC valve adapter plate on began to back out. They were the only two bolts that I didn't loctite on the thing haha. Would've been near impossible to find the leak without the brake clean trick due to the location. After hitting those with some loctite, I never had another issue with the TB.

And to add to the peanut gallery, hell yeah your truck is sick haha

 

Thanks again guys! I really do love that truck, and it's a time machine for sure. It doesn't have completely original running gear, but it's still an old 292 straight 6 and a 4 speed with granny low. You have to float every gear or it'll grind, gets like 10 MPG maybe, and doesn't do freeway speeds happily, but it's still super fun to pull it out every for a quick trip to the hardware store and such.

 

I made a couple modifications to the throttle body in the past week. Last weekend I went out to a drift event to spectate and on the way home the throttle body started sticking and making the car idle at 1500 until I pulled the throttle pedal out. I think the issue was the throttle stop screw on the TB wasn't set correctly, so I screwed that in a bit further. Hard to tell if that fixed the issue since it hasn't been quite as hot recently, but I feel pretty good about it.

I had previously thought I had a boost leak as well, so I went to home depot's plumbing section and made a teeny tiny boost leak tester from a PVC cap and a Schrader valve. A little gorilla tape was required for a "custom" fit, but it seemed to work well enough. I used my portable tire inflator and other than being a bit finnicky with pressure spikes and the auto shutoff feature, it seemed to work well enough.


Everything checked out as far as I could tell, so I'm guessing the issue was psychosomatic.

We were supposed to do a small Miata cruise yesterday up to the mountains, but it ended up just being me and my old roommate. I was planning to switch out my autocross tires after another weekend or so, so I figured I'd throw those on early (we have an event this weekend) for the twisty roads.

Well... I think I jinxed myself because I was thinking about how I hadn't ever picked up a flat in the car and we didn't have an inflator, etc....

Can we get some f's in the chat?

We called a buddy who showed up with a tire inflator about an hour later. Thankfully none of that was necessary since the tire was still holding pressure, so we had a beer and drove home without issues. I had also forgotten the key for my lug nuts at home since I had been swapping them earlier in the day. Could've been much worse.

What all of that meant for me, was that I got to wake up early today to run to Discount Tire. I picked up some older takeoff Nankang CRS' about a month ago, so thankfully I was able to go get them swapped onto the wheels pretty quickly today.

Still tuning as always. I'm finally getting around to dialing in closed loop boost control. It's oscillating a bit, but I'm trying some new PID settings, so hopefully that fixes it.

Tangentially, I've been working on another project a good amount during the past week. On my Speeduino, I could connect to the ECU via bluetooth to view temps and whatnot, but unfortunately I can't do that on the Link (at least without more work). However, this provides a perfect opportunity to tinker with some new hardware and software I've been looking at. Enter the ESP32.



The plan is to use this as a CAN gauge that will sit atop the steering column cover. Currently I've got the logic setup, but am spoofing the numbers. I've got IAT and CLT (ECT as Link refers to it) sensors setup, but I built those upon a class that should allow more sensors to be programmed in pretty easily. One of the onboard button cycles through the sensors and pushing/holding will reset the peak values. The code for interfacing with CAN is in the project as well, but I need to run the physical connections to the Link to test it. I've got the JST connectors and wire now, but still need to sit down to pull the ECU and figure out the subharness for this.

Not sure when I'll get it finished, but hopefully in the next couple weeks or so assuming scope creep doesn't ruin it. I originally didn't plan to run the LEDs, but they were laying around so I figured I could use them to show sensor conditions. The limits are programmed into the board, so when the sensor value hits a certain threshold the LEDs will change color appropriately. I figured I could run a gear indicator off of this as well if I threw a 7 segment display on, but that's a bit much I think.

So far I think I'm about $50 into this with a lot of leftover material. For $20 these boards are pretty wild, including bluetooth, wifi and a display. I don't have a plan to use the bluetooth or wifi yet, but if I think of a reason, they're there. Other expenses are from the connectors, buck converters to get 3.3V from 12V supplied by the CAN harness, protoboards to package it. Realistically, once I've got a better idea of how it all goes together I bet this could be made for ~$40 in materials, maybe even less.