26 March 2018

Here you go – Rear engine mount test video

Looks like the lower most layer or two need stiffening up, which is now easy enough to do.

I enabled the HDR-AS300’s GPS overlay and while it’s interesting, it may prove to be something of a novelty since GPS speed lags so far behind (how does my dash keep up with the same data?). The route information is interesting, but again, not sure how useful it’ll prove to be.

Forgot to mention yesterday that the transmission shifts so easily, I twice shifted into the wrong gear. Doing so while just cruising (like I was) isn’t a big deal, but having that happen on-track is a different story. Going to have to get better accustomed to the new gears, syncros, and shifting effort.

Lastly, my dog-box transmission is being boxed up and shipped home. Once it’s here it’ll officially be for sale.

25 March 2018

Spent the weekend building the new rear engine mount, which took way longer than expected. Part of this is my own doing though, because with Kimini, I planned everything out to an extreme and as a result, fabrication went smoothly and very little had to be redone. With parts of Midlana though, I’ve been testing how much I can “wing it” and still have it turn out right – this one just made it.

The plan was to have the engine mount rubber “field-tunable”. The OEM mount works fine in an OEM application – but not so much with 400+ ft-lbs of torque. Also, applying torque to the side of a bolt in a rubber-filled tube just doesn’t work well when a lot of force is applied because it’s so concentrated.  That’s why a 2″ x 4″ steel “foot” is used to spread out the load and rests between layers of polyurethane sheet. Being a rear engine mount on a clockwise-spinning engine means that the layers below handle acceleration torque and the layers above handle deceleration. This allows using different durometer rubber for each layer. So the prototype was built but the unknown was how much it would deflect under power and deceleration – and how much vibration would be transferred to the chassis.

“If only I was able to watch it.” Presto, that’s what the new Sony camcorder is for, so it was attached to a rear tube and aimed at the engine mount. About now you’re probably looking for the link – well, there isn’t one yet. It’s late, the camera’s new, and I have to figure out its editor. Hopefully it’ll be  good enough else I’ll have to find a “real” video editor. I watched the raw video and it’s pretty cool what you can see and hear – I’ll post it up sometime this week.

In other news – the clutch! With the new transmission having synchros instead of dog engagement,  I again used Competition Clutch’s instructions  to set the clutch stop for the twin-disc clutch. With the dog-box, I couldn’t set it as instructed because it would instantly drop into gear even without the clutch. The instructions say to gently push the gear lever like you’re going into a gear, while at the same time slowly depressing the clutch. At some point it’ll drop in, then push the pedal another 1/4″ and set the clutch stop there. Well, I did, and holy smokes does it change the character of the car. Clutch throw is now much shorter and with the close gear ratios, it makes shifting much faster. I’m really happy how that turned out.

23 March 2018

Every now and then I get caught up in the excitement of buying stuff for the car but getting too far ahead of what’s needed right now, such as wanting to pick up aluminum stock for the wing while the rear engine mount isn’t complete. I learned the hard way that if I have parts on-hand for half a dozen project, I actually make slower headway than if I just focus on one at a time.

Somewhat related, before the wings are built, air flow over the car needs to be researched, and the new Sony camcorder should help that happen.

Then there’s the higher-output alternator which was almost ordered, but again, first things first. Even when it does percolate to the top of the list, it needs to be seen if just running cool air to it might be enough.

Just remembered another task – radiator ducting. The car never overheats, but when cruising at freeway speed, coolant temperature gets higher than when driving hard on the track – why is that? The theory is that some (or even a lot) of the air coming in the nose goes around the radiator instead of through it. At freeway speed, there may be insufficient flow through the fins to carry away all the heat, but at high speed, even with much of it going around, there’s still plenty left over for actual cooling. Will probably tape up some cardboard and see if the theory’s correct.

 

17 March 2018

Weather cleared up so an 80-mile drive broke in the new gears/synchros/LSD. Observations:

The ratios are noticeable closer, which isn’t a surprise but I kept catching myself pausing between gears, waiting to match gear speeds, a habit learned with the straight-cut gears, but when I let the clutch out with the new gear set, it’s clear I’m waiting too long. That’ll solve itself with time.

During the drive, 80 mph (GPS) was 4000 rpm, so back-calculating, the rolling diameter of the tires at speed is 25.1 inches (they compress about 0.5″ due to running ~15psi). That rpm is a bit high for cruising and will ironically serve to keep me more in line, read: driving slower on the freeway. Another reason to slow a bit is because boost is right there and ready to go by 4000 rpm, so it’s like riding a thoroughbred racehorse at a trot but who is ready to go right now. A third reason is that when in boost, fuel mileage takes a nosedive. That said, though the rpm is where MAP can reach maximum, since the throttle’s mostly closed, it’s only about 60 KPa (40 KPa below ambient). I read somewhere that a turbocharged engine can actually improve gas mileage somewhat by overcoming the pumping inefficiencies inherent in gasoline engines due to the throttle plate obstruction. Obviously not a big goal.

(Because of the rolling diameter of the rear tires, if I absolutely must reach 60mph in first gear, I either have to increase the rev limit to 8150 or put enough air in the rear tires to increase the OD to 25.6″, hah.)

After the drive, the OEM transmission fluid used for break-in was drained and replaced by magic oil supplied by the gear manufacture in unmarked bottles. Went for a short drive for gas and it “seems” to shift a bit easier, though it could also be my imagination. I assume it’s going to take several hundred miles for the carbon synchros to wear-in. Speaking of oil, I had an issue with the old transmission where the gear manufacturer, PPG, recommended brand X, while WaveTrac specifically recommended not using brand X. With the new transmission it’s similar, with Gear-X recommending their stuff (of course) and Giken recommending their stuff (of course) which, of course, wasn’t the same. I ended up getting both of them to hash it out on a group email and Giken finally said that Gear-X’s mystery oil would be fine.

There hasn’t been a peep out of the limited slip, or maybe I can’t hear it. Some people complain that Gikens makes noise, though others say it’s silent. Doesn’t matter either way, just a note.

If there was any question before, the test drive confirmed for sure that the engine mount has to be redone – way too much vibration.

 

16 March 2018

I started typing up what’s “on the list” in the Midlana forum and it just kept growing, so I thought I’d post it here as well since it sees more visitors. In no particular order.

The transmission shop is repairing and inspecting the transmission in preparation for its sale – ad here http://www.midlana.com/forum/viewtopic.php?f=22&p=8941#p8941

During the test drive, logger data was used to recalibrate the ECU’s calculated “gear”. The transmission doesn’t produce gear position directly but the ECU has the variables to create one. It’s handy for various things, such as boost-by-gear. Speaking of that, boost in 5th and 6th was increased (back) to the maximum value – that’ll be fun. Assuming it’s clear this weekend I’ll do a longer drive to fully break in the gears, then change the transmission oil as requested by the gear manufacturer.

I reworked the rear engine mount (which resists torque) while the engine was out but don’t like the result, too much vibration. I have a plan to basically roll my own and I’ll post pictures. The sweet thing is that the new design will make it easy to change the stiffness on the fly.

There’s the wings to make, which is a significant project but since it’s fairly compartmentalized, the car can continue to be driven while that’s underway.

There’s the rear diffuser, and right after that, filling in the gap above it, created when the damaged panel was cut out after my off at Willow Springs. Will probably use screen mesh for that.

Engine cover: Been wanting to redo it for awhile because without it, the car looks unfinished. More concerning though is the small worry about an engine fire at-speed, there’s a strong likelihood that the flames will be swept forward by the swirling air. That would be bad.

Upgrading the alternator. If I’m driving at night in stop-and-go traffic, the lights, electric water pump, radiator fan, fuel pump, and of course the ECU are all on, which is around 80 amps. I’m considering adding a small oil pump and cooler to the transmission (already have both) which moves the total current closer to potentially 90 amps at idle. The OEM Chevy pickup alternator produces around 14V when I first start the car, which is fine, but as it warms up it drops off. On the freeway with just the essentials (water pump and fuel pump), battery voltage ends up around 13.5V, and around 13V at idle when fully warm, lower than I’d like. I’d like to be able to run everything instead of having to sometimes load-shed things as the battery voltage drops off.

There are a couple solutions, like feeding cooling air to the alternator and putting on a slightly smaller-diameter pulley, though it’s being spun about as fast as it should be (18,000 alternator rpm at 8000 engine rpm). I’m currently leaning instead toward a unit that can support everything even at idle, such as the PowerMaster 478618. Better yet, it has remote sense and adjustable  output voltage .

Long ago I bought LED signal flashers because the old-school mechanical ones don’t work with LEDs. Until recently, LED car lights weren’t a “thing”, so it’s random chance how the mechanical flasher sockets are wired (since polarity didn’t matter). Of course mine are backwards backwards (both the turn and emergency flasher) so  the new LED-compatible flashers don’t work. I’ll have to pull out the fuse block and swap the pins.

Other things on the back burner are adding a transparent bulkhead window behind the seat to see what that does for possibly reducing wind and noise. Then there’s door fabrication. Pretty sure how I want to do them; it just endless details like: material, frame substructure, hinge type, fabrication, and placement, weather stripping, and a latch.

Lastly, I finally had enough of the buggy GoPro and have ordered a Sony action cam.

11 Mar 2018

The pieces of debris are from a synchronizer hub, which is probably the best of all the things it could have been. “Best” meaning that they’re not bits off the expensive aftermarket gears and being an OEM part, it’ll be less expensive to replace. The transmission will be sent to the same place that built the new one, which works out well since they regularly build PPG gearboxes. When the unit is put up for sale, it’ll be advertised as having been verified as 100%-good.

The rain let up so the car was taken out for a short test drive. The new gear ratios are closer, with first gear being the most noticeable. Now, the car sounds much more like a road-racing car when leaving a stop; with the lower ratio, the ratio has to be slipped a bit more. Being new, the synchros are a little sticky but that’s to be expected. It’s true what Honda owners said about these gears (and the ratios) are terrible – for OEM-weight cars.

With everything that was removed and replaced, it was good to see that nothing leaked or fell off. The rebuilt rear engine mount though, is transferring too much vibration. I’ll probably have to redo it again and am considering something like having a block mounted off the engine that in cruise conditions, “hovers” between two rubber-lined stops in the engine mount. That way, vibrations will only be transferred when under hard acceleration. We’ll see.

10 Mar 2018

First, the good news –

Got the axle CV cup back, assembled the driver’s-side axle, then filled the transmission with OEM fluid to break it in. With some rare rain going on though, the test drive has to wait.

With the car stuck in the garage, finally got around to added 15-mm wheel spacers, since I’ve long had tire scuff marks on the inboard panels. Adding the spacers necessitates cutting down the OEM wheel studs, which went fine and while I was congratulated myself on my fine work, my brother called. I asked what his tire-to-chassis clearance is and was surprised when he said less than 1″, which is what I had before adding the spacers. Well nuts. He reminded me that the tires I’m now using (same as his) have stiffer sidewalls (though I don’t know how he knows that), so that’s one variable. Another is that he has roughly 450 lbs on each tire, while I have around 600 lbs on the rear tires due to being mid-engine. Another difference is that my rear suspension is IRS, so the tops of the tires move inboard under acceleration and braking. Between all these differences, it’s unknown how much the tires will squirm around. The irony is that having added the spacers and switched tires, while there won’t be any rubbing, I won’t know why. Oh well.

The bad news, well, I’m not sure how bad it is yet.

When I took my old transmission  to WaveTrac to have them fix their differential design flaw, I expected them to do just that, pop out the stuck axle stub, fix the LSD, then give me a call. Well, they did:

Them: “While we were in there we also found some gear bits stuck to the magnet. We’re sure you will want to fix this so we’ll hand it back to you taken apart.”

Me: “No, I want it reassembled, then I’ll decide what to do after seeing the little parts.”

They agreed, I drove up to get it yesterday, and:

Them: “Okay, here it is, reassembled but not sealed.”

Me: “huh?”

Them: “We’re sure you’ll want to take it apart, so there was no reason to seal it.”

That isn’t what they agreed to do… Anyway, when they handed me the parts, they did indeed look like broken gear teeth. After thinking it over and looking at them again later, I’m not so sure; the “teeth” on them are really small, flat-topped, and not helical. I’m wondering if they’re off some sort of slider component, though why that would break instead of the gear teeth is a mystery.

Anyway, the first step is to identify what these bits are. At best would be hearing they’re of no consequence (yeah, I know) and at the other extreme, it gets shipped to a tranny shop and torn down – again.

4 Mar 2018

Made the self-imposed deadline – the drivetrain is back in, hooked up, and running. Driving it has to wait until the missing axle piece is back, but it’s basically done.

I’ll check online to see if the gear manufacturer, Gear-X, recommends any particular break-in oil, or just go with the stuff they gave me.

With this out of the way, it’s on to wings!

3 Mar 2018

Drivetrain reinstallation should be complete tomorrow. The goal is to have the garage cleaned up before she gets home.  It will be, well, all except for one rear wheel and tire because I don’t have the driver’s-side CV cup back yet.

Speaking of that, the differential shop said they were able to remove it without damage and also fixed the differential. The transmission will be picked up this coming week and then it’ll go up for sale.

Pictures from today show there’s a lot of stuff in a twin-scroll turbo car with a dry sump! Several hours were spent looking for hoses touching anything else and they got the dual zip-tie treatment to keep them from abrading.

The last shot is a reminder to all builders to always snip off the left-over tang on Nylon zip ties. I can’t count the number of times an overlooked one caused needless bleeding.