sxuxrxf's Class 11...

[Hedrock]

My speedo does exactly the same thing.

[sxuxrxf]

Baja5 suggested separating the wires that feed the speedo from the rest of the gauges. I might also try the diodes in the two wires and see what happens.

[Hedrock]

My Brother said that when he put one in his Street Rod that you had to twist the wires in a drill. He also said something about keeping them separated and maybe shielding them some how.

[sxuxrxf]

The street rod guys do the drill trick, not sure why other than keeping the wires tight together. Mine are in a plastic loom, so I will pull out the speedo wires and put them in a smaller loom this week.

[Skidmark]

I have had the same thing going on. I used RF shielded wire from the magnetic sendor to the guage, but also put in a resistor at the gauge as well. It toned most of it down, but it still bounces around from time to time. I have been told it's inteferrence with the tach wire causing it, but I am not sure.

[motorbreath53]

DAMN this thing looks good....makes me want an 11 car in the worst way.

Strong work.

[Lotrat]

Stolen from the interwebs...

One of the key problems in transmitting data or any kind of computer type signal from one device to another is the electrical "noise" or Radio Frequency Interference (RFI) that penetrates the cable and gets mixed with the useful data or signal. The longer the cable, the more likely the RFI.

RFI, radio frequency waves that travel through the air, are intentionally and unintentionally generated by a wide variety of electrical equipment. These include TVs and radios, electrical motors, elevators, photocopiers, microwave ovens, fluorescent lights, all broadcast antennas, and all the communications equipment and computers themselves.

The first line of defense against RFI is to shield the cable with a conductive material that has been electrically grounded. However, even with the best shielding, cable length is quite limited. To overcome such limitations, equipment designers have turned to a technique of transmitting computer signal called the DIFFERENTIAL system.

With the differential system each signal is transmitted on two lines at the same time. On one, the signal is transmitted as a POSITIVE (+) signal, on the other as a NEGATIVE (-) signal. At the receiving end of the cable the receiver device gets two signals. Both of them however, have been changed by the noise that penetrated the cable. The changes came in the form of unwanted voltage added to the wanted signal. At this point it is important to note that the unwanted voltage got added to both lines at the same time and by the same amount. The essence of the DIFFERENTIAL system is that the receiver is designed to take the difference between the two signals on the two lines. In doing that, the noise part of the signal, equal on both lines, gets eliminated, and what remains is clear signal.

As indicated above, the DIFFERENTIAL system works well if the noise added is equal on the two lines, i.e. the POSITIVE (+) and the NEGATIVE (-). To ensure that the noise hits both of these lines identically, both of them need to occupy theoretically the same physical space. Practically, the closest we can get to this requirement is to have the two lines TWISTED together tightly. The tighter the twist of (+) and (-) lines the cleaner the transmission, and the longer the acceptable length of the cable.

In conclusion, a DIFFERENTIAL CABLE is a TWISTED PAIR cable between devices that use (+) and (-) values in transmitting their signals to another device. In some instances i.e., V.35, X.21, etc. the letters (A) and (B) are used to designate (+) and (-) respectively.

When MAKING a DIFFERENTIAL CABLE, always the (+) and the (-) sides of each signal are twisted together. For instance, to make the "Transmit Data" pair, TxD(+) can be twisted ONLY with TxD(-). Similarly, RxD(+) is twisted ONLY with RxD(-). When using alternate notations, TxD(A) is twisted together with TxD(B), TxC(A) with TxC(B (Transmit Clock), and so on...

Not all signals used by a particular differential device are transmitted as a (+)/(-) pair. For instance, control signals like RTS (Request To Send), CTS (Clear To Send), DSR (Data Set Ready), etc., are transmitted in V.35 as (+) signals only. Such signals can be paired two ways: with each other or, for higher quality cables, each of these signals can be paired with the Signal Ground. See specific cable diagrams on the following pages!

DIFFERENTIAL DEVICES are devices that use the above described differential system for transmitting data and control signals. The most common Communications Standards dealing with interconnecting differential type devices are: RS-422, RS-449, RS-423, RS-530, V.35, X.21, SCSI, Token Ring, Ethernet, etc.

By comparison, devices that do not use the differential system when transmitting data to another device are called SINGLE-ENDED. Examples of Single-Ended Communications Standards are: RS-232 Serial, CENTRONICS Parallel, and some SCSI.

[Ol'fogasaurus]

FYI. The RV industry is just starting to have to deal with RF. Our friend’s just bought a new, pretty expensive MH. The are having problems with the heat pump where it works intermittently. We called the dealer and he said that Fluorescent light can cause problems with the micro switches. When the problems first started, the Fluorescent lights were not on and it had been working several days prior.

The morning we left the ocean, still no heat so we started unplugging the computer, printer, etc and again still no heat. Once everything was connected from the house and no heat, I finally I suggested unplugging the night light (it changed colors and she used it as a mood light). As soon as it was unplugged, the heat came on. Go figure! She did say that the night light did put out a soft hum though. With my GoPro Hero 5 camera; the RF signal from my non-radio resistant spark plugs or plug wires is picked up by the camera. Also, the load on the solenoid or a leaky 8 gage wire is putting out an RF signal that the camera, when the sound is on high, picks up.

[sxuxrxf]

Thanks for all the input guys, I appreciate it. I will be trying these suggestions later this week and will report back.

On a lighter note, I got 15+ mpg on my 150 mile freeway trip today. I know it doesn't sound that great, but I'm happy with it. When I had the engine dynoed a while back it peaked at 115 hp / 128 torque @ 4800 rpm. I think it may get better when I change the ring and pinion, as it's a bit of a dog with the 4.12's. I figure 4.86 will put it very close to stock gearing.

[zancat]

Your car looks great!!

Bummer on the bouncy speedo, I am watching with interest. FWIW, I haven't seen this yet, but have been using the Speedhut gauge kits which come with a shielded pigtail on the sensor..... Hmmm

Would it help to put the tach wire inside a shielded cable as well?

[tikotiko]

if all class 11 cars looked like yours i would like them more thats a nice looking car good job homie

[sxuxrxf]

Thanks guys.

I haven't even touched the speedo yet and I'm already thinking of upgrades.
Front end rebuild including fully welded beam, shock tower gussets and another set of trailing arms with new German ball joints that I will be attempting to clearance for a little more travel. Gonna beef up the tie rods, steering shaft, and shim the pitman arm.
Gonna cage it, as someone requested. I'll tie it into the beam, torsion housing and frame horns.
Then I will make a new gas tank to sit in the rear, like the one in my last car. Maybe pull the stock tank out in favor of a storage box for crap and the Optima battery. Also fit a full size spare up front.
Then, when the cage is in, I'll make some skid plates and side bars.
And then...and then...

The stock tank just doesn't get me very far on 15 mpg, so about double the capacity should help out.
Here's my old 20 gallon tank: (sorry for the giant pics, they're from my gallery on TOS)

[sxuxrxf]

I've been playing with the car some more. Got the Empi 6-point cage installed. I did some tweaking here and there to get it to fit just right. I can roll down the windows with the doors closed, as well as still open the glove box door.



I went through the front wall to the beam. This is a much tougher job in a full-bodied car. There was so much room to weld in my last car with all the sheet metal cut off. Foot rest is the stock gas pedal. I wanted to put a diagonal bar from just under the dash going down to the lower bar at the front wall, but I just can't get in there to weld all the way around. Makes it very tight on the pedals too. I will be putting triangle plate at many of the joints instead. I have been looking at soo many pictures and reading everything I can and then I just go stare at the car in the garage. Too much thinking and not enough doing.



I'm doing all of this with a headliner, door panels and carpet all in place! It hasn't been too bad. No damage yet. I can roll the carpet out of the way in many of the spots. I have been using a thin piece of sheet metal to protect things, as well as a little square of "something" that is supposed to absorb the heat. Using MIG for most stuff so far, and my TIG with all of the tiny attachments to make the torch as small as possible for the tight fit areas or where I just can't have sparks.



From the center piece, I will add a "V" from center out to the sides and then a cross bar just above the window at the bends. This will be a while before the cage is finished. I will be boxing the trailing arms and bringing the shocks inside. So when that happens, I will continue with the lower back half of the cage. I will attach to the torsion housing at the same time and then add the door bars.

I attached the cage to the seat belt bolts on the body. I kept the stock bracket at the bottom that holds the belt reel as it fit perfect with the middle hoop. I just welded to the cage. My after-market reels bolted right up (facing the rear).






I'm over the idea of a Long Ranger tank inside the car. I will keep the stocker up front and put the spare on top of it. That's right...the full size tire just fits with the hood closed.
I redid the exhaust too. I put on a Flowmaster Delta 40 muffler. It now sounds like it should! It was a much tighter fit than the little turbo hideaway muffler. It is still tucked up like before, just tighter.

This is a much slower build than I thought it would be. No money = no motivation.

[fusername]

good to see you back in the game tho, you always bring the good stuff.

I took a shot at a foot rest, really nice, but so not worth the effort to sell. Ah well, you can't win em all.

[SANDDUDE]

Awesome Build!

~SD