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If I were interested in buying a device to measure my air/fuel mixture to tune my carbs, what would be my best bet?

Is this the one? http://vwparts.aircooled.net/I...-p/innovate-3837.htm How hard is something like this to use? Do I need a lap top? Be gentle, I still have a flip phone.

My only problem is that my exhaust from cylinder 1 and 2 never joins 3 and 4 until the very end. It's a Seduction thing. I'll have to weld in a bung for each side. There is a nice spot right before the mufflers.

engine comp

Thanks,

CG

 

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Original Post

That's an Innovate LM-2. It replaced the Innovate LM-1 I've got. Summit Racing has them for $246. No, you don't need a laptop. I just look at mine while driving around to see what's going on. The information it provides will be a benefit in getting a perfect tune.

Others might not agree-- but with carbs, whatever you do to one side you're doing to both, so you wouldn't need to weld a bung in both pipes. I probably would anyhow, but it'd just be overkill and redundancy.

Your mileage may vary.

$246? That's an awful lot of coin for that device today. My Innovate MTX-L turned to junk after a few uses, then sat on the shelf for a couple years. Tried to use it and the screen went dark. Never worked again. They won't get any more of my money.

The one Ed references is $150 today. I recall it being less when I bought it

Last edited by DannyP

@Carlos G all of the 4:2:1 Spyder exhausts of that design have the same issue and have for the 15 years we've been using them.  L&R don't blend until the tip, and you'll find that with a tailpipe sniffer you can get it into one side or another, BUT you can get some odd readings at times, plus you will get a huge influx of fresh air sucked back into the exhaust when you lift off the throttle.  you can get a descent tune this way,  but nothing beats having o2 bungs further up the system, just before the mufflers is my preferred spot.

Two bungs would be the way I'd go. I would think this would aid in tuning seeing that I'd be reading exhaust gas from two at a time versus all 4. But what do I know.....

I don't think my exhaust blends very much at the tip. My tip is just a band to keep both ends together.

exhaust 2

The spot I also thought would make the most sense would be between the flange and the muffler. One question though, does the two pipes coming together before the flange going to mix enough before hitting the sensor?

exhaust 1

I've got a bit of an exhaust leak on one side. When I take the exhaust apart to weld in the two bungs, I was thinking of using some kind of exhaust sealing paste to make a better seal. Is there a better way?

exhaust 3

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Yes, Carlos, I used NAPA exhaust system sealer on my old exhaust. My new one doesn't leak thankfully.

My exhaust bung is in the last 6 inches of the final outlet. But I also have a Vortex cone insert in a 6" extension on top of the regular exhaust. My gauge readings are steady and not too jumpy to read and/or dial in. Plus there isn't any drone when cruising, it's actually quiet enough to converse. Until I put my foot down. Then it sounds like every other Spyder at full song.

Thank you, Ed. I took an hour and a half solo ride yesterday, it was above 90 and a bit humid. The back of my shirt was soaked. Why, you ask? Because, Spyder! 

But also because it was the first time since last summer's rebuild that I drove it that hot out and that aggressively. Temperatures stayed right where they should, 180-185 on the oil. Fan came on infrequently, like it's supposed to. I was trying to get it hot to see what the limits are, if any.

Once it got really warm, I had to richen two cylinders and lean the other two and boost the idle speed a couple hundred rpm. Purring along at 900-950 hot idle now.

I'll say it passed the test. Soon, I'll be installing 4 CHT displays to go with the K-type thermocouples that are already on the engine.

@DannyP posted:

Thank you, Ed. I took an hour and a half solo ride yesterday, it was above 90 and a bit humid. The back of my shirt was soaked. Why, you ask? Because, Spyder! 

But also because it was the first time since last summer's rebuild that I drove it that hot out and that aggressively. Temperatures stayed right where they should, 180-185 on the oil. Fan came on infrequently, like it's supposed to. I was trying to get it hot to see what the limits are, if any.

Once it got really warm, I had to richen two cylinders and lean the other two and boost the idle speed a couple hundred rpm. Purring along at 900-950 hot idle now.

I'll say it passed the test. Soon, I'll be installing 4 CHT displays to go with the K-type thermocouples that are already on the engine.

Teby and I drive Saturday. My fan comes on at 190 degrees and it only came on a couple times and for not very long. Outside temps were nearing mid to high 80’s by the time we got done. The 2110 Pat Downs built for me runs exactly as it should. Glad to hear you got out. 

So I was getting ready to install my WB Wideband gauge, sensor and wiring. I'm not going to permanently install it, but long enough to do what I've got to do, then I'll remove it. 

Danny, do you also remove the O2 sensor from the exhaust when your finished tuning? I would think this would be a good idea.

The instructions that came in the box just has wires, no fuses or anything else.

In the PDF on line, they have a fuse on the red (power) wire and nothing on the black (ground) wire. 

Wide band

My harness came with the fuse on the black wire and some kind of resistor on the red wire.

Wide band 2

@DannyP is this how it came for you? If not, how? Thoughts anyone?

I do have an inquiry in to WB Wideband to see what they say, but I thought I'd also run it by the brain trust.

I'll shrink wrap the other 3 wires separately since I'm not going to use them, but I don't want them making contact with anything. 

I also have two bungs that'll be welded onto my exhaust. 

Thanks.

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OK, sort of in order: 

  1. I bought an O2 sensor replacement plug to fit the bung from CB Perf.  I am planning on removing my gauge and sensor from a permanent install to a “bring it over when I need it” install.  One less thing in the cockpit to distract me.  It is pretty handy for finding a leaking manifold gasket, but that doesn’t happen very often.

  2. A circuit is a circuit so from that aspect, and looking at it from a current draw point of view (which is what is coursing through your fuse), having the fuse on the hot (red) side or the ground (black) side should make no difference.  Only convention puts it always on the hot side (although I’ve seen ground-side fuses on some Chinese circuits from time to time).  Physics is Physics.

  3. The device on your hot (red) side is a diode, which is a one-way resistor.  The purpose of that is to prevent damaging the circuit board components in the event of some old guy from the backwoods of North Carolina wiring it up bass-ackwards (+12v to black, ground to red).  Normally, that’s a BIG no-no but that diode would save your bacon by acting like a resistor in one direction only and blocking the bass-ackwards current from frying the gauge circuit board till you figure out why the hell it isn’t working at all and wire it up right.
  4. Somewhat unrelated, but is there a dedicated 12v line running to the O2 sensor?  You would have a 12v wire, a gauge wire and a ground wire, in that case.   I have a 12v line on my sensor as the sensor has a heater in it to bring it up to operating temp quicker.   Just curious, Carlos.
  5. I also think that if you sample exiting gasses from one  Or two cylinders you should be all set.  Sampling 2 cylinders is better than one (it smooths the data a little), but two at a time should be fine for tuning your carbs.  You can always point to the exhaust when hob-nobbing with a Porsche purist and tell him/her that you have a Custom, “double-bunger” exhaust (say that with a fake German accent, like a “Doppelpfropfen” exhaust.   Guaranteed, he will agree and look at it with enhanced respect, as purists often do.
  6. Yup.  Shrink wrap the extra wires and insulate them from everything.  Always a good practice.
Last edited by Gordon Nichols

 

I think the main reason for traditionally putting the fuse on the hot lead is that the closer to the battery the fuse is, the more of the circuit the fuse protects.

Most anywhere in a car, and especially under the dash, there are lots of other paths to ground than the dedicated ground wire of this device.

So, if the body of the gauge is metal and rests against some other grounded metal, AND if something hot in the gauge shorts to the body of the gauge, the fuse in the ground wire won't help and sumpfins gonna burn up.

Likewise, if the insulation on the hot lead itself, between the battery and the gauge, is damaged and the lead brushes against a grounded bit, sumpfins gonna burn up.

My guess is they assume you're hooking the hot lead to a 12V source from the fusebox (that's already fused to protect the wiring ) and the fuse in the ground lead is a much smaller-valued fuse that's there to protect the circuitry in the gauge.

 

Carlos, I hooked mine up to a cigarette lighter plug with an internal fuse. I do a temporary install, I have a plug in the bung now, at the point where both tubes converge.

The plugs are available at any auto store, no need to get one from CB, all O2 sensors have the same thread(18mm).

A diode is not a type of resistor. A diode is a one-way electrical valve. There is 1.7 volts of voltage drop across the diode, as it is a SEMI-conductor. But yes, it is there as a wrong-polarity safety device. It isn't necessary if you wire it right. Which is kind-of stupid that they put the fuse on the ground wire, that could confuse people. 

I got word back from WD wideband and they say the harness is correct. Whatever. I'm going to run it their way for warranty purposes for now.

It will be a temp install. I might differ from Danny and not use the cigarette lighter plug. We'll see. I do have an idea to mount the gauge on the dash with a suction cup for diagnostic purposes though. More later.

I took off my exhaust to drill some holes and I took it over to a buddy to weld on the bungs.

exhaust sens 1

I had ordered and extra one when I ordered the wideband, so there will be two.

While it was apart, I investigated the leak I had that I had shown earlier.

Well wouldn't you know.....

exhaust sens 2

No wonder it leaked. May the fleas of a hundred camels infest this fabricators left arm pit.

If I had the inclination, I'd weld in a piece of tubing to do it right, but I'm going to slap on some sealant for now when I put it back together.

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Just got my bungs welded. One on each side.

exhaust sens 3

I also messed around with a temporary suction cup mount for the gauge.

exhaust sens 5exhaust sens 4

I'm also going to make a hood, like on a traffic light, so I can clearly see the number.

I also had the same idea for the gauges. The oil and alternator lights aren't very visible during the day time. 

I might semi permanently install the wiring harness that the WB gauge came with. When I'm not using it, I'll just remove the gauge and O2 sensor then tuck one end under the dash and secure the other end in the engine bay. I'll wrap the plug on the end in the engine bay to protect it.         Any reason this would be a bad idea?

If the weather permits, I'll start measuring O2 tomorrow, after i calibrate it as per their directions of course. Then I can start buying jets. I might even do some jet doctors too.

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Calibration of the WB wideband gauge that Danny and I have is as follows, according to their website:

-Hook red wire on the wiring harness to a positive source and black to ground.

-Plug wiring harness to gauge and oxygen sensor. Sensor is not installed to exhaust yet. It's in open air.

-Turn the positive source on.

-Wait until the gauge shows 19.0.

-Push the button on back of gauge and hold it until it shows A 6.

-Release button and wait for the gauge to read 19.0 again.

-Done, install sensor into exhaust and go brapp around the hood.

I got a little ambition with how long the wiring harness actually is. It will not reach the dash where I originally wanted the gauge to be. The problem is I have to have the plug for the O2 sensor in a spot where I can test both sides. Because I want to.

So I mounted it low. It's still visible, but not as convenient to look at when you've got the pedal to the floor. I'll work on that later.

exhaust sens 6

So I took it out for a spin and got some numbers.

At idle and warmed up thoroughly it reads 11.5ish.

Pedal to the floor 11.9 - 12.1ish.

Cruizing at 2500rpm 12.1ish.

Off throttle at 3000rpm 14.7ish.

Cool. Now what in the hell does this mean for a VW type 1 2276 with 44 webers?

I'm running 55 idle jets, 150 mains and 220 airs with an F11 tube.

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So the theory is the idle mixture screws really aren't idle mixture screws. They are idle VOLUME screws. The mixture is a set ratio defined by the idle AIR snorkel hole versus the idle FUEL jet size.

You could probably go with a 52.5 or a 50 idle jet in order to lean the idle and part throttle.

You want 12.0 to 12.5 on WOT only. Part throttle and idle can be closer to 14.7, closed throttle decel can be all the way up to 19.

John Connolly at aircooled.net has a really cool thread on thesamba.com about jetting, but I can't remember the title exactly. It is definitely under the performance engine/transmission tab though. Happy reading!

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