Triumphrat

PaulBx · 11-07-2012, 09:12 PM

Perhaps only some kind of sensors work that way. I did not dream this up myself; I got it out of the manufacturer's manual. Presumably they would know. I have to admit some doubts myself, i.e.
1) Will the pipes melt the sensor wire insulation?
2) Will the diameter of the sensor even fit, or if it does will it create unwanted back pressure?
... and so forth. So I will just have to see how this goes. I will let you know.

WSC · 11-08-2012, 12:00 PM

Quote:

Originally Posted by PaulBx

I did not dream this up myself;

I didn't mean to imply that. I knew you were quoting the literature. Still, I have my doubts... Wouldn't be the first time marketing and engineering weren't on the same page...

(Checked their on-line support info and didn't find a statement to that effect, although they do mention an adapter that allows you to install the sensor into the end of the tail pipe. Optional at extra cost, of course...)

PaulBx · 11-09-2012, 05:43 PM

I found out it wouldn't fit in the stock muffler, because it is too large around, at the nut. Maybe just the tip is good enough. Will have to experiment...

Mandres · 11-09-2012, 05:50 PM

Quote:

Originally Posted by PaulBx

It is too large around, at the nut. Maybe just the tip is good enough. Will have to experiment...

Been there, best of luck to ya!

bigbofo · 11-10-2012, 04:48 PM

Quote:

Originally Posted by PaulBx

Interesting!

It sounds like you have a good idea. Keep in mind what you want to accomplish. If you are getting proper jet sizes and needle positions, would you install different jets in different carbs due to a different reading between the headers? If not, then one is probably good enough.

It would be interesting to get readings from the bung you install, then take the sensor and put it in the muffler exit and see what difference you get, if any.

One idea that MIGHT be worth checking is an adapter for the CO sniffer bung. If the sensor does not have to be right in the stream, that might be good enough. The ratio of the different gases is probably going to be the same just outside the stream, within an adapter, as it would be within the stream.

Another thing would be to simply replace the CO sniffer bungs with the larger O2 sensor bungs. If you ever needed to use CO you could presumably get an adapter to go the other way. This is assuming your CO bungs are not being used...

It might be an idea for someone to buy one of these and rent it out to others on the forum so they can get their jets right, assuming a muffler reading is good enough. 3 or 4 rentals might pay for the thing.

Here is the problem with that thought - sniffer bungs are only on the stock header pipes - i got an aftermarket system. Plus stock header bungs are 12mm, o2 sensor is 18mm, which means you need to cough up another 50 bucks for an adaptor (plus change your exhaust system back to stock).

At this point i see no other option though in order to dial in each carb to near ideal.

bigbofo · 11-10-2012, 04:50 PM

Quote:

Originally Posted by PaulBx

Perhaps only some kind of sensors work that way. I did not dream this up myself; I got it out of the manufacturer's manual. Presumably they would know. I have to admit some doubts myself, i.e.
1) Will the pipes melt the sensor wire insulation?
2) Will the diameter of the sensor even fit, or if it does will it create unwanted back pressure?
... and so forth. So I will just have to see how this goes. I will let you know.

The wire look fireproof... kinda asbestos like.

They also sell an adaptor bung thing.

bigbofo · 11-10-2012, 04:53 PM

Quote:

Originally Posted by WSC

Something struck me as wrong about this. Today, in a flash of insight, I thought I had it. After doing a little research. I'm convinced it will not work. As it turns out, the O2 sensor works by comparing the O2 content of the exhaust to that of the atmosphere. To that end, the external part of the sensor has to be exposed to atmospheric air. How it would work shoved up the tail pile escapes me.

The sensor get calibrated to atmosphere BEFORE you screw it in. The cpu will store that information and then compare it against the exhaust reading.

So no - there is no external part since our atmosphere is pretty constant...

WSC · 11-10-2012, 05:54 PM

I am pretty sure that is not how it works. The voltage generated by the sensor is proportional to the difference in O2 content between one side of the sensor material and the other (an oversimplification...). The external part of the sensor is vented to the atmosphere.

The calibration procedure is just to calibrate the CPU to the value generated when both sides of the sensor see the same amount of O2.

Here is more info than anyone I know could ever want on wide band sensors.

PaulBx · 11-11-2012, 11:56 AM

Quote:

Checked their on-line support info and didn't find a statement to that effect,

The manual says, "Alternatively, you can also use the optional exhaust clamp (part number 3728) to sample exhaust gases at the end of the tail pipe." See page 5:
http://www.innovatemotorsports.com/s...Manual_1.1.pdf

Since the thing really doesn't fit in the end of the muffler anyway, I may try to make a small adapter, a short piece of pipe, that fits into the hole and have the sensor mounted to it at right angles which would keep the outside of the sensor in the air stream rather than inside the pipe. That would take care of any problems you mention (assuming there are any) and allow me to easily switch between the two pipes. Only other things I'm wondering about are 1) air leaks at the muffler/pipe junction, and 2) is the sensor designed to run hot, and would it have trouble heating up enough (since they mention end of pipe readings this seems unlikely to be an issue).

<later>
Ah, on reading the link you supplied it says the sensor has a heater to make the temp correct, so I don't have to worry about that. I suppose I could use a little high-temp silicone to fill any holes at the pipe/muffler junction.

One other thing I wonder about is the reading procedure. Those charts you see, are they done with the engine in a no-load condition? Obviously, one has to open the throttle more with a load, than one needs to without a load, to maintain a given rpm. And the amount of load matters too. Different throttle openings translate into different carb circuits in use. I suppose a load is needed anyway to check the main jets as I don't think it is good for an engine to have the throttle pinned while sitting in your garage! I just need to find a place where I can get away with going that fast...

bigbofo · 11-11-2012, 02:35 PM

Quote:

Originally Posted by PaulBx

The manual says, "Alternatively, you can also use the optional exhaust clamp (part number 3728) to sample exhaust gases at the end of the tail pipe." See page 5:
http://www.innovatemotorsports.com/s...Manual_1.1.pdf

Since the thing really doesn't fit in the end of the muffler anyway, I may try to make a small adapter, a short piece of pipe, that fits into the hole and have the sensor mounted to it at right angles which would keep the outside of the sensor in the air stream rather than inside the pipe. That would take care of any problems you mention (assuming there are any) and allow me to easily switch between the two pipes. Only other things I'm wondering about are 1) air leaks at the muffler/pipe junction, and 2) is the sensor designed to run hot, and would it have trouble heating up enough (since they mention end of pipe readings this seems unlikely to be an issue).

<later>
Ah, on reading the link you supplied it says the sensor has a heater to make the temp correct, so I don't have to worry about that. I suppose I could use a little high-temp silicone to fill any holes at the pipe/muffler junction.

One other thing I wonder about is the reading procedure. Those charts you see, are they done with the engine in a no-load condition? Obviously, one has to open the throttle more with a load, than one needs to without a load, to maintain a given rpm. And the amount of load matters too. Different throttle openings translate into different carb circuits in use. I suppose a load is needed anyway to check the main jets as I don't think it is good for an engine to have the throttle pinned while sitting in your garage! I just need to find a place where I can get away with going that fast...

Innovate is also selling the adaptor -

Link to item on ebay

The sensor is designed to run as a permanently installed, so heat is no problem and yes - you want readings over the entire rev range of your engine.