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Wideband o2 on a zzr1100
nick9one1 - 11/7/21 at 12:13 PM

I haven't worked on my kit car for about a year, but I previously had a few issues getting the zzr1100 engine to run well.
So I've bought a cheap used wideband kit to help.

I presume I need to mount the o2 ports where the manifold exits the engine and before the collector. Then I can use the o2 to monitor each of the exhaust ports individually while tuning. E.g tune port 1, remove o2 and install bung, move o2 to port 2, tune port 2.
I don't plan on running the o2 permanently, just for tuning.


Is this how it's normally done?

Cheers.

djtom - 12/7/21 at 01:15 PM

You could do that, but it's not usual. Most have it mounted downstream of the collector so that you are monitoring all 4 pots combined. High end tuners may use 4 x sensors to simultaneously monitor all 4 pots individually (but rarely, unless you are Cosworth or Mountune!) but it tends to be at the extreme end of tuning. The problem with monitoring one pot at a time of that you don't know whether what you are reading is unique to that cylinder or reflective of all four. Any changes to the tune would then need to be verified by identical runs checking the other individual cylinders before chaning anything else. That takes a lot of time and effort, and unless you have access to a dyno it's very hard to replicate the engine load from one pull to the next....

nick9one1 - 12/7/21 at 01:54 PM

Thanks. You make a good point regarding tuning. Although I was planning to use it as more like a carb synchroniser to make sure they are balanced at idle.

I had a tough time getting engine running well last year. I did a full teardown of the carbs, cleaning and replacing everything inside I could.
The engine still didn't run very well even after they were synchronised.

russbost - 13/7/21 at 08:59 AM

Far , far easier to use a carb synchroniser, they're not dear

Link to Carb synchroniser

nick9one1 - 13/7/21 at 09:04 AM

Thanks. I have that exact one.

But from what I understand carb sync and wideband don't do the same thing?

The sync ensures all the carbs are balanced and running equal. The wideband measures the air/fuel ratio.

russbost - 13/7/21 at 09:11 AM

quote:
Originally posted by nick9one1
Thanks. I have that exact one.

But from what I understand carb sync and wideband don't do the same thing?

The sync ensures all the carbs are balanced and running equal. The wideband measures the air/fuel ratio.


If all you're trying to measure is air/fuel, providing it's a standard engine, it should just be a tweak on each of the air idle screws on each carb to get best idle, then a check with a 4 gas meter to see what's coming out of the tailpipe, unless you're running something heavily modified & injected looking at each individual header output is of pretty much no benefit

nick9one1 - 15/7/21 at 01:14 PM

That would work fine if its a single carb. When you have four, measuring after the collector is pretty pointless. You could have two running rich and two running lean. You wouldn't be able to tell.

Being able to measure each cylinders a/f individually is surely far more beneficial.

e.g measure cyl 1, 'rich' tweak the pilot. measure cyl 2, 'lean', tweak the pilot.

russbost - 15/7/21 at 01:29 PM

quote:
Originally posted by nick9one1
That would work fine if its a single carb. When you have four, measuring after the collector is pretty pointless. You could have two running rich and two running lean. You wouldn't be able to tell.

Being able to measure each cylinders a/f individually is surely far more beneficial.

e.g measure cyl 1, 'rich' tweak the pilot. measure cyl 2, 'lean', tweak the pilot.


Nick, you should be able to hear it, you don't need any equipment to set the idle idle air screws, I've set up loads of bike carbs & never used anything other than a synchroniser. You'll usually find a "base" setting like, 1 & 1/2 turns out given in the manual or on forums, so I'd start with that & then just tweak each one individually for best idle, everything above idle is controlled on the needle/main jet anyway & if you check overall output you can see if it's very lean or rich (either of which usually gives a horrible idle anyway) if you found you'd got one screw 2 & 1/2 turns out & another only a 1/2 turn or something then there would be something wrong with one or both carbs, very strange if the screws finish up in massively dissimilar positions

If you think about it when most carbed bike engines were made CAT's & lambda sensors were only just about becoming fairly common & no one would have dreamt of looking at individual cylinders on anything other than race engines

nick9one1 - 19/7/21 at 12:05 PM

Thanks. That all makes sense.



I've bought a full rebuild kit for the carbs, so I'll see how it goes. Maybe the issues I had before were due to a blockage and not so much the tune.

coyoteboy - 19/7/21 at 06:13 PM

No hope in hell you can keep all other variables the same to match afr between restarts etc.

Steef74 - 14/1/22 at 01:32 PM

Yes I agree, that would require EFI and a wideband lambda in closed loop. However having a wideband lambda and a controller, you will be able to verify the engine is running next to Lambda=1 meaning AFR of 14,7 at low rpms.

coyoteboy - 14/1/22 at 10:00 PM

quote:
Originally posted by nick9one1
That would work fine if its a single carb. When you have four, measuring after the collector is pretty pointless. You could have two running rich and two running lean. You wouldn't be able to tell.

Being able to measure each cylinders a/f individually is surely far more beneficial.

e.g measure cyl 1, 'rich' tweak the pilot. measure cyl 2, 'lean', tweak the pilot.


Ideally, yes. But that's not how most people tune because the overhead of 4x bungs and 4x sensors is huge for the sake a next to nothing.

Use the carb balancer to ensure identical airflow through each throttle, and rely on the precision parts (injectors, ECU) to ensure the fuel delivery is close enough, so the average of all 4 will be right. You might have 2 a little lean and 2 a little rich, but if you're not planning to squeeze every last horse out, you won't notice.