I'm checking/testing tps, balancing throttle bodies and setting co with Gunson digital pro, i have eprom and Termi open pipes, so looking for a a little info- 1 size of sample tube fittings required 2 Gunson state test in exhaust is this ok or best the use points in the headers. 3 It states set the Gunson to 2% in clean air, then I'm looking for 4 is this accurate enough, unsure why 2 to start. Just looking to get all parts needed together before is start, Thanks
The take off bosses are 1/4" NPT. It's best to sample in the headers as the measurements will be much more accurate and you're getting specific cylinder readings. Gunson will have their reasons for the calibration, but be aware that reaction times on those units are very slow. Make an adjustment and wait until it stabilises. If the motor gets too hot, wait for it to cool and carry on. You want to be adjusting in the 80/90 degree range. No more and any less and it won't have cleared the cold running trims.
That's great info thanks, Any idea what fittings are required for the vacuum gauge take off (M4/5?), I have dial gauges and hope they are accurate enough.
Iirc, they’re M5. Dial gauges should be ok if they have dampers. When you do the mechanical balance, make sure the air screws are closed.
Yes they have dampers, i used/purchased to balance twin 40 webbers, they may have m4 or 5 brass extension nipples with the kit. Thanks for the input
If you use the 1/4” bsp take offs, do not put the plastic pipe from the Gunson straight onto them as the tube will melt. Get some heat resistant tube to put in between with the diameter of the Gunson plastic pipe. With no catalysts in the exhaust I used to sample straight from the exhausts.
Yes I have ordered some high temp tube, be interesting to see the difference in readings from header to 200-250 inside the can.
When you warm your gunson gas tester up an get it settled down it reads 2 because thats the% of CO in the atmosphere. Don't have it sat behind the exhaust when testing. The best readings are from the headers because the exhaust is linked in the link pipe I've tested mine in the end of the silencers and you still get different readings.
Just thought if you live in London you need to set the gunson to 1 because of Khan's highly effective ULEZ charge
Nooooo if we had 2% co in the atmosphere we would all be dead ! i assume its a base line setting your looking at less than 1 ppm in the atmosphere.
What we need is a modification to the ecu - a toggle switch that sets 1% or 4%. Set at 4 for normal and track use, and when you’re driving through London just leave the damn thing set at 4 cos you’re making absolutely no difference to Khunts fantasy-land numbers.
Set at 1%, I doubt it will run well at all. When I rebuilt my 916 engine after having the heads gasflowed, on first startup it was popping and farting with small flames blowing out of the throttle bodies due to being too lean. Obviously all sorted by altering the mix and then optimised on the dyno but, had I tried to ride it I don't think I would have got far and I didn't much fancy the idea of flames hitting the underside of the fuel tank...
This subject has been on my mind for many years ..... [ I am afflicted with a scientific mentality ] . I haven't found any treatment available , so I guess I'm stuck with it now ..... @nelly mentioned some crucial points in his post . There's no doubt that sampling the gas at the headers is the most accurate way to go , by far . But the devil is in the details , and it's about how the Gunson unit "pumps" the exhaust gas in for testing . It uses a diaphragm that vibrates back and forth and is powered only by the pressure pulses from the exhaust. That's how it was designed to work , by having the sample tube shoved into the end of the exhaust . I've never been able to get useful / sensible measurements from the headers I agree . I bought a 4-way Carbtune gauge many years ago , back when they had mercury in the tubes , ( which is perfectly self-damping , because of it's weight ) ..... they were later forced to replace the mercury with metal rods , and the result was ..... err Yeah , very good point there ! Once I've tuned my bike to where it pleases the deepest core of my entire being , I mark the spot on the trimmer pot , inside the ECU . Then I go back to the Gunson and find a setting that's lean enough to breeze through any emissions test . I mark that point as well , and I set it there , but only for one day per year ..... Did anybody on here choose to buy a Ducati based on fuel efficiency , or for touchy-feely environmental reasons ? A vital question I'm left with , is the effect of having that "X-piece" in the exhaust system . How much mixing of the exhausts of the two cylinders is actually going on there ?
I be very grateful If someone knows where I could read up on the details of typical motorbike fuel/ignition/engine management......up to euro 5. I need to get my head around what's happening on my 2014 multi. I "hear" stuff ..but would like to read about it's development and evolution... emissions issues etc. Sorry for slight hijack ... I spoke to Chris at CJS the other day regarding my bike and he told me what my options are .. but I probably remembered 15% of the conversation... Gerr
I tested my newly acquired Gunson gas test pro today on my car that has been Mot recently, the emission test on mot was 0% at idle, assuming the tester was accurate with testing, the gunson was reading -0.65 so reading around -.5% low. I assume this is possibly as good as it gets from one of these. Then left in fresh air and it returned to 2% can we call this a result.
