The 16V G60 thread.

Toyotec top tip....Listen to what AS-TECHNik has to say particularly where knock is concerned....

 

Hi Trev, yeah its great to discuss these things

2.6 is quite common in certain filters found in production knock systems. I totally agree with finding the knock also at 16khz. As a rule of thumb most 1.8 to 2.5L 4 cylinder engines will have a knock second harmonic frequency around 14khz give or take. So if you pitched your bandpass about there you probably wouldn't miss much. Id be interested to see your FFT analysis of the engine noise.

With 2 sensors you want to get the sensors as close as possible to the interface between block and head. On the 16v engine I simply pick up of the existing bosses. This way 1 sensor gets most information from cylinders 1 and 2, the second from 3 and 4. I built 2 circuits to filter and amplify each of the sensors indepenantly. I then found by connecting the 2 amps to the same headphone jack it mixed the signal. (Never thought of sending it to L and R separately,,,,i like that ). The 2 sensors gives you better clarity of the outer cylinders but also increases noise also. It also gives you the ability to play with different locations symultaneously.

In reality you can keep it simple and get away with 1 sensor. For these type of mapping applications you would expect/assume all the cylinders will start to knock at the same spark so by listening to 1 cylinder only will be okay. In the end, its just a lot of trial and error of sensor positions to get the best results. By keeping your filter broad you are then even less sensitive to positioning.

 

Right, the saga of my bag of crap 16V G60 continues. Lots of stuff happened over the last year including a house move. Car just sat around doing nothing. Today however I took it for its MOT again so I can resume development.

Failed MOT. Mechanically, just needs a new tyre and handbrake cable. But more seriosuly, exhaust hydrocarbons way, way up. It drinks through fuel like there is no tomorrow and tester commented on terrible rich smell. However, I have MS setup so that I have not too far off stoich on idle; I'd say it's around 14.0 at worst though of course it does vary. It just idles better there than it would at 14.7. Perhaps I can just iron that out by pulling out the Gastester and tweaking the CO down myself. At what RPM do they do this test? When I was waiting for it to be done, I could hear the car being revved quite high. I always thought it was done at idle. Is it done at 2000rpm?

Other major issue is that the exhaust system becomes terribly smoky after only a few minute drive to the MOT station. I mean, I got out thinking it could be on fire. I have a Zeitronix unit monitoring EGT. I have the EGT thermocouple mounted into one of the four-branch tubes (the one nearest to the cambelt), about 1.5 inches from the head. At hot idle, it's about 850 to 900F. When I start driving the car, even driving it as gently as I possibly can and crawling like a snail, it's hard to keep it below, say, 1100 or 1200F. When I was going to the MOT, I am sure I saw it register about 1500F.

The MOT tester also commented that the oil temperature was 102 degrees C.

Spark is about 10 degrees BTDC at idle. Tried playing with both spark and mixture at idle; neither seemed to shift the EGT at idle much below 850ish F.

Not sure if these EGT readings really are out of the norm or not. Do I just need to drive the bloody thing and let all the crud burn off the exhaust wrap or something?

Extreme 'throb' from the exhaust system continues to bug the hell out of me. I don't understand if it's just characteristic of having a four-branch fitted (together with the fact that the system is one silencer less now) or if it indicates a problem with the engine.

Been working on this for too long. Might just get shot and give up.

 

I daresay you've found this yourself by now Trev, but from the motuk.co.uk site:

"Note: If a vehicle meets the CO requirement at its normal idling speed but fails the HC check, re-check the HC level at a high idle speed of 2000rpm. If the HC reading is 1200 ppm or less, the vehicle will meet both the CO and HC requirements."

There's also some references to revving to "2500 or half the maximum if lower" during the pre-measurement phase, I think.

 

Passed emissions this morning!

And now has MOT!

When having a chat with Toyotec, he suggested that the exhaust temperature was probably fine, and that the smoking was more than likely droplets of oil getting onto the four-branch. I managed to cure the oil leak, and it doesn't smoke from the engine bay at all now. Cheers Ed. In fact it's almost a novelty to look at the bottom of the bell housing and sump and not see a single drop of oil anyway...

Just need to get it taxed now and I can resume tuning.

 

Nice one Trev, I'll have to have a look next weekend

 

Took a mate out in the car last weekend; he's good at hearing pinking (which I am not, thanks to crap hearing). With my human 'knock detector' on board I was able to open the throttle and actually properly give the car some welly around the country roads. So after I started the project, uh, I don't know - four years ago? - I actually properly drove the 16V G60 in 'anger'. It is flat as a pancake at the moment, but at least being road legal (again) and free of other stupid niggles means I can start mapping it now.

 

How's your coming on Trev?

Mine is all up and running on the stock BBM check on Digipants, got some turd polishing to do in terms of loom tidying and a couple of mounting brackets to fab but aside from that is should be off for an MOT in a month or so.

I think the BBM chip and spacer bushes were about the only things I ended up using from that kit..

 

Hello Yandards,

I decided to stick up a new thread in the Members' Motors section, as it's now pretty much complete and on the road:

http://www.clubgti.co.uk/forum/showthread.php?t=202362&highlight=16v+g60

Still a long way to go and desperately in need of proper mapping, but it's on the road!