Knock Senor hearing

[max_s2]

I've connected OEM bosch knock sensor directly to my laptops input. Made some tests hiting the sensor with screwdriver and I think it will work OK. Just need to order mic shielded cable and some connectors to make it all well together with laptop.
As an alternative, I will built myself a knock listener from here http://home.netcom.com/~bsundahl/kno...ten/listen.htm

Hopefully this week I'll post results here

[Billman]

what camdyou running. i get issues on the 7a about there. im sure its the cams. above there its fine.

find a bolthole thats over a coolant channel. thats how knock sensors minimise mechanical sounds away from knock.

I run 7A cams with different timing on the inlet. You have this sound on the lower RPM 1500-2000 or up between 4500-5000?

I am hearing the stock sensor on stock (stroker new hole) position.

@Jamo
i also used some settings with VEMS but didnt get anything out of it or any readings in general. Did you post these settings somewhere?

[GazzaG60]

i have a sound thats at about 1500 to 2k. more 2 k it sounds a bit misfire like. hoping the injector angle is good.

are you sur ethe rod bearings are the correct size. it sounds like big end knock to me that one or the cams.

[Billman]

Machine shop said the crankshaft has small wear so we are within tolerance.

About the 4500-5000 noise. Can too small ignition advance also induce knock?

[max_s2]

About your question - no. If its not totaly lean+hot+high boost @ low rpm.

[Billman]

About your question - no. If its not totaly lean+hot+high boost @ low rpm.

I am talking about the 4500-5000 RPM noise at 1.5 bar boost and 0.85-0.82 lamda. With less timing it is more obvious than with more. Note here that i find my EGT very weird. I see at this full throttle and/or cruise EGT no more than 650 Celcious. Sensor is new.

[A80Avant]

has the EGT probe been calibrated?

[Billman]

It is set up to the standard 75 value. When the car sits fo longer time overnight or so the it shows pretty close to ambient so I think it is right. At idle I see 390-400 degrees and and If I let it idle for 4 min it drops to 350.

[A80Avant]

it seems quite low, but with all the changes you have made, i cannot say if it is because of a large hotside or a bad sensor.

[GazzaG60]

too low an advance will cause big heat buildup.

the first ever basemap i used. my first ever tune was on a 95 impreza with a link ecu. the ecu was specifically designed for rally and subarus by possum bourne RIP. the base map we got with it had so low a timing it was luck the ported headers were too thin and blew a hole in them after about 300 yards.

checik the position of the sensor. ensure its in the flow of the gases and calibrated. 650 is possible i suppose though at those figures. i rarely see over 750 or so and thats on the 2.2 with 1.8-1.9bar

[Billman]

I will check the sensor position one more time but i think its ok since the idle temps are reasonable. It could be because of the massive exhaust housing i am running now. Downpipe is 3" and the WG comes back just before the cat.

[gnutz2]

What fuel are you using Billman.

When i use premeum, no matter how far i retard the ignition i still get knock.

Started using tesco 99 (momentum) and all is fine now.

[Billman]

I used 98 Ron fuel. I run 8.25:1 CR so I think I should not get knock at this "low" boost but who knows....I will check with other fuel company.

[Billman]

I made some test since i sorted the issues i had out and i heared the sensors. At about 4000 RPM and 1 bar i hear a sound that is close to your file at about 23-24 second and not like 21-23 (that is lauder and consistent). My question is should i retard till i hear 23-24 sound or 26-27??

In another run with a bit more timing there and i heard 2 separate and clear knock sounds. Without the cable there is nothing to listen to.

[Billman]

Small update with question: I couldn't get any 98 or higher fuel today so I tanked 95. With the cable I hear minor detonation at 1.3 bar even with a timing of 9 degrees at 4000rpm and above.

Question: can too small advance give knock? Egts are always ok!