knock detector vs EGT readings

can i use EGT readings instead of knock detector ?

For knock detection and control? No, the EGT probes do not have a fast enough reaction time, and you can't window the reading to know which cylinder is knocking.

it just a matter of time ?

By the time the EGT has moved (if it does) in relation to the knock events, your engine will have died. There are knock sensor for that reason, to detect knock, and the EGT sensors are to measure the temp of the Exhaust Gas, using them for other functions, that they are not designed to do, is a false economy.

I agree with BlackRex - EGT sensors aren't useful for knock detection and are incredibly slow to respond.

A knock sensor is a pretty cheap investment and many current ECUs are now incorporating pretty advanced knock detection and control strategies so I'd suggest relying on this.

and to add what Andre said, the bosch donut style knock sensors are cheap as balls these days too.

I'm not sure I want to know what balls are going for these days on the open market in Canada 13bjunkie? :)

But yes, the Bosch knock sensor is very cheap.

HAH!. I guess i chose a funny idium. Depends on the ball, bowling, golf, tennis, ;)

For the last knock detection setup i did on a 2jz, i had him order two sr20det knock sensors. I think they were like 65$ us or something.

I tried to machine up adapters to adapt to the stock locations of the original tuned sensors for the 2jz, but failed miserably and ended up bolting them to a different location. Worked great still.