i need to get my ecu reprogrammed because of my new valvetrain. i am looking at a few different companies and they all say they disable the knock sensor. what are the advantages and disadvantages of doing this? thanks for the help

 

I was wondering about that too. Everybody says not to worry about the knock sensor, it's not necessary.

I refuse to believe that it's not necessary. If I put down $5000 for a motor that makes an ungodly amount of power for its displacement and it's an miracle that it holds together at preposterous rpms in the first place, I'm not gonna go ahead and disble the knock sensor.

I'd be very intersted in finding out how to get an ecu reprogrammed with the knock sensor.

 

Hondata recommends disabling it because aftermarket pistons tend to normally rattle a bit, which is picked up by the knock sensor as knock.

 

That's great, but what if I had a stock engine?
By saying that they recommend disabling it, does that imply that you don't have to disable it?

I'm planning on getting an R motor in my crx, and that's going to require getting an ecu chipped. I'm not really interested in running a motor like that without a knock sensor...

 

By reccommending it should be disabled, they are telling you to disable it. If your car is tuned right it won't knock. Look into the J & S Safegaurd equipment if you want some really good detonation protection.

 

Can you really tune it right, though? I mean, a knock sensor will take the motor right to the limit of detonation so that it can make the most power.

If you tune it right to the limit of detonation and the temperature goes up a couple degrees, or they decide to reformulate the gas, or anything, the thing's gonna detonate. You have to tune it conservatively...am I wrong in saying this?

Maybe I'm exaggerating the importance of a knock sensor....but there has to be a drawback to not using it.

 

I agree.. the ECU only looks for knock when the RPM is low... For higher rpm ~4000+ it doesn't even work.... If your stock ECU detects a knock then it just compensates by pulling a little timing and dumping a little more fuel... If you wanna bybass it yourself ground the KS and run the main plug on it to the pinout on the ECU just as it normally would be wired... All it really does is turn vibration into an AC pulse... The ECU interprets that as a knock, ping, or detonation... If you are really worried about your motor which you shouldn't be if you have built and tuned it right then yes look into a J&S safegaurd as xThexHeadx said... Latez


[Modified by JDMspecEG6, 5:32 PM 12/25/2002]

 

if i was you and was unsure about the whole engine building process, as well as forced induction i would seriously look into the j&s system, he is right stock knock sensors dont sense the higher rev detonation which just so happens to be the worst... (HEAD right off of block). If your planning on dumping some major cash into a motor you better be looking to dump additional dough into safeguarding it.. good luck bro

 

I don't understand...if the knock sensor doesn't do anything at higher rpms, how is it that cars are less powerful with crappy gas? I saw about a .3sec difference in the 1/4 mile with my crx between crappy gas and good gas. I am sure the gas was responsible for this difference because I raced my car every week for months and could account for any variation in the times it was running.

Also, Car and Driver did a test that showed significant decreases in maximum power on knock-sensor equipped cars when crappy gas was used.

http://www.caranddriver.com/xp/Caran...l?keywords=gas


[Modified by Lsos, 4:17 AM 12/26/2002]

 

It's when the ECU looks for a signal.... Now if you are detonating a lot on bottom end then it's most likely going to make your ECU run your motor in it's "safety mode" therefore taking away performance... Now if it's on the high rpm band then it doesn't really matter because the little switch in the ECU that completes the "look for KS input" is turned off.... Latez