I was looking at pcm 4 less website and said in the faq that it's a good idea to have one.Why should I buy one and where can I get one?

 

The LT4 module is less sensitive then our stock ones, hence if you have headers or rockers on your car the stock module may pick up the additional noise and retard your timing. The LT4 module will greatly reduce your chances of timing be retarded.
You can purchase one on ebay or there is a guy on here ( can't remember his name ) that also can get you one. Around $40.

Adam

 

Jason Cromer sells the knock module pretty cheap.

 

You can also order one from jason cromer from samtaylor.com . I tried to insert link but couldn't get it to work.

 

i wouldn't say that it's less sensitive but rather more accurate in terms of detecting knock
like you said though, the stock one will detect false knock from headers and/or rr's and retard which is a drop in performance
for the price and ease of installation, there's no reason you shouldnt get one
also, i think someone said that gmpartsdirect.com and jason cromer are right around the same price after s&h

 

does the lt4 knock module have to be programmed into the pcm after you install it?

 

No "programming" required. Think of it simply as a "filter".... it eliminates noise signatures that are know NOT to be knock. Filters the signal received from the knock sensor.

 

Sweet....thanks for info......thanks to everyone who replied and thanks to the thread starter, because I was wondering what that thing did and if it was worth it to get it when I do my longtubes.