Do you think it would be smart to keep the balance shafts then? Maybe this could be causing some bad vibrations? Maybe a fluidampre and BS would keep the false knock to a minimum?

Dan

 

I have a buschur built 2.0 motor with no balance shafts on the way...I'll see how it behaves on the stock ecu first but I have an AEM EMS sitting here ready to go...should be interesting.

 

Not fair mellon! I hope everything works out for you! I dont want to run into any issues with the Stock ECU after I build my motor...

Dan

 

I tune quite a few built motors and don't have problems with knock so maybe ours will be okay. My real concern is limitations of the stock ecu/mas. I'm already pegging the load at 380kpa with only 30psi on pump and I really don't care much for the GM MAF solution. Hence the real reason why I bought the AEM setup just in case.

 

No.

People have destroyed motors from what I have heard from the balance shafts failing.

 

That was the main reason I took it out, reliability.

 

I have mine in...seems pretty relabel.

Mine is a stroker though.

 

On anything revving below 8500 RPM, I'd leave the balance shafts in. Anything over, I'd take them out - which is why my built 2.0 had them removed.

IMO, if you're seeing false knock above 3800 RPM, then it's probably not an issue related to the balance shaft removal. IIRC, the balance shafts on the 4G63 have the biggest impact between 3000-4000 RPM. False knock can be due to any number of other contributing factors, though ... chattery clutch, exhaust vibration, upgraded engine mounts, internals, etc...

l8r)

 

I just recently had a balance shaft seize on a fairly new mitsubishi factory short block and it snapped the timing belt detroying my pistons and head. Thankfully it didn't damage the cyl walls/block/rods etc. I am now putting some rods and pistons in it as well as lightening the crank a little. I'm assuming all this plus removing the balance shafts will force me to go stand alone. Hopefully you can get your issue sorted though and won't be forced to do the same.

 

what about how tight the actual sensors were tightened? Could it be possible that they were torqued down too tight?

 

I wanted to add a few points to this topic

With stock ecu and a modfied car often the knock sensor can pick up sounds which are interpreted by the ecu as knock

This happens on stock engines with bolt on mods as well

It is important to rule of any loose parts or parts contacting - e.g. a exhuast contacting the body when the engine tq's over for example

A sure fire way to determine if false knock is at the root of the problem - pour in a tank of race gas - if the false knock suddenly goes away - well your tuning is too agreessive

Stand alone ecus provide the ability to custom set the knock threshold for response, but you can not tune the frequency of the sensor

Making the determination what is really detonation or preignition and what is a sound of the engine usually requires a set of head phones and reading the plugs

Oddly the IX was super bad with false knock and the X has turned in a great direction, really a great knock system on the X

Al

 

Well said. There are aftermarket knock systems that can listen as well.

Some are definitely more sophisticated than others and I think any tuner could implement them and build a good timing map.

Even the stock ECU can have the knock count effective timing pull altered and still register knock. I have noticed that some forged motors are just noisier than others as well, wall to piston clearance and piston material undoubtedly play a roll in this.

aaron

 

That's what I was trying to get at before. All these motors that have false knock, what are the build specs of the engine? What does your built sheet say?

 

I had phantom knock with the factory bottom end with the balance shafts, then I had phantom knock after I rebuilt the bottom end and took the balance shafts out. I really don't think taking out the balance shafts is going to hurt anyone. Thing is however I did have a 36 counts of knock issue that went away after I rebuilt the engine. The knock is still there but its at 8 counts.

 

What is this, "mild valve job", mentioned in your modlist? Do you mean a mild port job? What exhaust manifold are you running incidentally(stock or aftermarket)?