ECU knock discussion (was silver supra)

[Guest Usmann A]

CJ, pls stop stressing yourself, u checked out every other ems available to man, yet how could you miss to check for knock control.

 

Problem is, everything I add is constructive,if anything my frist response was tounge in cheek with my"whos ur daddy" comment towards chris.

If it seems like im being a c*nt,I apologise, for those that know me, know its not my style.

 

Chris, knock happens ultimately when there is too much heat in the chameber(likeu say), this is caused by hotter charge temps, lean AFRs, etc, these two are the route causes for DET and pinging. (also ign timing, too much causes too early a pressure increace according to crank angle and this pressure then rockets twofold,as its hitting the piston as its not got to TCD yet. )

The reason why methanol is used because it burns hellova lot slower, which uses all the flame energy, means less heat,less pressure, and the cylinder runs alot cooler, same sort of thing which race fuel does too.

Knock is just when detonation occurs, two flame fronts collideing and sort of thunderclap in the chamber and cause a 2-3000+psi increace in chamber pressures. So basically everything gets a serious hammering.

 

Ive got nothing against the motec, but i looked at it around 2 years ago, but it wasnt for me.

Now I know you guys arent drag racers and these arent racing cars, which is why I am kind of shocked you didnt want the knock control. But hey, its ur $$$

 

No one is saying dont use methanol,its good stuff, but it seems to be your just trying to convince urselves and everyone else that the knock control thing isnt bothering you.

 

Have fun

[CJ]

CJ, pls stop stressing yourself, u checked out every other ems available to man, yet how could you miss to check for knock control.

I dont do stress. And yes, I did check out lots of the EMS available. The last thing I wanted was to see my engine go eh?

 

Chill out time for you now mate eh?

[Guest Usmann A]

CJ, what can I say, shit happens, and when your pushing alot of HP the safety margin decreaces .. especially when your on stock rod bolts ... hehehe

[CJ]

I hear what you're saying. I decided that when the engine was apart to try and strengthen up as much as I could (afford) so got the head bolts and rod bolts uprated and the bottom end built too.

 

Now only time will tell whether I have done enough

[Miguel]

O lets not ge into a flaming war here . ECU' s do different jobs in different ways ..each has its out flaws and bonuses. This is quite an informative thread . And although some may think 'U' May be coming across a bit he really is making some valid points. So lets keep this one informative eh

 

Methanol although great and does the job IS not a permanent meassure. Remember "street car " as in can be used "anytime" "anywhere" once again meth is a form of safety which although good is not something you find if stuck in the middle of the new forrest on a run . All these forms of protection are brilliant for a day at the pod or the track but on a run to spain you would either have to bring a damn lot of the stuff with you or make sure you know where to stop to get it .

 

Now as for EMS whether it being Motec, Autronic or AEM being responsible for . I have a hard time believing this, No ECU can blow a lump on its own only Very bad mapping can ,now is this the Hardwares fault or the tunner? you decide. Now this is my own opnion and I am not forcing it on anyone but for a road car I would want all the meassures that came with the factory ECU as well as the flexibility of an after market one and that includes knock control. There are far to many variables in this world that can affect the way and engine runs from day to day ...crap fuel, atmospheric changes the list is endless. Most of them can be "safe banded" with good mapping and set variables IE boost but most of us change the boost on a regular basis depending on mood so having some of the Original ( or as close to it ) safety margins is IMO the only way to go.

 

CJ- A 1.1 BAR WG will only allow 1.1 bar of boost to be run ( running direct of wastegate/ BC turned off) . If a car is over boosting its because the BC is not doing its job ( remeber a BC can and will only raise never lower boost) . So a good test before you run BC is to run wastgate only to see if its cut of is correct .If it is then its only plumbing or BC to blame.

[Guest Terry S]

Guys, no one is flaming anyone, and Motec makes a good ECU fact. Horses for courses. It is however, important to point out the limitations of each system, and they all have there limitations, they just differ between ECU's.

 

CJ, stock BL kits generally come with a 1.1 bar spring, yours may have a 0.8 bar one. If you have a decent WG like the HKS, with say a 1.1 bar spring, and say the car is tuned to 1.3bar via the ecu, which in turn operates a solenoid to control boost to the WG port, but the car is still over boosting, the system is not controlling it correctly.

 

That is why I told you CJ to put an EBC in instead of use the Motec one. The downside of this is that there is no boost temp correction, but if you look at the comparative boost curves you will see a good EBC will have a smoother curve than the ECU controlled solenoids I have seen.

[JohnA]

... Those with access to the programmes for road cars using knock sensors with a stock ecu will tell you that they are listened to over such a narrow RPM band that once you move peak torque somewhere else they don't really operate properly.

This is a very interesting comment.

I had been suspecting this for quite some time.

[Guest Usmann A]

Just thought id resuerrect this one, after some more info digging,

I have just seen a GTR33 running a Motec M880 with a seperate Motec KNock box, the M880 also has this feature optional from itself, and needs the extra $$$ to be unlocked ...

 

im unsure to the 800s and 600 units ....

 

but this still doesnt mean EGT comp on the 800s is good ....