I really don't know what kr is?

how do I make sure that I have 0 knock retard?

If im not mistaking I will have to buy a scanner right?

even when I get the scanner how do I know how to read it to see how much kr I have?

I keep hearing about it but I don't really understand it.

 

Yes, you need a scanner to read "knock retard" as in timing in degrees. You need more than a code reader. It's a tough issue. I haven't been able to get rid of it totally, but I'm running a 3.4" pulley, too. Probably should go to a 3.5", but I'd rather add other parts to deal with it, like headers and an intercooler.

 

It is the computer's response to the engine knocking. Basically, when the knock sensors hear a knock, the pcm immediately pulls timing until the knock is gone (how quickly it does it, how far it goes, and how quickly it adds timing back are all parameters set in the pcm). If I remember right 1* of KR = 2* of timing pulled, but I could be wrong on that.

Many L67s have KR even stock, some don't. Most of the reason its a problem, is the M90 puts out a lot of heat (I've heard outlet numbers over 300*F), obviously this high temperature coming into the cylinders makes it more likely to combust before the spark plug gets a chance to fire (knock).

The reason you want to avoid knock is because if it gets too high, it will chip the tops of the piston ring lands off.

The thing you want to do is avoid slapping too small a supercharger pulley on for your mods. With basic bolt ons (intake, downpipe, etc)- you should stick with the stock supercharger pulleybecause you're still getting rid of factory knock. When going to a smaller pulley (ie 3.5", 3.4", etc), you need to do plenty of supporting mods BEFORE you install the smaller pulley, or you're asking for knock. Its not uncommon to have to add PEMs/PLOG and 1.9 rockers to be able to run a 3.4" pulley. Many people do it backwards (add a small pulley without doing supporting mods first)- and most of them end up chipping pistons (whether they know it or not).

Yes, you need some sort of scan tool. You can buy one, or you can go on clubgp and find someone local who will scan for you for a couple bucks. One other thing to keep in mind- you can easily pay $100-300 for a scan tool; you can buy a pcm tuner that has a scantool built in for $400-500. So if you plan to keep getting deeper into modding, it may be more cost effective to just go straight to a tuner, but its up to you.

They will have a list of parameters that can be displayed that you must check which ones you want. Since connection speed is limited as to how much/fast data can be transferred through the OBD port. You hit a certain point where you can monitor too many parameters- and they refresh slowly (ie it keeps scrolling through the list updating individual parameters instead of constantly updating all of them at once).

All you need to do is select knock retard on the list (as well as any other parameters you want to log), and it will display on the screen.

 

KR is acronym for "Knock Retard".

KR is a result of baddetonation, or "Knock".

KR is actually good to protect your engine, but you never want to see it.

When you have pre-detonation, it's beacuse of a lean condition (not enough fuel), or because of a hot spot in your cylinder, which pre-ignites theair/fuel mixture before the spark hits. This sometimes causes 2 flame fronts within a cylinder, and creates that "ping" or "knock" when the flame fronts collide. The knock sensors detect this pinging, and the PCM compenstates by reducing the advanced timing of your spark, so basically, it's reducing your horsepower to protect your engine. This gives it that sluggish feeling when you have alot of KR, like 10 degrees...

Sometimes, PCMs create false KR as a means of torque management, so your cylinders aren't really knocking, it's just your PCM that's trying to reduce your torque based on the programming in your PCM. That's why we remove alot of the torque management settings, as this can keep all the power to the wheels.

If you have too much boost for your setup, you're overheating your blower, increasing your intake temps, and that can induce knock, and results in "KR".

If you don't have sufficient exhaust modifications, things heat up going out of the manifolds, you lose exhaust velocity, and you have heat that stays behind in your cylinders, and this can induce knock, and resulting "KR".

You get what I'm saying now?

Your goal in reducing KR is actually achieved by lowering intake temps, making it as easy as possible for cold air to get in, and make it as easy as possible for hot exhaust air to get out.

Dropping to a smaller pulley size without proper tuning is dangerous, because you're increasing your intake temps because of spinning your blower quicker at a particular RPM, so it jams more air in... but if your engine can't use it efficiently, you end up with less power in the end, because you'll be running with KR, which reduces your horsepower.

Ways of quenching knock without actually physical mods is through tuning... you can add more fuel in certain areas of your powerband, based on throttle %, or based on how much air is going into your throttle body, which is calculated through your MAF sensor... there's TONS of other parameters when tuning a PCM, and getting a canned PCM can only take you so far... every engine is different, so it's always best to have someone tune your PCM "in car".. .NEVER on a dyno, ALWAYS on the road, or at the track for WOT tuning... when you tune on a dyno, you're tuning your car to be a dyno queen... sure you'll have 0 KR when on the dyno, but the dyno doesn't create the same load that pavement does.. you're spinning a drum, whereas on the road, you're pulling your whole vehicle, and more load creates more manifold pressure, and heat, and possible knock. So, that's why it's always best to tune your vehicle under real time conditions, because you're don't drive your car everyday on the dyno...

I can keep going on and on, so I hope you get what I'm saying here...

Let me know if you have any other questions.

 

ok I defenitely get what u are saying.

like I said before I'm getting the K&N CAI in the spring along with my other mods

my mods are:

high flow cat
res delete
ubend delete
exhaust(turbo mufflers)
and soon the CAI

I know these are just beginner mods but I thought that with a 180 degree thermostat and colder spark plugs that I would be able to switch to a 3.5" pulley.

I am not trying to mod my whole car up like that just want add alittle more power.

also I will get my PCM flashed.

with those mods u don't think that is enough for just a 3.5" pulley?

 

I can't answer that question. Only a scanner can tell you if you can a run a 3.5" pulley safely.

Odds are most likely, but it depends on what kind of tune you have along with those mods. Don't drop the pulley until you do your CAI, and check for KR. If you have 0KR when stomping on the throttle, and through WOT in 2nd gear (60-95mph), then you can drop the pulley size, swap PCM for the tuned one. I assume you'll go with a canned PCM, since you won't be going for more performance than a 3.5 or 3.4" pulley and what mods you have now. Once you've swapped, and driven around conservatively without any WOT for at least 30 minutes, then scan and try a few WOT runs. If you still have KR, then you can either pay for in-car tuning, or buy a few more mods to try and reduce the knock.

 

Keegan (Explosive Sounds) lives one state away from you and has a tuner. Maybe you should chat with him to see if he can scan with you.

 

not trying to sound ignorant but isn't a canned PCM the same as getting your PCM flashed from ZZP

 

also with my mods that I currently have and adding a CAI and then maybe a smaller pulley how much torque and hp would I gain?

does anyone have an estimate or actually know?

again my mods are:

u-bend delete
high flow cat
RES delete
turbo mufflers

 

Yes. If you mean buying the $89 PCM from ZZP.