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Knock Retard

bluegtp91 said:
I think it is more like Knock SJAndrew-tard.

You have a 3.2" pulley with no flow mods and crap octane...I bet if you pull out your plugs or when you took out your old ones...you'd fine missing electrodes or totally busted plugs from your lack of obvious caring and tight ass wallet...you can't be more jewish than I am about my car money wise and I use premium...are you really complaining about the extra $3 every fill up? If you are...just sell your boosted car now. Seriously. A 3.2" with the correct flow mods is headers/cam/intercooler territory...not bone stock. Even back in the day they tell you that you needed at least a cam and headers to run anything less.

"Should I care" about your ignorant equations and blunt fact of not listening to anyone on here that knows? I don't care. It's your car...why not put straight pipes on it and throw a 2.8" on there and watch the injectors run static and it'll explode the first time you WOT. Just please video tape it for our enjoyment...haven't seen fire works over a month.
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Thanks.

And to SJAndrew. I dont car about all the caclulating you have done, Your a frigging retard for runnin that small of pulley and no other mods whatsoever. You questions about KR and shiz should not be the things to be asking. You need to pull your head out of your ass and read before you start asking and doing **** to the car.

But like what blue said, fireworks are cool.:th_thumbsup-wink:
 


WOW You're Running a 3.2 Pulley on a stock motor with 85 Octane ??? YOU ARE CRAZY! IT SAYS TO RUN PREMIUM RIGHT ON THE FVCKING GAS TANK DOOR:th_shakinghead2:

Let alone you're running that small of a pulley. No you won't hear the KR... But your engine will not like it. Will it throw a code probably not until you eff it up bad. Why do people even think of running anything less than 91 in a boosted car ???

Were not trying to dog on you because you're new but because your doing insane things to your car that are beyond stupid. Please take that pulley off and put on your stock one until you can get some more modifications. Also start putting 91 octane in your car.

Read this... http://www.grandprixforums.net/safely-modding-your-3800-powered-car-17482.html
 
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SJAndrew said:
I just checked - it's a 3.2. I've had it in the car for over a year with nothing but 85octane pump gas (and a lead foot).

At altitude, I get 20% less o2 than the rest of you. With operating o2 sensors, I should get 20% less gas than you too.

I've not run the CFM or stoichiometry calculations on it, but I always figured that a smaller pulley put me closer to stock at sea level.

I figure that the rotational speed of the pulley is close to linear to its output (this is not really the case as air is compressible, but it's close).

The rotation speed os RPM*pi*d. Since the first two variables are the same regardless of pulley size, I can also say that the speed is linear too. In short, a 3.2 pulley is less than 20% smaller than the stock 3.8 so its rotational speed would be less than 20% faster.

If the rotational speed is somewhat linearly representative to the CFM, then I'm getting back to sea level (or so).

The bottom line - I would like to scan it just to make sure.

One question along those lines: do you monitor KR real-time (my assumption) or is it stored in the ECM?
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the concept seems somewhat right. couple things though: are you just looking at the diameter when you're calculating percentage of the stock pulley? because i'm pretty sure you'd be looking at circumference with that. also, you might get 20% less O2, but you're injecting the entire contents of the atmosphere, so you should think about air density as compared to sea level and not oxygen density.

another thing to think about is that the pcm is used to the density of the air, and was getting the correct air fuel mix before you put the pulley on. if what you think is happening is the case, then the pcm probably just has enough timing to pull to have you not knock.

i'd really really like to see a scan on this motor.
 
rynoman03 said:
I'd really like to see the aftermath of him blowing it up if he doesn't start listening. :th_shakinghead2:
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i've seen plenty of that already lol. such a waste... a used 3" pulley from zzp for like 20 bucks shipped blew up a perfectly good running 60000 mile L67. no use in wasting another one
 
Poil336 said:
the concept seems somewhat right. couple things though: are you just looking at the diameter when you're calculating percentage of the stock pulley? because i'm pretty sure you'd be looking at circumference with that. also, you might get 20% less O2, but you're injecting the entire contents of the atmosphere, so you should think about air density as compared to sea level and not oxygen density.

another thing to think about is that the pcm is used to the density of the air, and was getting the correct air fuel mix before you put the pulley on. if what you think is happening is the case, then the pcm probably just has enough timing to pull to have you not knock.

i'd really really like to see a scan on this motor.
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pi*d is the circumference of the pulley. Since pi and crank RPM remain constant, the only variable is d.

I've pulled the plugs many times and they pristine.

The reason I asked "should I care" is because if the ECM via the KS is capable of properly retarding the timing to prevent knock, then what is the issue?

I will write this once again...

It's never once thrown a code. It's never once not run propely. I've had the pulley on for 1+ year and have almost 20k miles on it.

Do any of you have any information for running a smaller pulley at 5500 ft altitude and 20% less dense air? My guess, I could take my car to sea level and immediately see problems. But, I'm not at sea level.

My uncle has a scanner. I'll pull the info and see what's happening. But, nobody answered my question: do you scan as it runs in real time to monitor KR or does the scanner store its values?

I don't have the pulley on for performance per se. I changed my coupling year ago decided "while I'm at it...". This is my daily driver - I have another car for my performance fix.

In short, I have no interest in seriously undermining its reliability. But, I've also seen no problems whatsoever (other than people telling me "no!!!").

So, what's left to be determined is whether or not you guys are underestimating or ignoring the effect of air density or whether I've just been lucky over the last year or so.
 


No, your air density kick isn't effecting it THAT much...a 3.4"...MAYBE...but your in no where NEAR safe territory to run that size pulley. How many miles on the car? 20K on that pulley? Just wait.
 
Hi, I'm at 6000ft here, been running stock pulley and I run 92 octane fuel on a 98 GTP.

1. when I first bought the car, I used regular fuel and the car ran like crap for a week until I found out that it should be premium fuel.

2. I could tell if I had KR without a scanner when I was almost stock: When I did WOT from 0, after I got to 2nd gear, I let go off the gas pedal just a little bit, the car would actually accelerate more at around 90% than it did at WOT.

The more mods I did, the less I could feel this, first with a Ubend delete, 3" DP and now with headers it's completely gone.

3. I'm installing a 3.4 pulley next week or so then I'll actually find a way to scan the car for Knock although I should probably do it first.
 
I'll tell you a perfect way to find out how good it is knocking or not...if it is bone stock take it all the way to its fuel cutoff at 126 or whatever. If it isn't knocking it'll just hit the limiter...and if it is knocking really bad...well...you'll have to take pictures afterward.
 
SJAndrew said:
if the ECM via the KS is capable of properly retarding the timing to prevent knock, then what is the issue?
Click to expand...

You've got it backwards. KR prevents more knocking. the PCM doesn't have ESP to know to prevent knocking from starting. You have to knock FIRST before the timing gets pulled. How the hell else would it know? For all your education, you're making yourself out to be a box of rocks. Here's a simple, chronological list of events that are happening to your car:

1. Open throttle
2. Knock
3. Knock retard; Engine power decreased; Possible continued knock

You see, every time your foot touches the petal, you knock at least once before the timing gets pulled. So, you're knocking... a few hundred times a day at least, granted that knock retard pulls enough timing to prevent more knock?

But hell, you're right: Your unfounded assumption just might be right (unknown unknowns don't remotely make an "equation" valid [read: No.]). Unfortunately, nothing you say will make a difference to anyone else until you have proof. So, do what everyone else says: Scan it, or GTFO. Seriously, you came to us; we didn't come to you.
 


I've had this car since it was brand new - 13 years. I ran 92 octane for the first ~9 years of its life until I ran some 85 octane when gas skyrocketed in price. Other than the $0.80/gallon saving, there was no difference whatsoever. Mileage, performance et al all remained identical.

The car has 124k miles on it - 20k on the new pulley.

My assumptions aren't unfounded. Air is less dense here - about 20%. That isn't something I pulled out of my ass - it's a fact. Other than an simple assertion that I'm wrong - please, someone, give me insight as to why I'm wrong.

The bottom line here: none of us knows for sure what's going on.

I will scan it and find out. I'd love to know either way.

Perhaps it's a combination of altitude, a worn out timing chain, and luck.

What I'm disappointed in is that answers to my question are in the form of mockery and insults. I came here for information - I presented my case, and will endeavor to prove it (if nothing to myself). Your responses, for the most part, has been disappointingly negative and uninformative :(

I'm sorry for wasting your (and my) time.
 
A bit more straightforward:
SJAndrew said:
My question: could I still be having "too much KR" as a result of the pulley swap but not know it because my ECM is doing the work for me?
...
Or - let me put it another way: do you need a scanner to know if you're getting too much KR?
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Yes, you absolutely must scan to know if, and how much knock retard you have and where in your powerband.

SJAndrew said:
I always figured that a smaller pulley put me closer to stock at sea level.

I figure that the rotational speed of the pulley is close to linear to its output (this is not really the case as air is compressible, but it's close).
...
If the rotational speed is somewhat linearly representative to the CFM, then I'm getting back to sea level (or so).
...
One question along those lines: do you monitor KR real-time (my assumption) or is it stored in the ECM?
Click to expand...
There's a lot of assumption here that will be fixed with a scan; when it comes to blowing up an engine, that simply won't cut it.

SJAndrew said:
nobody answered my question: do you scan as it runs in real time to monitor KR or does the scanner store its values?
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KR is monitored close to real-time. There's a delay, as I understand it.

SJAndrew said:
I ran some 85 octane ...there was no difference whatsoever. Mileage, performance et al all remained identical.
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My understanding of fuel in extreme atmospheres is lacking... perhaps someone like Reptile could point you in the right direction here.

SJAndrew said:
What I'm disappointed in is that answers to my question are in the form of mockery and insults. I came here for information - I presented my case, and will endeavor to prove it (if nothing to myself). Your responses, for the most part, has been disappointingly negative and uninformative :(

I'm sorry for wasting your (and my) time.
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1. Everyone's a dick on the Internet, especially forums. It can't be helped - it's a land of chaos where children and adults mingle. If you're here, you deal with it.
2. You've shown little in the way of your own research regarding the topic, but persist in your point. This is irritating to some of the community, because many of them have provided a lot of information to help others (which you seem to have ignored/disregarded) - many, to the detriment of their vehicles and wallets. There is a collection of generally-accepted rules-of-thumb because the combination works every time. You challenged this unprepared, and received the response you deserve for it.
 
SJAndrew said:
The reason I asked "should I care" is because if the ECM via the KS is capable of properly retarding the timing to prevent knock, then what is the issue?
Click to expand...

Because it cant.

Our cars dont have sensors that retard timing based on the octane of the fuel we're running through it.

If they did, then putting race gas in it would actually make it much faster without any other adjustments.

Since they dont have these sensors, they can only react.

And a reaction to detonation is not what you want.

You want there to be no detonation to begin with.

If you dont understand that, then I dont see any hope in you "finding" the answer on your own.

As for the negativity.... You're running your car with a 3.2 pulley on 85 octane fuel.

That is typically a recipe for disaster but you seem to say "its been fine so it'll still be fine".

Your claim holds no weight here unless you actively scan for KR.
 
Hey man,

I just moved from Denver. I'm going to PM you the number of a shop that has HP Tuners and can scan you for KR. For some $$$ (he's a speed shop), he can try and tune some of it out, but these guys are right, you are going to need some more mods to run that low of a pulley without KR.

FYI, I had the mods below and when I put on the 3.4 I was knocking 7*..... which is not good. Though, that was with the stock tune. ....obviously, I was having the car tuned the same day the 3.4 was put on, that was about as long as I wanted the car to have that much KR. I'm KR free now :) Might want to call him today.
 


Your questions have been answered more than a few times by more than a few different people. I was going to go through this whole thread and do a Q and A of your questions and multiple people's replies, but that would take a while because there are so many answers. It's called Knock RETARD. Key word is RETARD. I AM NOT MAKING FUN OF YOU. The key word is RETARD. The PCM sees KNOCK. The PCM RETARDS itself to eliminate as MUCH knock as it CAN. The only way the PCM would possibly eliminate ALL the knock would be to swiftly deploy the airbag and maybe knock some sense into the driver. Of course, GM couldn't do this for legal reasons so that's why the cars come factory with a recommendation to the driver to run premium fuel only and a 3.8" pulley on the supercharger. At 5,000ft, this does not make you able to run a 3.2" pulley on the ****tiest octane available.

We have answered all of your questions but your still in disbelief and the only thing that is holding that car together is the ****ty power it's making and a well built factory 3.8L
 
woah woah woah, hold your horses bluegtp91. He said he's gonna try and scan it this weekend. (according to his PM) I wanna see the results.
 
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