Help: Knock Retard

Speed3 · Postby **Speed3** » Tue Sep 13, 2011 9:14

So I've recently been monitoring my knock retard and it seems like i'm getting some count of knock just about every time i drive.. when i'm just driving through the city i'll usually get .3 knock every once in a while (just for a split second) and the highest i've recorded is .7. Last week I went cruising with a bunch of legit cars and of course we were cruising to a spot at about 80-90 mph give or take and i happened to look down at a point and it was fluctuating between .3 and 1 count of knock quite frequently. The highest it got was 1.2-1.4 I think during that cruise. Mods are in my signature, is this normal or something to be worried about? Anything I should avoid? Thanks in advance.

kingtut · Postby **kingtut** » Tue Sep 13, 2011 9:14

Speed3 wrote:Anything I should avoid?

Mods.

I recall reading that below 2.0 isn't out of the norm. That said, I'm sure a Pro-tune wouldn't hurt either.

~Barn~ · Postby **~Barn~** » Tue Sep 13, 2011 9:14

That's what the Cobb AP documentation confirms as well. KR is next to unavoidable from what I've read, but as long as it's <2.0, you're okay.

I'm sure you're already using a flavor of 91 octane petrol, but maybe try switching brands and seeing how the behavior changes. (?)

jamiel · Postby **jamiel** » Tue Sep 13, 2011 9:14

sort of off-topic, but GRM (I think) had an article about about a new Mustang built for road racing. They were experiencing power loss at speed on track but couldn't reproduce it on the dyno. Traced it to the knock sensor- which apparently was interpreting the extra NVH from the stripped shell as knock.

chickenwafer · Postby **chickenwafer** » Tue Sep 13, 2011 9:14

Mazda knock sensors are notoriously horrible, I'm not sure how they are on the Speed however, but they are/were bad enough on the RX-8 and FD I just turned them off. They would pick up way too much NVH and pull timing erratically. Again, tuning a rotary is a completely different animal, but I digress...

The factory ECU is very sophisticated and as long as nothing it out of the norm (such as a mechanical failure) it can pull timing dynamically and your motor should be safe.

Speed3 · Postby **Speed3** » Tue Sep 13, 2011 9:14

kingtut wrote:Mods.

I recall reading that below 2.0 isn't out of the norm. That said, I'm sure a Pro-tune wouldn't hurt either.

You mean i should avoid further mods? or the ones i have now

Speed3 · Postby **Speed3** » Tue Sep 13, 2011 9:14

jamiel wrote:sort of off-topic, but GRM (I think) had an article about about a new Mustang built for road racing. They were experiencing power loss at speed on track but couldn't reproduce it on the dyno. Traced it to the knock sensor- which apparently was interpreting the extra NVH from the stripped shell as knock.

What's NVH?

Speed3 · Postby **Speed3** » Tue Sep 13, 2011 9:14

and i've had the smell of gas burning a lot when i'm driving or idling is that ok too? i'm catless so is that why i'm smelling that? sorry i'm trying to learn lol

dsm_luck · Postby **dsm_luck** » Tue Sep 13, 2011 9:14

Its nothing to worry about. Its actually pretty common to see random "knock" up to 6 degrees while off boost and low throttle conditions. Whether the knock is real or a symptom of a over sensitive knock sensor is a topic of debate. Either way knock at that low of cylinder pressure is not going to be harmful. I have never seen it last for more than a data point or two. Knock while WOT below 1 degree is insignificant. I see .3 to .7 WOT here and there. Run some WOT logs and if your knock is under 1 degree you are solid. Under ATR you can set the knock sensor to not kick in until it gets above a certain load. I use this to get rid of the bogus low throttle no boost KR readings and only see the actual WOT KR readings with the AP.

Also the gas smell when catless is normal. Mine smells of E-85..

kingtut · Postby **kingtut** » Tue Sep 13, 2011 9:14

Speed3 wrote:You mean i should avoid further mods? or the ones i have now

Naw, I'm just giving you a hard time. There's some knowledgeable people around here that can advise you on what to/not to do.

erod550 · Postby **erod550** » Tue Sep 13, 2011 9:14

What dsm_luck said. Anything below 1 or 2, especially while just cruising around, is nothing. Mine used to get pretty crazy knock, like up to 7 when it was cold between 3k and 4k rpms under very light load. After it warmed up it was fine. But seeing the occasional .3 or .7 while cruising is pretty normal on those cars.

Really the only time you need to worry about KR is when at WOT. On hot days when my intercooler started getting heatsoaked and my boost temps were going up to 180 I would see around 2.0 KR at times under WOT, but that wasn't very common.

Speed3 · Postby **Speed3** » Mon Sep 19, 2011 9:14

So at wot i got 1.8 in 5th the other day is that fine? Anything under 2 at wot is ok right?

Edit: I just got 2.4 or 2.5 (I don't remember which one) while wot in 4th and shifting into 5th

Speed3 · Postby **Speed3** » Mon Sep 19, 2011 9:14

Oh and under hard acceleration my AFR's seem good (high 10's to low 12's) until i let off the gas to shift. It seem like as soon as the bov lets out air, i drop to low 10's and high 9's, is that normal also?

dsm_luck · Postby **dsm_luck** » Tue Sep 20, 2011 9:14

You need to post up some WOT log so we can see whats going on. Its impossible to tell without some data.

Speed3 · Postby **Speed3** » Tue Sep 20, 2011 9:14

Ok I will on Thursday

Help: Knock Retard

Help: Knock Retard

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