New MMS billet tranny mount for 3.4L GA's.

[eric99gt]

There's a thing called false KR....It's introduced when part of the motor hit off of things in effect causing the knock sensor to feel vibrations. When that happens it does the same thing when true KR is felt. It reduces timing and makes the overall driveability go to hell.

[xxbackhillxx]

werd, I took a scan right before and right after and my kr went from 3-5 to 1-3 degrees at WOT.

[AaronGTR]

I never noticed this effect on my car. Didn't have any change in KR before/after the mount. Technically that shouldn't be true because the knock sensor looks for certain frequency of vibrations that shouldn't be able to be duplicated by engine movement. The only possibility would be from an extremely over sensitive knock sensor which I at least haven't noticed on my car. Anyway, what would it be hitting too? There isn't anything close enough for the engine to actually hit.

[xonelith]

I think my problem was the headers bouncing off something. Technically, the knock sensors read a metallic noise, BETWEEN certain frequencies. They arent super sensitive, but if you tap on your header while scanning (with something metal) you'll see it register KR (but not if you tap on your exhaust tip).

False KR is nothing new. Many get it. A new mount may have corrected it, but the benefits of a stiffer than stock mount brought me to this decision.

I'm quite surprised you haven't heard of it.

Originally Posted by AaronGTR

wtf are you talking about? Engine movement has nothing to do with KR and will not affect it at all. That's all fuel and ignition timing.

Well, the scanner doesn't lie. I scanned it throughout the rpm range and through different gears, and the only change made, was the mount. I was getting 12 degrees of timing during downshifts and at 4000rpm. Now it's all gone. If it wasn't the mount, I enjoy the magic that happened, cuz it feels great!

[Sprucegagt]

Originally Posted by AaronGTR

I never noticed this effect on my car. Didn't have any change in KR before/after the mount. Technically that shouldn't be true because the knock sensor looks for certain frequency of vibrations that shouldn't be able to be duplicated by engine movement. The only possibility would be from an extremely over sensitive knock sensor which I at least haven't noticed on my car. Anyway, what would it be hitting too? There isn't anything close enough for the engine to actually hit.

You never knew about false KR? Where the hell have you been? Crawl out from that cave you call a garage and get on the DHP forums. It has been brought up many times.

What may be the problem is in the mount itself. Over time the rubber gets a little weak and allows the center of the mount to "vibrate" off of the outer portion. When I took mine off, I noticed wear marks where the center of the mount had been hitting the outside portions. That constant bouncing at the right frequency and its location being closest to the knock sensor could be the cause.

[AaronGTR]

Originally Posted by Sprucegagt

You never knew about false KR? Where the hell have you been? Crawl out from that cave you call a garage and get on the DHP forums. It has been brought up many times.

What may be the problem is in the mount itself. Over time the rubber gets a little weak and allows the center of the mount to "vibrate" off of the outer portion. When I took mine off, I noticed wear marks where the center of the mount had been hitting the outside portions. That constant bouncing at the right frequency and its location being closest to the knock sensor could be the cause.

No... pay attention to what I wrote. Of course I've heard of false KR . Just never heard of it being attributed to engine movement. And like I said already, I didn't see any difference in KR before/after my engine mount in any of my scans. Maybe I was just lucky and my engine wasn't hitting anything. Whatever. My engine seems to be extremely resistant to knock compared to some people's anyway because I've tortured the hell out of it and run extremely lean without getting KR. I've pushed it to the limits before KR has just now started showing up (basically after the cam).


And btw I am on the DHP forums all the time. You should know that already if you're paying attention at all...

[eric99gt]

That's usually the major cause of false kr...I'm surprised you've never heard of it.

[xonelith]

Aaron, have you checked your knock sensor.... every grand am that I have scanned has some KR. I'm surprised you have rarely seen it.

[CUSTOMGAGT2000SEDAN]

guys i am missing the boat here on this kr topice. what is kr.

[harvester45]

Originally Posted by CUSTOMGAGT2000SEDAN

guys i am missing the boat here on this kr topice. what is kr.

It's called Knock Retard. If I understand it correctly, it is an adjustment that the engine makes in the timing to correct for and prevent "knock." Knock is premature detonation within a cylinder. This is basically due to the air/fuel mixture being compressed to the point of detonation, before the spark from the spark plug can ignite the mix. Knock is hard on your engine, and the engine's solution to the problem, Knock Retard (KR), is bad for power output.

Eliminating knock can be done by raising the octane level of your gasoline, there might also be a way to do it with a power tuner.

If I was wrong on any of this, feel free to correct me.

[O1GAGT]

The majority of my KR was due to fueling issues, mainly running on the lean side however there were points where I was a bit rich. I am using the powrtuner, so I richened/ leaned out the fuel tables in the approx area and my KR has greatly diminished. I am going to start out by filling my stock mount with urethane and see if that fixes my Max of 5* of KR.

[CUSTOMGAGT2000SEDAN]

so are you guys saying by mounting these new custom made trans mounts . besides the vibration it causes the engine to knock ? i have no knocking now.

[eric99gt]

It's not an audible knock...for you I wouldn't have any worries about it since you're basically stock motor wise I'm assuming.

[CUSTOMGAGT2000SEDAN]

no stock right now . but intime engine mods. only thing right now front and rear stb bars.

[AaronGTR]

Originally Posted by xonelith

Aaron, have you checked your knock sensor.... every grand am that I have scanned has some KR. I'm surprised you have rarely seen it.

Ok, I'm sorry... but really... have I ever checked my knock sensor? Yes, of course I have and it's working perfectly. I never used to get any knock even when I dyno'd it and was running nearly 14.5:1 A/F at redline and 9psi of boost. I did get knock when I tried using the nitrous at the track though, and I'm getting knock now with the cam in at about 5000 rpm and 80% throttle (injectors are maxed). So yes the sensor is working and yes I scan it all the time. Like I said though, I've never got any KR that could be attributed to an engine mount.


Like I also said, maybe I've just been lucky which is why I haven't seen that before. I think spruce probably hit the nail on the head with the problem of a worn or torn mount vibrating and causing the problem. I agree, if the center section was hitting the other part of the mount that could certainly cause a metallic pinging that would set off the sensor. When I replaced my mount of course, it was only a few years old and was still in good shape, other than being a typical squishy stock mount.

[xonelith]

Originally Posted by AaronGTR

Like I said though, I've never got any KR that could be attributed to an engine mount.

Actually, you said:

Originally Posted by AaronGTR

wtf are you talking about? Engine movement has nothing to do with KR and will not affect it at all. That's all fuel and ignition timing. The only thing reducing the engine movement helps is power transfer to the ground, especially on shifts, and reduced stress on things like the exhaust that don't want to move with the engine.

Since I'm not very good at explaining things, or using MSPaint, I couldn't draw you a picture (mentally or physically).

Producing the power you are producing, I just suspected you had been in this situation before (I'm not producing NEARLY as much as you and I assume your motor is movin' around alot more than mine). Sorry for suggesting that your Knock Sensor may be in need of replacement! I apologize if I came off sarcastic in my earlier posts, as it was not intended to be that way.

[MilzyZ34]

Originally Posted by CUSTOMGAGT2000SEDAN

so are you guys saying by mounting these new custom made trans mounts . besides the vibration it causes the engine to knock ? i have no knocking now.

there saying that the new mount makes the knock go away.

[El_Diablo]

well the false knock, we all know engine mounts cant perform miracles

[MilzyZ34]

Originally Posted by El_Diablo

well the false knock, we all know engine mounts cant perform miracles

correct, should have put "false" in there

[cmtapanes]

I don't have the Milzy transmission mount. But I do have some vibrations under my seat and stearing wheel. Reading these thread gives me an idea where the vibrations comes from. I'll check my transmission mount and see the conditions of the mount.