Why is everyone so afraid of the mitsu knock sensor???

[turboglenn]

For years (over 10) I've been installing and tuning full stand alone ECU's and only in recent years have there been any with a provision for knock counting (save for certain expensive systems and some specialty setups that were available for grand nationals)

I've got well over 2 hundred stand alone installs to my name with probably 40 or more being on DSM's, and only a dozen or so that were full stand alones with knock on those dsm cars (mainly AEM ECU's)

Now why i am bringing this up is everyone is so afraid of a little knock count and how severely the DSM ecu reacts to it, and i can only ask why??

A recent thread brought me to bring this up, but out of all the cars I've tuned, NONE have died from a result of detonation or a lean situation. And only one has blown up in the past 6 years and that was because the wastegate blew the vac line off on the preious run and for the next entire 1/4 mile the car ran as much boost as it could. I remember the owner saying "it pegged past 30 psi" and i had even put a failsafe in there because we had not tuned it that high, so the timing was pulled to 8* under that The only reason i can think that it blew was either a lack of ARP fastners on the heads or we simply ran out of injector even firing them at full duty cycle and it popped from lack of fuel supply. We were only running 850's

I will normally run a DSM with at least 16 - 20* advance under full boost(17-20psi) on only pump gas depending on the overall setup, CR, AFR and turbo size. ( now i know 16-20 is about what the factory ECU offers up, but it is a safe and good range to use, so i do when on pump gas, but i have gone higher, but with minimal result it wasn't worth the chance on a DD tune) Race gas is a whole different ball game. I just don't get why everyone is so afraid of the Mitsubishi knock sensor and its hypochondriac behavior. Mitsubishi set the ECU's up to keep the car safe no matter what dumb-ass drove it, meaning it's made for people to accidentally put 89 octane in, beat the piss out of, not have the oil changed on a regular basis and still last 100k miles. The motor is not going to fall apart at 4 counts of knock on the mitsu sensor, let alone 1.

When i was taught to tune cars on the dyno by our former local dyno shop owner we were doing a lot of ACCELL DFI Gen V systems. The guy ( E.J. a.k.a. Eugene ) has now sold the shop to a member of the local corvette club, and I'm teaching him stuff every time i go there. But anyway, i was taught to tune with no way of measuring knock except inspecting the spark plugs, listening to the engine's overall behavior and even a way to watch the exhaust to look for knock signs in it. Severe knock will kill any motor(save for diesels), but all motors make noise, and all 4g63 motors being pushed hard will have noise that the factory mitsu sensor will pick up as knock. Especially if you have JE pistons

Now, don't get me wrong, products like the MSD and my favorite the J&S knock sensors are very nice for keeping you in the safe areas, because if you set off one of them (the MSD especially) you are knocking pretty good and need to let out of it NOW. And yes, since the products are there, i do monitor knock through electronic devices mainly when tuning on the dyno(unless it's a car i'm really familiar with), but the mitsu sensor is about as trustworthy as a politician so i don't get why everyone puts so much faith in it.


DIsclaimer for those who are pissed off at this point :

Now for those of you who run a system that utilizes a factory ECU and have to watch for knock or you'll lose performance, I understand why YOU have to watch it so carefully, and maybe that's why i see so much about it. I can truly sympathize with you because I've been there before and going full stand alone took the biggest pain in the ass part of tuning a Mitsubishi away and I'm still very happy about that one little thing being out of my hair. Even the Grand Nationals stock ECU doesn't cry wolf every time there's a fart in the engine bay .

But for you guys running megasquirts, AEM's and other ECU's (Motec, Haltech, Autronic ) Don't be afraid to run the timing up a little, and if you need any advice on anything because you didn't do the setup or tune on your car/ECU, Or, if you just wanna BS stand alone stuff, PM me and I'll help you out the best i can or we can just talk ECU's. I don't know everything, but I've been through quite a few ECU barbeque's in my time, and would be glad to help anyone out that asks. Given you have the ability to behave like an adult and listen to advice that is.

 

[FonZ454]

Good post.

I do use the Mitsu sensor to tune by. To try to eliminate any timing retard. I do believe that 90% of the time it's fake knock, but I still lose power because of that. I will agree it is probally very innaccurate and goes off a lot, but when running piggyback/stock ecu you do need to factor it in. And I would rather not totally eliminate it, even if I'm running safe AFR's and resonable timing and boost.

 

[turboglenn]

Fonz, that's a fair arguement, and since you're running a stock ECu at the heart of your system you have no choice. But man what a joy it is to tune and not even think about that damn sensor

 

[FonZ454]

Hah, you have no idea how many times I see my CEL (CEL is triggered to come on in dsmlink over 2.0* of knock retard). I know a lot of times it's from phantom/ fake knock... I'd really love to have a more useful sensor.

 

[dsm-onster]

Hey, I cut my turbo tuning teeth on a turboford. Those guys just unplug the knock sensor and roll. Our sensors don't seam to be as sensative at the ford piece. But still, my dsmlink detects knock only after 4500rpms and 50% throttle.

After I found out where in the rpm range my phantom knock occurred, I havnt had 1 instance of knock retard even winding out my small 16g to 36 lbs/min on pump gas and no injection at all. I also "padded" my 1g knock sensor with a little jb weld in the hole where the mic receives the noise. This seams to dull the phantom knock and only lets through that true knock. And I'll tell you, if you knock enough for you engine to pop you WILL hear it. You may not be able to let off in time, but it is very loud. So the sensor could use a "chill pill" with respect to sensativity. I think having a knock sensor is a good thing. Like you. When it's in its place. But if you pop an engine and didn't hear knock, that's because the first or second detonation event detectable by the sensor is enough to pop the engine and no sensor would have saved you anyway.

We fresh tuners who don't know what a/f ratio yields the most torque, etc. should use our knock sensors. 1-3 knock counts is a good tune, as much as you can eek out of your setup. Those who have dealt with the phantom knock plague begin to take a chance and understand that if the other sensors don't throw red flag then the knock sensor should be null. I mean come on: 11:1 a/f ratio, stock timing curve, and 20 psi on an FMIC on a 16g with injector dutycycle under 80% and a fuel pump upgrade is NOT going to yield damaging knock. If you have a wideband, a logger, and plumbed your base timing; you can do fine with no knock detection at all assuming you know what numbers you should see.

 

[kahl23]

At least with DSMLink its fairly easy to see whats the real deal and what's phantom. Doesn't make it any less annoying though when it happens...

 

[GVR4592]

But anyway, i was taught to tune with no way of measuring knock except inspecting the spark plugs, listening to the engine's overall behavior and even a way to watch the exhaust to look for knock signs in it.

In most cases if you can tell detonation has occurred from any of those 3 things, chances are there was engine damage. If you can look at the plugs and see the silver specks of aluminum from the pistons, obviously there is damage to the pistons.

I mean come on: 11:1 a/f ratio, stock timing curve, and 20 psi on an FMIC on a 16g with injector dutycycle under 80% and a fuel pump upgrade is NOT going to yield damaging knock. If you have a wideband, a logger, and plumbed your base timing; you can do fine with no knock detection at all assuming you know what numbers you should see.

You would be making a lot of assumptions by tuning like that.

Have you guys ever used det cans?

 

[turboglenn]

No, I've have only heard of them. Actually I've been wanting to know what a det can is, but keep forgetting to look it up. I've watched for the 3 signs that you say would have already damaged an engine and found them, backed things off and the motor was fine. Although i never got aluminum pieces on my plugs i watch for speckles of color and small pits in the surface of the carbon instead of looking for metal. Old plugs actually work good for this if you want to test, I'll sometimes stick an old plug on the cylinder that runs leanest because of the manifold design if it's an in-line motor since most V configurations have pretty good manifold design when it comes to equal distribution of air, but i only do this maybe for a pull just to see how things are going.. some may say it's stupid or pointless but it seems to work for me.

I agree that knock sensors are a nice tool no matter how experienced a tuner is, and that's why i stated that my favorite is the J&S, although I'm stuck with an MSD unit for now. I just hate the Mitsubishi one and want people to know that it reacts way, way, way before there's any substantial knock and that i feel for anyone who has to tune around it on a DSM. I've seen the ford guys dsm-onster talks about and think that's just a tad silly, some of the people in that same crowd are the kind that unplug o2 sensors to get extra fuel from their EEC IV ecu's

It was a bad case of phantom knock that led me to want to go stand alone even more, my car would show knock and hold the entire curve back but still slightly advance it after the initial retard at 4500 rpm or so

 

[GVR4592]

Hey Glenn, you might find a lot of useful info over at this site:

EFI University Electronic Fuel Injection Tuning :: Index

There's a couple of threads on det cans and how to make them. It's basically a crushed copper tube bolted to the block with rubber fuel hose attached to it, running to a set of ear muffs. You should try it out.

 

[dsm-onster]

You would be making a lot of assumptions by tuning like that.

If you're not running lean and your timing is stock, then there is only one assumption . Somany tuners in other relms have done this for years. I'm not saying that you shouldn't use a knock sensor in your tuning exercises, but if nothing indicates you SHOULD have knock and you know your boost and setup is what is acceptable, then there is still only one assumtion . I like my knock sensor. But, if the board of sensors dissagree with it, it doesnt have th power to veto.

 

[Turbo Monk3y]

I use dsmlink and tuned for 0 knock on all my runs. This was on my old stock 6 bolt bottom and .63 a/r 35R setup.. Full weight 2g doing 128-129mph @ 28-29 psi and 23 degrees advance with 13.5 AFRs 0 knock 400+ track passes hundreds of steet races and daily driven since it was put together a couple years ago. I've even had the wastegate line come undone 2-3 times logging boost to 42psi and 12-15 counts of knock on one gear pulls. I just sold this motor right before christmas with this exact setup to a local guy and its already up and running fast.

I really don't see the problem in tuning for 0 knock?

 

[turboglenn]

GVR4592... That's a great link, thanks for the info, I'll be all over it tomorrow when i am awake!!

Turbo monk3y.. i never said there was anything wrong with tuning for 0 knock, it's just that i see so many people so afraid of tuning past the knock sensor reading a few counts that they are losing potential power and potential learning experience because they dint' want to go over what the knock sensor wants to see. I'm just disappointed i guess, there's so much more to the spectrum of tuning than balancing everything to avoid tripping the 5 dollar burglar alarm that Mitsubishi calls a knock sensor, and i hate seeing people confined to halting what could be a good tune or a good test procedure because they see some knock.

Without people that aren't afraid to push past the stock ECU and it's venerable knock sensor there would be no great achievement in DSM tuning, I'm just trying to keep peoples minds open and looking for something else besides pleasing the knock sensor gods, or just setting their ECU to the "industry standard" in AFR and timing curve values.

In no way do i claim to have or know the next great tuning secret... i wish i did, but face it, at some point, some one is going to think outside the box enough to make significant horsepower gains on the 4g63 if not all motors, while playing with a fuel injection system at some point. I just hope I'm still alive to witness or learn about it when it happens...that's the goal of my post, to keep people on their toes and to keep them thinking. I hope it works

 

[wishihadatalon]

I completely agree with this thread. Here are a few reasons. I see far too many people who use a factory knock sensor and rely on it after putting forged internals into their motor. That knock sensor is specific to the factory internals and the sounds that they make. When you add different internals made from different materials, all of the variables are different.

I use megasquirt with the stock ecu to monitor knock. I don't really use it to tune, because if I feel that I am pushing the motor really hard, I will pull the plugs out and inspect them. But if I am see that the knock sensor seems to be acting different from before, I will take a look and see if anything is different. FWIW I have had the stock sensor display 43 counts at peak tq in every gear and have never had a problem with my motor.

And I agree that the J&S systems is the best out there. Individual cylinder control is very nice. Lets you keep making power in the cylinders that are working, while keeping others safe, where the stock sensor pulls back timing for all 4 cylinders. I myself will probably just end up with a set of cans and probably trying to dyno tune the car to find the most power that I can from my setup while being safe-ish.

 

[wishihadatalon]

I use dsmlink and tuned for 0 knock on all my runs. This was on my old stock 6 bolt bottom and .63 a/r 35R setup.. Full weight 2g doing 128-129mph @ 28-29 psi and 23 degrees advance with 13.5 AFRs 0 knock 400+ track passes hundreds of steet races and daily driven since it was put together a couple years ago. I've even had the wastegate line come undone 2-3 times logging boost to 42psi and 12-15 counts of knock on one gear pulls. I just sold this motor right before christmas with this exact setup to a local guy and its already up and running fast.

I really don't see the problem in tuning for 0 knock?

13.5:1? Were you tuning a NA honda?

 

[green92gsx]

After you get a good base line tune with knock counts it can really help when you start cranking the boost up. I wouldn't say disregard it by any means.
Even with stock internals I noticed my engine got somewhat noisier with the more power I made.

 

[turboglenn]

13.5:1? Were you tuning a NA Honda?

That was my fist thought when seeing that AFR, you'd have to be real conservative on timing at 13.5:1 during WOT.

wishihadatalon and green92gsx are both seeing what I'm getting at i think .

keep the discussion going!

edit: when i spell cheked this iwishihadatalon came out to be warmheartedly

and green92gsx wanted to be replaced with greengages

 

[SBstar]

I totally agree with you turboglenn, although my knowledge of tuning is very limited. Having said that however, for most of the members on this site it is wiser to tune very conservatively as they wish to drive these vehicles every day and really aren't looking for the highest hp figure or best E/T possible out of their setup, as long as it's decent. For those looking to push their vehicles to the peak of performance it would be very wise to "ditch" the stock ecu and knock sensor and move on to a standalone system and use a knock sensor such as you described.

 

[FonZ454]

Has there been any *proven* methods to make the 1g knock sensor less sensitive? I've heard of nylon washers, softmounting, etc. I know it should be just snug in the block, but theres got to be other ways. The JB Weld idea... I don't know what you get out of that?

I've had many runs down the track on pump gas, 20ish psi, with dsmlink reading 4-7+DEGREEs of retard. I don't know what that would work out to pocket logger "counts" but that's a good amount and the car is still the same as ever. And I know that those times the car wasn't actually knocking (or bad I should say)... mid 10's afr's, conservative timing, etc...

There are tons of variables to get knock count down, but when the sensor picks up every noise our noisy motors makes, it makes it tough to tune it all out!

My friend was into Turbofords... I always thought he was funny when he'd say "disconnect your knock sensor, you'll gain some power"... hah silly Fords

 

[turboglenn]

I totally agree with you turboglenn, although my knowledge of tuning is very limited. Having said that however, for most of the members on this site it is wiser to tune very conservatively as they wish to drive these vehicles every day and really aren't looking for the highest hp figure or best E/T possible out of their setup, as long as it's decent. For those looking to push their vehicles to the peak of performance it would be very wise to "ditch" the stock ecu and knock sensor and move on to a standalone system and use a knock sensor such as you described.

That's basically touching on one of my main points. My last engine had a full stand alone put on the car at 24k miles, the motor didn't pop until one night at the track when i borrowed a faulty wideband and went too lean and popped the head gasket ( at around 92k miles ). Upon tear down there were no signs of wear or failure due to long term detonation. It's all in the tune, my car went close to 75k miles with no knock sensor, at least 40 different tunes from part upgrades to just getting a little more power out of it or trying different combos of timing and AFR to get the best result in the end. The car has been my DD for almost 10 years now and the car has NEVER been babied to try and conserve it's parts, i beat the piss out of it, i replace what needs replaced when it comes time, and all I've ever really needed was basic maintenance and she is still in better shape than a lot of peoples DSM's that i know. The point being you can make a completely reliable daily driver on a full stand alone and still not have the worry of the Mitsubishi's stock knock sensor a.k.a. "the drama queen" .

I guess what i'm saying is that i've had my timing locked at anywhere from 18-20* on pump gas under WOT and full boost (which is less than the full boost and timing i use on race gas) were talking 17 - 20psi at 18-20* timing, and i've never had a problem with detonation hurting anything in the top end, or even seen signs of long term detonation.

Now i have experienced issues with medium load pinging around 2-3k while lugging the motor around neighborhood streets, so i lowered the timing a bit in those areas and revamped the entire curve to smooth in the changes, and it's been like butter ever since.

Now i know there's a lot of poeople that live in places where you just can't get away with taking out the stock ECU or even modding the car much around it due to emmisions testing and inspections. I'm trying to find a way to get ready to live in such a place and would love to find an ECU that's OBD-II compliant, completely tunable and has either A.) no knock sensor..... or B). a provision to "filter" or "supress" what the knock sensor picks up or what the ECU does with the info from the knock sensor. It's these circumstances that have me pondering the next great advancement in stand alone ECU's... the OBD-II compliant stand alone !!!!!!!!!!!! some day, i hope

 

[mavisky]

Anything under the knock sensors limit of 7 (before it pulls timing) is perfectly fine in my book. Even if it goes over by a bit, the ecu pulls timing back all the same so it's not like you're damaging it. People who tune for 0 knock are usually leaving alot on the table. Then again I'm not making enough hp to hurt anything anyways

 

[GVR4592]

I see a lot of damaged engine's in the near future.

 

[turboglenn]

^^that depends on who reads it, how they interpret it, and what they do with the information

 

[Black95TSIawd]

Anything under the knock sensors limit of 7 (before it pulls timing) is perfectly fine in my book. Even if it goes over by a bit, the ecu pulls timing back all the same so it's not like you're damaging it. People who tune for 0 knock are usually leaving alot on the table. Then again I'm not making enough hp to hurt anything anyways

On the contrary. Timing is pulled immediately once knock is detected.

 

[Turbo Monk3y]

13.5:1? Were you tuning a NA honda?

No just a fast 4g63.... I wish I could see more people stretch the stock shortblocks for as long as some people can. But they just blow them up because of their horrible tuning abilities. I bought that motor @ 60K and when I sold it last month I had 110K on it. Still runs like a champ in another locals car...

I never had a problem with phantom knock, I get 0 knock when I have my tune perfect.. If I did not run out of fuel pump(walboro 255 not the high pressure version)and injector. The car would have done 132+mph. But thats in the past. I have a 2.4L + t67 now. I'm just saying Not everybodys problems are a knock sensor. I mean This is tuners for crying out loud not NABR. I can guarantee your pretty much in a .001% catagory that runs Haltek here.. And you may get like 5-10 guys here than run AEM and thats it too... So the mitsu knock sensor will save 90% of this boards motors if you follow me...

 

[turboglenn]

Yea, i know i'm the minority as far as my ECU, but this is out there for anyone to read. And i'm hoping to park some thoughts or ideas, and maybe catch up with some other people that are running full stand alones to swap ideas with and keep the learning alive. By doing it in this public forum puts it there archived for less experienced pepleto read and learn from. So even though it's the lesser count of people this thread applies to , there's no reason not to have it out here for discussion, follow me?

I just like to start threads that get people to thinking and learn from pooling together thoughts and info from numerous sources/tuners. It's not like there's anyone in town to discuss tuning on a higher level than AFC and chips, so i'm on here because i don't get into many forums ( i admin 2 others) so this is the only car forum i'm on and i just post everything i have about car tuning that's DSM related here. If i post about a 4 wheeled vehivcle in depth on one of my motorcycle boards i might get over-thrown