Zoom zoom BoOm x2.

[TurfBurn]

No offense but you are giving people bad advice for tuning the MPI.

Massive retard above rpm's you plan to use is not bad advice though.... it is a good way to have a preventative step in place.. I'd go the opposite and cut all fuel completely above the rpm you intend to use. At the least I'd make sure the extra injectors are off at any rpm you wouldn't want to be reaching.

 

[TurfBurn]

I did just build a simple circuit this weekend that makes it so I can plug into the stock knock sensor and listen with headphones as to what is happening on the block... I'll be giving it a try tomorrow night. I already tested it and know it works, now I'm just curious to see what I do and don't hear!

 

[Focus]

make sure the extra injectors are off at any rpm you wouldn't want to be reaching.

Exactly. Set your own rev limiters!

 

[Brian MP5T]

I did just build a simple circuit this weekend that makes it so I can plug into the stock knock sensor and listen with headphones as to what is happening on the block... I'll be giving it a try tomorrow night. I already tested it and know it works, now I'm just curious to see what I do and don't hear!

(poke)

 

[TurfBurn]

(poke)

I'm guessing you are after more info???

I'm basically hoping to correlate what I hear on the block against what the JandS shows... and to make sure the JandS is being effective (if it is, I shouldn't really hear anything... even if it does light up saying it is stopping knock). That way I also have extra assurance my motor is safe. I have a pair of noise canceling headphones (20 bucks at Wal Mart.. Maxell brand.. ) so I can cancel out all the car, road, and exhaust noise and concentrate on just what i hear from the block.

The circuit is simple and takes about 12-15 dollars worth of parts from Radioshack. It's a simple 200 gain amplifier based on the LM386 National Instruments chip. If you look up an LM386 datasheet the circuit is printed right in the datasheets.

I can also tell you that the knock sensor is a "tuned" sensor... you don't hear a lot of noises and the like with it.. it's not a true "microphone" you really only hear vibration and impact with it from the little bit of messing around I did with it tapping it against the metal on the car when I was testing the amplifier.

I'll know more, and maybe produce some recordings for you guys in the next few weeks... have other projects I have to tackle though as well right now.

Later.

 

[igdrasil]

I did just build a simple circuit this weekend that makes it so I can plug into the stock knock sensor and listen with headphones as to what is happening on the block... I'll be giving it a try tomorrow night. I already tested it and know it works, now I'm just curious to see what I do and don't hear!

It works, detonation is very very noticeable thru the microphone. I used a cheap ebay spy ear and it works. Theres some minimal pinging you will NEVER notice without it...

...and its also very loud in the headphones.

You will also detect missfires that are not heard on the exhaust.

 

[TurfBurn]

It works, detonation is very very noticeable thru the microphone. I used a cheap ebay spy ear and it works. Theres some minimal pinging you will NEVER notice without it...

...and its also very loud in the headphones.

You will also detect missfires that are not heard on the exhaust.

Where did you mount your microphone? Right now I'm using the stock knock sensor as my mic.. it seems to be a tuned mic... so we'll see... the sensor for the JandS is in the proper position up by the head on the back of the block... the stock sensor I'm now moving to the only open spot which happens to be right by the crank flare about 2/3's of the way down the block... I'm going to add a second channel to my amplifier after a while and then I'll add a condensor mic up under the intake manifold... then I'll have the knock sensor on my right ear, and the condensor mic on my left ear.. then I should be good.. that with the JandS and I should be able to tweak my timing pretty safely.

 

[TurfBurn]

did you literally buy one of the spy ear 'listening device" packages they have on EBay for like 99 cents.. little clear plastic thing with two ear phones and runs on watch batteries??? And again then my big question is where did you mount it.

 

[igdrasil]

Yeah, that same .99 thingy, it works, I took the mic and glued it with hot plastic glue on the knock sensor. Also tested it on the T clamp for the oil feed.

I heard some pinging and after pulling some degrees it disapeared. The sound is more like a loud clap.

I also figured out that when its running lean, engine noise overall is louder, like you could hear the combustion louder, as you go rich, combustion noise fades out.

 

[TurfBurn]

Well at 99 cents and it working that well everyone should be hot gluing those things to the back of the knock sensors!

 

[Bigg Tim]

Where did you mount your microphone? Right now I'm using the stock knock sensor as my mic.. it seems to be a tuned mic... so we'll see... the sensor for the JandS is in the proper position up by the head on the back of the block... the stock sensor I'm now moving to the only open spot which happens to be right by the crank flare about 2/3's of the way down the block... I'm going to add a second channel to my amplifier after a while and then I'll add a condensor mic up under the intake manifold... then I'll have the knock sensor on my right ear, and the condensor mic on my left ear.. then I should be good.. that with the JandS and I should be able to tweak my timing pretty safely.

I thought it said to put it on the lowest point on the block? Why up by the head then?

 

[TurfBurn]

I thought it said to put it on the lowest point on the block? Why up by the head then?

I've heard low on the block as well... I said "proper location" because that is where I pulled the stock sensor from. I'll email John at JandS and see if he has any comments and maybe I'll move things around... to me putting it up high makes the most sense as most detonation will occur when the pistons are near TDC, so I'd think you'd want to be listening right next to where it would occur... so that's my thought process on that.

 

[peepsalot]

and contrary to popular belief.. they go DOWN during detonation.

WHA?! I should be wiring up a wideband and EGT soon, and plan to do some road tuning once they are set up.
Now I don't even know how to read my EGT gauge.

From what I understood before, you get a good idea of "normal" operating temps while driving and if it ever goes above normal, then there is a problem going on. What is "normal" could vary greatly depending the placement of the sensor.

So you are saying that on a hard run I should watch for the EGT to dip, and not rise?

 

[TurfBurn]

WHA?! I should be wiring up a wideband and EGT soon, and plan to do some road tuning once they are set up.
Now I don't even know how to read my EGT gauge.

From what I understood before, you get a good idea of "normal" operating temps while driving and if it ever goes above normal, then there is a problem going on. What is "normal" could vary greatly depending the placement of the sensor.

So you are saying that on a hard run I should watch for the EGT to dip, and not rise?

Yes, it will potentially dip.. but EGT gauges are SLOW... so you'd be in seriously deep crap before it's show up...

Just think about the fact that detonation is early/rapid combustion.. combustion completes sooner... so there would be more coolign less continuing combustion when the exhaust valves open... so the temps of what comes out would be less than what you saw normally.

Normal does vary a lot on sensor placement.. and the only thing you really get from EGT is if you are going lean, or if you are overheating your valves or turbo... I'm running an iconel bladed turbo now with special exhaust valves so I can cook the living crap out of both without any issue...

basically helps you keep an eye on overall engine health and during a race lets you know if you are starting to work it a bit too hard...

 

[TurfBurn]

I'd do like Igdrasil did, and go buy one of those "spy ear" things and glue it/strap it to the back of the knock sensor.. it'll give you a really really good indication as to what is going on in the motor and you'll be much safer that way than anything else.

 

[JDM Sam]

if u put the graph at 8krpms doesnt that limit ur resolution since 1500rpm wont be used unless somethings afoot?

You dont want the resolution to go beyond the RPM Range you are using.

 

[JDM Sam]

I guess that would have been a good question to ask like 3weeks ago. lol.

You mean 1-1.5 degrees per psi past the stock boost level? I always thought the timing curve was pretty conservative as it was on the MSP.

Your car is flashed and at your psi level you should have had at least -15. Flashed ECUs have at least 10 degrees more advanced across the map. It's safe to say too much timing played a role in your blown motor.

 

[igdrasil]

You dont want the resolution to go beyond the RPM Range you are using.

why not? u dont know what will happen there...what happens if you accidentally down shift @ high rpms!!!

 

[BlkZoomZoom]

Fsd7-13-65mm

 

[acidbug]

wow man..that sux to see...how she blew...

chas