How do you make a "det can"

[turboglenn]

in sa few threads, when talking about no knock sensor on my setup people have mentioned using a det can. I always so that i've only heard of tehm but have no idea what theyare, then i ask them to explain and no one ever does.

So i'm asking, does anyont know how to make one of these things and can you explain how it's used to me?

 

[turbosax2]

Quick google search came up with this:

EFI University Electronic Fuel Injection Tuning :: View topic - Going to buy a knock sensing device for dyno/road. Which?
Honda-Tech.com: Forced Induction: Det Cans

Alright basically you need to get about a 3/8" brass pipe about a few inches long. You need to crush one end completely flat so there is a seal and no sound can get out. Then you construct some way to attach a real long hose line to it(it needs to be a very thick rubber line like fuel line or else it wont work). Then you T that line into 2 seperate lines and run them to a pair of ear protectors(the things that look like head phones). You cut a hole in each side and shove the tubes in there and glue them in if you have to. The Tubes must be air tight. Then you just drill a hole in the brass pipe and mount it somewhere on your block. I chose to mount mine on the front of the block near cylinders 3 and 4.

 

[turboglenn]

Damn, i can't even google worth a damn, i got everyhitng down to the patent on "det cord" but couldn't find anything tuning related

All i found were a few pics of it in the enginebay, and a bunch of talk abotu them but no "how to make a det can" that's more of what 'm looking for i guess..maybe i missed in while skimming through near 5 pages of honda chatter , and the EFI link i couldn't find anything but a box you can buy ...I feel tarded on the net sometimes

I would just like to find a parts list and a simple how to

Maybe i'm too lazy to search through forums that i'm not signed up on for hours*shrugs*

The engien bay part looks easy to make, i just want to know if there's special materials that work betteer as far as the tubing end and the hose. and what does teh "listening end" of it look like?

Found this interesting link, i wonder how it performs, i hear good things about it on a volvo forum while searching for a how to on these damn things

Engine knock detection and indication for all vehicles

Not bad for the price!

 

[GVR4592]

EFI University Electronic Fuel Injection Tuning :: View topic - Looking for detonation

 

[turboglenn]

Awesome thanks, I'll build one this weekend most likely, but i tihink i am going to order that "knocksense" for ~60 bucks for a stand alone knock sensor that can stay in the car, it might be worth it. I'm waiting to hear back if they've ever tested one on a 4g63 before i order though.

 

[GVR4592]

Get a small piece of copper pipe, crush one end in a vise and drill a hole in it and attach to your block. Attach a good length of rubber hose(fuel line or whatever) to the pipe and connect the other end to a set of earmuff's(drill a hole, and rtv the hose into the muff. You can get a t-joint and split the hose so you have sound going to both ears, but I don't think it's necessary.

 

[GVR4592]

THE KNOCK BOX - Knock sound recordings

 

[Defiant]

Any good det job starts with C4. Much more is always much better.

I don't know if this could affect your little project:
"I can't find instructions on how to wire up a knock LED! Where are they?

Many of the older pages referring to the poorly-named 'knock LED' modification are now gone. Any new ones will be found at faqs.dsm.org.

If you can't find any instructions on how to do this mod, don't worry too much. The 'knock LED' does not really measure knock. The author of these pages would like to think that the knock LED FAQs faded away because DSMers in general realized just how awesomely useless and misleading this modification really is.

For more information on what the knock LED will (not) do for you, please see "What is a knock LED?" in this FAQ. If you really feel you need one, use the results of this search to help find some current pages.

The Last Word: Don't waste your time.

Left arrow. Don't see frames? Click here! Submit new information now!

How does the [DSM] knock sensor work?
Can you hook up an [LED/display/indicator] directly to the knock sensor? Will it work?

No, it will not work.

First of all, the knock sensor for a DSM engine is nothing more than a microphone. It picks up engine noise - all of it. There is no signal processing or filtering. The output signal is difficult to interpret, to say the least. It is not possible to hook up an LED, DMM, digital display or any other form of indicator directly to this signal.

The ECU is responsible for processing this signal and getting useful information from it. The results do not exist outside the ECU memory. So, to measure knock as the ECU does it would be necessary to duplicate the ECU's signal processing algorithms.

To make things more interesting, the ECU only 'listens' for knock in certain portions of the engine cycle. So timing would have to be known as well. A short, comprehensive explanation of some of the difficulties can be found in this post by John Hopkins.

It is far easier for most people to simply purchase a datalogger or Pocketlogger. These instruments will read the correct knock sums directly from the ECUs memory.

The Last Word: Ages ago, there was a way to hook up an LED to the knock sensor "microphone" using a threshold detector. The LED would light up - sort of - when the signal from the microphone got "loud" enough, which supposedly indicated knock. Cute, but not necessarily a good idea. "
From
1000 AAQ - Gauge questions

 

[turboglenn]

I don't want a knock LED, as a matter of fact there's no knock sensor on my car period, so a box to listen to it, an LED, or a logger won't do me any good, my haltech doesn't have a provision for a knock sensor so i have to find other wyas to monitor it. The MSD box i use on the dyno is too bulky and is set up to be "universal" so i can tune a wide range of cars, if i install it permanantly into my car it would be okay, but i'm really not too pleased with it's performance on DSM's. So the ear mufs det can should be fun to play with a little, but i'm still saving for a J&S after i get my cams and stuff out of the way this month.

 

[TurboTiger]

You'll find quite a few people using the knocksense in the megsquirt crowd. I've got one hooked up to the stock 1g dsm knock sensor.

 

[aero_sallee]

Its amazing what you can hear with one of these simple det cans. Excellent tuning tool for anyone, especially someone on a standalone without knock sensing IMO.

 

[turboglenn]

Its amazing what you can hear with one of these simple det cans. Excellent tuning tool for anyone, especially someone on a standalone without knock sensing IMO.

DO you just run the tubing up through the back of the hood, then open the window and run it to the ear muffs? I wouldn't think you'd go through the fire wall with it, but i guess you have to get it inside the car some how.

Anyway, i cna't wait to build one, but i want to find out the perfect lengths, OD of the copper pipe and what if any fittings are best for transferring sound to hook it to the hose with. Just want to make t he best one possible when i do make one, as i imagine it will get years of use on a couple hundred cars minimum if i like how it works.

I go to the dyno on friday at 1 PM, so i'll use teh MSD knock sensor for that, but i do want to get something to use for either rough tuning or when tuning on the street.

As soon as i get my first government paycheck i'm ordering a J&S for my car it connects from the between the ECU and power transistor and is programable to pull spark and you can "filter" junk noises out wuth it as well. IT's just pricey, i think after all these years they are still around 500 or above for the mitsubishi tuned unit with a mitsu "race motor" tuned sensor that can differentiate between knock and other engine noises associated with running pistons slightly loose and other things like that, or so i've been told by them anyway

 

[GVR4592]

J&S makes a great product, you won't be disappointed.