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Discussion Starter #1 (Edited)
So I've been playing with some more aggressive basemaps lately. Since
my exhaust is a little loud and you can't trust just checking for detonation
at idle, I figured I had to do something about it. I also had to do something
about it for free because I don't have the money to be blowing on crap.

I've always checked my car with a doctor's stethoscope. What I needed to
do was lengthen that so I could drive and listen at the same time. I found
some rubber tubing that was about the same diameter as the stethoscope's
tubing in the corner of my garage. it was new in the plastic but yellowed. I
think it came from an old aquarium setup that never got used. -




I stuck the "ear" or resonator on one end and sat it in the engine bay.
Then, I had to start running the other end through my fender and into my
door jamb.

Resonator end in the engine bay -




Starting to run the tube through the top of the fender and routing it into
the engine bay -




Then by lightly pulling, I was able to get the right amount of slack in the
cabin. You need enough to be able to move freely and drive -




For the first experiment, I used duct tape (FTW!) to attach the two
ends of tubing. I have a slightly more advanced technique that looks better
aesthetically, but duct tape works just fine as pictured -



The best place that I found for listening is to the right of the exhaust
manifold. However, your experience may vary because there are lots of
people who have kept their AC or Power Steering. For those people, I have
another technique I'll show later on. The "sweet spot" as pictured -





Part 2 Below
 

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Discussion Starter #2 (Edited)
Now, the "ear" or resonator isn't going to hold itself up. This is where
I ran into a slight dilemma. After staring at the block for awhile, I came up
with a solution. I used two of the original AC bracket / torque mount bolts
and fabricated a small bracket out of aluminum. Then I cut two pieces of
rubber hosing to size to act as grommets. Now, these grommets are especially
important to use with bolts when making pressure. A doctor doesn't just push
the stethoscope against your chest with 20 pounds of force. The "ear" or
resonator has to be able to resonate. The rubber grommets are especially
helpful when using bolts because you can adjust how much pressure is being
used to hold the resonator against the block.



Here is the bracket setup -



Here is the bracket setup installed and adjusted with the amount of pressure I
found suitable to my needs -




Here is the whole setup in the bay -



Start car and listen for detonation or drive and listen for detonation. The
best part of this is that you can drive your car in real conditions while listening
to your motor instead of just listening to it at idle or by giving it gas from the
throttle body.

First ten second test. It works! Make sure there aren't any kinks in the hose and
the sound will be much better. It's not as good as say, a 1 1/2 foot stethoscope
against the block. The length does lose some quality. But it's still very good. You
can hear the engine's natural "clicking" similar to the sounds here -
The Knock Box
The main difference between the stethoscope and the Knock Box recordings
is ambient and other engine noises getting into the stethoscope. It's very audible,
though.




For those of you without your AC/PS removed, I found that clay/putty can
easily by attached to the ear like this. Keep in mind I haven't done a long run
with this to see what heat does to the clay. I'd do short runs or experiment. -




And attach it to anywhere on the engine. I put it in the same spot to test it out.
After doing so, I found that a nice ring of clay that goes around the entire diameter
works better and keeps out outside noise better than two pieces on each side -

Attached -



If you're listening to your head, I found that attaching it to the rear/intake side
gets the best sound. In my first experiments, I attached it to the back, passenger
side and it resonated excellent. Here's one of the first pics. Duct taped -




Also note the kink in the hose. This hurt the sound quality big time. When
I caught it, I trimmed that piece out and reconnected the "ear"..much better sound.

This stuff was free for me. When it was bought, I think the hose costs $2-$3 if it
was, in fact, aquarium hose and the stethoscope was about $4 according to my
fiancee. That's $7.00 tops for peace of mind. Well worth it.

Happy engine tweaking with Doctor Det!!

-Jay
 

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Discussion Starter #5
Rep for that, never even thought of doing that.
Thanks, man. I left quite a bit of slack for routing purposes and dispite
the length, the sound didn't dissipate all that much before reaching the
ear buds. I actually routed it through the entire fender this morning so
when I'm not using it, the resonator end rolls up and tucks behind the
headlight. The other end goes under the seat.

not bad man. i would rep you but just did...

i think ill wait for a nice day and try this out.
You'll be surprised when you find the sweet spot on your block and
can hear everything.
 

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Discussion Starter #8
Good stuff, Jay. Once I get into the tuning aspect, I"ll be doing this. Rep.

Edit: Bah..+rep after I spread some. lol
Thanks, mang. I'm going to be using it in about ten minutes as I just
finished a map I've been slowly tweaking for a while..

very nice right up
Thanks, man. I'm going to mess with the clay/putty that I was using
later and see what else comes out of it. I realize that most people won't
be able to use the bracket I made due to still having AC/PS or
whatever down there. Through messing with it, I'm hoping to
come up with something that's a little more reliable as far as keeping
the "ear" glued to the block. Not only for other people, but I'd like to
attach it to different areas of the head as well.
 

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Discussion Starter #13
Thanks, guys. I've actually used my "Doctor Det" more in one day than things I've
bought in the recent past.

I tested a map out for about 30 minutes a little while ago. Everything was really
clear. Out of experimentation's sake, I rolled some putty/clay into a thick string
and "insulated" the edges where the "ear" meets the block. It actually did a lot
for cutting out ambient noise at higher RPMs. It works either way..but there's
another tip for the night.

...just remembered my grandmother is a nurse. Im'a see if she can get me a stethascope for this. lol
Hah! My fiancee is in nursing school. Score! I've got a few of them around the
house.
 

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heh nice, i have similar setup with stethoscope on the listening end is a ground cable clamp(like the clamp on the end of the negative terminal cable that bolts to the frame) then just stuck a barbed fitting in it then put a bolt through the other end and bolt it to the engine.
 

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thats not an ac/ ps mounting point.......thata were your driver side lower torque mount should be.....

..although i think the ac bolts into the torque mount?


nice right-up non the less +1 rep for you
 

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thats not an ac/ ps mounting point.......thata were your driver side lower torque mount should be.....

..although i think the ac bolts into the torque mount?


nice right-up non the less +1 rep for you
Jay is baller. He doesnt need a torque mount. :lol:
 

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very good write up/idea... rep'ed
 
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