Author Topic: DB KILLER or HP KILLER (Read 3568 times)

Steve in Sunny Fla · « **on:** June 13, 2018, 04:13:43 pm »

I've told many folks and posted previously how DB killers in slip ons are really HP killers. Well here you go, these runs are 15 minutes apart, and the only change was to remove the DB killer from the Delkevic slip on. From a fellow COGGERS bike, runs done 5 days ago.

Steve

Wolverine · « **Reply #1 on:** June 13, 2018, 04:16:17 pm »

what's a DB?

EZ · « **Reply #2 on:** June 13, 2018, 04:21:59 pm »

Quote from: Wolverine on June 13, 2018, 04:16:17 pm

what's a DB?

Decibel...

Steve in Sunny Fla · « **Reply #3 on:** June 13, 2018, 04:22:51 pm »

Quote from: Wolverine on June 13, 2018, 04:16:17 pm

what's a DB?

Decibel. I think most / all of the slip on manufacturers have some method of quieting their mufflers. Usually a reduced output restriction. Commonly referred to as DB (decibel)killers.

My C-10, Shoodaben, lost a measured 10 HP with the same setup. I ended up using a TI muffler from a stock zx12, with no power loss. "Stock" doesn't always mean "bad" . Steve

Wolverine · « **Reply #4 on:** June 13, 2018, 04:24:49 pm »

Thanks Steve, I knew what a db is as a measurement of sound, I was more looking for context as you provided.

So you are stating that slip ons are robbing horsepower?

Mine (CSone) sounds so sexy though

Quote from: Steve in Sunny Fla on June 13, 2018, 04:22:51 pm

Quote from: Wolverine on June 13, 2018, 04:16:17 pm
what's a DB?

Decibel. I think most / all of the slip on manufacturers have some method of quieting their mufflers. Usually a reduced output restriction. Commonly referred to as DB (decibel)killers.

My C-10, Shoodaben, lost a measured 10 HP with the same setup. I ended up using a TI muffler from a stock zx12, with no power loss. "Stock" doesn't always mean "bad" . Steve

Steve in Sunny Fla · « **Reply #5 on:** June 13, 2018, 04:27:36 pm »

Quote from: Wolverine on June 13, 2018, 04:24:49 pm

So you are stating that slip ons are robbing horsepower?

I'm not stating anything that's not supported by an actual measurement. The issue isn't the slipon, the issue is the DB killer. Steve

strum · « **Reply #6 on:** June 13, 2018, 05:03:33 pm »

Interesting. I have a Muzzys and i like the sound but wouldn't not mind a little more volume. If I can get a little added HP.(like I need it lol) Thats a plus.
Of course with out a dyno i wonder if i would know the diff?

SVonhof · « **Reply #7 on:** June 13, 2018, 06:24:27 pm »

I have a Two Brothers Titanium with the DB reducer installed. I don't like waking up all the neighbors when I leave the house at 4:45am.

Maybe I need to remove it and check the noise level...

cuda · « **Reply #8 on:** June 13, 2018, 09:30:05 pm »

!3 HP

You must have put some 87 in to make all that power, ECO mode...

Steve in Sunny Fla · « **Reply #9 on:** June 14, 2018, 12:56:59 am »

Quote from: cuda on June 13, 2018, 09:30:05 pm

!3 HP

You must have put some 87 in to make all that power, ECO mode...

it's not even my bike, and we didn't change anything between runs except to remove the baffle. The bike is an 08 or 9, no eco mode. 3 guys watching, 2 of them COG members, not including me.

I was wondering when someone would point out that it's a 13 hp difference... people will pay a lot of money for a 13 hp difference.

Steve

cuda · « **Reply #10 on:** June 14, 2018, 01:42:20 am »

Does the older bike have Cats ?

I have duals so it would have less restriction with the inserts ,

I drilled about 10 holes in each insert , and it really made it much louder , so I filled them with red RTV .

smokin · « **Reply #11 on:** June 14, 2018, 02:09:17 am »

So Steve the stock muffler even though its ugly seems to be very well designed in terms of killings noise/db without to much loss of power?
Considering there is only a small power gain say compared to a good slip on with the mountain runner flash.
True or not?

Bruiser · « **Reply #12 on:** June 14, 2018, 05:35:12 am »

I have the 18" Delc, and really don't notice a diff in Db with or without the baffle

ghostrider990 · « **Reply #13 on:** June 14, 2018, 12:19:43 pm »

Totally 100% agree with steve's obvious charting.

I've experimented with adding my DBkiller inserts on my Dual Akra's, and can FEEL a very obvious difference
each time I do it, no matter what flash I'm running. Stock was the same.

The only time the extra noise bothers me, is the RARE occasion I ride around my neighborhood without earplugs in.

No DBkiller inserts for THIS guy!!

gr

khager01 · « **Reply #14 on:** June 14, 2018, 11:26:20 pm »

Thanks for the post Steve. That's quite a difference! $:-\$ More than I would have thought, no DB killers for me. I wear earplugs anyway for the windnoise.

Wolverine · « **Reply #15 on:** June 14, 2018, 11:56:42 pm »

I have the CSone exhaust so don't see how to pull the baffle out of that unless someone knows a way?

Steve in Sunny Fla · « **Reply #16 on:** June 15, 2018, 01:31:21 am »

if you can see a 2" diameter hole through the muffler, it doesn't have a restrictor. Steve

Wolverine · « **Reply #17 on:** June 15, 2018, 01:36:13 am »

That would be what I have.

Took the slip on off for grins, man that sound reminds me of the 80s running a kerker pipe on my GPZ1100

😁

Quote from: Steve in Sunny Fla on June 15, 2018, 01:31:21 am

if you can see a 2" diameter hole through the muffler, it doesn't have a restrictor. Steve

Jim Snyder · « **Reply #18 on:** June 15, 2018, 02:49:23 am »

If you have a Delkevic muffler the baffle can be easily modified to have quiet and power both. As soon as I get back from the national I will post the picture of the mod one more time.

Daboo · « **Reply #19 on:** June 15, 2018, 04:48:57 am »

I have to admit that although I get on the throttle a bit once in awhile...most of the time, I have a tendency to ride like the old man I am. I keep the rpms down in the lower end of the rpm range. Even if I'm not feeling like an "old man", I am boxed in often by cages that don't move all that fast. So I often find myself riding in the lower rpm range again, instead of keeping the engine to the redline.

So I looked at the chart and decided to disregard the redline area and looked at what the benefit would be at the lower rpm range where I'd probably spend most of my time at. I'm guessing at about 5500 rpms, there's maybe 5 hp difference between the baffled and non-baffled horsepower figures. And less at about 3000 rpms.

I doubt I could feel a difference.

Now is the time you start throwing rocks at me...

Chris

RoadKillHeaven · « **Reply #20 on:** June 15, 2018, 06:46:48 am »

The HP increase is where most riders don't venture under normal conditions.
There is, however, difference in daily-use powerband, but it isn't enough of difference to notice, but noticeable enough to be pulled over by PoPo for excessive noise pollution. And get stink-eye from people around you for being "loud pipes save lives." douche.
I had a neighbor who has screaming eagle pipes on his bagger (not Harley). It was beyond obnoxious and illegal where I live. He had to change exhaust. Everyone around was glad he did.

ANTHONY · « **Reply #21 on:** June 15, 2018, 02:22:26 pm »

I am running the Delkevic 13" oval can and have been for about a month with the baffle in till I read this post yesterday. Steve is spot on with results, I don't have a dyno to see actual numbers but i spent a good 4 hrs yesterday going out using a timer app doing roll-ons in several gears and I was quicker from any speed and the throttle sensitivity and response with baffle out was instant where as with it in there was lag. Anyone running this exhaust - KEEP BAFFLE OUT!!!

Daboo · « **Reply #22 on:** June 15, 2018, 02:34:59 pm »

Quote from: RoadKillHeaven on June 15, 2018, 06:46:48 am

The HP increase is where most riders don't venture under normal conditions.
There is, however, difference in daily-use powerband, but it isn't enough of difference to notice, but noticeable enough to be pulled over by PoPo for excessive noise pollution. And get stink-eye from people around you for being "loud pipes save lives." douche.
I had a neighbor who has screaming eagle pipes on his bagger (not Harley). It was beyond obnoxious and illegal where I live. He had to change exhaust. Everyone around was glad he did.

There's a trend going on across the country to ban motorcycles, any motorcycles, from housing developments because of noise.

Wolverine · « **Reply #23 on:** June 15, 2018, 02:36:54 pm »

Good thing I don't live in a development...

as a side bar it's why HOA's and the such are ridiculous, expanse of power inevitably happens

Colt45 · « **Reply #24 on:** June 15, 2018, 05:51:05 pm »

My Duc has a 50mm (+5mm) Termignoni full exhaust with 2 glass-packed mufflers. Stupid loud. I bought a set of db Eater like this:

It cut the noise ~10 dB, half as loud. I don't doubt it costs HP, but I can't feel the difference and have not tested it on a Dyno. This design is about as good as such a flow restrictor will get (a stepped reduction).

I rode it to an evening concert series downtown that is popular with riders and bikers. Without the dB eaters is was SOOO much quieter than the other twins with open exhaust, I took them out.