Bike dynoed wit and w/o dB-killer

[R1000]

Here is a Dyno curve that compares the Busa 08/R-77 with and w/o dB-killer. The readings are a bit low on the specific dyno, but the difference with dB-killer can be seen. The dB-killer takes out about 10 hp on high rpm, but it also reduces the power are a bit down and makes the curve less linear. The bike was dynoed with the R-77 map on www.powercommander.com

The lower pic is a compare with the dyno curve for my previously highly modified Blackbird. The Busa is on top

 

[Busa08]

Dyno's are nice, but get it on the TRACK numbers are better!

 

[R1000]

I know, the purpose was only to find out how the dB-killer affected the power curve. I was hoping that the dB-killer wouldn't reduce the power much but now know it will. The A/F ratio was fine over the rpm range w/o dB-killer, about 13 to 1, but was noticeable fatter with dB-killer, about 12 to 1. In case I was running a lot with the dB-killer, which I won't, the PC should be loaded with a map that is optimized for the dB-killer.

Here is a diagram that shows how unlinear the power curve is on the Busa in stock shape. It is presented on www.sportrider.com

 

[boostin20]

Wow, I didn't think it would really have much of an effect at all to have the insert in. Learn something new every day.

 

[hans]

Mine showed a 14hp difference with an without, 4 hp under stock with, 10 over without

 

[R1000]

Mine showed a 14hp difference with an without, 4 hp under stock with, 10 over without

Is that with the R-77? What is the max power without dB-killer?

 

[Tufbusa]

I guess I'm still living in the stone age!

What's a "db-killer" and what's it's purpose?

 

[Dobieman]

I guess I'm still living in the stone age!

What's a "db-killer" and what's it's purpose?

Its the decibel killer or baffle in the exhaust can. On the R77 it removable.
It keeps the sound levels quieter.
I left my DB killer in as I like it quiet and stealthy but for a 10-14 hp difference I may have to pull it out and do a butt dyno test for myself

 

[Warchild]

I guess I'm still living in the stone age!

What's a "db-killer" and what's it's purpose?

A "dB-killer" is a baffled insert that keeps the pipe from being obnoxiously loud. The Yosh R-77 canister is shipped with the dB-killer pre-installed... it is easily removed via a single allen-head bolt.

I have kept mine installed because I do not want the noise. Still, the pipe has gotten WAY louder over time (I realize I am woefully overdue for re-packing). At this point, without the insert, the resulting noise would cause some hate/discontent among my neighbors, given that I depart for work at 5:30am every morning.

Still and all, I was unaware the insert robs quite *that* much power.... that's a drag. Perhaps after I repack the canister, I'll try it without the insert....

 

[R1000]

I guess I'm still living in the stone age!

What's a "db-killer" and what's it's purpose?

The dB-killer insert for the R-77 system is a simple pipe about 10 inches long and with a smaller diameter than the muffler core. The R-77 insert reduce the sound level 4 dB @ 5600 rpm, which I have measured.

My original plan was to use the insert since it is quite effective, but after seeing the curve in the first post it will be stored and only used at MOT visits.

The bike also runs quite fat with the insert. I will install a A/F-meter on the bike to keep control over the A/F-ratio. The bike must be farkled
Here is a link to the meter I've bought, they are quite cheap on ebay. http://www.autometer.com/cat_gaugedetail.aspx?gid=3604&sid=11

 

[Commuta_Busa]

I wonder what the hp difference would have been if you mapped the bike for the same A/F with the baffle. It probabaly wouldn't have been as drastic. By just sticking the db killer in and using the same map you show that it ends up being way to rich and that 'll cause a hp drop.

So you're kinda saying without a remap sticking the dbkiller in will result in less hp.

 

[R1000]

Yes, but I beleive the restriction that is caused by the insert can not be compensated by another fuel map, other than marginally. I watched the A/F meter on the Dyno with insert, and the A/F ratio was more like 12 to 1 than 13 to 1. 12 to 1 is still not a problem for an engine, the greatest effect by running 12 to 1 is increased fuel consumption, not the power loss.