Full Yoshi vs Akra Comparison

**r1elkins** · 08-26-2011, 03:28 PM

So I got my bike dyno-tuned today. I installed a full Yoshimura exhaust, BMC race filter, removed the PAIR valves, the exhaust servo motors, the complete emissions system and installed a PCV. The tech who dyno'd my bike also did a 2010 S1000RR with a full Akrapovic system last year. I asked him to compare the graphs and here's the results (elevation is over 5000'/1.5km):

Red = my bone-stock bike
Blue = my modified tuned bike
Green = another modified tuned bike

Not bad, plots mirror each other which is good. I'm not worried as to why my bike puts out 5 hp less, not a big deal and there are dozen factors that can contribute to that. Overall I'm very happy with how the bike turned out...it rides so much better than before. I highly recommend getting a custom map done, especially if you are at altitude like myself. The bike was pig-rich in some areas and lean in others, and the drive-ability is night and day difference.

I also noticed around 11,700 rpms there was a flat spot, both on the stock plot and on the tuned. I asked the tech why it was there and he thinks it's due to some ignition retarding. Too bad Dynojet doesn't have any plans on making the ignition module, cause there are gains to be had.

http://www.elkins-mb.com/S1000RR/ELKINSS1000RRFULLYOSHI.zip

Nigel · 08-26-2011, 05:53 PM

Thanks for the info, but unless they were run on the same bike as close as possible to each other, the power desplayed is of no comparison value. Your bike may just be the strongest. It is more the curves that interest me, not where they lie if you get my drift

but for the punters who don't get how well a full pipe works on this bike, get your peepers on the graph and your finger hitting the akra, AR, Brocks, Dan Kyle et al tel numbers!

Thanks for the effort to share. You will feel like you got yourself a completely new bike!

N.

Nigel · 08-26-2011, 06:03 PM

P.s. I have seen that 11k thing on most pipes. Dont think it has anything to do with the pipes rather BM sw or something.

N.

**r1elkins** · 08-26-2011, 07:05 PM

Nigel, you are correct sir. No definitive information can be concluded except to say that a full exhaust and a dyno-tune make big improvements over stock. My comparison was just to illustrate how similar the plots are. I have no idea what mods the other bike had, tire pressure, chain adjustment/lubrication, gas type, etc... But just looking how close the 2 systems mirror one another, it's a good bet that whichever pipe you buy is going to open these bikes up, a lot. I did quite a bit of searching on this forum on full exhausts to see if one stood out among the others, and I concluded that they all are fairly equal and it comes down to personal preference. I got a good deal on the Yosh, which is why I chose it over the others. I really wanted a Devil, but they were just too expensive compared to the Yosh. Anyways, I hope my post helps others to decide which exhaust to buy and the potential gains they can expect.

FWIW, I'm at over 5000' (1.5 km) altitude.

Jason

**r1elkins** · 08-26-2011, 07:08 PM

Quote:

Originally Posted by Nigel

Your bike may just be the strongest.

Actually my bike was the weaker of the two.

Nigel · 08-26-2011, 11:23 PM

On the same dyno here at 6000ft we get the same bench mark numbers if it makes you fell better about not having the 190 bragging rights by the way. Your bike is spot on with my mates full akra same mods.

N.

miker1 · 08-27-2011, 04:21 AM

You CAN compare dyno runs from diff days as long as the dyno is set up the same and the weather conditions are not way diff. You will get diff results from the same bike on the same dyno on the same day if you dont make sure that your test procedures are the same. You must compare apples with apples. If you want to compare heat soak the bikes and that would only normally be the second set of runs or after a tuning link tune.

I have rerun my bikes with a year inbetween and ended up with very similar runs.

Thanks for the test info.
everybody is always to quick to knock other persons test instead of taking the infromation out of it.

**MotoMadMan** · 08-27-2011, 05:16 AM

Wow those systems help a ton.

**r1elkins** · 08-27-2011, 12:48 PM

Yes I was very happy with the gains...and the weight loss. I'd really like to get control of the ignition and see what gains can be made, but until someone comes out with an ignition module I guess this will have to do.

Next on my mod list is new suspension and carbon wheels, but that will happen over the winter as money becomes available.

dagor6 · 08-28-2011, 12:37 AM

The flat spot is probably the velocity stacks moving