s4r engine rebuilt need help!!!

[Metzis]

I did put the exhaust cams to std specs and retard the inlet cams just a little bit, now i have 9.1 torque and 108hp crank horse power at 10000ish rpm. In the afternoon i will try all std specs to see what happens. I have though to ask what is the difference between Sae horse power and crank horsepower? Are my numbers ok because i don't have a comparison from before overhauling the engine... All these measurements are without the new exhaust that i am planning to install std headers, custom rubbish cat eliminator, danmoto mufflers... I will keep just the mufflers for the new exhaust and i will modify a st4 termi full system to fit on mine...

[koko64]

There is rear wheel hp and crank hp and different kinds of hp, SAE, STD, DIN, KW, etc. Brad has a good article on hp on bikeboy.org. He also has good articles on the S4R, MS4 and ST4 models including exhausts.

[Metzis]

I have already download and print those articles i am reading them as we speak!!!

[koko64]

Great stuff neh?

[Metzis]

Yeah Brad has made an absolutely amazing job gathering all those info... You go from noob to duc expert (ish) after few hours of reading. So far i didn't know that each tooth change on the pulley is around 40 degrees so i came to a conclusion of what went wrong... The first run was with the centerlines around 104 inlet 106 exhaust which is low and the run from today where inlets around 123 and exhaust around std spec. I will try to put every pulley in std spec and then i will try an another run to see what happens...

[koko64]

It's very good stuff. A generous sharing of knowledge.

[brad black]

crank hp is power measured at the crank.  some will give you a relationship for how rear wheel hp compares to crank power, but i've never seen a scientific justification for it.  the power you get at the rear wheel is the power you have.

sae is a correction standard, as is din or std.  it just accounts for the difference in ambient air temp and pressure at the time of testing.  each standard is different, sae gives the lowest corrected power.

[Metzis]

i set the cams around std specs i now have 108 crank horsepower and 10.1 ft of torque, i am on the exhaust now because my cheap custon catalitic remover maybe cause this mess otherwise the high compression of the pistons cut from my bike top end power which can be fixxed with cam instalation but not for the moment because my pocket is pretty empty!!!!  I wish i'll gain few horses after the exhaust installation. lets see....

[Metzis]

Brad can you please tell me what is your recommended air to fuel ratio on these bikes?

[brad black]

12.8.

[Metzis]

Ok thansk a lot.... !!!!

[Metzis]

Heyyy all i have very good news... After the exhaust installation http://www.ducatimonsterforum.org/index.php?topic=66915.msg1260446#msg1260446 i run the bike one more time... The results.... Amazing!!!! The bike now has 115 whp and 10.4 ft of torque
previous dyno with same power commander and cam set up was 95 whp and 9.8 ft of torque. I have also to mention that we don't have yet make the maps for the pc3 i run now a slightly changed can map.... We will dial cams first to move the curve where we want and after that we will work with the pc3.... I am looking forward to see the final outcome of this project...

[Metzis]

Heyyy all i have very good news... After the exhaust installation http://www.ducatimonsterforum.org/index.php?topic=66915.msg1260446#msg1260446 i run the bike one more timeon the dyno... The results.... Amazing!!!! The bike now has 115 whp and 10.4 ft of torque
previous dyno with same power commander and cam set up was 97 whp and 9.8 ft of torque. I have also to mention that we don't have yet make the maps for the pc3 i run now a slightly changed can map.... We will dial cams first to move the curve where we want and after that we will work with the pc3.... I am looking forward to see the final outcome of this project...

[brad black]

does that exhaust give you a dip in the midrange?

[Metzis]

The curve is really very smooth from 3+ to 9+... on Monday i will take a photo of the dyno chart comparing before and after the exhaust installation because i am not 100% sure, i was really too much happy with the results that i didn't pay any attention to the details... I know the bike isn't nothing too special at the moment but because the numbers from the first rolls where very disappointing that is why i am that glad, i feel that i am on the right direction for bigger numbers right now.