[Discussion] Exhaust Systems - YOSHIMURA

[nigaman]

Originally posted by Lass@Nov 22 2005, 09:04 AM

yeah i saw oso *drools* but v ex

 

does petrol consumption go up after u fit w aft mkt exhaust?

 

does the titanium sound diff fr the steel end can?

 

wat's the reason for the backfire? should i b concern and try to solve it?

 

solly lah newbie

My petrol definitely went up (i installed other products, other than the exhaust).. now going at around 280 for full tank

 

Was using the titanium full sytem, and changed to the tri-oval, tri-oval (steel) louder than the titanium..

 

As for Backfire, heard from expert (Fat di) that it's caused by the fuel being too "Rich", tink its my jet kit.. and its not good for the bike...

Not too sure bout the reason can anyone care to elaborate on this backfire thingy?

Thanks!

 

Hope it helps..

[Lass]

okie thks

[MrLau]

Originally posted by nigaman@Nov 22 2005, 01:09 PM

As for Backfire, heard from expert (Fat di) that it's caused by the fuel being too "Rich", tink its my jet kit.. and its not good for the bike...

Not too sure bout the reason can anyone care to elaborate on this backfire thingy?

Thanks!

The stock exhaust is design in term of balance in fuel economy, performance and emission.

 

The after market exhaust normally put priority in term of performance.....

 

Those performance exhaust usually straight through, this make the exhaust gas can flow faster.

 

As the exhaust gas flow out faster, it create a higher "back-pressure" to suck in more petrol (as compare to stock exhaust).

 

With the stock jet-kit, it tent to suck too much petrol (too rich), some of this unburn mixture get into the exhaust system and causing back-fire. This also explain why the petrol consumption is higher.

 

The backfire is worse if you have install with a high flow air-filter.

 

To resolve this problem, you need to replace a carb jet-kit or re-tune. (for carb model) or install Power Commander (to reprogram the EFI injection).

 

Remember, a well-tune engine should work with optimum performance, you should see better performance with just slightly increase of petrol consumpton.

 

[floppy]

Originally posted by MrLau@Nov 24 2005, 01:33 AM

The stock exhaust is design in term of balance in fuel economy, performance and emission.

 

The after market exhaust normally put priority in term of performance.....

 

Those performance exhaust usually straight through, this make the exhaust gas can flow faster.

 

As the exhaust gas flow out faster, it create a higher "back-pressure" to suck in more petrol (as compare to stock exhaust).

 

With the stock jet-kit, it tent to suck too much petrol (too rich), some of this unburn mixture get into the exhaust system and causing back-fire. This also explain why the petrol consumption is higher.

 

The backfire is worse if you have install with a high flow air-filter.

 

To resolve this problem, you need to replace a carb jet-kit or re-tune. (for carb model) or install Power Commander (to reprogram the EFI injection).

 

Remember, a well-tune engine should work with optimum performance, you should see better performance with just slightly increase of petrol consumpton.

 

 

sums it up real nicely.

[nigaman]

Originally posted by MrLau@Nov 24 2005, 01:33 AM

With the stock jet-kit, it tent to suck too much petrol (too rich), some of this unburn mixture get into the exhaust system and causing back-fire. This also explain why the petrol consumption is higher.

 

The backfire is worse if you have install with a high flow air-filter.

 

To resolve this problem, you need to replace a carb jet-kit or re-tune. (for carb model) or install Power Commander (to reprogram the EFI injection).

Have already changed to an after-market jet kit.. and it still backfires at low RPM.. do i need re-tuning? FYI My idling rpm is at 1.4.. and it does not flactuate at all.. thanks in advance!

[Kinetic]

i dunno abt u all..

but i install yoshi street legal, no tuning or anything done

bike everything else stock

FC remain same as before, if not slightly better.

before - 21-22km/l

now stable @ 22km/l

i ride like before, if not even harder.

no backfire or problems encountered.

 

so i not sure wat causes the problem for u bros..

[floppy]

Originally posted by nigaman@Nov 24 2005, 11:41 AM

Have already changed to an after-market jet kit.. and it still backfires at low RPM.. do i need re-tuning? FYI My idling rpm is at 1.4.. and it does not flactuate at all.. thanks in advance!

probably.

 

sounds like the mechanic never got it right leh. if tune correctly, i.e. with the right combi of air jet and fuel jet, i don't think u will have this problem. jetting isn't some kind of plug-and-play option (at least not for 4 cylinder 4 stroke bike). u'll need a proper dyno machine to get it right.

[nigaman]

Originally posted by floppy@Nov 24 2005, 08:28 PM

probably.

 

sounds like the mechanic never got it right leh. if tune correctly, i.e. with the right combi of air jet and fuel jet, i don't think u will have this problem. jetting isn't some kind of plug-and-play option (at least not for 4 cylinder 4 stroke bike). u'll need a proper dyno machine to get it right.

Went for a dyno run at Unity.. just did a base run, did'nt do a top-end run or any tuning done by them...

 

The results as follows:

Max power=62.26 Hp

Max Torque= 29.10 Ft-Lbs

 

Heard from di that 62 is not a bad result for the HP..

 

As for the backfire thingy, yah u guys were right about the air/fuel stuff.. apparently my fuel was abit high at low Rpm, and too low at high speed, thus, in short, the air/fuel intake is not ideall.. solution was to leave the bike there overnite for them to "Tune" the Jettings.. But after consultation with the pro (Diraj lah..) i decided not to, as i am comfortable with the bike as it is..

 

I understand the Hp for a stock S4 is around 40 plus?

 

FYI, the changes i did was the jettings, installed the tri-oval F/system, and Knn filter..

 

Hope it answers some queries that u may have..

 

[nigaman]

Originally posted by nigaman@Nov 24 2005, 11:41 AM

Have already changed to an after-market jet kit.. and it still backfires at low RPM.. do i need re-tuning? FYI My idling rpm is at 1.4.. and it does not flactuate at all.. thanks in advance!

Correction to previous posts...

 

My idling RPM when "cold" is 1.1 - 1.2 k, after it "warmed-up" the RPM is 1.2 - 1.3K.. it was never 1.4k..

my apologies.. Parrallex error from seeing the analog meter.. saw it clearly on the dyno machine (Digital)..

 

Also realised that my Fuel Consumption was 230-240/full tank, instead of 280 as i previously claimed..

this one human error..

 

My apologies for the inaccurate information posted!!!

[MrLau]

Originally posted by nigaman@Nov 25 2005, 12:45 AM

The results as follows:

Max power=62.26 Hp

Max Torque= 29.10 Ft-Lbs

 

Heard from di that 62 is not a bad result for the HP..

GOOD leh....

 

http://www.ibike.com.hk/03_knowledges/05_d...cb400vt2/01.htm?

 

This guy only got 59hp....

[nigaman]

Originally posted by MrLau@Nov 25 2005, 11:00 AM

GOOD leh....

 

http://www.ibike.com.hk/03_knowledges/05_d...cb400vt2/01.htm?

 

This guy only got 59hp....

Yah loh, they using they using the same machine.. the graphs on the monitor and the set-up is similiar...

But his graph is smoother, mine's a bit jagged, but steeper than his.. its my air/fuel thingy, according to the very informative ah xiong from unity..

[Kinetic]

dyno run is for wat purpose?

[floppy]

Originally posted by nigaman@Nov 25 2005, 06:13 PM

Yah loh, they using they using the same machine.. the graphs on the monitor and the set-up is similiar...

But his graph is smoother, mine's a bit jagged, but steeper than his.. its my air/fuel thingy, according to the very informative ah xiong from unity..

nigaman,

if u dun mind, can post up ur graph?

[nigaman]

Originally posted by floppy@Nov 28 2005, 01:02 PM

nigaman,

if u dun mind, can post up ur graph?

Wah how ah? A piece of paper nia.. i got no scanner lei..

See wad i can do..

[299]

Originally posted by Kinetic@Nov 28 2005, 12:55 PM

dyno run is for wat purpose?

To check for how much Bhp is obtained at ur bike rear wheel.

[Turbo08]

Originally posted by nigaman@Nov 28 2005, 04:09 PM

Wah how ah? A piece of paper nia.. i got no scanner lei..

See wad i can do..

u can try to sketch it out dun forget, u r sbf writer... u should be gd wif ur pen

[sahabudeen]

Hi guys, i whan to ask u guys how many KM do u all go for full tank? for Ver S? resantly my bike only give about 230 only. It was use to be 300KM. any one can help me...

[nigaman]

Originally posted by Turbo08@Nov 28 2005, 09:30 PM

u can try to sketch it out dun forget, u r sbf writer... u should be gd wif ur pen

Erm.. my the other "Pen" more powerful lei..

 

Jokes aside, maybe i can describe a little, the graph is 45 degrees upwards, and according to ah siong (Mech who did the Dyno), the graph is quite swee, one of the best he seen for S4.. less the jagged "teeth".. and that is due to the air/fuel thingy..

 

Haiz.. okok, i look for scanner, tink confuse u guys liao..

[Lass]

my indicator starts to blink at abt 285 w yoshi. shd b ok rite? sheesh hv to go pump petrol soon.

[nigaman]

Originally posted by Lass@Nov 29 2005, 09:28 AM

my indicator starts to blink at abt 285 w yoshi. shd b ok rite? sheesh hv to go pump petrol soon.

wah compared to my.. urs is a "fuel efficient" bike lei!

[Lass]

Originally posted by nigaman@Nov 29 2005, 10:01 AM

wah compared to my.. urs is a "fuel efficient" bike lei!

er dun mean to rub it in, when i started to ride again, it went bk to 1 bar & started to really blink consistently when reaching 300 when i when to pump just now. sheesh 14.5 ltr cost me 26plus bucks!! but aft discount is abt 23plus.

 

keke when i ride, i try to maintain my rpm below 6 or at abt 6 loh & of course bkside itchy at times play w the v tec a bit lah

[nigaman]

Originally posted by Lass@Nov 29 2005, 09:49 PM

keke when i ride, i try to maintain my rpm below 6 or at abt 6 loh & of course bkside itchy at times play w the v tec a bit lah

FIERCE!

:bouncefire:

[Lass]

Originally posted by nigaman@Nov 30 2005, 02:42 AM

FIERCE!

:bouncefire:

no lah like tat where got fierce, only slow pooch's petrol can last so long......orh u talking abt urself haha lagi fierce!!

[Guest quizesilver]

die then mine even much slower.

did 320km liao. still got one bar...

[nigaman]

Originally posted by Lass@Nov 30 2005, 09:33 AM

no lah like tat where got fierce, only slow pooch's petrol can last so long......orh u talking abt urself haha lagi fierce!!

I very good-hearted one hor.. not fierce lah