[Discussion] Technical - Exhaust Systems

[ghost04]

You didn't change the carburettor jets yet? Sorry there was another thread about exhaust. So I posted my interview with Loois Motor meng tong regarding exhaust full system here. He said the max hp after rejet is 65hp & peak torque is 46Nm. He also said amongst all the street legal brands, Yoshimura Cyclone is the best in performance.

 

i using micron full system with baffle removed, k&n air filter, stage 1 dynojet kit and 45t rear sprocket.

[biting_point]

Whao.. Power explaination by you also..

 

I never knew it'll give 12HP increase... how much for dyno?? may wanna go in future..

 

Comparing aftermarket endcan only and full system:

 

endcan only: increase 1-2HP, price $650.. so 1HP is abt $300

fullsystem: increase 12HP, price $1700.. so 1HP is abt $150

 

by roughly comparing, it's more worthwhile to get fullsystem, IMO..

[Mussolini]

carburator jet change to japan brand>>>> ???.... can explain more on this?? u mean our carburator is not made in japan??

[tt6389]

carburator jet change to japan brand>>>> ???.... can explain more on this?? u mean our carburator is not made in japan??

 

after full system upgrade, the stock carburettor jet need to be replace with bigger ones - get jap brands jet is better.

[ghost04]

get dynojet.

[ghost04]

Thanks for the detailed explanation.

 

Yesterday, i went to Loois Motor and asked Meng Tong which brand of street legal exhaust full system gives the most increase in hp for S4 bikes. Bearing in mind that Loois motor has perform dyno test for decades for numerous bikes exhaust & they don't sell exhaust system - which means they're less likely to be biased towards one brand.

 

His reply was Yoshimura Cyclone street legal full system is the best. It gives between 8 to 12 hp increases & peak torque increase by about 8Nm. The maximum hp gain of 12hp is achievable when the carburettor jets are changed to jap brand ones.

 

Compared to the stock endcan, the manufacturer specs say the original hp is 53hp (39KW) at 11000rpm & 38Nm @9500rpm. My dyno test last year on my stock endcan bike confirms this. This would means the final hp after mods will be 65hp & peak torque is 46Nm.

 

In terms of % , there is about 20% gain in performance. I think this is pretty significant.

 

I also asked him the inspection certificates for street legal full system, does it includes both noise & CO emission test or just noise level? His answer was it covers both. Although the full system does not have catalytic converter to remove the CO, there is no emission problem during LTA inspections.

 

Can read about the Yoshimura Cyclone review here. The review also say the lack of catalytic converter in the street legal cyclone contribute greatly to greater gas flow & power delivery.

 

 

wa my dyno result max hp is only 55.81 max torque only 27nm nia using micron full ...difference alot man...somemore using dynojet...

[tt6389]

wa my dyno result max hp is only 55.81 max torque only 27nm nia using micron full ...difference alot man...somemore using dynojet...

 

my Spec3 when new, I dyno it last year shows 55hp with stock exhaust - same as manufacturer specs. Spec2 what's the manufacturer's spec? If lower, maybe the hp got increased.

[ghost04]

my Spec3 when new, I dyno it last year shows 55hp with stock exhaust - same as manufacturer specs. Spec2 what's the manufacturer's spec? If lower, maybe the hp got increased.

 

i think stock is around 53 or 54 ...if tats the case spent so much money for tat 2-3 hp increase is definitely not worth it. tat cyclone i will find if i sell my full system away.

[biting_point]

stock HP should be 53..

[megayon]

Hi S4 bros and sis... I'm thinking of getting a stock spec 3 endcan... It can fit my spec 2 right? Anyone selling???

[tt6389]

stock HP should be 53..

 

my dyno was really 55hp, maybe coz its still new & got KNN filter & iridium. Manuafacturer spec is just rough guide, they can't ensure all their products to be exactly 53hp. So safer to state it lower to avoid customer complaints..

[tt6389]

i think stock is around 53 or 54 ...if tats the case spent so much money for tat 2-3 hp increase is definitely not worth it. tat cyclone i will find if i sell my full system away.

 

Maybe you can ask Loois Motor 's Meng Tong to take a look?

 

What I understand is if you want hp to increase, the FC must increase. The FC can only increase if you change to bigger carburretor jets. If your FC not increased after changing jet, then the carburettor tuning/ adjustment not done properly. Carburettor tuning/adjustment is best done in a workshop which has his own dyno machine to re-check the hp increase & adjust accordingly.

 

 

[stkoh78]

Hi S4 bros and sis... I'm thinking of getting a stock spec 3 endcan... It can fit my spec 2 right? Anyone selling???

 

 

No problem . My spec2 bike with spec 3 stock end can .

[megayon]

Thanks stkoh... Now... it try to find anyone who wants to sell me the exhaust...

[calvinlim_83]

recently polish my exhaust pipe usin wax become not shiny . than i realise use eraser to rub . Guess wt it become shiny haha.not e best method but at least better than nth

[ShnHwA-]

hey..i also looking for tat protection sticker..haha..anybody found it?

[ck_yeo]

hi guys, this dent can repair bo?? sian... accidentally hit against a high kerb... if sengkuang can do it, roughly how much?

http://i118.photobucket.com/albums/o119/yeochris/Photo_0002.jpg

[ZzGaNgStErzZ]

kaoz ur pretty exhaust kena kerb. BTW tot kena curb is kena e bottom? u kena side kerb?

[biting_point]

heartpain sia..

 

should be able to knock back..Sk might able to do it..

 

*eye pain* too blink blink liaoz..

[skateboy]

that have to ask seng kwang for a quote liao... hope can knock back swee swee with no micro dents...

[ck_yeo]

corner of the kerb lor, very high kerb.i ka-you... bo bian..

 

pain pain... there goes my pretty exhaust.. btw, two of my header bottom also abit dent. tomorrow will go SK ask ask. any idea how long it takes for them to do it? HEART PAIN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[ck_yeo]

didn know the cement kerb 'tougher' then my metal pipe!!

[ZzGaNgStErzZ]

didn know the cement kerb 'tougher' then my metal pipe!!

 

but they realli are, coz our metal pipe is hollow. cement kerb isnt.

[skateboy]

n the metal pipe is not those very thick n hard pipe... so any hit on the headers while riding will dent.

[sky_vinz]

ck_yeo: Bro, update me abt SK's reply alright? I've some dents on my headers too, caused by previous rider. Wish to hav them back to perfect round shape if possible. =) Thks.