Wira 1.5 4G15 Exhaust Piping

[mizi0604]

i think compress is good for back pressure... n again, correct me if i'm wrong bcoz i'm getting confuse right now..:hmmmm:

of course NA need back pressure unless u are using mivec or vtec...Obviously dont go for 2" piping bcoz u will lost top end, i've experienced it before,u better go for 1.8" and use orginal route...Swirling bullet type is good if you running on auto tranny.

 

[tofu_manic]

please correct me if im wrong... at top speed, s flow is better than straight flow?

Bump: please correct me if im wrong... at top speed, s flow is better than straight flow?

i may be wrong as well, wanna hear why u think so, the explanation may make more sense than mine

 

[K_Takuya]

Ive read some articles..tofu_manic is correct

Bump: Ive read some articles..tofu_manic is correct

 

[ACQ2305]

of course NA need back pressure unless u are using mivec or vtec...Obviously dont go for 2" piping bcoz u will lost top end, i've experienced it before,u better go for 1.8" and use orginal route...Swirling bullet type is good if you running on auto tranny.

but i have heard alot of good feedback from 91 users using 2in piping..1.5 also but an extra cam..

 

[civic EdGe]

of course NA need back pressure unless u are using mivec or vtec...Obviously dont go for 2" piping bcoz u will lost top end, i've experienced it before,u better go for 1.8" and use orginal route...Swirling bullet type is good if you running on auto tranny.

So i think its confirmed, that as expected, the swirling bullet makes the air travels a longer path -> more "restriction" -> helps in low end torque -> suits auto tranny .....

Ive read some articles..tofu_manic is correct

Bump: Ive read some articles..tofu_manic is correct

Izzit from teamintegra.net??

 

[mizi0604]

but i have heard alot of good feedback from 91 users using 2in piping..1.5 also but an extra cam..

4g91 is a DOHC version and its okay to use 2" piping, but if it is 4g15 which is SOHC version,better use 1.8" only...4g91 has more hp than 4g15,its also can beat 4g92 SOHC version...

 

[tofu_manic]

of course NA need back pressure unless u are using mivec or vtec...Obviously dont go for 2" piping bcoz u will lost top end, i've experienced it before,u better go for 1.8" and use orginal route...Swirling bullet type is good if you running on auto tranny.

just curious, y issit that u say NA engines need backpressure, except mivec or vtec?

Ive read some articles..tofu_manic is correct

Bump: Ive read some articles..tofu_manic is correct

yaka? can put the link here? would be interesting to see

 

[K_Takuya]

I found out from

(this is not exactly for 4g15..but with good general idea)
http://auto.howstuffworks.com/frame...ngine_performance_tuning.html#Exhaust Systems

and this..
http://nismoclub.6.forumer.com/viewtopic.php?t=9108&postdays=0&postorder=asc&start=0

 

[mizi0604]

i just give my opinion base on my experienced...i can feel the different before and after using the straight piping...a lot of mivec owner also suggest me to do straight piping also,but i dont know how to expain why,sorry bro...

 

[SkYwAlKeR]

i just give my opinion base on my experienced...i can feel the different before and after using the straight piping...a lot of mivec owner also suggest me to do straight piping also,but i dont know how to expain why,sorry bro...

so u can feel more power when mivec open...

but in expense, u loose abit of low end torque due to more free flowing exhaust...

 

[mizi0604]

yup,correct...but my concern only for pickup bcoz i prefer to drag...

 

[ACQ2305]

4g91 is a DOHC version and its okay to use 2" piping, but if it is 4g15 which is SOHC version,better use 1.8" only...4g91 has more hp than 4g15,its also can beat 4g92 SOHC version...

thanks,..another confirmation abt 2in piping..cant waste cash on mods that dont work..
was still in a dilemma as 2 which size is suitable...

 

[4gManiaC]

yup,correct...but my concern only for pickup bcoz i prefer to drag...

owh really??ur car sure quick in achieve 0-100kmh..what car do you drive?what engine installed?can u share with us mod u have done including ur piping size?

 

[bfb515]

hi
im using wira 4g15 carb manual tranny
just want to ask for opinions
what size of piping is the best for my car?
my setting
4g15 carb manual
pz 421 extractor
pz camshaft
2' inlet s-flow muff

but now im thinking of using carb weber dcnf 40
whats the best piping size for my car, wif standard carb and weber dcnf 40?

tq






Bump: hi
im using wira 4g15 carb manual tranny
just want to ask for opinions
what size of piping is the best for my car?
my setting
4g15 carb manual
pz 421 extractor
pz camshaft
2' inlet s-flow muff

but now im thinking of using carb weber dcnf 40
whats the best piping size for my car, wif standard carb and weber dcnf 40?

tq

 

[SkYwAlKeR]

hi
im using wira 4g15 carb manual tranny
just want to ask for opinions
what size of piping is the best for my car?
my setting
4g15 carb manual
pz 421 extractor
pz camshaft
2' inlet s-flow muff

but now im thinking of using carb weber dcnf 40
whats the best piping size for my car, wif standard carb and weber dcnf 40?

tq

1.8" piping... if possible get mandrel bent piping...

 

[ken12292703]

1.8" piping... if possible get mandrel bent piping...

How about my 4g15 bro? I am planning to install Pipercam, 1.8" enough?

 

[simon]

im a wira 4615 user ......changed to 2in piping the other day..same time also changed to lighten crank pulley....just wanna try...i still have my standard piping....tested and i found the car pick up have improved slightly & it feels light but...but....

my top speed suffered most serious....after 140km/h there was no torque....it could only pull up to 165km/h ++ needing downhill assistance to reach 170km/h.... i was shocked...

previously my car could reach 190km/h.....from what i read here many has advised against 2in piping for stock engine...so now shall i (1) change back to ori size or (2)continue to do some other modifications to extract more power from the engine ??? if option 2 pls specify what other mody i can do....that can actually increase the power or (3) shall i transplant 4G91 ??? my current engine has clocked 180,000km.....never been overhauled yet...tks tks

 

[SkYwAlKeR]

How about my 4g15 bro? I am planning to install Pipercam, 1.8" enough?

more den enough... marco tauke also said his 4g93 using 1.8" piping only.... so i guess 4g15 use back 1.7" piping will be nice...

im a wira 4615 user ......changed to 2in piping the other day..same time also changed to lighten crank pulley....just wanna try...i still have my standard piping....tested and i found the car pick up have improved slightly & it feels light but...but....

my top speed suffered most serious....after 140km/h there was no torque....it could only pull up to 165km/h ++ needing downhill assistance to reach 170km/h.... i was shocked...

previously my car could reach 190km/h.....from what i read here many has advised against 2in piping for stock engine...so now shall i (1) change back to ori size or (2)continue to do some other modifications to extract more power from the engine ??? if option 2 pls specify what other mody i can do....that can actually increase the power or (3) shall i transplant 4G91 ??? my current engine has clocked 180,000km.....never been overhauled yet...tks tks

2.0" piping too big la bro...

change back to 1.7" piping....

 

[tictac~]

in my opinion NA car need a back pressure from exhaust system.

In turbo engine.. exhaust with no back pressure is preferred. Because fresh air is forced into combustion chamber. Then exhaust air will be use to rotate the turbo.. air after turbo banana need to go out fast... no need to add more pressure to it.

For NA engine... the fresh air is not forced into the combustion chamber... when the piston moved down to suck the fresh air. Intake valve open and the exhaust valve is still partially open. A bit of exhaust air is sucked back into combustion chamber. That is the reason why it need a back pressure from exhaust.