1mm bore

[normality78]

Guy's,

currently my piston dia was 81mm and i would like to bore into 82mm piston use. i wonder how much significant different would it make in terms of performance?

 

[Fluffy]

okay.when u bore ur engine 1mm u will increase torque thus increasing hp in theory.based on the calculation

hp = torque(lbs-ft) x engine speed (rpm) / 5250

so,when u bore ur engine,u will increase the displacement.based on this calculations:

.0031414 x stroke(mm) x bore(mm) x bore(mm)

*the value .0031414 is for 4cyl engines.
for 6 cyl it is .0047123 ...this is just for rev.

urs is an inline four rite? :_:

 

[normality78]

Tks for the explanation. Yes, im 4 in-line. actually im aware about the calculation and also more on increasing torque thn hp.

the thing i wanna know is more on how big significant improvement to justify over the cost. i mean something like spending x amount of money but in return only gain back 10hp. worse it does compromise the reliability. so i would need to justify over it. shld the improvement on respond or gain around 30hp or more, thn it do think its justifiable

 

[Fluffy]

how much will the bore cost u actually?

i dont think it would give u 30hp gains..but it would surely improve on response.coz surely a slightly larger displacement would spit out a lil more exhaust gas thus giving a lil more momentum to turn ur turbine.

 

[normality78]

hm... the labour itself i havent check it out but the piston set will cost me around RM1.3k

 

[MitonCT26]

isnt it better if you increase stroke rather than bore as you want to increase torque right?

 

[SkYwAlKeR]

how to increase stroke??... change to larger stroker kit??...

 

[normality78]

isnt it better if you increase stroke rather than bore as you want to increase torque right?

miton bro,

i think i've reached the max stroke laio so the next thing i can do is to bore frm stock 81mm to 82mm max.

 

[Fluffy]

i think for 1.3k its not that worth it. :P

u could be upgrading ur snail rite? IMO.

 

[SkYwAlKeR]

wah, need 1.3k arr??...

drop in 1.5L block la... after that do PNP.... no need rebore la..

or like fluffy said, keep a snail inside.... hehehe...

 

[khoyos]

usually people change piston to alter the compression ratio. 1mm increase in piston bore wont bring such great diffrence, unless u get pistons that has ur desirable compression ratio.

IMHO, rather than increasing the bore (reduce reliability and the painful 1000km running in period), u would do better if u upgrade cams(for NA) or change to bigger turbo if u running turbo engine...

 

[normality78]

wah, need 1.3k arr??...

drop in 1.5L block la... after that do PNP.... no need rebore la..

or like fluffy said, keep a snail inside.... hehehe...

drop in 1.5l? what r u talking?

 

[normality78]

IMHO, rather than increasing the bore (reduce reliability and the painful 1000km running in period), u would do better if u upgrade cams(for NA) or change to bigger turbo if u running turbo engine...

hm... tks for the info bro. will think twice now. hehehehe

 

[alvin24]

Hahaha... if your stoke is long, then you might feel it lar. =Þ

But u also need to think in terms of reliability... 4G9X series engines for instance have poor reliability after a rebore.

 

[SkYwAlKeR]

drop in 1.5l? what r u talking?

err..... this only applicable to 1.3L la...
if u car 1.5L, cannot change block la... jz drop in 1.6L stroker kit....:tongwink:

 

[Fluffy]

the reliability also depends on the material of the block.

sky : he maxed out his stroke. :)

with 1.3k..banana manifold?hehe!

 

[normality78]

actually i wun syaing i maxed out also la. u see, toyota normally plp use either supercharged or 20V. but both were 1.6l engine.

now on toyota celica which do have 1.8l engine on some country. so its enable us to hybrid the engine block over. its almost 99% compatible with 1.6l with little stuff need to mod around. basically it carry longer conrod with the block 3mm higher thn 1.6l, however the piston do share the same dia 81mm.

that why im saying its already maxed out. well side track here abit. RM1.3k for banana is worth investing provided its frm those performance tuner products like HKS, TOmei or so. At least thier stuff was flow test proven. but for toyota, there is no tuner ever come out with such product. yes, it can be locally made but does any local made with dyno flow proven?

 

[Fluffy]

actually i was wondering about the same thing.im not too sure about the flow for a custom banana/turbular manifold.

btw,wat block are u using?i saw ur BOT pic, it didnt look like a 20v. :P

 

[normality78]

as i mentioned lor... im using the 1.8l block

 

[V8_nutter]

actually i wun syaing i maxed out also la. u see, toyota normally plp use either supercharged or 20V. but both were 1.6l engine.

now on toyota celica which do have 1.8l engine on some country. so its enable us to hybrid the engine block over. its almost 99% compatible with 1.6l with little stuff need to mod around. basically it carry longer conrod with the block 3mm higher thn 1.6l, however the piston do share the same dia 81mm.

that why im saying its already maxed out. well side track here abit. RM1.3k for banana is worth investing provided its frm those performance tuner products like HKS, TOmei or so. At least thier stuff was flow test proven. but for toyota, there is no tuner ever come out with such product. yes, it can be locally made but does any local made with dyno flow proven?

What's the use of banana manifold for NA cars ? Any explanation on this ?