DOHC to SOHC

[!!4g91!!]

I'm so curious about my engine performance and really not satisfied..
Current using 4g91 DOHC and the performance for pickup very worse than previous proton engine.. Fuel consumption oso not so good..
If im using the original 4g91 manual gearbox its quite lost of power..

Now I'm using rojak gearbox 1.3//1.6 and its increase a bit for the pickup n torque.. no major modd.. using metal head gasket/ 1.8 na tb/ 1.8 cam pulley + adj pulley and fuel regulator..

So i need opinion from all sifu's to convert DOHC to SOHC coz on my thinking SOCH is really good than DOHC performance..

 

[deacon]

I hope you're not really considering this mod seriously.

 

[!!4g91!!]

myb got good or reasonable opinion b4 conservation.. then thinking for twice to make good feeling of my car performance.. i'm oso feel crazy modd like this but if anyone can suggest another way...

 

[jeremy]

time to transplant another engine?

 

[!!4g91!!]

i got some opinion from other sifus.. they said to plunk higher cc such as 1.6 or 1.8 block including conrod by repunch the engine number but its ilegal..

like jeremy said to change another engine is way but thre a lot flow out of money involved.. i'm not rich guy to make its posibble.. hehe

btw.. myb i'm need to try it out to combined dohc to sohc as majorities said imposibble.. :p

 

[khoyos]

bro, if DOHC is no good, local racers and also all car manufacturers worldwide will not use it.

have u considered some tuning? i mean fuel injection tuning. safc or emanage? based on the specs u mentioned, there are some mods done but no tuning. if no tuning, power may be worse than standard.

 

[g88]

if you use to drive SOHC car then with sudden change to DOHC car YES you will find DOHC bit underpower BUT when u understand the powerband between SOHC and DOHC you will find DOHC have wider power bank + it's a high torque engine...

meaning for SOHC if your usual power kick between 2.5K-4K RPM...most properly DOHC will come at 2.5 to 3K then upto 5-6K RPM....but that time u are at high speed de....

Also as per other sifu mentioned, CHECK your car setting, check your ECU see anything wrong with your settings...tune it nicely and you will fine 4G91 DOHC alot lowerful then 4G15 SOHC...

FYI, 4G91 is short stroke engine...power would even better...

hope this help !

 

[!!4g91!!]

khoyos n g88..
Thanks

oic.. I'm still using standard factory ecu.. oredi tuning for cam but didn't use any perfomance electronic stuff for controlling the fuel injection.. Myb i should go for safc bcoz emange will be costly.. once again thanks for + opinion..

 

[HKS-GT2835R]

I'm so curious about my engine performance and really not satisfied..
Current using 4g91 DOHC and the performance for pickup very worse than previous proton engine.. Fuel consumption oso not so good..
If im using the original 4g91 manual gearbox its quite lost of power..

Now I'm using rojak gearbox 1.3//1.6 and its increase a bit for the pickup n torque.. no major modd.. using metal head gasket/ 1.8 na tb/ 1.8 cam pulley + adj pulley and fuel regulator..

So i need opinion from all sifu's to convert DOHC to SOHC coz on my thinking SOCH is really good than DOHC performance..

sohc is actually better fer low down torque (read : non racing environment)
but i take it you're not so interested in city driving?

 

[!!4g91!!]

normal street driving.. its non for racers or for make killed story..
Sometimes want to overtake others or been tailgating by road racer will make blood temperature upstair.. so need the little bit performance on my hood will be challenging and not so "malu" except been meet TC or SC wheel..

 

[HKS-GT2835R]

normal street driving.. its non for racers or for make killed story..
Sometimes want to overtake others or been tailgating by road racer will make blood temperature upstair.. so need the little bit performance on my hood will be challenging and not so "malu" except been meet TC or SC wheel..

i'd stick to the DOHC, if i were you. plus, having a tuned car helps a lot.
before any mod is applied, are you sure your engine is in a good condition?

 

[!!4g91!!]

not so sure about engine cond.. sluggish n lost of power.. i cant see any leaking and if running on aircond sure i said on my mind "oh god what happen to my car" then running at highway oni around 100-130kmh max top speed...
I will make a tuning and check is there any wrong..

thanks again.. hope so..

 

[ACQ2305]

not so sure about engine cond.. sluggish n lost of power.. i cant see any leaking and if running on aircond sure i said on my mind "oh god what happen to my car" then running at highway oni around 100-130kmh max top speed...
I will make a tuning and check is there any wrong..

thanks again.. hope so..

using 4G91 s well,nt bad,cn max it to 180km/h,nt sure if gt speedcut.. mods powerzone extractor..4-2-1... only. can out run a waja campro. so power wise,i think its not a bad engine to start with,FC very gd... think u jst need to tune it again n service watevr parts needed...hehe..

 

[!!4g91!!]

bro im driving wira ab, how about urs?.. can u tell me how much improvement after u're using powerzone extractor instead stock?? issit really increase our hp?

 

[ACQ2305]

mines a wira sedan.used 2 hv an auto gearbox,nw using a manual 4G91 gearbox.abt d extractor,der is a definate increase in power,from mid all d way 2 arnd 6000rpm,..recomended.bt nt sure abt hotbits n others.usin 17in rims btw... ,try servicing ur injecters,i did,n nw revving feels light... =) n oh ya,try getting d timing right...did tat gain alot more power.cheers....

 

[Dino@Casper]

go do a compression test on your engine

 

[!!4g91!!]

mines a wira sedan.used 2 hv an auto gearbox,nw using a manual 4G91 gearbox.abt d extractor,der is a definate increase in power,from mid all d way 2 arnd 6000rpm,..recomended.bt nt sure abt hotbits n others.usin 17in rims btw... ,try servicing ur injecters,i did,n nw revving feels light... =) n oh ya,try getting d timing right...did tat gain alot more power.cheers....

u r using 17" rim? wow ur engine on good performance le.. im using 16" oni..
How about 4-1 extractor?

now using 240cc install by yesterday.. didn't feel any inprovement..

go do a compression test on your engine

sory.. not understand how to do compression test??

 

[mag9556]

check ur GB...gear ratio sometime cause this kind of problem...
thus check ur ECU....
metal gasket on N/A car?? wht a waste..
Good Luck..

 

[ACQ2305]

u r using 17" rim? wow ur engine on good performance le.. im using 16" oni..
How about 4-1 extractor?

now using 240cc install by yesterday.. didn't feel any inprovement..

yup 17in,if only cud afford 18in..hehe... well can say i was fortunated enough to find dis engine,wen found it mileage only 6000km++..yes six thousand only.so cond so far quite good. 4-1 if m nt mistaken only high revving then can feel power.4-2-1 mid n end can feel more..


sory.. not understand how to do compression test??

dis u gotta go to a workshop wit dis device.it checks ur compression,duh.hehe .mayb ur pistons rings r worn off.or a crack in ur pistons.or u might need 2 rebore ur block...change new pistons...

 

[Dino@Casper]

you say like your engine gonna fall apart.. maybe the problem is not with the engine head.. with the engine block..