Difference VTEC Sohc & Dohc

[Babyflirt]

i think there is a few on the road with this setup. most of the eg SOHC or DOHC end up with either a higher block, change engine to a higher wan or TC the engine.

[Freestylers09]

T

[Dynaway]

except for Honda Civic R eninge claiming cam phasing with SOHC configuration, this partially right only for marketing purpose.

 

1. Would you say Honda SOHC V6 VTEC engine used in their RL model is also partially right only for marketing purpose?

 

2. Would a SOHC VTEC be really less tunable? SOHC would be cheaper to manufacture? Why are we not seeing cheaper SOHC Cars around like Impreza, Civic, Octy and etc? May be DOHC makers enjoy econ of scales.

 

Regards,

 

I mentioned that so far I never see cam-phasing ability on SOHC, honda call them i-Vtec on R18 engine because it can shut one valve during low RPM not really cam-phasing true meaning. Marketing strategy.....

 

Subaru claiming DOHC, another marketing ploy. Boxer engine is 180 degree oppossed of courde there 2 cam shafts one for intake and exhaust left bank pistons and the other for right bank pistons. True DOHC in Subaru boxer enginer is called QUAD CAM!!! there will 4 cam shafts so each cylinder bak will have individual intake and exhaust cam shaft.

Example Legacy i only 120 HP (not sure) running on SOHC (false DOHC as claimed by SE).

Legacy R is 165 HP running on quad cam (this real mc coy DOHC engine)

 

The rest no comments I am not a auto maker...

 

cam phasing on SOHC unlikely unless the Exhast cam lobes comes with switch over cam lobes.... cause they are on a single cam... if u advance, both will advance...unless there is additional lobes for the exhaust valves tat runs retard.

 

 

anyway, Quad Cam is jus a name tat confuses the consumers... its jus a "ho tiah" name to call V or Flat engine with DOHC config.... they are still effectively DOHC if u mesh them together....

 

for DOHC there are only 2 cams, Intake & Exhaust.

the so call Quad Cams are still only having 2 type of cams, Intake & Exhaust

[Dynaway]

you are right.

 

i qute u an example, my fren said to test my ride against a EG, so i ask what engine, he say same engine as mine lor H22A 2.2L. then i say, test for what sure lose what, his power to weight ration sure win me liao... then he say but both same engine mah.

 

somemore he say, if the guy engine is only 2L or smaller than it is like i play cheat, i 'makan' him like that...

 

i was like . Certain cars have bigger CC for a certain reason. den argue and argue, then i say orh ok lor u win....

 

so after everything, it only depends on how deep your pocket is

 

H22A VS B20 overbored with H22 piston.... u may not loose to the H22A.

 

H22A seems very high lap engine in its original state...

 

for street use i would prefer a B18C over the B20..... they got a much better power range all round.....

[Mcff_1980]

actually personally i feel b20 more suited for street and b18 more suited for track

[Weichien]

what is the different between b20 and b18 what is the power differents.

abd hw much cc is both? which car use b20 and b18?

[Galantspeedz]

eh... thanks but both of us are H22

[Turbonetics]

B18C or C5(1.8litre) is found in the Integra Type R aka DC2.

B20B(2litre) is found in the older CR-V.

B18 is DOHC Vtec but B20B is not.

B18 power range between 190-210bhp while B20B is about 140-150bhp.

most common mods for B20 is to swap a B16 or B18 head to make it DOHC Vtec,power wise iam not sure for this set-up.

[Weichien]

so swaping the whole engine and just swaping the engine head is no different?

cos swaping the head can make it to dohc v-tec and it seems powerful enough and swaping the engine is rather the same?

so it seems b18 is better and it's 1.8

[Babyflirt]

B20 AFTER CHANGING THE HEAD DEPEND ON WHAT HEAD YOU USE. STOCK YOU CAN GET ARD 200-220BHP. B18 I SUPPOSE IS AROUND THERE OR LESS.

[Galantspeedz]

eh... if change d*ckhead how much more bhp?

 

sorry just could not resist....

[Turbonetics]

are you sure a stock head can get 200bhp?

because i think B20 even with vtec head cannot rev too high.

what is the peak rev of this set-up?less than 8000rpm?

[Slowmo]

spend money wisely.

buy a kelisa and lup V12.

 

Driver may need to sit in the rear passenger seat already.

[Babyflirt]

my friend eg6 b20 with a b18 or prelude head (can't remember what head. not sure whether got such prelude head anot)without mod, he dyno at 215bhp. he show me the chart. true anot i can't comment. mayb have to ask the expert. any expert out there can advise? mine can rev quite high 6000-7000 no pro. tho vtec on at 5500rpm.

Edited September 13, 2007 by Babyflirt

[Mcff_1980]

stock b20 bottom end is not meant to rev high, around 7500rpm only, but it has good low end torque

in order to rev it high, pple usually change like ARP rod bolts and aftermarket rods in order to rev it up to 8500rpm or beyond 9000rpm no problems

 

hope this helps

[Turbonetics]

i was thinking remove the rear seats and give up the boots and put the engine behind.

[Turbonetics]

7000rpm is not high for vtec engines.

[Turbonetics]

the problem is without cams upgrade and tuning,rev so high also no use.

power might drop in the high end if the peak power is at 7000rpm..

and a stiffer set of valve springs are needed too.