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Difference VTEC Sohc & Dohc

Llfr

By Llfr,
in Japanese Talk

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Linus

Linus

Clutched

hi guys,

 

with due respect to the threadstarter, he started the thread to find out more about this topic.

 

yes, the search function is there for more reference as well.

 

kindly keep all the OTs and non-related discussions to a side.

 

regards,

linus

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Mcff_1980

Mcff_1980

Neutral Newbie
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you got it.

when you reach the Vtec gear,it can send your head sticking to the seat.

 

the legendary vtec turbo.. look at how this freaking monster pull [sweatdrop][sweatdrop][sweatdrop]

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Turbonetics

Turbonetics

2nd Gear

i don't think this is in singapore as the speedo shows MPH.

there are many done up civic with turbo in other countries.

i had seen countless of them featured in magazines like Hot4s,Japanese,Import tuner...etc.

you must have deep pockets to play.

a cheap job will make not last the engine for long.

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Mcff_1980

Mcff_1980

Neutral Newbie
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you won't believe until you have tried it.

GOD INVENTED TURBOLAG TO GIVE THE NATURALLY ASPIRATED CARS A CHANCE,and they are Vtec.tongue.gif

 

GOD INVENTED VTEC TO BRING MORTALS CLOSER TO HEAVEN [:p]

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Dynaway

Dynaway

1st Gear
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Vtec controller is use to control the old Vtec...can't be use in the new R18A engine.

This new engine is more of a fuel consumption and better torque output with variable length intake manifold

 

i'm sure they'll come out with a new toy for the new R18A engine..

 

not too sure if the Greddy V-Manage will be able to work on it.....

 

but that engine has some limitations due to the exhaust portion on the cylinder head....

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Dynaway

Dynaway

1st Gear
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I'm no expert in this field. Logically if you want power, the engine has to suck in more air, more fuel is burnt and thus give you the go. Of course, there is a chance to alter the air/fuel mixture to optimize usage but by how much is a question mark for the tuner.

 

Regards,

 

u'll need a wide band sensor to correctly adjust the A/F mixture....

 

engage too early u may end up loosing power instead.....

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Knighthunter

Knighthunter

4th Gear
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VTEC and SOHC/DOHC are totally unrelated concepts.

 

VTEC = opening more of the valve via lift so the engine can breathe better (sorta like the human nose)

 

SOHC/DOHC = number of cams and valves

 

More valves = Engine breathes better cos more openings

 

VTEC is controlled by the cam design.

 

I dunno whether some correct you on this, SOHC & DOHC is not about the the number of valves per cyclinder. The name itself tells what it is:

DOHC - Double Over Head Camshaft - One cam shaft for intake (doesn't matter how many valves), One Shaft for Exhaust. Benefit of DOHC is more tune able due to opening angle of intake valve and exahust valve can be adjusted. In the old school this was done during tuning manually. Now most of new car coming with VVT (variable Valve Timing), the cam (cam phasing) amgle can be adjusted up to 7 degree depend on engine load and RPM for fuel efficiency.

So, VVT (VANOS, DVVT, etc..bla..bla..) is applicable on DOHC configuration except for Honda Civic R eninge claiming cam phasing with SOHC configuration, this partially right only for marketing purpose.

 

SOHC - Single Over Head Camshaft - intake and exhaust valves controlled by single camshaft, this is gives compact engine size (look at EK3 engine) and cheaper to manufactur since lesser parts.

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Kelpie

Kelpie

2nd Gear
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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,

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Dynaway

Dynaway

1st Gear

SOHC have limitations to certain extend.... u cant really adjust the overlaping timing for SOHC with adjustable cam gear since both exhaust & intake lobes are on the same cam....

 

that is why in my eariler post i mentioned that the DOHC are having a more precise timing.....

 

SOHC would have fewer mechanisim as compared to DOHC... 1 less cam, 1 less sprocket...less raw material..... be in mind that all this are made/manufactured with precise engineering process.

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Kelpie

Kelpie

2nd Gear
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SOHC would have fewer mechanisim as compared to DOHC... 1 less cam, 1 less sprocket...less raw material..... be in mind that all this are made/manufactured with precise engineering process.

 

I'm just wondering whether it is cheaper to manufacture high precision SOHC mechanism than a normal DOHC. I don't see cars with SOHC engine selling cheaper than DOHC cars of the same class.

 

Regards,

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Dynaway

Dynaway

1st Gear

it is definitely cheaper if u factor in the raw material cost & number of items/parts to be produced...

 

dun compare against different brands....

 

take a look at the EG VTi vs ESi, Airtrek vs Airtrek Turbo

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Mcff_1980

Mcff_1980

Neutral Newbie

u must go change your tacho to 20000 type.. or else the needle cannot go up anymore la.. [:p]

or remove the small thing blocking the needle so it can spin 1 more round [:p][:p]

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Turbonetics

Turbonetics

2nd Gear
(edited)
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i need your advise.

iam caught between Ninja capsules,Vtec and Turbo.

which should i install for my BMX?rolleyes.gif

 

Honestly speaking i would recomend the Vtec ... why? Because the Vteck allows your BMX to have a sudden surge at high Leg Rotation per minute... if u have turbo.. there will be a lag.. at low RPM... so Vtec is the best

 

seriously iam more interested in the Ninja capsules.does it gives Vitamin P(Power) to my BMX?

i thought you are the German engineer also the spokesman for "Ninja".

my BMX don't have ecu can use Ninja capsules?or Ninja magnet?

Edited by Turbonetics
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