SOHC to DOHC?

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By any chance is their a way to make my sohc vtec, to dohc without a whole engine swap?

posted by  sxyqbano

Hahahahahaha :mrgreen: ....


Never heard of being able to do that, and do they even make SOHC vtechs?

posted by  RusMan

hehe yeah, and sadly i have one... My girlfriends uncle said I could make it dohc by changing the head and the cams, he has been racing and building cars his whole life so I thought he was right...

posted by  sxyqbano

1st of...if you have a Single OverHead Cam....you cant change CAMS since you only have ONE!!!

And where are you going to put the other one? I am sorry...I think you need a whole engine swap...very good engine's to choose from...either the B16 (the Civic Si Motor), the B18 (the GSR motor), or the H23 (the Prelude Motor)...IIRC...I dont know the codes precisely...but close enough

posted by  NISSANSPDR

Ok, cool. Thanks alot!

posted by  sxyqbano

Which is why he said: "My girlfriends uncle said I could make it dohc by changing the head and the cams"

By changing the HEAD to a DOHC head, you GET the place to put the other cam. Sheesh!

As for the head swap, it can be done (Hondas are very interchangeable) but it's usually better to swap the whole enigne (as it's easy enough to find the entire engine vs just the head and associated swap parts).

The best place to get Honda questions answered is here: http://www.honda-tech.com/

posted by  ChrisV

your best bet would to keep the engine configuration stock and intall a turbo kit from greddy or elderblock for 2500-3500 bucks youll easyly be maken 200hp opposed to the stock 127hp for the civic 99 ex , I agree a motor swap is a good idea remember it cost alot more money to make that kind of power with the b18c for the swap . so I say get a turbo and be done with it. GL

posted by  skillzilla

If you have a SOHC Vtec D series motor, then no, Honda never made a DOHC head for the D series. On my engine however (the F22a1, which is SOHC non-vtec) they have a DOHC head for the F series motor that will easily bolt up to my block (from the F22b). B series motors to my knowledge are all DOHC, as are all K series motors. All C series motors are DOHC except the 5th gen Accord's C27. All J series motors are SOHC as well. The H series is DOHC vtec and DOHC non-vtec.

Any more questions are welcome.

And to whomever posted asking if there are SOHC Vtec motors... YES, they made TONS of iterations of the D series in SOHC Vtec. The J series is SOHC vtec. They had SOHC Vtec F series motors...the list continues...

Just to show you out of the Honda/Acura lineup TODAY, these are all the cars with SOHC vtec motors.

Accord V-6
HX/EX Civic
Insight
LX/EX Odyssey (EX w/leather and Touring use SOHC i-Vtec)
LX/EX Pilot
Ridgeline

RL
TL
MDX

posted by  thunderbird1100

I just love when ChrisV throws a big old Pimp slap at somebody. :thumbs:

posted by  Voda48

he's not putting up with our sht anymore, either. I expect to see a lot of pimp slaps in the near future.

posted by  Godlaus

According to this...I was not exactly fully pimp slapped...I ducked just in time

posted by  NISSANSPDR

i HAVE in fact seen one before... some guy rigged a b series head onto a d series block... ran no problem... pretty darn quick too... good for boost, better timing, and stronger block...

posted by  mazda6man

i dont think you can do that

posted by  Alpha Lobo

Is a DOHC engine better than SOHC?
I'm not sure about this but with a DOHC you can time the valve overlap right??
What else does the DOHC have an advantage over the SOHC??

posted by  CarEXPERT

I've certainly never heard of it...links?

posted by  thunderbird1100

I just want to correct myself on one thing.

I just remembered the ZC motor (some people consider it a D series, some not) comes in SOHC vtec and DOHC non-vtec. So I guess honda did make one DOHC D series engine (although it's debateable if the ZC is a D series or not). But, the ZC never came to the United States. I've never heard of anyone putting a DOHC ZC head on thier D series...everyone buys the whole motor since it's only $800 complete with tranny (pretty decent engine too, only 130hp but is very tunable and much better than all U.S. spec D series motors).

posted by  thunderbird1100

il see if i can manage to find it...

posted by  mazda6man

BOOM!
good thing people are helpful in finding things i woulda never found it on my own... haha
http://www.honda-tech.com/zerothread?id=1079426

posted by  mazda6man

That's a ZC head on a D series motor, they bolt up I know that. You said B series head on a D series block, that's what I want to see.

posted by  thunderbird1100

oh... my bad... i shoulda probably read a little more closely... instead of just looking at pictures... my bad... the ZC isnt one of my most knowlegeable honda catagories

posted by  mazda6man

Common cars have SOHC vtec, like the Honda Accord V6.

oops, thunderbird said that already, didnt see it.

posted by  BuggatiV

Generally, engines with dual overhead camshafts (DOHC) are higher performance engines, they produce more power, and can run at higher speeds. The biggest difference is that the DOHC has two camshafts, one thats controls the exhaust valves and the other that controls the intake. The SOHC just has one that regulates both. So the DOHC has better performance b/c of the two independent camshafts.

posted by  BuggatiV

DOHC makes the car run smoother, i can tell the difference, similar thing happened in the garage i work in with a CR-X, where he wanted to change his modified SOHC into a DOHC, but wanted a completely new engine. But yeah, DOHC runs smoother than SOHC, add's quite a bit of power too.

posted by  Zenith

im throwin on a SOHC vtec cam on my hondee this weekend,... a built one (score) built as in new cam, camgear and springs... but anyways, yeh, its possible for SOHC vtec... oh yeah... ITS VTEC! NOT VTECH! ....sorry

posted by  mazda6man

Its VTECH!!! Not VTEC!!!! :banghead:

SOHC has no exhaust and intake overlap?
DOHC can have overlap?
Mazdaman..? why get the SOHC?

posted by  CarEXPERT

SOHC do have overlap, just about every car has intake and exhaust overlap especially single cam engines

posted by  carlos

NOO your wrong. DOHC will have more overlap and you can make it have more overlap because it has 2 cams that control the intake and exhaust.

posted by  CarEXPERT

my point was SOHC do have overlap you said they didn't

posted by  carlos

Why would a DOHC have more or less overlap than SOHC or OHV for that matter?

AFAIK DOHC generally allow for better VE, less valve harmonics, less valve bounce, less valve train losses, etc.

posted by  Wally

YOU TELL ME..

posted by  CarEXPERT

overlap is actully a very important matter a DOCH engine is capable of changing it(at least a VTEC)to make more power through the entire rpm band a SOCH is more limited sure it can make power but depending on the overlap that will determinhe at what RPM as far as VE that really MOSTLY relates to the head,intake manifold and exhaust system

posted by  carlos

wat is VE? How do SOHC vtech cams look like? are they like the DOHC with 3 cam lobes for a pair of intake and exaust?

posted by  CarEXPERT

VE stands for volumetric efficiency and increasing it can give you great amounts of power. if you port your heads and have an exhaust(headers) and intake manifold to match its efficiency you will get greater amounts of air in your cylinders with more air you can now add more fuel and that makes for greater pressure pushing down the piston which in turn makes more power

posted by  carlos

thanks but what about the cam question I had, can you please help me

posted by  CarEXPERT

Yes I understand that VVT is easier with DOHC, but generally LSA can be the same across engine types.

VE is very dependent on the valves even though the throttle/choke plate has most of the authority on air flow to the bowls. The fact that VVT modifies the VE is proof of valve function.

posted by  Wally

damn you guys are car geeks.. i didnt understand one word you said.

posted by  CarEXPERT

not famaliar with the term VVT what does it mean? as far as lobe seperation angle yes it can be the same accros the board but the overlap can still be different

posted by  carlos

varible valve timing. its in toyota cars. also VVT-i

posted by  CarEXPERT

so VVT timing is the equivalent of VTEC then

posted by  carlos

Wait 'til we move to direct injection systems :laughing:

posted by  Wally

I was using it as a generic acronym, so the foibles of Vtec are not brought into play.

posted by  Wally

wait till we move to solenoid actuated valves probably further away than direct fuel injection but it will come. power throughout the entire RPM band will be possible

posted by  carlos

Ah yes those whacky Germans. The Japs will beat them to mass production.

Carlos you seem to walk the walk....do I know you?

posted by  Wally

OH that reminds me... when you intall nitrous system, your fuel and nitrous lines have to go through this solenoid before it is injected into the intake. what does this solenoid do. it's like 2 little can things that say their nitrous company names.

posted by  CarEXPERT

VVT is like VTEC but it doesnt have 3 cam lobes per intake pair. Also it doesnt use 3 rocker arm for a pair.

posted by  CarEXPERT

they don't really do anything but open when you want nitrous and close when you don't it's like a valve but istead of mechanical it's electronic

posted by  carlos

speaking of nitrous, do you press the nitrous button or hold it? I heard that you can have stage nitrous too where it activate for you? HELP ME CARLOS PLEASE please. Im very confused

posted by  CarEXPERT

Vtec doesn't use rocker arms though they use whats called buckets and are directly under tha cam

posted by  carlos

wtf your trippin. vtec uses 3 rocker arms the one in the middle is the one that opens the valves when vtec is kicked in, using pressurlize oil for this

posted by  CarEXPERT

depends on your system the one i've used is activated by a WOT sensor(not really a sensor just a contact switch) so no one can inject nitrous while the engine is off or at part throttle only at wide open throttle

posted by  carlos

what do you mean by injecting nitrous when the engine is off. WHO WOULD INJECT IT WHEN ITS OFF? the vtec computer activates it when it gets to the right RPM.

posted by  CarEXPERT

like I said it depends on your system and how you want for it to be activated that's why i said "the one i've used"

posted by  carlos

OHHH THANKS

posted by  CarEXPERT

sorry..but do you have to hold it or press it for the nitrous.. what is a 80 shot nitrous. I hear this alot but dont know what it is? Carlos please help.

posted by  CarEXPERT

usually a number refers to the estimated HP you will gain from the shot and torque gains are usually higher than this

posted by  carlos

forgot to answer first question by having the WOT sensor in there anytime you floor it and the system is active you'll get a shot of nitrous. it keeps injecting as long as you hold the pedal to the metal and it's the same with the push button systems

posted by  carlos

see thats what i mean... what is a 'shot of nitrous'. So a 100 shot bottle will give you close to 100 hp?

posted by  CarEXPERT

their really is no such thing as a 100 shot bottle they're rated in pounds. if the bottle is small it's posibble to kill all the nitrous in it in just seconds yet you can have a 150hp shot. a 100hp shot system will give you 100hp anytime nitrous is being injected a shot does not contain a set amount of nitrous it's just a common term used "shot"

posted by  carlos

oh... when nitrous is in the bottle, is it in the form of liquid or gas, I know when it gets to the cylinders it is gas? What is the best nitrous?

posted by  CarEXPERT

when in the bottle it's liquid because its compressed and when injected it's gas because it evaporates but it can also evaporate in the lines which is why people purge them before they actually try to use it

posted by  carlos

Then why are there Dry systems and Wet systems? do wet mean taht when they are injected the nitorous is liquid?

posted by  CarEXPERT

Does anyone lese think this is a post whoring thread gone wrong?

posted by  Voda48

Back to your vtec question, the SOHC vtec, the follower is in between the intake valve rockers and the intake valve rockers are in between the exhaust valve rockers, and all are on the same camshaft.

posted by  BuggatiV

A "dry" nitrous system simply means that the fuel required to make additional power with nitrous will be introduced through the fuel injectors, and this keeps the upper intake dry of fuel. The "wet" kit includes a plate system and add nitrous and fuel at the same time and place, thus making the upper intake wet with fuel.
and nitrous is NEVER injected as a liquid, ALWAYS a gas.

posted by  BuggatiV

Every picture (http://asia.vtec.net/Reviews/VTECCityPrev/rockers.jpg) tells a story. Second rocker changeover setpoint is 3400 rpm part throttle and 2300rpm for full throttle.

posted by  Wally

Ohh yeah...

posted by  Zenith

Is i-vtech like regular vtech but only it works at low rpm too??

:driving: vrrrooomm..(vtech)WRROOOOMMMMMMMMM PsH(BOV) VrOoOoMm,,,WROOOOOOOMMMMMMMMMMMMMMM(redline) MMMMM BOOOOMMMMMMMMMMMMMMMMMM

posted by  CarEXPERT

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