Dem_z

iTrader: (1)

The search feature isn't really working out for me , so I was like fack it.

Okay to start off, I'm really lost on this whole DOHC and SOHC deal....And when I google'd it... I got even more lost.

You see, from what I got:

SOHC = cheaper
DOHC = More Expensive but better.

But heres the kicker, AMG engines use SOHC engines.... Now AMG to me is like the king of cars (...and price)... So why don't they use two camshafts on their engines? Like their V12 engine is more powerful than ferrari's ENZO's engine but it's SOHC.

Okay relating back to the lancer. Our engine is SOHC, so can we some how make our engine out perform the g63 (i think that's what the EVO engine is called)?

and
Can someone please explain the whole concept of SOHC and DOHC engines to me... And try not to be positive towards DOHC engines w/o explaining why AMG uses SOHC over DOHC, like there has to be a reason? (maybe there's some hidden secret to SOHC engines that few people know about :/)

Any help would be great.

ghostrider

iTrader: (13)

SOHC has only one cam to control the duration of both the intake and the exhaust ports opening. DOHC uses two cams to independently control the openings. Performance-wise, you won't gain any power just by having a DOHC version of an engine versus a SOHC version. What you do gain, however, is increased tuneability which in turn is what gives you performance gains.

Evo owners can choose any combination of cams to suit there needs, where the SOHC 4g94 can't. Instead, we have to decide how much power to sacrifice on one end of the powerband in order to gain power on the other end.

As for what AMG does to create more power, did you check to see that other factors like curb weight, engine displacement, etc. are the same? If not, then the difference in power can be attributed to something other than the difference in cams. In the long run I can't think of any downside to having DOHC over SOHC other than price.

Tweak3D

iTrader: (7)

Well, one disadvantage is that you have more rotating mass that the engine has to move which always hinders performance in one way or another. thats all that I can think of this early in the morning =P.

-Justin

rhyzin

iTrader: (1)

outperforming a 4g63 is gonna be hard just because of the way the two engines were designed out the factory. there was comparison somewhere on the internet with pictures between the 4g93/4g94 head and 4g63(eclipse/evoIII) head. despite both being 2.0 liters, you could tell off the bat from the pictures which one was the 4g63. sorry, dunno what site it was.

AMG is tuned as far as it will go from the factory, hence the SOHC. normal consumer cars with DOHC still have leeway in terms of tweaking for max performance. people who retune an AMG are WAY few and far between. also, i believe these cars have variable-everything like variable intake runner length and other weird **** we won't see on normal consumer cars.

mitsumichael7

iTrader: (1)

This was actually a HUGE topic of discussion in the 3G Eclipse board when the 3G eclipse was released with SOHC. As far as the Evo vs. US Lancer goes, the Evo is built to perform, mroe than just an extra cam. Everything from the intake and exhaust ports, to cam lobe duration, to ECU programming. The US Lancer is an Econobox designed to be reliable. Now as far as DOHC vs SOHC (and I am not even going into the Benz AMG line) the DOHC has 1 cam for intake valves and 1 cam for exhaust valves which makes tuning better. Other than that there is very little difference in a motor design.

Dem_z

iTrader: (1)

Disadvantage to the SOHC engines?

But thx everyone for your help... Still don't really understand AMG's mojo, but yah it's all good.

ghostrider

iTrader: (13)

Tewak3D is saying that the DOHC has another cam to rotate, therefore it takes that much more power to move it; power that could be used turning your wheels and creating power. One thing to remember, however, is that I'd be willing to bet that the amount of power you lose in turning a second cam is far less than the amount of power that you can gain by adding that much more tuneability.

And as far as AMG's magic, they have a LOT more thought put into their designs than your average question of SOHC vs DOHC. Maybe run a google search on what they do since rhyzin summed it up pretty much in his post.

Tweak3D

iTrader: (7)

what I am saying is that if an SOHC can produce the same power as a DOHC then isn't the extra weight of the second cam a waste and just one more part you have to spend money on?

-Justin

ghostrider

iTrader: (13)

Not necessarily. Like I said, the extra cam does need more power to turn but you stand to gain more power with it than without it. Take a supercharger for example. The sc utilizes a pulley system which takes initial power to turn. This power is taken from your car, but the initial loss of turning the supercharger is nothing in comparison to the gains you get once the supercharger is flowing.

Granted, an extra cam (upgraded and tuned) will give you more gains overall.

Nm0ney34

iTrader: (3)

if i remember right, there really isnt a huge diff. of the outcome when tunning the 2... I thought that was discused on here somewhere too.

But anyway, The power and tunabilty u get from a second cam isnt always that great. U get that tunability but its a little harder that way too. Ive heard of alot of guys ****ing their engine up messing with there DOHC's. SOHC is simpler, and the power to turn the second one can be used elsewhere like everyone said, but then again like GR said u can stand to gain a bit more from the second can...So in the end I guess its the tuners call, But as to advantages and disadvantages they both got them.

I really dont see griping over SOHC and DOHC. As far as the 4g63 and 4g94 go. U got so much more potential with the 63. The problem with the 94 is there isnt that much potential for it unless u go turbo.

But tuners call, just gotta have fun with it

Btw where did u get SOHC cheaper? it all depends on the car really.

Powder

iTrader: (1)

The reason the AMG cars are more powerful than the Enzo..........superchargers and turbos. Works every time................

Dem_z

iTrader: (1)

"As for DOHC, again, there is an advantage in weight, at an extra cost, both financially and in complexity. It costs more to grind two camshafts than one and it takes more stuff to drive two cams than one." I copy'd that from the link below.

[link]http://www.allpar.com/eek/cams.html[/link] (I'm hoping that thing works)

It's a good article, and worth the read if your interested in the glorious world of DOHC, SOHC, and pushrod engines. But then agian, I posted my question after reading that article.

The Enzo is NA?... But yah I was just getting that if DOHC is "better" than SOHC then why doesn't AMG jump on the bandwagon?

------

But meh, I guess I have to research everything alot more throughly... Because I always thought, the 4g63 and 4g93 are practically identical, and whatever is different between the two you can just replace. Like the Cams or ECU or flywheel.

Does anyone have any good links that go indepth with the two engines?.... Maybe some PDF links to the Engine Manuals? Anything would help...

But yah, thx agian guys!

Powder

iTrader: (1)

Yeah, the Enzo is a N/A V12 against the AMG's which are either supercharged or turbo-charged V8 or V12, depending on model.

rhyzin

iTrader: (1)

technical manual for the 1G eclipse. strictly the old 4g63. download all 4 files and run dsmtech.exe.
http://www.twingles.com/manualcd/dsmgift/

technical manual for the 2G eclipse. gives technical information on just about all aspects of the 95-99 eclipse 4g63/420a. download all 4 parts to the file and run 2gdsmtek.exe.
http://www.crco.com/95-99techmanual.html

this is more of a shop manual for the 4g93. same head as the 4g94. has internal diagrams of the engine. doesn't describe all the engine systems like the eclipse tech manual. haven't found one yet.
http://www.ecanfix.com/users/manualc...cer_engine.pdf

TypeIII

If you never touch your cam phasing via cam gears (and most of us probably don't anyway) then there's nothing a DOHC can do a SOHC can't.