VERY in depth article about why 4 valves ARE better!

[G-E]

let me chime in with my gray goo since I'm "back" for a while

let me first ask what is it that makes a 4 valve head flow any more than a 2 valve head?

there is no reason a 2 valve head can't flow as much, the valve like anything is an orifice, the bigger the orifice area the more the flow... the total combined area is one factor, the other is the way the air mixes with the fuel, and again there is no reason a 2 valve head can't swirl the air as much as a 4 valve head...

Maxmaxima91 showed perfectly the difference between the E and DE motors, and the simple fact that the HP is higher is because it still breathes at higher rpm, and fuels/times more efficiently, but this is a design issue of the whole system which could be corrected on the earlier motor... the E could have sequential injection, the E could have a split chamber plenum like the z32, the E could have twin exhausts, the E could have had better stock cams....

as pointed out, compare the power graphs, at low rpm the E and DE are very similar in power output, and if you exclude the enhancements and benefits afforded to the later engine (see previous paragraph) we could even see almost identical output... so then the only difference becomes the usable rpm range...

if we then look at the rpm range of a normal car, why does the car idle at X rpm? why does the car redline at X rpm? why does the car have X gears in the transmission?

like I was saying in another thread about why a motorcycle engine isn't well suited to a car, torque... the reason a car idles at a certain rpm is because there is a bare minimum rpm required to keep it from dying, and while engine harmonics and noise along with emissions play a part, the simple answer is to stay running.... at that rpm the car needs to have enough torque to move the mass of the vehicle, cargo and occupants (and possibly anything towed) and it all has to be moved within a certain acceptable acceleration or no one would tolerate it....

therefore an engine with good torque down low will be able to idle lower than an engine with little torque, if the engine only has usable torque beyond a certain rpm then the engine needs to be kept above that rpm no matter how much HP it produces on a dyno

does high-rpm HP then mean much? not really, the number of gears and their ratios will determine how well that usable rpm range is utilized, and at the end of the day the only thing that changes is top speed.... which is kind of irrelevant in north america isn't it?

[OK85ZX]

SATAN wrote:

Dammit man, I should kick you in the nuts for that statement! :lol:

Answer this then, if two valves make more torque than 4 then what the hell is wrong with the difference in these two engines???????

VG30E torque=182 ft lbs Hp=153
VG30DE torque=198ft lbs Hp=222 no VVT either!

DE makes 16 ft/lbs more torque. Ok i'll say that at best case scenario the better head design along with the intake "might" make the torque about the same as the vg30e IF the 4 valve design makes less torque like everyone says it does. BUT do you think just by better head and intake design they made the torque not only equal, but, 16 ft/lbs MORE than the E! I dont think so! And thats not even using VVT yet!

Now lets look at the HP factor. Whats this?? 69 more horsepower just by using a DOHC 4 valve design?! THE HELL YOU SAY!



I'm sorry but the two valve argument has lost its case.

I just for the record!!!! I'm not mad at any of you guys. I like having debates like this because this is how smart people get smarter. I'm glad I have people to converse with about this stuff.

VG30E torque=182 ft lbs Hp=153
VG30DE torque=198ft lbs Hp=222 no VVT either!

Lets look at these numbers again to find out why that shows the SOHC having a torque advantage.

The torque rating of the VG30E is indeed 16ft/lb's less than the DE. However, the torque rating of the VG30E is also higher than the HP rating.

Now, look at the VG30DE torque rating vs HP rating. The torque rating is a good amount LESS than the HP rating.

Take both engines, tune both to having the same HP rating, and what happens? The VG30E will have the same HP, while having a higher torque rating than the DE. THIS is what those numbers are showing, while as what you were describing was pretty irrelevant considering the HP and torque increase could have easily come from many other things in the car, being tuned more overall, new technologies etc...

I definitely agree with everything you've said so far, I know where the 2/4v and sohc/dohc advantages are etc.. However this post struck me as odd.. because the numbers were basically showing the opposite of what you were trying to prove.

[Domdogg123]

Also Satan, what is the piston compression between the two engines? That could make a big difference in power levels.

[Kennedy]

SATAN wrote:
VG30E torque=182 ft lbs Hp=153
VG30DE torque=198ft lbs Hp=222 no VVT either!

Euro spec's:
E - 170hp / 236nm (174ftlbs)
DE - 222hp / 268nm (197.7ftlbs)

Just incase someone is intrested

[OK85ZX]

Domdogg123 wrote: Also Satan, what is the piston compression between the two engines? That could make a big difference in power levels.

I believe the VG30DE Z32 NA engine comes stock with 10.5:1 comp ( the 222 crank hp figure) over the VG30E's stock 9:1

[William86Turbo]

Firehawk Wrote:

the Z33 still have less low end power than a Z31T.

Completely correct. As do all Japanese cars that i have driven, Supras, Z32s, R31,32,33,34 Skylines... There is nothing out there in the japanese 6 cylinder market that has just that ball tearing low down grunt that comes on quickly. It is so good no matter what way you look at it. You can throw all your twin cams and VVt bullshit in the rubbish bin, Ive smashed so many of those nobs time and time again with old school power. And the ones i havent are dicks for spending enough money to buy a house on their Dyno time and tuning.

Give me a blown V8 anyday over all that wanky shit.

VVt?
Whats the point in advancing/retarding cam timing electronically in a desperate attempt to make up for what all your over complexity has ruined? Those engines are designed to be like that, smooth, refined, motherloads to go wrong... and well... boring. Get over it.

I think the ls1/2/7 are fucking awesome engines... They arent overly complex because they prove that you dont have to be... I guess at the end of the day it comes down to different strokes for different folks. :lol:

[sil89via]

These are some Killer numbers
sr20det
205 hp
200 ft lp
9.5:1
7 psi boost
no vvt, red top

I put one in my 89 240sx it's a rocket hella torque from a 2.0
im running 10 psi and smoke 5.0 all day long.

The VG**E is great bang for the buck with vast potencial

The ka24e is a 3v head for anyone that cares

Even the big torque engines are 4v now Cummins

4v just out flow.

[saltyslug]

not to burst your bubble with the red top, but the 2v ford 2.3t puts out 190 hp and 220 lbs of torque at 15 psi crank it to 20 and you blow the doors off 5.0 also, but in a 3500lb car.

[Z31SPL]

Just to cause u ppl to argue for another 4 pages, what about 5 valves! 20v 4-ag comes to mind

[sil89via]

saltyslug wrote: not to burst your bubble with the red top, but the 2v ford 2.3t puts out 190 hp and 220 lbs of torque at 15 psi crank it to 20 and you blow the doors off 5.0 also, but in a 3500lb car.

Pretty cool, I had one in my old sand rail running 15psi boost
it was a great motor
But I would say the redtop is far better when looking for hp

[MrwassmanNA2T]

Z31SPL wrote: Just to cause u ppl to argue for another 4 pages, what about 5 valves! 20v 4-ag comes to mind

The guys article mentions 5VPC, specifically the 20v 4ag. It says something like the valves are to close together so there is more "squish" points were the air coming thru all the valves "hit" each other and kind of mess of the flow process a little bit. Said something about F1 trying 5 VPC and went right back to 4.

[Az4u2c]

Yamaha has run 5vpc for a long time in their racing engines (and factory crotchrockets too i think). Just recently while poking through a Cycle World at breakfast I read that they have switched or are considering switching to a four valve setup. Like Wassman said, I think if there were a real and true performance advantage to a 5-valve setup, the endless-budget world of F1 would have found a way to use a setup like that.

In response to the electromagnetic valve: I love the idea and I completely agree that the future lies in some kind of development like this, but you can't ignore than that would take some pretty strong magnets. The added strain on the alternator MIGHT (i'm ASSuming here) negate any benifit from decreased mechanical friction. Just a thought.

Also, thanks to Satan for giving us an informational website to read. This is an interesting guy, I'm sure i learned a thing or two poking around this site.

[MrwassmanNA2T]

Mighty strong Electromagnets, but i see how it would be done... May put alot of weight up high too, making the center of gravity a little higher. Imagine 16 Spools of copper wire in a 4 cylinder head

[Z31SPL]

u wouldnt need a huge load on he alternator, it would probably work like a regular ignition coil as a small magnetic field is created then closed and the resulting voltage spike could be harnessed.

[MrwassmanNA2T]

Or starter solenoid/ Fuel Injector