4 Valves better than 2 ???? June 26, 2011, 08:50:45 PM We all know that more valves are better no argument. But wait?????Both the latest Four- and Three-Valve heads offer exceptional flow compared to the older Two-Valve motors. Sure, Ford improved the situation with the Two-Valve motors by offering the so-called Power Improved version back in 1999, but even the improved version was a far cry from its Three- and Four-Valve cousins. With similar displacement and wild cam timing available for all the mod motors, the thing that differentiates the Two-Valve from the Three- and Four-Valve motors is basically head flow. With little to no aftermarket support (until Trick Flow offers up its new Two-Valve head), the choice is limited to porting the stock castings.In stock trim there is no comparison, and this trend continues even once ported. Where a fully ported Two-Valve head may reach 245-250 cfm, a ported Four-Valve motor will be a minimum of 50-cfm, better and may actually offer as much as 100 additional cfm per cylinder. That is a big performance obstacle to overcome, and the main reason why the Three and Four-Valve motors will be chosen before the Two-Valve for serious power levels.With all that buildup, you might assume this is a story on the superiority of the Three- and Four-Valve motors, but nothing could be further from the truth. Despite the valve deficiency, the lesser Two-Valve mod motors can be made to produce some serious power. Just how much you ask? How does an honest 1,000 hp sound? That is a big number in anyone's book, but a serious step for the lowly Two-Valve. Naturally such prodigious power will require the use of forced induction, something that will help us overcome the breathing inefficiency inherent in the Two-Valve motor.1000Hp Two Valve Engine Power Improved Front ViewThe increased stroke length... Now the LS motors with their shallow intake runners flow well into the high numbers without porting. With porting they flow like Niagara Falls. Many believe that the additional valve train increases internal frictions and load. This in turn offsets the advantages of the extra valves. With that said with a pressurized engine the extra valves may not flow more. This in turn as 2 valve engines have less rotating MASS in general. Basically a NA small displacement engine will make more HP than a 2 valve in some cases. It all depends on the shrouding and the angle of the runners. Sometimes more is not BETTER. Just saying. The HP rating on the GM Ls series motors is beyond comparison that is why GM did not go 4 valves and still make tuns of hp. They have the flow they need. And the push rod engine is lower and can allow the engineers to design lower frontal area cars for better high speed handling and cornering. Just a discussion on the differences in the valve number discussion. More is sometimes not better in all cases. Thanks Quote Selected
4 Valves better than 2 ???? Reply #1 – June 26, 2011, 09:04:54 PM I wonder which one of you two (Tom and Beau) can pee the farthest. Quote Selected
4 Valves better than 2 ???? Reply #2 – June 26, 2011, 09:29:53 PM Quote from: vinnietbird;362304I wonder which one of you two (Tom and Beau) can pee the farthest. I hear you Vinnie just wanted to post some good info on the subject. Its a forum and i thought if i posted a new title we could discuss it. Just a discussion issue. NO WORRIES Thanks Quote Selected
4 Valves better than 2 ???? Reply #3 – June 27, 2011, 03:39:33 AM Take the blowers, shrouding, and all that and toss it.Humor me here; imagine a stock 5.0HO with the normal 2 valve E7 heads...yeah, it's..peppy, and flows decent for a stock design. Now, imagine the same IDENTICAL engine, with the same chambers, with 4 valve heads. Yeah, it may just be a little heavier, but it will also produce more power.With today's technology, VVT, cylinder deactivation and what's it/who's it and such..it's all moot.And I will agree the LS engines are very moddable with crazy power gains, however, GM has been building the small block in one version or another for almost 60 years...it makes me cringe to see these clowns with new Camaros thumping their chests like some kind of Columbus just discovering North America....guess what Captain...it's already been done before. Originally Posted by vinnietbird I wonder which one of you two (Tom and Beau) can pee the farthest.Depends on how tall the building I'm standing on is, and how hard the wind is blowing behind past me lol Quote Selected
4 Valves better than 2 ???? Reply #4 – June 27, 2011, 05:45:56 AM Thats true but you will also notice that with VVT it is activated at a set RPM. This way the engine can accomplish a dual function. Good torque and drivability at low end and good breathing and flow at the TOP. Yes its all ready been done before but chevy is still doing it and getting tremendous results. Yes its like Columbus discovered America. But Chevy gets the ships their FASTER!!!The building thing does not work for me. At my age i have to do it in stages. Then add it up. Quote Selected
4 Valves better than 2 ???? Reply #5 – June 27, 2011, 02:06:48 PM Quote from: ThunderbirdSport302;362318Humor me here; imagine a stock 5.0HO with the normal 2 valve E7 heads...yeah, it's..peppy, and flows decent for a stock design. Now, imagine the same IDENTICAL engine, with the same chambers, with 4 valve heads. Yeah, it may just be a little heavier, but it will also produce more power.lI'm trying, but all the 5.0s I see have aftermarket aluminum heads that flow 2x more than those door stop E7s... Quote Selected
4 Valves better than 2 ???? Reply #6 – June 27, 2011, 06:08:22 PM Tom Rezno, VVT is so that a small displacement engine can have some low end torque. It's not there because of any 4-valve heads. Intake runner flaps are there for the same reason.Engines make power by moving air. The more air an engine can move, the more power it can make. Multi-valve engines can move more air, ergo they can make more power (all else being equal). This is a simple geometry issue - with a round cylinder there is only enough real estate available for valves. With round valves in a round cylinder it is more efficient to use multiple valves than it is to use two because multiple valves allow for more valve area. Add in the fact that virtually all multi-valve engines feature overhead cams, usually two per side, and can therefore generally rev higher (overhead cams eliminate a lot of reciprocating weight, or inertia, from the valvetrain), which means they can move more air. And because manufacturers don't have to bend intake ports around pushrods they can make larger, cleaner-shaped ports.I have the greatest respect for the GM LSx series of engines, but they make good power despite their two valve heads, not because of them. Displacement is a big factor (the 5.0 4-valve Ford makes pretty much the same power as the ~20% larger 6.2 LS3, for example). Boost is another factor. GM uses both in order to make up for the inherent inneficiencies in the 2-valve, pushrod-activated design. To great success, I will add. And although the pushrod deisgn is less efficient in that respect, it has its advantages: Cost, weight, and packaging (an LSx is tiny compared to a 5.0 Coyote, for example).Even GM knows that 4-valves are the present and future in terms of efficiency and power. Every engine GM offers, aside from the LSx and diesels (and possibly the 4.3 in the truck, if they even still offer those), uses 4-valves per cylinder. The antiquated 3.9 in the Impala, GM's last pushrod V6, is finally being replaced by the 4-valve 3.6.Gm's 3.6 makes ~312 horses in the Camaro. Try that with a naturally aspirated pushrod V6 of the same displacement. Certainly nothing in GM's arsenal can compare. That's even more power than the legendary turbocharged and intercooled GNX made.Ford's 3.7 makes ~305 horses in the Mustang. No pushrod engine Ford ever made of similar displacement (or even much larger displacement) ever came close.Chrysler's 3.5 SOHC 24-valve V6 made ~250 horses, far more than their largest pushrod V6 (the 3. ever made. And the 3.8 and 3.5 are of the same engine family! Even the lowly 2.7 DOHC, which is also in the same engine family, made more power than the pushrod 3.8. And the 250-horse 3.5 has been bested by the new 290+ horse Pentastar.In fact, I can't think of any pushrod engine, past or present, from any manufacturer, that ever made numbers anywhere near these examples without forced induction. Or much, much more displacement. Or both... Quote Selected
4 Valves better than 2 ???? Reply #7 – June 27, 2011, 08:55:01 PM Somebody is going to be pouty when the Vette receives a small displacement, high revving over head cam twin turbo engine. Quote Selected
4 Valves better than 2 ???? Reply #8 – June 27, 2011, 09:22:04 PM Quote from: shame302;362382Somebody is going to be pouty when the Vette receives a small displacement, high revving over head cam twin turbo engine....that's even faster... Quote Selected
4 Valves better than 2 ???? Reply #10 – June 27, 2011, 11:06:11 PM Yes the c7 will be something else. I know 4 valves are more efficient but ford has fallen short of HP compared to GM ls engines. Ford has much less hp than chevy. And ford has more valves. Now the fastest 2,3 ford i know of has a 2 valve cylinder head. Bottom line is i know 4 valves flow more but not all engines need it. Just sayingYouTube video: Quote Selected
4 Valves better than 2 ???? Reply #11 – June 27, 2011, 11:26:30 PM Quote from: TOM Renzo;362393but ford has fallen short of HP compared to GM ls engines. Ford has much less hp than chevy.Dude!Compare the hard, basic facts of the 5.0 Coyote to the 6.2 LS.A smaller engine making more power. What are you not getting here?I will grant you that the LS has tons of potential power inside with a few simple mods...be that as it may however, the new 5.0 is kicking the LS's ass...Time to take off the blinder grampa...the LS isn't the king of the hill anymore. Quote Selected
4 Valves better than 2 ???? Reply #12 – June 27, 2011, 11:55:32 PM "Boost is another factor. GM uses both in order to make up for the inherent inneficiencies in the 2-valve, pushrod-activated design" ThunderchickenI dont agree here, it was Ford that had to strap a supercharger on in 03 to give the fords a chance against the N/A Fbodies"Dude!Compare the hard, basic facts of the 5.0 Coyote to the 6.2 LS.A smaller engine making more power. What are you not getting here??????!!" Lets face it, the LSX is an old platform , why it may have slight changes over the years its basic design has been the same since 97' and its gotten faster since. After close to 15 years of production and tweaking the DOHC platform ford hasd to come up with an ALL New Dohc N.A combo ( the coyote) that can compete with the LSX platform After Years all those years getting Trounced by its LSX counterpart :punchballs:I have driven a few new 5.0s and an actually gona be swaping one in a customers 65 mustang convertible when im done with the mini tubs and suspension and such. I will say i was impressed, Aside from The supercharged cobras/shelbys its the first stock mustang ive driven in years that i felt really had some nut, and its a pretty badass looking motor. They scream with boltons and heads/cam, they really did their homework on this engine, but after years of LSX domination, they had to do somethingI know you guys all think im a Chevy lover and this and that, but ive worked on a number of badass mustang, and each car/ engine will always have its highs and lows. While the Dohc motors can be made to be serious screamers, on the swap end of things, they are just too expensive to play with for alot of people, when most good used N.A dohc powerplants are around $2500 and an iron 6.0 GM lsx counterpart can be found for $1,000 bucks and is a cam change away from 400whp, its hard to think of buying a more expensive dohc and modding it to make as much as the GM 2 valve counterpart. Trust me if 03-4 Termi swaps were cheaper, id be throwing one in my 89 Gt mustang and not an LS14 valves and small motors are a thing of the future, But i will say this.. Chevy's old 2 valve motor did pretty good job at the 24hr Lemans beating all its supercar 4 valve competitors ;) :rollin: Quote Selected
4 Valves better than 2 ???? Reply #13 – June 28, 2011, 02:39:08 AM Quote from: Glocklimited9;362395I dont agree here, it was Ford that had to strap a supercharger on in 03 to give the fords a chance against the N/A FbodiesActually, Ford did that before Camaro was even a word...read some history..Thunderbird history. Lets face it, the LSX is an old platform , why it may have slight changes over the years its basic design has been the same since 97' and its gotten faster since. After close to 15 years of production and tweaking the DOHC platform ford hasd to come up with an ALL New Dohc N.A combo ( the coyote) that can compete with the LSX platform After Years all those years getting Trounced by its LSX counterpart Let's face it, give the devil his due....the current argument is about 2 valve vs 4 valve engines...I dunno how a supercharger fits in as neither the coyote nor the LS are (for the majority, and in this instance) forced induction...Also, sometime soon, even the folks at Generic Moturds will be abandoning the miracle LS and going to the dual cam, non pushrod design that nearly everyone else is doing. So they've made a nearly 65 year old design (basically) produce 400 horsepower? Hell, I'd say it's time to learn to walk on the hind feet and get modern, eh?I have driven a few new 5.0s and an actually gona be swaping one in a customers 65 mustang convertible when im done with the mini tubs and suspension and such. I will say i was impressed, Aside from The supercharged cobras/shelbys its the first stock mustang ive driven in years that i felt really had some nut, and its a pretty badass looking motor. They scream with boltons and heads/cam, they really did their homework on this engine, but after years of LSX domination, they had to do somethingNot so sure that "pretty badass looking motor" was what they were about when the design was created, but yeah, it is impressive in the power level. I know you guys all think im a Chevy lover and this and that, but ive worked on a number of badass mustang, and each car/ engine will always have its highs and lows. While the Dohc motors can be made to be serious screamers, on the swap end of things, they are just too expensive to play with for alot of people, when most good used N.A dohc powerplants are around $2500 and an iron 6.0 GM lsx counterpart can be found for $1,000 bucks and is a cam change away from 400whp, its hard to think of buying a more expensive dohc and modding it to make as much as the GM 2 valve counterpart. Trust me if 03-4 Termi swaps were cheaper, id be throwing one in my 89 Gt mustang and not an LS14 valves and small motors are a thing of the future, But i will say this.. Chevy's old 2 valve motor did pretty good job at the 24hr Lemans beating all its supercar 4 valve competitors I KNOW you are a chevy lover....ever since you've been here, it's been LS this, BBC that...whoopity doo....you seem to forget that Ford, and Shelby, that old tightwad sumbitch himself took a small British car, stuffed it full of good ole American 2 valve/cylinder V8 sweetness, and kicked Ferrari's ass from here to Maranello and back again.You're so pumped on GM stuff you can't accept that pushrod engines are the equivalent of sharks, turtles and birds: mere descendants from a stone age. With that, I leave you with this to ponder: Quote Selected
4 Valves better than 2 ???? Reply #14 – June 28, 2011, 08:10:56 AM As im happy Lol thats a funny picture and it is true... Because power for dollar show me another motor that can make the same power.. 2 valve, 4 valve, 156 valve, it doesnt matter you wont find it. There is a reason many guys are putting LSX power in place of their old 5.0s and newer 4.6s, even supercharged 2 valve 4.6s have a hard time making the power a bolt on LSX makes, thats just the cold hard facts.While i do love my chevys, i actually like anything thats fast and makes power, if i was all about power i would have taken the 2.3T out of my turbocoupe long ago and replaced it with an LSX, but to me, that would ruin what the car is. Ive had tons of diffrent rides, had supercharged/ turbo civics,Turbo Gti's, many 5.0 mustangs with 306's, 347s, and tons of 2.3s The Dohc 4.6 5.4 and new 5.0 are excellent engines, as is the new hemi, but people are swapping then into cars because the cost to play is just too much.Like i said i would love to put an 03-4 termi in my mustang, ive done a few of them with stegmiester and KB blowers, and they are lightning fast with badass supercharger whine to boot. But the prices are just so much higher, Hell i bought a complete 25k LM7 5.3, with all accessories, cats, 02, maf, wiring, computer, for a measley 400 bucks, im gonna swap in one of my old Texas speed cams, long tubes, and stick it in my 97 2wd short cab/bed stepside silverado.BTW I never mentioned anything about a BBC, thats not my style, i like modern performance. No paperweight heavy bbc's here Quote Selected
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