gen 3 bu

iTrader: (2)

i have already talked to the guys that are making these and the 4v ls1 heads are in the prototype stages. they are concentrating on getting the sbc,bbc, and sbf heads perfected for regular production.

rons 00z

iTrader: (10)

if your talking about russ at arao when he means by prototype stages he means a cad drawing. i directly deal with him so i know a good amount of info about his company. To get technical he's working on a sweet set of bbc boat heads. cant really say much about them since the deal hasnt been finalized but lets just say they flow ALOT

gen 3 bu

iTrader: (2)

http://www.ronsraceshop.com/displayP...?productID=162
this is the link to rons race shop that sells them. i actually talked to ron and he put me near the top of the list for one of the first sets of these.

instaed of comparing a built 5.0 to a 5.0 cammer motor, because this compares too many different variables - ohv vs ohc, lets compare the 4.6l sohc to the 4.6l dohc. the difference is a lot more accurate to the effects of 2v vs 4v heads for the same application, then lets throw in the new 3v 4.6l heads.

the arao heads are designed as a bolt-on. they work with stock intakes and exhas systems.

rons 00z

iTrader: (10)

PM sent

ChucksZ06

iTrader: (9)

I think the curtain area theories are weak in that they do not take into account the valve guide intrusion into the flow area. Remember you now have 2 valve guides and 2 valve stems. On a smaller port these are large obstructions as a percentage of the total area the air can flow through. Another consideration is the loss of available port area taken up by the width of the seat. On smaller valve sizes the seat area is a larger percentage of the total valve area than on larger diameter valves. Another loss in flow comes from the increased surface area of 2 ports as opposed to one larger port...You have to physically look at and compare some of the 4 valve and 2 valve heads to realize that some of these theoretical discussions do not hold up in the real world.

slyws6

I'd be curious to see how the ford 4.6 would perform if you could somehow put an LS1 based head on it. I bet it would outperform both the 2v and 4v head setups.

-Sly

slyws6

It's kind of like ford tried solving a *lack of performance* problem they were having by throwing more valves at it lol. If they would have just rethought the design of the upper engine assembly they could have solved the problem with a higher flowing head.

rons 00z

iTrader: (10)

well if they had a better intake and exhaust port it would flow better four valves and big ports doesnt make a head work good a good design is what makes a head work good

DavidNJ

Chuck,

There is no question, that all things being equal, more curtain area is far more important than the valve stems. The curtain area is nearly double. Even if valve stems ate half of that, it would still be 50% higher.

And where it makes the biggest difference is at low lifts, before the the port because a restriction. At peak flow the gain may be only modest. At lower lifts the difference is huge.

However, that doesn't negate the weight and packaging issues with the 4-valve heads. Which is were the large displacement LS1s come in.

These heads seem to provide the best of both worlds.

David

chuntington101

4 vcalves per cylinder are great! and i love those strange valves Sly. got any links or info on them?

Thanks Chris.

slyws6

www.coatesengine.com I believe it is. Pretty interesting design!!!

-Sly

ChucksZ06

iTrader: (9)

I am working on my 4 valve 4.6 at the same time as my ls motor. For those of you who are interested the heads with cams on the ford weigh 63 lbs each... the chevy heads are 23 lbs each. That is 40 lbs x 2 . 80 lbs more. Then you add the blower and intake assembly which is about 70 lbs heavier than the ls1 intake. I admit using a ford 4 valve as an example of 4 valve engines is not fair because almost everything ford makes is pig heavy and gets lousey mileage compared to the similar gm products.

zamboxl

iTrader: (1)

well the 3 valve head cant be that bad the new stang has a 3 valve head and it's rated at 305 up from 260, and thats with a lower compression of 9.5

slyws6

More than likely it's due to the fact that the extra valve allows more air to flow into the cylinder wheras if they would have just designed a better intake port they could have stuck with 2 valves in the head and seen the same increase. For instance here's a flow sheet of a set of *unnamed* aftermarket stage 3 4.6 heads:

Stage III 1020 Superflow Bench 3.552 Bore
1.84" Intake Valve
1.452" Exhaust Valve

.100
in- 68 cfm
ex- 53 cfm

.200
in- 121 cfm
ex- 100 cfm

.300
in- 169 cfm
ex- 138 cfm

.400
in- 203 cfm
ex- 165 cfm

.500
in- 219 cfm
ex- 186 cfm

.550
in- 223 cfm
ex- 196 cfm

.600
in- 226 cfm
ex- 201 cfm


Those numbers don't even match a set of stock LS1 heads.

-Sly

zamboxl

iTrader: (1)

whaaaattttttttttttttt god damn is that for sohc or dohc 4.6 damn those numbers suck and thats a stage 3 damn how could the cobra be making so much power even with an sc with those heads i imagin you would make **** for power.

Another_User

My experience has always been that Ford has very restrictive intakes on their engines. From the MAF, to the TB, to the intake manifold, and even their poopie heads. 3 valve heads where both valves open at the same time is a gimmick. Nothing more. There is nothing that can be achieved by this. It is a dumb idea. Actually, I would think it would introduce some turbulence...

technical

You mean just the Ford heads or in general?

There are a couple of foreign cars that use 5 valves to acheive a power to displacement ratio that's mind boggling.

slyws6

The flow numbers I posted are for the Stage 3 SOHC PI heads. Flow numbers for the cnc ported DOHC heads are not available yet.

-Sly

zamboxl

iTrader: (1)

holy crap that is just craptacular

Big-DEN

The numbers posted where for SOHC 2V heads. A proper comparison
would be against a head with similar valve size or GT40 Ford or Ported Stock
with 1.84/1.54 valving.

The funny thing is the numbers for ported stock or GT40 ford are very similar
to this SOHC ported head....

The numbers posted for the 4V heads peak and .400" lift flow are similar to
that of serious race heads.

The multiple intake ports do provide a benefit, EVEN if both valves open at same time. The intake manifold can have 16 runners on a 8 cyllinder motor. At low speeds half of the runners can be shut off through buffer fly valves, so that you are running off of one port, this would provide better low speed TQ, cyllinder fill and mileage.

But then again, more moving parts to malfunction. The other poster posted the head weights of the 4V ford, which is only a 3.58" or whatever bore size... 2x heavier than an LS1 head.

When looking at the similar packaging spaces, the LS1 produce better fuel mileage, can hold a larger displacement, make more N/A power, more TQ and is lighter. i am not seeing a downside.