ChrisB

I would please ask that you refrain from personal attacks - it doesn't really do anything to prove your point, and doesn't really lead toward any sort of constructive discussion. It would be much more interesting to try and discuss the technical merits of something rather than resorting to name calling (at least, imho ).



How is it a better design? Again, I listed what I thought were important metrics -

1) Power
2) Physical Size
3) Physical Weight
4) Fuel Economy
5) Emission
6) Cost

The 4.6 fails in all of those vs. the ls1 - now it is, as you point out, a smaller displacement engine, so it should have advantages in 2-6 - but it doesn't - mainly due to the 4v design - which is a choice ford made to try and make more (1) - Power - and it still doesn't top the ls1, while negating all it's advantage in the other categories.

Adding cubic inches would make it fail even more miserably in 2-5 probably, at least 4&5 - and whose to say you couldn't also add cubic inches to the lsx based motors (which Chevy is doing in the new vette)? - and likely the lsx would still retain the advantage in all said categories.

After all, there is *no* reason to say "cubes should be even". They themselves don't directly matter, it is their effect on metrics such as those above that matter. If Chevy can have a smaller, lighter, cheaper, more efficient, and cleaner burning engine that still has more cubic inches - and makes more power, I can't see how you could help but call that a superiour design.




There is more to getting there air in there, it is what you do with it - mixture motion, etc. Sure, possibly on an all out peak rpm only race engine you can say a *properly designed* 4v (which I will not submit the ford 4.6 is, at least in comparison to the ls1) will make more peak power, but then I believe the application we are addressing is that of a production vehicle. If you are building such a vehicle you probably wouldn't start with either motor, but a DRCE big block, etc.

I would still like to see some arguments or evidence that support your contention that the ford 4.6 is a superiour design? You have presented a platitude that states air+fuel = power, and claimed that 4 or 5 valves will also move more air. But out of curiosity I looked around the internet - flow numbers for a 4.6 DOHC head - I didn't really see any? If you have some handy it would be interesting to compare.
But also, I think it has been pointed out that flow isn't the only issue, along with the already mentioned mixture motion, there are other issues such as velocity, turbulence, etc.
How many fast NA 4.6's do you see out there? None (that I am aware of) - but plenty of fast FI vehicles. It seems most of the ford aftermarket has gone FI also, conceding the NA market. Now even ford has done this from the factor.

I just honestly don't see how you can claim the 4.6 dohc is a superiour design?

jrp

iTrader: (16)

and the ease of working on a pushrod design cant be beat. the average joe blow with average mechanical skills can easly work on an ls1 or any other SBC..

Black99

First post, NOT trying to **** anybody off.
The Ford modular does leave a few things to be desired - like the bore sizes. The max bore is 3.700", which isn't much. However, that overbore does open up the valves alot, and can produce some nice power results. Like a few people have said, the biggest drawback is the CI and the bore spacing.
With that said, the problems with the modular motors aren't insurmountable. Here is a 600 horsepower (at the crank, I assume) 5.4 4V that makes peak power at 7200 rpm: http://www.enduroracing.com/truckspecs.htm
Here is Al Papito's 5.4 4V 97 Cobra, 500 rwhp: http://www.corral.net/forums/showthr...&pagenumber=25 I pasted to one of the most recent pages, the thread is some 800 responses long... not worth the entire read. But his is the large pic, and his info is in his sig. He revs the snot out of that thing to run 10.30's at 13X mph.
Like I said, not here to **** anyone off, just offering up some info on the competition.

Fulton 1

iTrader: (9)

Just to add a bit of anecdotal info to jmX's comment and Chris' points above; having had both an LT1 and an LT5 in pretty much the same engine bay, I can tell you that the additional size of a comparable displacement DOHC V8 vs OHV V-8 is no small matter. The LT5 (being all-Al and same bore spacing as SBC) was a monsterously large motor (rivaling a BBC in size) compared to the SBC, which is, of course, less compact than an LS1. When you factor in the additional weight and cost the decision is really a no-brainer in most applications IMO.

In my experience, the arguments of "high revving" and "old design" are nothing more than magazine hype. I could give a **** how many RPM's I'm turning (assuming proper gearing of course) or how "old" the technology is perceived to be, if it costs less, weighs less, burns comparable fuel, is easier to service, has comparable reliability, and makes more power, then its better.

jrp

iTrader: (16)

exactly. the people who get caught up in the high revving vs old design are the same kinda people that believe if honda made a v8 or v10 it'd have 240+hp/liter

i have a cammed bolt on ls1 and a stock DOHC mk1 mr2 and love both cars equally, one revs to 8k w/o problem and the other well, you know

cyphur

iTrader: (10)

afaik the new 'vette motor(the ls2) is NOT a 24v motor. the only updated designs on the motor are concering the oil galleys, the oil pan, they moved the camshaft position sensor to the rear, and they changed the heads a little bit. The 3v heads are supposedly going to come out with the new Z06 design that is slotted to come out sometime around 2007/2008. Both motors should support DoD. They DID change the head design a little, however it wasn't to the new 3v design...that and the new exhaust manifolds are 33% lighter then prior models. Correct me if I'm wrong...not a 'vette expert.

427

iTrader: (3)

Thumbs up for the Gen III
On a warm, sunny day in May 1992, a ‘blind’ comparison test was performed by General Motors’ executives on a massive pavement area called Black Lake, deep within the secretive GM Milford Proving Grounds outside of Detroit, Michigan. The conclusions drawn from this test would change the course of history for General Motors Powertrain, its customers and the automobile industry.
At the time, the automotive business was ferociously arguing the merits of building complex, seemingly high tech, dual overhead cam (dohc) internal combustion engines versus building simple, seemingly low tech, pushrod engines. This hands-on comparison by the execs was to put the debate to a seat-of-the-pants experience and allow the leaders of GM to decide the course for the future for GM Powertrain.
The executive leadership of GM would drive pairs of similar appearing vehicles and compare how each vehicle felt—not knowing what engine type was powering the vehicles. Of most interest to readers of this book were two black Corvettes parked at the end of the lineup. One ‘Vette was fitted with a 330 hp, early version of the LT4 Gen II V8 pushrod engine. The other ‘Vette was equipped with the ZR1-spec, Lotus-designed, all-aluminum, dohc engine. Both vehicles were equipped with automatic transmissions. Both were fully integrated for their specific powerplants to give a real world experience to the executives.
The results surprised even the most ardent supporters of the pushrod architecture. The executives couldn’t get over how one of the ‘Vettes pulled from the moment they pressed on the throttle. The surge. The thrust. The torque.
In contrast, they commented on how the engine in the other ‘Vette seemed to take a moment to ‘wind up’ before pushing them back in the seat. This vehicle required more precision and planning when driving fast, to keep the engine up in the RPM band when the power was needed.
As the day went on, executive after executive came to the same conclusion. After all had tested the vehicles, the hoods were raised. To anyone who has driven or ridden in a 300+ hp small block Chevy V8 engine powered vehicle, it comes as no surprise the Corvette the executives liked was the Gen II pushrod V8-equipped vehicle.
From then on, the course for GMs V8 powertrain was set. The world’s finest pushrod V8 would be created to power the most profitable vehicle’s in the General Motors fleet. This was the birth of the Gen III small block V8.

This might be of interest to some.
Kurt

FAST LS1

iTrader: (2)

I too have to say that the Ford 4.6L and 5.4L engines in SOHC and DOHC form do not impress me after being out for over a decade. The LS based engines are actually far more technically advanced even if the general public doesn't see it that way. In actuallity DOHC and SOHC technology came before OHV, so technically OHV is a more modern design.
Ford has shown us that the most they could extract out of the 4v DOHC 4.6 was 320-330 fly wheel hp in the 2001 Cobra's. That was the limit unless they would have actually used some advanced engine technologies like a variable intake which they quit making, variable valve timing and or lift, a higher redline to take advantage of the DOHC design. They did none of these and ended up with what people thought was a more modern design, while it was actually far less advanced than any LS based engine. I think all LS based engines actually rev higher and make more hp per liter than any comparable mod motor NA. Compare their truck engines to LS based engines and compare the 320hp 4.6 to the LS6. LS based engines are more fuel effiecient, lighter, smaller physically, lower center of gravity, have better emissions, better power bands due to larger cubic inches while retaining all of the previous benefits.
From an engineering standpoint the LS based engines do everything better given the parameters Ford has imposed on their "mod motors".
Obviously 4v per cylinder and DOHC's are much more efficient and that's easily proven by looking at almost any Ferrari. Like the Modena that makes 400hp out of only 3.6L. The difference is Ferrari uses the advatages of DOHC, like extreme rpm's, and puts up the numbers. The DOHC design can make gobs more hp and trq, but not when Ford limits their engine from every technological advance all the foreign competitors put in their DOHC applications.

deviate42

iTrader: (2)

you havent driven a mach 1 yet?

samz28

you don't need two cams. Hell i think those honduh's have like two sets of lobe profiles for 4 valves per cylinder on a single cam. VTEC baby.

The question is why don't they do what companys like nissan are doing, lightening up the drive/valve train, then using a VTEC like design to allow the cam profiles to change.

With a good balance/light valvetrain, you could run a single cam for 4 valves per cylinder and two lobe profiles (vtec again,lol) to spin your 5.6 to 8500rpm's.

Then again, i think ferrari is already doing that kinda ****.

I think the LS(X) engine is a profit maker. It's cheap to build, works, alot of mods, RELIABLE. Why venture into new territory wasting millions of dollars, in this crappy market when you can just keep getting bigger on everything.

not the best time to be not making profit in the auto business eh. market sucks.

LS1derfull

WHATS YOUR POINT? Im just saying i finally see Mustang as a decent car with respectable style and power.First time since 1973 in my opinion.(Normally aspirated of coarse, supercharged Cobras are fast, just ugly IMHO)

niphilli

NA = Pushrod, No question

Blown and Turbo = 4V, No question - It is scarry how much power the 4.6L DOHC makes with a little boost, not talking about those crappy eatons...Turbo, Vortech, Procharged

BigPlanTransAm

what about nitrous? judging by the info in this thread, i would say 1 intake and 2 exhaust.
anyway, are there 4v pushrod heads? if so why go with the heavier, bulkier OHC design than a pushrod motor with 4v?

SMOKIN01TA

iTrader: (10)

just wait until the ls1 has been around for 12 years and see how it compares to the 12 yr.old 4.6 of today. i will wax the crap out of it even worse than now.

deviate42

iTrader: (2)

well thats your opinion and my point was the mach 1 came out before 2005

LS1derfull

I didn't mean to be ignorant, i did not know Mach 1 was mechanically superior to Gt? More power? My opinion of 260hp 4.6 Gt is that it was unimpressive, i dont know specs on mach 1.

Ragtop 99

iTrader: (7)

why not get the discussion back on track. He said 32 valve which doesn't mean it has to be a Ford 4.6l. Mercedes, Honda and others make V-8's (mostly small displacement) with a 4 valve design.

Interesting story on the GM executive test drive. Put a half way decent stall (even a 2600) in the vette and the results might have different.

H82BBad

280-300 peak

but the amazing thing on them is are under the curve they kick the dog snot outta an ls1 head in midlift flow.

deviate42

iTrader: (2)

i agree with your statment. The 4.6 is a pig without FI.

But the mach1 is quick
it has the marauder engine
305hp
runnin low / mid 13's stock

Black99

Some have broken into the 12's with a K&N or simple weight loss (jack, spare, etc).