really? please educate me on why is it that after 6100 rpm the stock 4v motors in machs fall flat on their face then? and I've seen lots of people shift these cars at 7k rpm, they're the ones that run 14s stock and don't understand why.

also, peak torque occurs at 3300 rpm, not 5000. You don't need midrange torque in a car designed to rev to 7200 rpm; not if your power band is going to be 4500-6000 rpm. I don't know of any times that I've been at 3300 rpm while going down the strip...

If your theory was true about the 13" runners, why is it the FR500 intake with it's 7" short runners allows power to run way up to 7000 rpm, and makes you able to shift at 7k without having the car fall flat on it's face?

And if your theory about the 4v heads flowing so well at low lift numbers was right, why is it the FR500 cams are 472 lift and why is it the cobra R cams are 510 lift? I thought the 4v heads didn't need much lift...

Seems to me we're back to my point of - ford choked the spots cars with small cams and long intake runners - stuff that would be suited more for trucks than cars trying to go fast.


last but not least, the navigator cams are identical to the 03/04 cobra/mach/marauder/aviator cams, which are very very close to the 99 cobra cams. so your point about them using less aggressive cams to retain the low end torque is moot, because they did use em.

 

I'm getting confused. We seem to have two conflicting things going on at the same time. We have one side complaining that the 3 valve OHC Ford engine needs to be a 4 valve double OHC engine to perform well and the other side is complaining that the Ford 3 valve OHC engine is outperformed by a couple of 2 valve OHV engines by GM and MOPAR.

Does this seem odd to anyone else? In the early days of DOHC 4 valve engines, the engineers said it was because 4 smaller and lighter valves would allow the engines to rev at a much higher RPM without floating. They were used in engines with small pistons that turned around 14,000 RPMs. Large engines with a long stroke and large pistons won't allow high RPMs so I'm not sure of a large advantage for 4 valve heads over well developed 2 valve heads.

 

the motors that revved to 14000 rpm are usually big bore and shorter stroke. that's exact opposite of the mod motors, esp the 5.4. The mod motors love to rev because of the overhead cam design, but they'd do much better with a bigger bore - which is what Ford discovered with the 5.0 cammer motor, and is supposed to fix with the boss/hurricane/whatever.

of all trucks, the 5.4 has the largest stroke and the smallest bore...

small bore means your valves can only be so big - therefore gotta keep adding smaller valves to be able to use as much of the little space that is available. I think the 3v was a huge improvement over the 2v with very minimal cost; while the 4v could be an improvement (big over the 2v, not so big over the 3v, if any, in a stock truck-like application), it would take a lot more than just adding in 2 cams and 8 more valves; thus upping the cost a lot. the 4v would be much more of an upgrade in a sports car application, when built right, not with truck intakes and cams.

hopefully ford will just hurry up with that boss/hurricane/whatever... and hopefully the heads will be interchangeable - because I wanna drop one in the mach...

 

yeah i want more hp as well, but if you look at the tourqe numbers ford is right there within 20lbs+/-....... i dont think 20 lbs is going to make a difference of if the job gets done or not....funny thing happened to me as i found myself in a toyota dealorship the other day looking at a rav 4 for the wife, and i drifted over by their full size to check it out and says it gets 20mpg hiway, i say no way it does!! either way i will still buy a ford truck any day of the week

 

might wanna watch this vid before you buy a Rav4:

http://www.youtube.com/watch?v=t09ExAUgtyE

 

There was no Rav4 in the test. Also I call bull on that vidio. It did not show the rear wheels outside of the building. We don't know if they were on a solid surface.

 

That's not unusual.




Since the 3V head seems to get it's **** kicked......maybe a 4V head with VVT (Toyota/Nissan anyone??) would help the displacement challenged Ford.


The Toyota 5.7 is a very undersquare design (much like the 5.4) and has no problem making power at both ends of the powerband.

It takes .5L extra for a "well developed" 2V motor to make similar power numbers (GM 6.2L)

 

The deed is done, the 3V heads have been out for 5 years now.....but I will NEVER accept that there was a cost savings over a head that had been bought and paid for.....the 4 valve heads had been out for 12(?) years.

No way 2 cams and 8 valves would run an extra $500 per motor.....VVT technology should have been applied to the 4V heads and we wouldn't be bringing up the rear in the power ratings.

 

A DOHC V8 can easily cost $500 more to produce than a SOHC V8. Its not just the price of the cams and extra valves. The heads will be larger so they will require more aluminum, there are extra valve seats and etc that will need to be machined, timing chains will have to be longer and etc.

There is more to it than adding parts.

 

Still wouldn't add up to $500 in a mass produced scenario.

But I'll give you the benefit of the doubt......It should still be an option ($500???) for people who want it.

My biggest gripe with Ford over the last few years (besides their sucky service) is they should at least offer us options to match the competition. (GM's 6.0, Toy's 5.7 etc..)

The 4V heads had been bought and paid for a LONG time ago.

IMHO, the development/new castings etc...of the 3V head was as, if not more, expensive than updating the CURRENT 4V heads.

 

I'll give you the "should be an option" part. hell, we should have an option for 4.10 and 4.30 gears... but bought and paid for years ago doesn't quite hold that true, the current design is not 12 years old. the latest incarnation, the only one in production actually, is the Ford GT/GT500 which is a revised version of the Cobra R head. your argument might have held a bit more true with the 03/04 cobra/mach/marauder/aviator heads, which were used on a larger production scale, but not with the last incarnation of the heads...

They still should have put in the option though, you're right. and an option for a variable geometry intake a`la aviator.

 

As far as I know, they (4V heads)are still being used down under and make......drum roll please.....aprox. 400HP on a 5.4.

VVT would keep peak power and increase low end.

No need to create a brand new 6.2. (even though it is a welcome motor and I look forward to it)

 

I agree with the VVT. But you can't compare peak HP in a Car (mustang) to the engine that will work in a truck. Pulling a hill at near peak tow rating for the 20 minutes it takes to get 2500 ft up a mtn. pass would cook the mustang engine. And that is what would happen to the Toy motor in real life, Not the fake *** comertials the play up on TV.

You guys that seem to be embarassed by your 5.4 should get a V-10 SD. 450 ft lbs to haul your loads.
If your not hauling or towing and just want a fast truck for a grocery getter than for gods sake go get a Super Charger. For $4000 you can have a very fast F150

 

you can't compare the power an engine makes overseas, where the emissions regulations are a lot less strict than over here, and gasoline is a lot better, with the choking manufacturers have to do over here and the stupid low octane gas they have to run on.

Also, those motors are in cars - not trucks - so you'd be giving up some of that HP to shift the torque curve a little lower... US had something close in the 2000 R

I'm not saying 4v heads wouldn't help (hell, I love the heads on my mustang), just not as much as some people think they would.

I have been looking at an F250 for a while now. I keep telling myself the truck is almost paid off and I should keep it for a while after that, but I don't know... the 08s are growing on me a lot If Kenne Bell and Whipple were still making their V10 blowers, I'd be driving a 3v V10 right now...

 

My '04 Mustang GT doesn't move under 4000 rpm's, but my F-150 move strong right at takeoff. Horse power and torque doesn't mean much in a truck if it can't be had down low when a truck with a load needs it.