After having a 99 cobra, i love how the 4v's rev,

but i feel on this engine that is too much. We really need the torque to get outta the hole.

I hear that 3v heads are in the works, and i think this would be a perfect mate for our trucks.

whadya guys think?

an example on my cobra was I was making about 704 crank hp but only 550 ft/lbs.

 

Join me in raising your virtual beer glasses. Anybody who posts something like....

an example on my cobra was I was making about 704 crank hp but only 550 ft/lbs.

ONLY 550 FT/LBS of torque. In a little Mustang no less. Brings a tear to my eye.

I am being serious no flame intended. I love torque and in a world of 8000 rpm Hondas with 2 ft/lbs of torque it does my heart good to see things like this.

So are tires for the Mustang just figured into the monthly budget or what.

 

with the 4v heads would we loose torque? or just not gain as much with mods?

later
joe

 

I agree .Posted this a while back and I still think 4 valves would sacrifice torque, unless you fiddle around with the cams (profiles and timing).I also own a 98 cobra and it needs a 4.10 to spool it up to hit the power band sooner.Even on a 3500 lb car and my 3.73's it takes a tic or two to get it going.On a 4800 lb truck with an automatic?? I just don't see it happening! Now a 3 valve..well, now you have my attention.

 

lol,

i was running 4.30's in my cobra, with all that power lol

 

I think the point that Beef is trying to make is that even though his 4V combo made tons of HP, it made considerably less torque. In a light Mustang, you don't need lots of torque because you are not moving heavy weight. You need lots of horsepower to maintain high rpm power. With a heavy truck like ours, the hp is not as important as torque, because you need the torque to move the weight. As anyone who races these trucks knows, the first 60ft is everything. Just for an example, our 01 test truck makes those same numbers, but in the opposite order.

As for the 4V heads on the Lightning, I'd really have to see how it performs in person. I used to be a Lincoln technician, and I can tell you when the Navigator switched from the 2V head to the 4V head in mid 99, the truck lost serious low end power. If you were cruising at 50 and mashed it, it would pull way harder with the 4V heads, but off the line it was a dog compared to the 2v Navigator. As a matter of fact, we had a customer trade his 98 Navigator (2V) in for an 00 (4V), and he wound up selling us the truck back and buying back his 98 because he didn't like how the 00 towed his boat.

 

Now thats what I'm talkin about. A 4.30 gear is ideal for the cobras high powerband.

 

well, i was shifting at 7650, so i needed some gear to get me there lol

 

Sal,

Could the low end torque be made up with additional mods??

I am interested in this conversion as is everyone else, but if it means the loss of low end torque.....No Thanks!!!

 

i think the low end could be made up with 1 mod

a turbo charger,

anything other than that is going to do as other mods do

now, a 4v turbo charged lightning would be the shiznit

 

I like how some some sportbikes have systems designed to get around this issue. Bikes like the Yamaha R-1 have a titanium valve incorporated into the exhaust that can regulate exhaust backpressure. As some of you sportbike fans know, Inlines don't produce torque until 6-7K or higher in the powerband, especially with these new 4 or 5 valve heads. The valve is computer controled on a servo and will restrict exhaust and build backpressure at lower throttle openings to "emulate" torque. It works VERY well! The downside is some minor lag. It works kind of like a turbo! I wonder if this has been tried in the automotive world. It may get around the problem with low end torque loss with these 4 valve heads. Toyota's Tundra with the four-valve V8 has got some realy good valve profiling because low end torque is massive for a small 4.7 liter.

 

You guys are also not taking into account the screw charger.. They always help with low end torque. Im with Sal when he says that he will have to see in person. I think that the combo of the 4v heads and the charger, the torque would be there... Maybe not more than they have now, but with more horsepower.

Just my .02

 

I thought turbo's have to wait to spool up thus "turbo lag". Isn't that why our Eaton screw type is sooo much better for this truck. Because there is no lag just gobs of instant torque and low end power. Correct me if I'm wrong.

Not a flame beef just a question.

---Joe

 

Go with the 4v heads and use smaller valves will help gain SOME of the torque back.

 

if your drag racing, spool it at the line,

and if your on the street, i have to say if your doing 40 to 60 mph and punch it, i don't think there is going to be a whole lot of "lag"