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Originally Posted by miketan
Man, you Ford guys crack me up! The Titan has 385 lb-ft of torque at 3400rpm. The 5.4L SOHC 3v has 365 lb-ft of torque at 3750rpm. Using 3rd grade arithmetic, that means the Titan has 20 lb-ft MORE torque at 300 rpm LOWER in the powerband. How is the other guy right?
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Go back and READ the post. Talking about off idle torque...not peak. If you are going to comment at least try and know what is being talked about in the first place.
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Originally Posted by miketan
Looking at the total picture, I see that the 5.4L desperately needs HP not TQ. Going to a DOHC 4v per cylinder setup would increase HP dramatically. However, we're talking Ford here, so I'm not sure if it could be done. Look at the fiasco they had with the '99 Mustang Cobra's. The DOHC 4v 5.4L Triton seems to put out about the same HP/TQ numbers as the SOHC 3v engines. Maybe it's the variable cam timing that helps the 3v modular motors perform so well.. Maybe they should try VCT on the underacheiving DOHC 4v versions as well?
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You obviously don't know enough about the subject at hand. The 4V heads flow very well so that obviously isn't the issue. It's about RPMs and that's where the 5.4L has problems.
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Originally Posted by miketan
However, it's hard to design a small bore/long stroke motor for high HP. Ask any 305 SBC guy. Alternately, I don't think you need to spin the 5.4L past 6000rpms to take advantage of 4v heads.
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Let's see...the 5.4 came out in 1997. The VK56 came out in 2004? So yeah, virtually a clean slate engine that could take advantage of a lot of technology advances. You are not bringing up anything new here as the modular engine's architecture has been brought up and discussed repeatedly. New would involve the upcoming 6.2L Mod gassers that can easily make 400hp/400ft-lbs n/a while still SOHC.
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Originally Posted by miketan
I don't think you'd want the Endurance spinning at 6500+rpms either. The DOHC 4v heads do provide an advantage, centrally located spark plug location for optimum targeting. Also, there's no complicated rocker arm assemblies to reduce valvetrain efficiency either.
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The VK56 can handle higher rpms a lot better. As for the rest of this...what and why was any of it brought up?
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Originally Posted by miketan
I would. It takes a larger 6.0L LS1 based Vortec engine to produce the same power as the smaller 5.6L Endurance. Remember, the Endurance is DOWNRATED by Nissan. The 2v pushrod design was probably deficient in the HP department, but had good torque. So they upped it to a jaw dropping 367hp for marketing reasons, but sacrificed TQ (only 375 lb-ft) in the process. The problem with GM and DCX is that they have to periodically increase the displacement to make any significant increases in power N/A. With a large bore/short stroke DOHC 4v design, you can remain at relatively small displacement levels and create insane levels of power.
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You are vastly under educated about the LSx heads if you believe they are deficient the HP department. You think F-body guys would be swapping 5.3L Vortec truck heads onto their cars if they would be sacrificing topend gains? GM engines are incredibly de-tuned in OEM specs and the factory intake and exhaust systems basically force them to breathe through a straw. The stock DCX 5.7L Hemi heads flow as well as many aftermarket racing heads. Sorry, you need to do a considerable amount of research before touching this subject again.