3.5 Chevy VS. 3.5 Nissan

[EspanolaGuitarista]

There is a difference of about 80-90 horsepower on these engines. Maybe one is for low-revving passenger cars and the other is for a sports sedan. With Variable camshaft phasing I would think the Chevy could make around 20-30 more horsepower with nay sacrifices. What do you guys think?

[bszopi]

RE: 3.5 Chevy VS. 3.5 Nissan

Isn't the Nissan a DOHC? I honestly don't know. But that right there is going to help it significantly in the top end power. How do the torque numbers compare? The Chevy has a good amount of torque down low, which will help it get off the line much better than I think the Nissan will. And remember, the Chevy, even though a VVT, is still a pushrod engine. So it probably dies off before the Nissan really starts to make power.

[pepsi_coke]

Your comparing a DOHC to a pushrod?

[EspanolaGuitarista]

Let's dispel an old myth....

OHC engines DO NOT make any less torque than a pushrod. The reason a DOHC makes more horsepower is because of the lesser valvespring pressure required to run the valvetrain. Since the OHC is direct acting most of the time valve timing happens more precisely giving a better range of power and not to mention the advancement of the camshaft works better on the DOHC design. Even still, the Chevy engine most likely put down more torque at a lower RPM. That is what it was designed to do. Make useable torque for the street and provide reliable service. My argument is that in the attempt to make it reliable they have limited(probably on purpose) the cam design. So how do we screw with those built-in issues? I say, "Reprog for more advance earlier with a diferent cam." Anyways that is my little rant for tonight.

[vsop4me3.1]

RE: Let

nissan has a good thing going with those engines

[geoffinbc]

Re: Let's dispel an old myth....

OHC engines DO NOT make any less torque than a pushrod. The reason a DOHC makes more horsepower is because of the lesser valvespring pressure required to run the valvetrain. Since the OHC is direct acting most of the time valve timing happens more precisely giving a better range of power and not to mention the advancement of the camshaft works better on the DOHC design. Even still, the Chevy engine most likely put down more torque at a lower RPM. That is what it was designed to do. Make useable torque for the street and provide reliable service. My argument is that in the attempt to make it reliable they have limited(probably on purpose) the cam design. So how do we screw with those built-in issues? I say, "Reprog for more advance earlier with a diferent cam." Anyways that is my little rant for tonight.

Oh god no you are so far off. Valve train weight or spring presure has NOTHING to do with the difference in power at all. DOHC engines typically flow a hell of alot more air which gives them the ability to breath better which is why they make power up high in the RPM range. However the small ports and valve area of a pushrod engine lead to higher intake velocities at low RPM which always makes for good low end grunt. But these are just typical cases. There is nothing saying either engine cant break the rules. Look at the new LS7 the new heads have extended port height and width and flow 360 CFM. Thats as much as a freaking NASCAR head. The engine also pulls to a 7000 RPM redline and it is a 7.0L.

The 3.5L can only advance or retard the cam it cannot change overlap. The new 3.6L VVT can change both intake and exhaust timing independant of each other which makes for a table flat torque curve. DOHC or not an engine that can manipulate the valves the most will make the best power.

SO comparing the Nissan to the Chevy is not fair unless you Compare the 3.6L VVT to the Nissan 3.5L Then you have a topic. And on that topic Chevy>Nissan

[JasonZ34]

Re: RE: Let

nissan has a good thing going with those engines

Quote from Motor Trend July 05 page 22.

"GM is said to be working on a new type of fuel injection system that'll boost power in it's high-feature DOHC V-6s. The 3.6 Liter engine used in the Cadillac CTS and Buick LaCrosse and Rendezvous Ultra is believed to make 305 horsepower (up 50 horses) with the new injection system. Where that leaves the 303 horse, 5.3 liter V-8 in GM's so-called front-drive performance cars is an interesting question...."

heh, not any more... if gm will push this out.

[SappySE107]

RE: Re: RE: Let

I really respect nissan and their motors, and I also agree that comparing DOHC to pushrod isn't apples to apples. I remember seeing a dual cam pushrod design but can't remember the engine. I also remember the 3 valve 3900 heads that aren't out (yet?). Could get real interesting then, thats for sure

[TheProfessor]

Re: Let's dispel an old myth....

Oh god no you are so far off. Valve train weight or spring presure has NOTHING to do with the difference in power at all. DOHC engines typically flow a hell of alot more air which gives them the ability to breath better which is why they make power up high in the RPM range. However the small ports and valve area of a pushrod engine lead to higher intake velocities at low RPM which always makes for good low end grunt. But these are just typical cases. There is nothing saying either engine cant break the rules. Look at the new LS7 the new heads have extended port height and width and flow 360 CFM. Thats as much as a freaking NASCAR head. The engine also pulls to a 7000 RPM redline and it is a 7.0L.

The 3.5L can only advance or retard the cam it cannot change overlap. The new 3.6L VVT can change both intake and exhaust timing independant of each other which makes for a table flat torque curve. DOHC or not an engine that can manipulate the valves the most will make the best power.

SO comparing the Nissan to the Chevy is not fair unless you Compare the 3.6L VVT to the Nissan 3.5L Then you have a topic. And on that topic Chevy>Nissan

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