Pushrod engines, why?

[recklessOP]

Originally posted by GAS,GRASS,OR ASS:

http://www.dodge.com/magnum/img/magnum_sub_displacement.jpg

 

can't find a better picture the pushrods on the new hemi are layed in at an angle so they don't affect intake runners

angling the pushrods just makes the flex problem even worse... smile.gif

 

to be fair, the engineers were more concerned with low speed power. a better port design should certainly help. you can bandaid the problem with stronger pushrods, but that valvetrain won't be doing the engine any favors at high rpm...

[Nitrousbird]

Originally posted by Mensan:

I was talking about this argument. You just mentioned previously that what counts is the physical size/weight of an engine:

My argument was that the hp vs. ci is worthless when the lower ci motor is physically larger than motor with larger cubes.

 

Originally posted by Mensan:

You just proved to everyone that there are 4V heads for SBC engines that are vastly superior to the 2V heads. This was another point I brought up earlier. The 4V heads have more capability. I feel the same way about OHC engines. With the availability of lighter materials, I think we will begin to see smaller packaging and more power out of smaller displacement.

I did not prove the superiority of 4V pushrods heads; I just proved that this is an option available to the pushrod crowd. You must realize that there is plenty of power from people running SB2.2 heads and the like.

 

And people, you are bitching about the NHRA holding back "technology" for the wrong reasons. There are two very good reasons they do this: safety and cost. Do you realize the cost of the development of F1 engines as an example. The NHRA doesn't want that. Also, making more power = going even faster. I'm sure 4 second 1/4 mile times at 330 MPH is dangerous enough!

[Guest FBody Addict]

but can you get 600 horse out of a DOHC 4 banger like you can from a pushrod v8

[Guest stevil]

Alot of race cars still use carbs too, do they suck as much ass as pushrods?

 

Technology is good, but there is nothing wrong with pushrods. The OHC idea doesn't do anything, it's the additional valves that are key. A 4V will flow better than a 2V, doesn't matter if it's OHC or pushrod. What would be better, an OHC 16V V8, or a 32V pushrod V8?

[Mensan]

Originally posted by Hoosier Daddy:

Alot of race cars still use carbs too, do they suck as much ass as pushrods?

 

Technology is good, but there is nothing wrong with pushrods. The OHC idea doesn't do anything, it's the additional valves that are key. A 4V will flow better than a 2V, doesn't matter if it's OHC or pushrod. What would be better, an OHC 16V V8, or a 32V pushrod V8?

Please see my argument on the 4237SOHC Ford engine mentioned previously.

 

Nitrousbird, the heads you showed flow better at all lift numbers. Let's put things like this: How do aftermarket heads make more power? The answer is the efficiency with which they supply air to the cylinders. If you can get more air into the cylinders more efficiently, then your car has the potential to make more power. You can accomplish this with larger valves, larger or more efficient ports, port length and angle, valve job, and a couple of other factors. If you look at the shape of the combustion chamber, you will always be able to increase the cross sectional area of the valve by switching to a multi valve configuration. It's just geometry. It is up to the engineers to decide on how efficient the ports will be. Fact of the matter is, You will always have the potential to flow more air with a multi valve head. Tinman has some kickass flow numbers on his SB2 heads. No one can argue with that. Compare those (at all valve lift numbers) with the flow numbers on Ponyfreaks 4.6 heads. They are both impressive, but it took far less work to get the numbers on the 4V head. They aren't even aftermarket, it was larger valves and port work to a set of stock heads. Look at what Hensler can do with a 4.6. Al Papito is going 10's in a 5.4 DOHC Mustang N/A. He hasn't even begun to tap the power potential of that combination (and he has plenty of TORQUE). It isn't about which production parts are better, it is a question of design. Can you really say you think the pushrod engine is a superior design as far as that is concerned?

 

wickedpyroclown what the fuck are you talking about? Your argument doesn't make any sense. "Well sure, an airplane is fast, but what about a spaceship?" Let's keep things on track.

[Guest Ponyfreak]

---------And people, you are bitching about the NHRA holding back "technology" for the wrong reasons. There are two very good reasons they do this: safety and cost. Do you realize the cost of the development of F1 engines as an example. The NHRA doesn't want that. Also, making more power = going even faster. I'm sure 4 second 1/4 mile times at 330 MPH is dangerous enough!---------------

 

 

It does not matter, power is not holding them back from going faster. It is all traction issues nowadays. Watch some races, most cars loose when they loose traction at 200-300+ mph when they get too far into the throttle.

[recklessOP]

Originally posted by Hoosier Daddy:

The OHC idea doesn't do anything, it's the additional valves that are key.

not true. OHC engines have more rpm potential. more rpm means more power... smile.gif

 

read the whole thread... tongue.gif

[recklessOP]

came across an interesting article on the LS1 today. here's a section discussing the cylinder heads...

 

Development of the cylinder heads was headed by Ron Sperry, with port development by his brother Ken, both of whom have spent their lives developing improved airflow for GM cylinder heads. Teams created the "cathedral" intake ports. Ron Sperry chuckles, "people wonder where the cathedral intake port design cam from. Hell, there wasn't really any room between the head bolts and the inline pushrods for a traditional port; the cathedral shape got us the port volume in the small space available to us."

[Lustalbert]

pushrods or dohc, dosent make a bit or diferance to me, as long as it goes fast and i can aford it.

but i am partial to the hemi for some odd reason.....