Modulars

[351wStang]

Why such a difference in performance between 2v and 4v? What makes 4 small valves better than 2 big valves? Accuracy?
Why are the 2v and 4v blocks different? What is different about them?
What makes mod motors respond so well to FI?
How do mod motors make so much power with stock cams? Does this have something to do with the difference between 2v and 4v? Do cams have that little of an affect on mods?
What cars had/have the 4v motor?
Can a mod motor be built N/A to stand up to a N/A pushrod motor (5.0)?
Do mod motors respond better to boost/n20 than pushrods motors?

[StangNut86]

actually, 2 big valves is better than several smaller ones, for flow reasons. you won't see many guys running an overhead cam motor running sub 8 second ETs, but all the top classes use OHV. the big advantage of an overhead cam motor is how huge the ports can be, since there's no need to create space for pushrods. if you ask me, DOHC is kind of a gimmic anyway.

2v and 4v blocks aren't any different from each other... it's all in the heads. they call them 'modular' for that reason.

mod motors respond to efi because they were designed with its flow characteristics in mind, whereas windsors were designed before EFIs time.

most guys running stock cams on a mod are also running roller followers with higher ratios, which makes a huge difference in flow and powerband.

high-end lincolns and mercuries, '99-04 cobras, and some trucks have 4v motors.

mod motors can do anything a 5.0 can, just depends on how deep your pockets are.

not really.

hope that helps.

[351wStang]

Thanks, but I meant FI as in Forced Induction, not EFI Electronic Fuel Injection.

[boosted331]

Originally Posted by StangNut86

actually, 2 big valves is better than several smaller ones, for flow reasons. you won't see many guys running an overhead cam motor running sub 8 second ETs, but all the top classes use OHV. the big advantage of an overhead cam motor is how huge the ports can be, since there's no need to create space for pushrods. if you ask me, DOHC is kind of a gimmic anyway.

4 Valve motors produce tons of port swirl and flow massive amounts of air at low lift. You can flow just as good if not better than a head with 2 valves, but you keep the port velocity much higher running the 4 smaller valves and it's easier to put together a high flowing head on a small bore motor.

Do you honestly think that the cars do not run 4V heads because they are inferior to 2V pushrod motors, or do you think that they don't run 4V OHC heads because class sanctioning prevents them from running them, as well as the massive cost of building an entirely big block engine from scratch with a set of custom one off heads?

The reason there is such a performance difference between the 2V and 4V modular cars is since the 4.6 runs such a piss-ant 3.55 inch bore it is hard to get 2 big valves in there, and it's hard to get them to flow well. They come with small valves, so the heads do not flow very well. Even full ported most 2V heads are cracking 200-215 CFM's, whereas a well ported 2V head for a 5.0 with 2.02/1.60 valves will usually flow in the 300-330 CFM range.

IMHO, mod motors take boost much better than the old pushrod cars. For 550+ RWHP out of a 5.0 you need 2000+ dollars for a new 4-bolt block. For 550+ RWHP out of a 4.6 you need new pistons and rods, and a cobra crank if it's a 2V. For 4.6 heads you need to drop some cash to port them, stock 4V heads will flow 320+ CFM. For 5.0's you are going to drop 2000+ dollars for a set of heads that flow 320+ CFM's. 4.6's can spin to the moon, so even with less torque they can make more horsepower.

[flex339]

Originally Posted by 351wStang

Why such a difference in performance between 2v and 4v? What makes 4 small valves better than 2 big valves? Accuracy?
Why are the 2v and 4v blocks different? What is different about them?
What makes mod motors respond so well to FI?
How do mod motors make so much power with stock cams? Does this have something to do with the difference between 2v and 4v? Do cams have that little of an affect on mods?
What cars had/have the 4v motor?
Can a mod motor be built N/A to stand up to a N/A pushrod motor (5.0)?
Do mod motors respond better to boost/n20 than pushrods motors?

You can correct me if you know I'm wrong

Well say you start out with a 2V motor. The head flow is ok on them. Well you decide to heavy port them to get more power. When you open up the ports a lot you tend to make the a/f mix lose velocity entering into the combustion chamber. With 4V heads you typically start out with more flow and better velocity right off to bat because of the less surface area the a/f mix has to fill getting by each port, but you have more surface area over all for power production. lt also take a lot of porting to lose a considerable amount of velocity on 4V's. The modulars also have many advancements over previous engines due to the modern engineering. One example could be the variable intakes which allow for good low end and top end power production.

[GTStang]

Originally Posted by boosted331

4 Valve motors produce tons of port swirl and flow massive amounts of air at low lift. You can flow just as good if not better than a head with 2 valves, but you keep the port velocity much higher running the 4 smaller valves and it's easier to put together a high flowing head on a small bore motor.

Do you honestly think that the cars do not run 4V heads because they are inferior to 2V pushrod motors, or do you think that they don't run 4V OHC heads because class sanctioning prevents them from running them, as well as the massive cost of building an entirely big block engine from scratch with a set of custom one off heads?

The reason there is such a performance difference between the 2V and 4V modular cars is since the 4.6 runs such a piss-ant 3.55 inch bore it is hard to get 2 big valves in there, and it's hard to get them to flow well. They come with small valves, so the heads do not flow very well. Even full ported most 2V heads are cracking 200-215 CFM's, whereas a well ported 2V head for a 5.0 with 2.02/1.60 valves will usually flow in the 300-330 CFM range.

IMHO, mod motors take boost much better than the old pushrod cars. For 550+ RWHP out of a 5.0 you need 2000+ dollars for a new 4-bolt block. For 550+ RWHP out of a 4.6 you need new pistons and rods, and a cobra crank if it's a 2V. For 4.6 heads you need to drop some cash to port them, stock 4V heads will flow 320+ CFM. For 5.0's you are going to drop 2000+ dollars for a set of heads that flow 320+ CFM's. 4.6's can spin to the moon, so even with less torque they can make more horsepower.