Guys just wondering this..

why is it possible for some 12V engines to have 450 Hp and well over 1000 ft lbs of tq, while most 24V's that acutally have 1000 or more Ft lbs are well over 550 rwhp? Why are 3rd gen 24's this way too?

Tx

 

Cuz our motor is better than yours!!! JK buddy.....idk ive had the same question for a while...and ive been round the block...althought its my belief the computer has somthing to do with it.

Best wishes all,
Dom

 

The 12V engines rev lower, plain and simple. The lower your rpm is for a given tq, the less hp you have.

I know-- it's ironic because all the pullers use the 12V because they rev higher. There are other factors like head flow and cam timing.

The stock 12V can't pull hard past 2500rpm or so. Yes, you can MOD them to rev-- GSK, 60lb springs, plate, etc. But they aren't like that out the door.

 

Cam timing is another big factor, as HOHN pointed out. The 24v cam timing was retarded for emisions purposes.

I think the injection pump has a little to do with it too...the P-pump pours the fuel in to get the fire going, while the VP44 kinda waits for boost before it really throws it in.

Chris

 

To answer the first question:

FUEL!

 

Its that good ol'e P7100 under the hood baby I have also noticed this, And i have to believe that its because the P7100 fuels like it does down low. My truck smokes as much as a 400hp 24 valve

Eric

 

Most of it is in the cam timing. The 12 valve engines ran 2600 rpm. The 24 valve engines dumped the cat, raised to 3300 and the cam timing was retarded which produces less nox, easier on the low end torque for the drivetrain and has power up in the higher rpm's. The commercial engines all use the same basic cam timing which is about one whole tooth advanced compared to the Dodge cam. I am running the full commercial engine and it picked up a lot of torque with the same injectors and EZ as the old stock engine. This is the major difference in my engine as compared to the Dodge engine but you would have to see it pull a hill with a load to get the full effect.

Years ago when I ran wreckers I used to advance the cam on gas engine to get the same effect. What was the big difference between the 318 in an 800 Dodge dump truck and a plymouth? It was mainly the cam timing. The car engine with the timing advanced would peter out at 4000 more or less but pull a house down. I ran several 429 and 460 fords with the cam advanced a whole tooth, amazing torque for a truck.

The whole tooth advance I have used on v6 buick, 2.8 chevvy v6, 302, 351, 429, 460 fords, 383 and 440 Dodge, just to name a few. It also increases the mileage. In the early '70s when all cars had to run on regular, ford decreased the cam timing 4 1/2 degrees. A few years later they retarded it another 4 degrees to cut nox. Advanced cam timing gives you lower rpm torque peak and less effective high rpm power, retarding it does the opposite. It also changes the compression pressure.

Detroit diesel with their 6v92 was 325 hp for the federal engine, the california version for pollution was 305 hp with 5 degrees less cam timing.

When you start racing engines you have to adjust the cam timing for the best comprimise of rpm and torque, makes the difference between the stock class engine running ten mph faster in the 1/8 as another completely stock engine. On a tear down they usually did not pick it up. Wonder how I know that??

 

I gues the next logical question from a 24V guy is can we just advance our cams and get the bottom end grunt back? Or is valve to piston clearance a concern? Like HID said I built a nice 383 but since it was going into a 4000lb car, I advance the cam 4degrees.

 

I'd say a Cather and Mach4s are pretty close to a tweaked 12V for bottom end fueling. That catcher is a mean sob.

 

Stroke that 383 with a 440 crank/rods. This makes a low-deck 426-- a SWEET little combo! This assumes Mopar 383, of course.

 

Yes, i have heard some awesome things about the Catcher ECM. If i had a 24 valve it would definatley be something i would be wanting.

Eric

 

HAHA. We have the 400/440 crank (451) In a 70 Challenger. Oh yes that that car is definately fun to merge on to the interstate with