A-413, is the 3rd design pump a good upgrade?

[turbovanman²]

Doing some light reading and Dodge updated the pump in 99. It will retrofit back to 87 soooooooooooo, they say

The 3rd design pump uses a dual cycloidal pump. The oil pump has increased flow and capacity at low idle speeds, also has reduced flow at high speeds which reduces the load on the engine resulting in improved fuel economy. The new pump is also quieter. It also features revised aka larger suction and pressure ports to accommodate the new design pump gears.

[Dave]

Less load on the engine means more HP. Yay I get a cookie!

Simon, if you don't hear if it's good or not then the next time I got my trans out I'll give it a shot. Not like it's really that hard to pull it.

[turbovanman²]

But less volume could mean less pressure which isn't good for performance.

[Stevien1]

The one in my van is out of a 2000 or 2001 31TH- so it obviously works in the older A413's! It has no problem holding 100+ psi up to 6000rpm at WOT.

[turbovanman²]

The one in my van is out of a 2000 or 2001 31TH- so it obviously works in the older A413's! It has no problem holding 100+ psi up to 6000rpm at WOT.

I know it works, lol, just wasn't sure if it WORKS,

[Torqueflite]

But less volume could mean less pressure which isn't good for performance.

The reduced volume at higher speeds is "relative to the older pump". Yes, it puts out less flow compared to the older pump, but the extra flow that the older pump puts out is not needed. The pump only has to put out a certain volume of flow in order to maintain the line pressure. Let's say for example, the pump just has to spin at 1500rpm in order to put out 100 psi line pressure, and this 100psi is sufficient to clamp the clutches in the tranny for your 300hp. Your engine could be winding at 6000rpm and putting out that 300hp, but really, your pump still only needs to be spinning at the 1500rpm, cuz that's all it needs to spin to flow enough fluid to make that 100psi line pressure. Any extra rpm out of the pump is excess flow that's not needed (which eats up hp), and the pressure regulator valve in the valve body must open up even more to dump the excess fluid in order to maintain that 100psi. A good example of this is your power steering pump. It only needs to be spinning at idle to put out enough flow to pressurize your rack so you have power assist when steering. Off idle, the p/s pump is moving extra fluid for nothing.

The old pump (which lots of people have seen) is an internal/external gear pump, with a bunch of little teeth. The new "dual cycloidal" pump is very similar to the older internal/external gear pump, except that it's teeth are round (think of a round tooth timing belt and sprocket). The teeth are also bigger than the old pump's teeth, and there's less of them.

The way this newer pump does the job of increased flow at idle and less flow at higher speeds (all relative to the older pump) is like this: Because the teeth are bigger on this pump, when the two gears come apart in order to suck up the fluid, the space between the teeth is bigger (compared to the old pump) and the pump will suck in a higher volume of fluid,and displace a higher volume of fluid per tooth. It does this well at idle and slow speeds.

At higher speeds, things are moving quicker, and the fluid can't move fast enough to completely fill the space between the bigger teeth. So, because of this, each tooth is not filling up completely, and each tooth is moving less fluid compared to lower speed. This is how it achieves "less flow" at higher speeds (again this is compared to the older pump). Just like your engine losing horsepower if you try to pull too many revs, this pump has a crappier "volumetric efficiency" at higher speeds. But the entire pump is still flowing a healthy volume because even though each individual tooth is displacing less fluid, the pump is spinning way faster than at idle, so there is more teeth going round and round per minute.

I wouldn't hesitate to use this pump. Can you get me that deal on a new one Simon?

Chad Kilback "Kil-time Tranny Tuning"
Calgary, Alberta SDAC
88 Daytona Shelby "Zedd"
12.43 @ 111 quickest time
12.6 @ 113.00 fastest time
87 New Yorker "Norker Zedd" 2.5L TII 14.6 @ 93

[turbovanman²]

Thanks Chad. I feel a trade is in order,

I had planned to change it this weekend and do your 2-3 shift mod but again, looks like I need to catch up, lost power again the other day and put me behind, on top of that, my brothers truck broke down,

[turbovanman²]

Well my parts shop threw me a friggin wrench, doing the pump now, took the pump apart to clean it-its brand new, and He didn't listen to me and gave me my year pump. So now I am screwed, there closed till Monday, the hoist is now tied up and yeah, I am severly f*cked until Monday. NOT NOT happy, this will be a free pump now or else,