Focaljet - Ford Focus Forums - View Single Post - How much power can a stock automatic handle?

**P-51** · 06-18-2004, 09:08 AM

Ok, I'm gonna hang this one out here once and for all, since we have this cool new forum. I'll only say this once:

I used to be an engineer at Ford Automatic Transimission Operations.

As has been mentioned, the 4F27E was designed for 270 ft-lbs AFTER torque converter multiplication. The torque converter multiplies the torque by almost 2, so the transmission is at it's design limit with a Zetec.

The issue is the durability of the 3/4 clutches (not the TQ). They just can't take the energy dumped in by a higher torque motor. It's the actual energy they have to absorb on a shift, not the actual torque while in gear, that is a problem.

As has been mentioned, tightening up your shifts will help, because the shift is faster, and thus you dump in less energy on a shift.

Ford was fully aware of the potential problem with the clutches and the PZEV. So, in mid-2004 model year, they upgraded the clutches to go with the introduction of the PZEV. Internally, they referred to them as "high energy" clutches. In fact, ALL Foci got the stronger clutches in mid-2003 MY, I believe the build date switchover was December, or somewhere thereabouts.

That also may not be a hard date... since the plant has a propensity for losing parts, then finding them a few months later and putting them on the line. Particularly for running changes, which is what this was.

IIRC, there is a code on the tranny that tells you which one you got, but I can't remember off the top of my head. I was able to verify I got it on our 2003 Wagon, built in January 04.

Also, IIRC, the new clutches were designed for 30-40% more energy than the old clutches. Again, not torque, but energy. You can even get some custom made 1-sided clutches that can take twice the energy, but they didn't go this route, I can't remember if it's cost or shift quality.

I would think a high energy clutch tranny, with tightened up shifts, might live behind a turbo Zetec. The early transimissions were at their design limit in stock form. You might be able to live with them if you don't do full power 3-4 shifts, or at least not many 3-4 shifts in close succession. It's the repeated energy dumps that overheats them, and kills them.

06-18-2004, 09:08 AM	#20
P-51 [FJ] Addict Join Date: Oct 2000 Location: Brighton, Ontario, Canada Posts: 14,939	Re: How much power? Ok, I'm gonna hang this one out here once and for all, since we have this cool new forum. I'll only say this once: I used to be an engineer at Ford Automatic Transimission Operations. As has been mentioned, the 4F27E was designed for 270 ft-lbs AFTER torque converter multiplication. The torque converter multiplies the torque by almost 2, so the transmission is at it's design limit with a Zetec. The issue is the durability of the 3/4 clutches (not the TQ). They just can't take the energy dumped in by a higher torque motor. It's the actual energy they have to absorb on a shift, not the actual torque while in gear, that is a problem. As has been mentioned, tightening up your shifts will help, because the shift is faster, and thus you dump in less energy on a shift. Ford was fully aware of the potential problem with the clutches and the PZEV. So, in mid-2004 model year, they upgraded the clutches to go with the introduction of the PZEV. Internally, they referred to them as "high energy" clutches. In fact, ALL Foci got the stronger clutches in mid-2003 MY, I believe the build date switchover was December, or somewhere thereabouts. That also may not be a hard date... since the plant has a propensity for losing parts, then finding them a few months later and putting them on the line. Particularly for running changes, which is what this was. IIRC, there is a code on the tranny that tells you which one you got, but I can't remember off the top of my head. I was able to verify I got it on our 2003 Wagon, built in January 04. Also, IIRC, the new clutches were designed for 30-40% more energy than the old clutches. Again, not torque, but energy. You can even get some custom made 1-sided clutches that can take twice the energy, but they didn't go this route, I can't remember if it's cost or shift quality. I would think a high energy clutch tranny, with tightened up shifts, might live behind a turbo Zetec. The early transimissions were at their design limit in stock form. You might be able to live with them if you don't do full power 3-4 shifts, or at least not many 3-4 shifts in close succession. It's the repeated energy dumps that overheats them, and kills them.