4L80E performance build
10-17-2014, 06:47 PM
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4L80E performance build I'm building a 4L80E and it is going behind a 540bbc pushing over 1000 fwhp. I'm putting a hardened input shaft, forward drum, 36 element sprag, red alto clutches and kolene steels, kevlar bands, and a full manual valve body. What other recommendations would you give to support the power being made.
10-17-2014, 11:43 PM
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Change the red altos to Borg Warner Hi Energies, ditch the Kevlar bands and go with a stock BW low band and either tan/Hi Energy intermediate band, depending on the year of the trans. No need for Kolene steels, it's a waste. Save the money. Full manual valve body is old news, a hassle to install and troubleshoot if not done properly (and many FMVB kits have their share of problems), a much better alternative for full manual control would be a Full Manual Box, a box that plugs into the trans connector and has two wires you need to wire up (One for 12v power and one to toggle lockup).
36 element sprag is a good idea. I wouldn't even bother playing with hardened stock parts, billet or don't even bother. Billet forward hubs are relatively cheap and an input shaft is a worth while investment. It may not be necessary, but a 300M main shaft has never hurt anyone as well
Don't bother with a 6 pinion planetary setup unless you are shooting for a custom gear ratio. If you are worried about strength you are looking in the wrong place. The stock 4 pinion planetaries will hold massive amounts of power without a hitch, they've been doing it flawlessly for decades in TH400s and just as well if not better in 4L80Es.
Hydraulic modifications will be critical to the survival of this transmission. Dual fed third gear direct clutches, proper valve body calibration, a few pump mods. I would also suggest rollerizing to free up some parasitic power loss and tighten up endplay. You will need access to a lathe to do more than just the rear. Rollerizing the rear will require a TH400 case bushing and a TH350 pump bearing (and a pack of shims).
New shift solenoids, new pressure switch manifold and new wiring harness are highly recommended. Stay with A/C Delco for your electrical parts, don't cheap out on the cheaper stuff.
36 element sprag is a good idea. I wouldn't even bother playing with hardened stock parts, billet or don't even bother. Billet forward hubs are relatively cheap and an input shaft is a worth while investment. It may not be necessary, but a 300M main shaft has never hurt anyone as well
Don't bother with a 6 pinion planetary setup unless you are shooting for a custom gear ratio. If you are worried about strength you are looking in the wrong place. The stock 4 pinion planetaries will hold massive amounts of power without a hitch, they've been doing it flawlessly for decades in TH400s and just as well if not better in 4L80Es.
Hydraulic modifications will be critical to the survival of this transmission. Dual fed third gear direct clutches, proper valve body calibration, a few pump mods. I would also suggest rollerizing to free up some parasitic power loss and tighten up endplay. You will need access to a lathe to do more than just the rear. Rollerizing the rear will require a TH400 case bushing and a TH350 pump bearing (and a pack of shims).
New shift solenoids, new pressure switch manifold and new wiring harness are highly recommended. Stay with A/C Delco for your electrical parts, don't cheap out on the cheaper stuff.