Maximum RPM for 4L80e
Thread Starter
Teching In
Joined: Dec 2005
Posts: 7
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From: Phili, PA
Maximum RPM for 4L80e I have done a fair bit of poking around and can't seem to find a definitive answer on what the maximum SAFE rpm of a 4L80e is.
I've seen some say that if you go over 7k with it on a regular basis, it should have an aluminum forward hub and billet steel input shaft while others say that they go to 8k and beyond with very lightly modded transmissions(ie aftermarket clutches, steels, and a vb mod).
What's your take and real-world experience?
I've seen some say that if you go over 7k with it on a regular basis, it should have an aluminum forward hub and billet steel input shaft while others say that they go to 8k and beyond with very lightly modded transmissions(ie aftermarket clutches, steels, and a vb mod).
What's your take and real-world experience?
Thread Starter
Teching In
Joined: Dec 2005
Posts: 7
Likes: 0
From: Phili, PA
Yeah, that's what I was thinking. I was hoping maybe Jake would see the thread and comment. I'm sure others have to have experience revving a GM 4 speed.
There are some pump mods we do in the real high rpm stuff. We can also do an aluminum direct drum upgrade. Both are good things to do if the trans frequently sees over 7500 rpm.
We rollerize all of our builds so it's not an issue but again, the higher the rpm, the more advantageous this modification is.
I don't know of an aluminum fwd hub for the 80E, we use a steel piece in our Stage 3 and up builds.
The input shaft is a known weak hard part in the 4L80E despite it being a robust piece. The oil holes drilled in the rear portion cause it to shear off. This isn't an RPM issue, it's a torsional load issue (power, weight, shock).
My "number" for the stock input shaft is 750 flywheel HP/TQ. I've seen some live at well over this and I've seen some break behind stock 6.0L engine in towing applications.
I base this number off a typical ~3600 lb car with no nitrous. If the combo is heavier or is making the power number using nitrous, I prefer to see the input shaft upgraded. If a customer is borderline but lives overseas, I also like to see an upgrade here for peace of mind.
There are also some mods we do to prevent centrifugal apply of the clutches. Definitely needed in a 8000+ rpm combo. I've seen issues in 6K rpm combos without these mods in other units.
We rollerize all of our builds so it's not an issue but again, the higher the rpm, the more advantageous this modification is.
I don't know of an aluminum fwd hub for the 80E, we use a steel piece in our Stage 3 and up builds.
The input shaft is a known weak hard part in the 4L80E despite it being a robust piece. The oil holes drilled in the rear portion cause it to shear off. This isn't an RPM issue, it's a torsional load issue (power, weight, shock).
My "number" for the stock input shaft is 750 flywheel HP/TQ. I've seen some live at well over this and I've seen some break behind stock 6.0L engine in towing applications.
I base this number off a typical ~3600 lb car with no nitrous. If the combo is heavier or is making the power number using nitrous, I prefer to see the input shaft upgraded. If a customer is borderline but lives overseas, I also like to see an upgrade here for peace of mind.
There are also some mods we do to prevent centrifugal apply of the clutches. Definitely needed in a 8000+ rpm combo. I've seen issues in 6K rpm combos without these mods in other units.
