400 Turbo vs. 4L60E transmission improvement in ET times?
07-12-2015, 02:30 PM
#1
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400 Turbo vs. 4L60E transmission improvement in ET times? How much on an improvement will one see in 1/4 mile ET by changing to a 400 turbo transmission from a 4L60E? I plan to get the Rossler 400 TH tranny.
07-16-2015, 04:30 PM
#3
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Why would you expect to see an improvement?
Depending upon you engine's power band and rear end ratio, you may see an improvement or you might even be slower due to TH400's numerically lower 1st gear.
Depending upon you engine's power band and rear end ratio, you may see an improvement or you might even be slower due to TH400's numerically lower 1st gear.
07-17-2015, 09:11 AM
#7
I stand corrected on the weight difference! From removing and installing each, I thought the TH 400 was heavier, but not so. Maybe bulkier, but not heavier.
As far as parasitic losses, the stock GM TH400 has cast iron forward and direct drums making for heavier rotating mass and thus absorbing more power to accelerate - especially when doing so quickly. Of course there are aftermarket versions that use lighter components to counter this.
The basic point was that simply replacing the 4l60e with a TH400 doesn't necessarily make a car quicker.
As far as parasitic losses, the stock GM TH400 has cast iron forward and direct drums making for heavier rotating mass and thus absorbing more power to accelerate - especially when doing so quickly. Of course there are aftermarket versions that use lighter components to counter this.
The basic point was that simply replacing the 4l60e with a TH400 doesn't necessarily make a car quicker.
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07-17-2015, 11:22 AM
#8
I stand corrected on the weight difference! From removing and installing each, I thought the TH 400 was heavier, but not so. Maybe bulkier, but not heavier.
As far as parasitic losses, the stock GM TH400 has cast iron forward and direct drums making for heavier rotating mass and thus absorbing more power to accelerate - especially when doing so quickly. Of course there are aftermarket versions that use lighter components to counter this.
The basic point was that simply replacing the 4l60e with a TH400 doesn't necessarily make a car quicker.
As far as parasitic losses, the stock GM TH400 has cast iron forward and direct drums making for heavier rotating mass and thus absorbing more power to accelerate - especially when doing so quickly. Of course there are aftermarket versions that use lighter components to counter this.
The basic point was that simply replacing the 4l60e with a TH400 doesn't necessarily make a car quicker.
But since you mentioned weight,
Both transmissions overall weight is similar.
The Th400 has a cast iron pump, valve body, and large heavy cast center support. All of which do not rotate.
The 4L60E pump and VB are aluminum.
Without going and weighing all the rotating parts from each unit, that tells me that it's possible the 4L60E actually has more rotating weight than a TH400. It is certainly larger diameter (parasitic losses due to rotating mass are greater when the diameter is larger for a given weight), and definitely has more clutch packs to cause drag, as well as makes more line pressure (pumping losses).
The basic point is that there are a lot of misconceptions about automatic transmissions that get perpetuated online because nobody actually fact checks.
I'll try to weigh all the internals sometime to give some actual numbers.
07-17-2015, 12:44 PM
#9
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Everyone ive ever talked to (that runs one) says their cars go quicker with a 400. Never got into specifics with them but thats always been the general consensus and ive never heard anyone say it wont make an improvement.
07-19-2015, 11:27 PM
#11
My car with a 5,000 stall and a 4l60e has been a best of 1.29 60ft. The gear changes are identical 1-2, 2-3 with the engine seeing a 7,000 shift point and a drop to 6,200 for a shift extension of 800 rpm. If you are running a real heavy car, over 3,500 lbs.It is more about a total package then a t350-400 might benefit you on the 1-2 shift. But with 1st gear being in the 2.48 range you will never leave the starting line as hard as the 4l60e will with the same converter stall. It is more about a efficient total package than just changing a transmission.
07-20-2015, 06:15 AM
#12
Its really hard to compare the 2-diff first gear ratio, etc-the converters would have to be an exact match, clutch pacs, same clearance, etc, etc
If the 60E was max'ed to the combo, and the 400 wasn't and went slower,
then you would say the 400 lost ET-same vice versus
strength, do you want OD, kind of determine choice-hell, some run faster with glides if it fits the package
I swapped out a 400 for an 80E-ran exact same times-was the 400 max'ed for the setup, prob not, but I didn't lose any time, and gained an OD, so it was a win for me
If the 60E was max'ed to the combo, and the 400 wasn't and went slower,
then you would say the 400 lost ET-same vice versus
strength, do you want OD, kind of determine choice-hell, some run faster with glides if it fits the package
I swapped out a 400 for an 80E-ran exact same times-was the 400 max'ed for the setup, prob not, but I didn't lose any time, and gained an OD, so it was a win for me
