60e vs 80e dyno comparrison and questions
11-25-2013, 12:31 PM
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60e vs 80e dyno comparrison and questions I found these 4l60 vs 4l80 dyno results on another forum. From what I am seeing, the difference it not NEARLY as bad as everyone claims... In another thread that I posted this info in, someone said that the difference would be MUCH larger if the test was done "unlocked." My problem with that statement, after thinking about it, is that doing the comparrison unlocked does not really compare the efficiency of the two transmissions, but rather compounds the difference by adding the converter to the mix as another deciding factor. We all know that different converters are going to affect the amount of parasitic loss based on their operating efficiency, stall size, etc.
Am I thinking about this correctly? I can't imagine that you would see MORE losses from the transmission ONLY by not locking up the converter- or would you?
My other thought is that the same comparrison done between a TH400 and an 80e would probably be similar, no? The internals of the th400 and the 80e are essentially the same and other than the 80e having 4th gear, they even have the same gear ratios available.
Please feel free to correct me if my thinking is completely out of line, I'm just curious if I am missing something or if the old wive's tale about 80e's sucking a ton of power are purely anecdotal or based on facts and evidence that I just haven't found yet...
Am I thinking about this correctly? I can't imagine that you would see MORE losses from the transmission ONLY by not locking up the converter- or would you?
My other thought is that the same comparrison done between a TH400 and an 80e would probably be similar, no? The internals of the th400 and the 80e are essentially the same and other than the 80e having 4th gear, they even have the same gear ratios available.
Please feel free to correct me if my thinking is completely out of line, I'm just curious if I am missing something or if the old wive's tale about 80e's sucking a ton of power are purely anecdotal or based on facts and evidence that I just haven't found yet...
I finally decided to stop pushing my luck on my old 4L60 and swap in a 4L80 while it was still worth something in good running condition. Through all my digging online (5 minutes) I could not find any real hard dyno numbers as to how much power is lost doing the swap so I decided to test it myself.
Some background on the truck... basically it's an LQ9 with a small N/A cam and a KB Racing turbo kit with a Master Power 76 Q-trim turbo. It's by far not optimal as the Q-trim wheel is restrictive, the N/A cam obviously isn't setup for boost, and it's 10:1 compression which here in AZ during the summer heat with our crappy gas means I'm only running approximately 6 psi right now. On top of that I have 33" tall tires which wrap heavily on the roller at higher speeds in 3rd gear which unfortunately is the only gear I can use for this comparison since the 4L60 and 4L80 have different ratios in the other gears. When dynoing in 2nd gear the power and torque peak numbers are pretty equal to each other, in the 3rd gear dyno graph below you will notice that peak horsepower is quite a bit lower than torque and that's due to the tire wrapping itself up on the roller at the higher speed and making neat (bad) shapes in the sidewall dragging the numbers down. However it's still adequate for a comparison between the two transmissions since it will do it equally as bad since 3rd gear is a 1:1 ratio on both.
I made two pulls in 3rd gear on the 4L60 before I pulled it, swapped in the 4L80, then brought it back to the dyno for 2 more pulls. I made sure to duplicate the running conditions as best I could so that there were no other variables involved that could skew numbers. I had a factory 4L60 converter and I also used a factory 4L80 converter, both locked on the dyno so no difference in stall rpm could change anything. Tire pressures, weather, boost, correction factor, you name it and it was basically identical. The only thing I noticed after reviewing the logs was that the 4L80 runs had a half degree more timing due to the IAT cooling off a bit more between the two runs than the 4L60 had a chance to. I know from previous experience that it's only worth ~5 rwhp/tq on MY setup in this condition so we could just add that to the difference if you would like.
Looking at the graph you can see how noisy the 33" tall tires are on the roller by all of the wavy lines even at smoothing level 5. I took the best of the two runs of each transmission to compare with. It shows an average of 5-10 horsepower and torque all over the curve, add in the 5 horsepower/torque that the extra half degree of timing gives and it all adds up to around a 15 rwhp/tq loss. I always thought that the difference would have been larger than this but after looking over the logs to make sure everything was the same I am very impressed with the power loss or lack there of. This also makes me wonder how much of the power loss is attributed to the additional weight of the factory 4L80 converter over the 4L60 and if some of the losses could be mitigated by running a smaller lighter aftermarket 4L80 converter.
Next up, I'm going to swap in a turbo cam with LSA heads and a factory truck intake and if I'm up to it swapping on the Holley hi-ram intake after that for a direct intake swap comparison.
Some background on the truck... basically it's an LQ9 with a small N/A cam and a KB Racing turbo kit with a Master Power 76 Q-trim turbo. It's by far not optimal as the Q-trim wheel is restrictive, the N/A cam obviously isn't setup for boost, and it's 10:1 compression which here in AZ during the summer heat with our crappy gas means I'm only running approximately 6 psi right now. On top of that I have 33" tall tires which wrap heavily on the roller at higher speeds in 3rd gear which unfortunately is the only gear I can use for this comparison since the 4L60 and 4L80 have different ratios in the other gears. When dynoing in 2nd gear the power and torque peak numbers are pretty equal to each other, in the 3rd gear dyno graph below you will notice that peak horsepower is quite a bit lower than torque and that's due to the tire wrapping itself up on the roller at the higher speed and making neat (bad) shapes in the sidewall dragging the numbers down. However it's still adequate for a comparison between the two transmissions since it will do it equally as bad since 3rd gear is a 1:1 ratio on both.
I made two pulls in 3rd gear on the 4L60 before I pulled it, swapped in the 4L80, then brought it back to the dyno for 2 more pulls. I made sure to duplicate the running conditions as best I could so that there were no other variables involved that could skew numbers. I had a factory 4L60 converter and I also used a factory 4L80 converter, both locked on the dyno so no difference in stall rpm could change anything. Tire pressures, weather, boost, correction factor, you name it and it was basically identical. The only thing I noticed after reviewing the logs was that the 4L80 runs had a half degree more timing due to the IAT cooling off a bit more between the two runs than the 4L60 had a chance to. I know from previous experience that it's only worth ~5 rwhp/tq on MY setup in this condition so we could just add that to the difference if you would like.
Looking at the graph you can see how noisy the 33" tall tires are on the roller by all of the wavy lines even at smoothing level 5. I took the best of the two runs of each transmission to compare with. It shows an average of 5-10 horsepower and torque all over the curve, add in the 5 horsepower/torque that the extra half degree of timing gives and it all adds up to around a 15 rwhp/tq loss. I always thought that the difference would have been larger than this but after looking over the logs to make sure everything was the same I am very impressed with the power loss or lack there of. This also makes me wonder how much of the power loss is attributed to the additional weight of the factory 4L80 converter over the 4L60 and if some of the losses could be mitigated by running a smaller lighter aftermarket 4L80 converter.
Next up, I'm going to swap in a turbo cam with LSA heads and a factory truck intake and if I'm up to it swapping on the Holley hi-ram intake after that for a direct intake swap comparison.
11-25-2013, 01:35 PM
#2
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I think you are right that the test should be conducted with the converter locked to remove the converter's efficiency (or lack of it) from the result.
I don't remember the specific thread, but I recall one where people compared their ET before and after the 4L60E to 4L80E swap. I recall it was around +/- .2 seconds; with some actually being faster due to the tighter gear ratios.
I don't have personal experience, but I suspect that the people with personal experience will say that "80e's sucking a ton of power" is BS.
I don't remember the specific thread, but I recall one where people compared their ET before and after the 4L60E to 4L80E swap. I recall it was around +/- .2 seconds; with some actually being faster due to the tighter gear ratios.
I don't have personal experience, but I suspect that the people with personal experience will say that "80e's sucking a ton of power" is BS.
11-25-2013, 02:09 PM
#3
The amount of HP consumed by different transmissions is blown way out of proportion and often argued by those who have little understanding of the operation of the transmission or the physics involved.
The results you saw were posted by one of my customers who is a very sharp tuner.
I would consider them to be very accurate. One thing to note, we do a couple of mods on our builds to free up some frictional losses that may have affected the results since the 4L80E was one of ours.
There are several reasons a 4L80E isn't as inefficient as some believe. There is MUCH more to the power consumed than just the weight of the transmission or it's rotating mass. What is moving in which gear, pumping losses due to pressure, frictional losses at the clutch packs (again depending the gear the trans is in this will vary).
The results you saw were posted by one of my customers who is a very sharp tuner.
I would consider them to be very accurate. One thing to note, we do a couple of mods on our builds to free up some frictional losses that may have affected the results since the 4L80E was one of ours.
There are several reasons a 4L80E isn't as inefficient as some believe. There is MUCH more to the power consumed than just the weight of the transmission or it's rotating mass. What is moving in which gear, pumping losses due to pressure, frictional losses at the clutch packs (again depending the gear the trans is in this will vary).
11-26-2013, 09:42 AM
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Staging Lane
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Thanks for the input guys. Pretty much confirms what I was thinking and sets my mind at ease a little bit on putting my car together with the 80e. Listening to everyone else, I was afraid I was going to seriously regret it. Glad I didn't back down and sacrifice driveability like I was thinking about doing. I've driven 3 speed cars before and I hate it...
11-26-2013, 10:16 AM
#6
11-26-2013, 10:19 AM
#7
Thanks for the input guys. Pretty much confirms what I was thinking and sets my mind at ease a little bit on putting my car together with the 80e. Listening to everyone else, I was afraid I was going to seriously regret it. Glad I didn't back down and sacrifice driveability like I was thinking about doing. I've driven 3 speed cars before and I hate it...
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11-26-2013, 04:17 PM
#12
I can also list probably well over 100 customers who have had 4L60E's from reputable builders fail at lower HP levels.
I JUST snapped one a few minutes ago myself in a customer's truck. Loud bang and no more forward movement.
11-27-2013, 07:56 AM
#14
Staging Lane
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I would be very interested if my car was closer to being done. I'm a couple months out unfortunately...
