AbotDaConqueror
Newbie
How was your experience with the holley 6L80 controller? I'm looking at picking up an awd 6L80, but can't find any actual hands on reviews on how it functions with the Terminator! Do you have an update on your build?
6L80/6L90 swap
- Thread starter RDF1
- Start date
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L31MaxExpress
I'm Awesome
I have been trying to find a documented performance gain of a 6L90E swap and have found very little. I wanted to approximate the performance improvement to expect, so I built my van on Drag Racing Analyzer Pro v2.0 software. It is currently very close to what the van ran in the performance analysis function from OBD2 data. The software triggers when the VSS moves and then calculates time and mph at a 1/4 mile of distance as well as logs 0-60 and a few other things. Not perfect but I am over 100 miles from a 1/4 mile track now and it is rarely open to street vehicles. The weather here had the air near Denver density altitude, it was ~4,800 ft density altitude. 1,450 ft elevation, 95*F, 38% humidity and 29.60 in/hg barometric pressure. Anyway I ran two passes logging the data to compare another tuning related question I had. I ran the 1st pass with the TCC unlocked. I ran the 2nd pass with the TCC locking right after the 1-2 shift, unlocking during the 2-3 upshift, and immediately relocking. The OBD2 data showed 0-60 in 7.35 and 15.58 @ 88.47 in the 1/4 unlocked and a 0-60 of 7.40 and a 1/4 mile of 15.43 @ 90.32 locked. Already having that data, I plugged the weather data into the virtual van to get an idea of how close the model was. Pretty darn close if you ask me. For grins I plugged in the 6L90E with a stock diesel converter. Software model shows the 6L90E will make a dramatic difference for the better. I like that the software modeling is very thorough, for example density altitude change shows both lost power and lost torque converter stall speed.
Unlocked Converter
Locked Converter
Here is the same settings swapping out the 4L85E with the loose 2,900 rpm converter modeled for the 6L90E with the stock converter.
I also went back and found weather data from a day that literally everybody was running new personal bests in their vehicles at Dallas Dragway. That track was at 577 ft elevation, it was 61*F, 24% humidity and 30.22 in/hg barometric pressure. Plugging that weather data into the model really livened things up.
Good Weather 4L85E
Good Weather 6L90E (I would be ecstatic with that kind of a performance gain from a transmission swap)
Unlocked Converter
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Locked Converter
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Here is the same settings swapping out the 4L85E with the loose 2,900 rpm converter modeled for the 6L90E with the stock converter.
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I also went back and found weather data from a day that literally everybody was running new personal bests in their vehicles at Dallas Dragway. That track was at 577 ft elevation, it was 61*F, 24% humidity and 30.22 in/hg barometric pressure. Plugging that weather data into the model really livened things up.
Good Weather 4L85E
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Good Weather 6L90E (I would be ecstatic with that kind of a performance gain from a transmission swap)
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L31MaxExpress
I'm Awesome
My swap will not be much help to answer your Terminator questions.
ITs going to be next year before i can get around to doing this swap. Im swamped in the shop with customers builds.
L31MaxExpress
I'm Awesome
Mine will be a while too. I am working on re-siding the lakehouse along with other things.
I am about to start on the 58X harness in my spare time though. I have an extra 01-02 van engine harness that came off one of the 8.1L engines I bought. The spare harness will be plug and play ready for that swap. The 58x, Erson cam and intake manifold swap will be first and the van will run the 4L85E until I get the PCM dialed in using a T42 TCM.
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How does the Drag Racing Analyzer Pro v2.0 expect you to parameterize the torque converter, e.g., by providing the TC's K-factor or simply its stall speed?
Offhand I would expect K-factor would give better results. Stall speed, being a function of the K-factor, might be used I suppose to infer the K-factor by making an assumption about the applied torque.
Can multiple stator converters be modeled as well?
I haven't had deep experience with such things, mind you. It was around 1995 when I last modeled 1/4mi performance (trying to take into account the TC's K-factor) using an Excel spreadsheet.
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L31MaxExpress
I'm Awesome
Torque converter is modeled by a factor called converter strength. Must be similar to K-factor. You can fill in a value for that or simply plug in a stall speed and it autofills it. Then when you change the torque curve it automatically adjusts for the stall based on input torque. You need to know the approximate STR though.
L31MaxExpress
I'm Awesome
Playing around with gearing calculators and the drag software, I think when I put a locker in the 10.5", it is going to get a 3.21 rear gear. It does not cost anything performance wise with the 6L90E. I modeled 3.21, 3.42, 3.73 and 4.10 gears and the acceleration is practically the same regardless. Even when I increased weight to 15K lbs it was still very close off the line and had better acceleration staying in the lower gears longer. With the 3.21 gear 4th is basically the same overall gearing as my current 3rd gear and 5th matches 4th gear. 3rd gear has a deeper overall ratio than my current 2nd gear. Then 6th will be ultra tall for high speed empty cruising on level ground. Comparing the wheel torque output against the old 5.7L/4L85E and 3.73 gear the 383/6L90E and 3.21 gear still makes more torque to the ground above 60 mph than the 350 did. 70 mph equates to 1,650 rpm and 85 mph is 2,000 rpm. The Erson 218/218 cam shows it will add something like 30 ft/lbs of torque at 1,500 rpm compared to the Comp 218/228 I am running now. Both the modified 350 and the 383 setup kill the bone stock 350 or 6.0L/4L80E and 4.10 setup for torque in overdrive at 60 mph. The 6.0L/4L80E and 3.73 geared vans have the least torque at 60 mph and they still cruise well unloaded. With the 6spd and tap shift I will always be able to gear down a gear or two when the road starts to slope and wind around.
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L31MaxExpress
I'm Awesome
Here are some gearing calculator numbers. 4L85E and 3.73. I picked the RPM points and road speeds I did because they are fairly common points. 40 mph around town, 60 mph on 2-lanes and 80 mph on the interstate. The 750 rpm is idle, 2,500 are part-throttle acceleration shift points I shoot for and 5,500 is WOT.
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L31MaxExpress
I'm Awesome
6L90E and 3.21s. 1st is still a relative stump puller and 2nd/3rd split the gears between my current 1st and 2nd. 4th and 5th are for all practical purposes identical to 3rd and 4th currently. 6th is definitely a high speed cruising gear. I like that 2nd and 3rd are also slightly taller than my current 1st and 2nd because that extends the MPH that gear can be used a bit, providing increased torque delivery over a broader road speed once you are already rolling. While their is less peak wheel torque in those gears, the torque is spread out to a higher mph for each gear resulting in more average torque being delivered compared to having to upshift ~10 mph earlier. I see why GM typically paired this transmission with a 3.08 gear and even the weak 4.8Ls in the vans only came with a 3.42.
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