"HammerheadFistpunch" (hammerheadfistpunch)
12/19/2018 at 11:28 • Filed to: Random things
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"HammerheadFistpunch" (hammerheadfistpunch)
12/19/2018 at 11:28 • Filed to: Random things | 4
| 21 |
King TChalla (wakanada forever) got me thinking about why they haven’t put the Toyota 8 speed, what toyota calls the worlds first 8 speed auto, into the tacoma where 8 and 10 speed autos are the norm. They even already have a version that mates up to the tacoma engine in the AA81...so why don’t they? I think I figured out why.
The 8 speed has a strange ratio spread. here
4.596 - .685 vs the 6 speed 3.52 - .586
The key takeaway is the overdrive ratios, .685 being the tallest vs .586 being the tallest.
Toyota uses this transmission in the land cruiser alone right now for 4wd applications and in that application it uses a 3.3:1 axle ratio which is way low for a Toyota truck. Normally they are in the 3.9-4.3:1 ratio I think because their transmissions give them very tall overdrives and big ratios mean strong gears and less transmission strain.
The Tacoma has a 3.909:1 axle for example in auto form (4.3:1 in manual)
If you took the Tacoma axle ratio and put the 8 speed in front of it it would have amazing low end torque, nearly 18:1 first gear crawl alone is nutty and it would take off like a rocket...but...at .686:1 and 3.909 its only 2.67:1 vs 2.29 for the 6 speed. So it would get worse economy both on the highway and city cycles because it would be in shorter ratios pretty much all the time.
Im guessing they don’t have a 3.3:1 ring that can fit the Tacoma’s carrier. Seems like a problem they can and NEED to solve. if you had a 3.3:1 ratio in the Tacoma like the land cruiser with the same transmission you would get better acceleration in all ratios and SLIGHTLY better overdriver at 2.27:1 It would actually make that high strung 3.5 feel pretty perky and they could relax the shift logic a little to allow it to stay in gear longer.
I personally wouldn’t mind the overdrive penalty on the Tacoma as it would be a killer towing machine even with that 3.5 and it would crawl like nobodies business.
Granted Toyota also has a new FR - 10 speed that is supposed to solve that issue
So...GET ON TOYOTA!
UPDATE: found the ratios for the AG A0 (10 speed) here is a comparison
Good gads that 10 speed 1st gear ratio is hot. Too bad overdriver is still less than the 6 speed. Still, with the new transmission you could easily get a 3.73 ring on that axle and be perfect.
Okay, thats pretty great. Even with the wimpy 3.5 I think the 10 speed would transform the Tacoma. DO IT!
For Sweden
> HammerheadFistpunch
12/19/2018 at 11:31 |
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Toyota of Wakanda would put an 8 speed in the Tacoma
Pancake
> For Sweden
12/19/2018 at 11:36 |
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We can dream....
Highlander-Datsuns are Forever
> HammerheadFistpunch
12/19/2018 at 11:41 |
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The 3.5 is a good engine for a car, not a truck. The taco I drove last week was hunting for gears constantly when under load. The previous gen I think was less power but had a flatter torque curve and I felt drove better.
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HammerheadFistpunch
> Highlander-Datsuns are Forever
12/19/2018 at 11:48 |
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I can tell you not everyone at Toyota was stoked on it either. I drove one not long ago and I kept thinking that it felt exactly like my land cruiser for feel, but backwards. You hit the gas the same for the same level of go but where the cruiser “mooed” and got on with it without shifting gears, the Tacoma shifted 2-3 times for the same forward progress. 4600 rpm torque peak and a 6000 rpm hp peak (and cutoff) is not great for a truck engine. I think its less an issue with displacement and more a requirement of keeping the engine in modified atkinson longer for emissions and mileage. The reason that only hybrids use modified atkinson typically is because of torque fill. Silly toyota. And just think how good it would have been with the new heads on the old 4.0 block.
davesaddiction @ opposite-lock.com
> Highlander-Datsuns are Forever
12/19/2018 at 11:51 |
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Precisely why I bought mine with a manual.
gmctavish needs more space
> HammerheadFistpunch
12/19/2018 at 12:01 |
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I think what your LandCruiser does is why I keep thinking the 4L60E in my Blazer was a better transmission than whatever my Legacy has. It wasn’t the transmission, the 4.3 just had enough torque that it didn’t have to downshift much at all. T he Legacy does not have enough torque, and needs to drop to 2nd in order to do anything resembling acceleration. It’s not smooth about it either.
Tekamul
> HammerheadFistpunch
12/19/2018 at 12:02 |
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Im guessing they don’t have a 3.3:1 ring that can fit the Tacoma’s carrier.
That’s gotta be a bean counter thing, because this should not be a big task.
camarov6rs
> HammerheadFistpunch
12/19/2018 at 12:08 |
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Ratios in a transmission seems like a pretty easy change of it means getting a better overall ratio spread for an engine that needs a bit more rev range to make power. I do wonder why Toyota isn’t taking the time to throw a simpleish bandaid on the Tacoma.
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camarov6rs
> HammerheadFistpunch
12/19/2018 at 12:10 |
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It’s interesting that Toyota is using the modified Atkinson cycle for economy on this engine, but Chevy is using 0.1 more liters in their engine and it gets more power with similar economy. Now that’s all EPA so real world numbers could be drastically in Toyota’s favor.
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HammerheadFistpunch
> Tekamul
12/19/2018 at 12:12 |
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well its a pretty big ring on the locked trucks 8.75 ring, but still...its doable.
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HammerheadFistpunch
> camarov6rs
12/19/2018 at 12:15 |
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Planetary ratios are no longer remotely easy to change. They use several compound sets so in order for the ratios to be spaced in useful intervals they have to consider not just, for example, what too th count for 3rd gear but for 7th and 9th as well. the ratios for transmission greater than 6 pretty much stay the same on all models and the final drive changes.
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HammerheadFistpunch
> camarov6rs
12/19/2018 at 12:21 |
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now remember that the chevy engine gets more power simply because it revs higher, the Toyota redlines at 6000 where the gm redlines at 6800 rp, (hp peaks for both). If the toyota engine reved 800 rpm more it would go from 278 peak hp to easily 305 or more hp. Not sure why they capped it at 6000 (my guess is hard and fast rules for truck engine longevity) but the camry with the same engine makes 301 hp at 6600 rpm, if they stretched that peak to the same peak as the colorado it would be 310 peak hp. Both engines have very similar power curves to that point.
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camarov6rs
> HammerheadFistpunch
12/19/2018 at 12:22 |
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Well said. Most of my transmission experience is from motorcycles where opening the case and changing ratios or ratio sets is not incredibly difficult.
nermal
> HammerheadFistpunch
12/19/2018 at 12:24 |
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The problem with the 3.5 isn’t that it’s wimpy, it’s that it needs to rev to make powahh.
A shorter overall top gear would make for better drivability at highway speeds. Not sure how it would fair on the EPA tests, which are realistically more important. Also not sure on how it would fair on 0-60 and 1/4 mile tests, which manufacturers focus on for advertising . Many cars are designed to hit 60 in 2nd to avoid the time lag of another shift. Theoretically hitting it in 4th instead would be better for drivability, although possibly worse for magazine #s.
Yowen - not necessarily not spaghetti and meatballs
> HammerheadFistpunch
12/19/2018 at 12:26 |
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Throw a gear vendor on it? Haha.
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camarov6rs
> HammerheadFistpunch
12/19/2018 at 13:00 |
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Since that’s the case I’m surprised I don’t read more reviews of the Colorado being sluggish.
Dr. Zoidberg - RIP Oppo
> HammerheadFistpunch
12/19/2018 at 13:13 |
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Have heard grumblings about the Taco from both Lexus and Toyota employees. I think the ancient 5-speed auto in my 2014 is more suited to "trucky" needs.
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HammerheadFistpunch
> camarov6rs
12/19/2018 at 13:18 |
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shift strategy. people who tune the shift computer are much happier
vicali
> HammerheadFistpunch
12/19/2018 at 14:11 |
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3rd Gen section on TW would die if we got 10 gears.. with no one complaining about the engine or transmission it would be pages and pages of eBay pro grille threads...
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HammerheadFistpunch
> vicali
12/19/2018 at 14:18 |
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*shudders*
Future Heap Owner
> HammerheadFistpunch
12/19/2018 at 15:10 |
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This is good Oppo.