Trim-matic 3 speed on a KA24det

[finn]

I'm sure most of you are familiar with the 9 second 510 on speed hunters... I was looking into this transmission option and can't find anything in North American about its usage or modification.. has anyone ever seen this used or know where to get some info?

DRIVELINE: Tri-Matic 3-speed manualized automatic transmission; B&M ratchet shifter; TCE torque convertor; R200 long-nose differential; 3.9:1 final drive; modified R32 GT-R axles; HPS billet companion flanges; HPS billet stub axles

http://www.speedhunters.com/2012/10/a-9 ... atsun-510/

[510rob]

The article says "In the driveline, the Datsun runs a manualized and “extensively modified” Trimatic M40 (aka TurboHydro 180 or TH180) 3-speed automatic transmission with a TCE torque convertor."

Turbo Hydramatics are GM automatics --> TH180 Transmission Wiki

[finn]

it looks as though the Australians have been working with manualizing auto cars for some time now. most of the articles and forums had guys installing tiptonics or related equipment but this guy went as far as to modifying the bell housing, creating a converter lock, building that shift kit, and god knows what else. I can't find any other project where someone tackled this type of tranny mod.. guess i'll leave it alone for now.

[okayfine]

What benefit are you looking at with a manual auto? Manual valve bodies are common in the muscle-car/street-strip world. For a non-drag car, I don't see a lot of upside.

[datzenmike]

Get a 3N71B zx turbo automatic. Higher stall speed torque converter, extra plates and clutches and a special modulator valve for higher pump pressures to limit clutch slip during turbo power shifts. The 1st and second gear ratios are also slightly lower than the normal automatic to spool the turbo sooner. Be sure to get the drive shaft yoke too as it's larger diameter than most Datsun ones.

[Byron510]

OK, this is where I need you old guys to chime in. And I mean the over 60 crowd. Hanging around my dad's budding where being 70 is still young, these guys talk about automatics with no torque converter. They used a clutch off the line, and then just banged gears from then on.
So, my question is - how long will an auto box last with this type of abuse and no torque converter to soften the blows?
Mike I'd be interested to hear what you think about this utilizing the Datsun auto boxes...

Byron

[510rob]

they used to call those a "clutch-flite" transmission

[finn]

What benefit are you looking at with a manual auto? Manual valve bodies are common in the muscle-car/street-strip world. For a non-drag car, I don't see a lot of upside.

simply put, the manual is practically useless at slower speed. its an inconvenience to say the least... I'm only using six feet at most with my hot and cold pipe combined and its 2'' diameter tubing. the T3 will produce boost with moderate acceleration which makes shifting a must to drive the car conservatively, since fuel will start to dump at the sign of compression.. so I'm wearing down the clutch faster and pouring fuel when not needed..

I'm just looking into different mods and the benefits they bring. no real issues with the car, just seeing what's out there and how it can make life more dangerous...

Mike, I looked into that 3N71B and read that paired to the L28 turbo, it had one of the fastest 1/4 mile times for '82! that seems ridiculous but its factual.. I can see why you had wrote that post about the tranny and why you didn't want to jump to the 5 speed bandwagon. a true automatic made me think I'd wouldn't get the full range of benefits from the turbo until I read that. i can see where it would take some fun outta driving but its already so freaking fast anyways... might need to look into this more...

[okayfine]

What about changing your rear gear? I forget if you have a Sube LSD with it's 3.7:1 ratio already, but if you're running a stock 3.9, then going down to the Z-car 3.5s (or lower, isn't there a 3.35 or something?) would make first more useful, and give you more mph range in each gear.

If you don't want to shift that's one thing, but there are other ways to change the behavior. Could also find an 71B trans that had lower gearing and have it mated with the KA bellhousing, or just bolt it on and deal with the tilt. There aren't any KA gearing options, but might be JDM-ish SR gearing differences that would just need your KA bellhousing swapped (no machining).

[datzenmike]

Byron I remember the Dodges having automatics with a clutch pedal. It was used only for stops and starts I believe. Shifting up or down above first was 'automatic'. There was no slipping torque converter to allow idle when stopped so a clutch was used. Presumably, it is permanently locked in first or there is some provision for driving the auto trans oil pump to hydraulically hold it in first. Wow that's going back some. I saw one on a mid/late '50s hemi powered Belvedere or De Soto or something. It was a friend's dad's old company car. He got a new one every two years and parked the old ones. There were 7 or 8 of them big old monsters we used to play in. They are curious things but better torque converters made them obsolete. (I think they made them because people were used to and comfortable clutches back then)

[okayfine]

http://www.zhome.com/ZCMnL/tech/GearRatios.html

3.364

[dislexicdime]

I loved having 336 is in my R 180 too bad I broke it with my SR

[datzenmike]

Depends what transmission ratios you have right now.

Wide
1st.... 3.592
2nd... 2.246
3rd... 1.415
4th... 1.000
5th... 0.882
* found on the '79 620, '80 2wd 720, all diesel 720s and 4x4s, '82-'83 S110 200sx and '85-'86 S12s may need an L front case swapped on.

Mid
1st.... 3.321
2nd... 2.071
3rd... 1.308
4th... 1.000
5th... 0.833
* found on '77-'78 280x, '79 280zx, 810/Maximas, '80-'81 S110 200sx.

Close
1st.... 3.062
2nd... 1.858
3rd... 1.308
4th... 1.000
5th... 0.073 or 0.045
* found on the '80-'83 non turbo 280zx.

As you can see the wide truck 5 (or 4 speeds) speed with the 3.592 first gear is 17.3% lower than the close ratio 280zx boxes. I've used the wide ratio and you go about 2 truck lengths and feel the need to grab second. Trouble is you can't quite use second for take offs.



Optional...
If you have a wide ratio with the 3.592 first gear you can swap the input/counter drive gears from a close 280zx box in and produce a mongrel box with even lower gears.

Mongrel box
1st.... 2.972 (20.8% lower than the wide)
2nd... 1.702
3rd... 1.171
4th... 1.000
5th... 0.745 (no change)

Swap these two gears, the two most forward in the box right behind the main and counter bearings.

[okayfine]

Finn has a KA swap, so:

1st: 3.321
2nd: 1.902
3rd: 1.308
4th: 1.000
5th: .7590

[datzenmike]

So turbo coming on so soon you have to up shift sooner or gas mileage suffers? right? Lower gears like a 3.365 means you will have to add more throttle to accelerate at the same amount as the higher gears.

Isn't there a way to raise when the boost comes on when not needed? Manually hold the waste gate or the BOV open.