Does anyone know how much abuse a 2nd-gens automatic trans can take?

I'm thinking the best use for my dead FC will be drag racing. Drag racing means automatic transmission. Fortunately, it already IS an automatic. Less work.

I've heard of people doing T2 engine swaps and keeping the autobox, but I've never heard FROM people who've done it. Meaning, I don't know how well it works. Worse comes to worse, I'll try to use the JATCO tranny's bellhousing to adapt it to a Ford C4 transmission (looks like doable with minor fabbing), which means I'd be giving up overdrive but OTOH I'd also have a wealth of aftermarket torque converters and internal parts available to me.

 

How strong? Not very. Stock power can kill them (usually slips in 2nd gear), and forced induction will certainly kill it. If you don't want to give up the "stock" Mazda tranny, Level10 can build one up for the right $$$. Another option is to source a J-spec auto tranny with ECU - the N/A auto ECU don't like turbo power.

Good luck!

Brandon

 

The tranny is junk! Do yourself a favor and find a better one. You won't be able to push more than 200hp through that mush box.

 

automatic J-spec Turbo II trans may work, but it's computer controlled.

 

Ok, ok, I'll work with getting a C4 behind it. Thanks.

 

Whoa, that's a new one to me...


-Ted

 

If you want any kind of consistency you need an auto or a clutchless manual...

 

I have a 3 rotor cosmo tranny

 

New one on you? Let's see, they launch easier and harder because the torque converter multiplies torque, and gets the engine into its powerband immediately... instantaneous shifts as hard or as soft as you want (i'm always partial to bang shifts but that's really hard on your u-joints), never have to worry about missing a shift, you don't have to let off when you shift... A well tuned automatic will destroy a manual trans at the dragstrip.

note i'm talking about RACE automatics... with manual valvebodies and extensive reworking.

 

Adam S. Ran a stock manual tranny, lifting and shifting, when his 7 was doing 10-sec. quarters. That's pretty good.

If you're just talking bracket racing, well a sequential is best, but there you go. My problem with autos is, when they run OK the shift slow, and when they shift fast they break (sometimes they break the rest of the drivetrain instead). Racing is expensive, though.
Isn't Soul Assassin running a sequential?

 

Automatic transmissions will launch harder than a manual, don't forget.

A torque converter isn't just a slippery way of connecting an engine to the ground. It actually multiplies torque, up to 2.5:1. If I have a torque converter that does 2:1 multiplication, with a 2.5:1 gear and 3.90 rear gears, that's 19.5:1 multiplication, of nearly peak torque (since the engine is at torque peak), RIGHT OFF THE LINE. With a 3.35 First gear and 4.10 rear gears, that's only 13.75:1 multiplication, and nowhere near peak torque is transmitted to the ground because of clutch or tire slip, or the engine being far out of its operating range.

Automatics RULE for drag racing, even for imports... there's a certain "local" low 8-second DSM running a "domestic" race automatic that launches EXTREMELY hard

 

Funny...
Top drag racers (NHRA Funny Car and Dragsters) are running Lenco's.&nbsp Lenco's are modular manual shifting transmissions.



-Ted

 

Shift it manually like I do. I got an 87 6 port turbo engine with stock 3 gear tranny (4 O/D). Hit the gas pedal and brake at the same time, let go of the brake and I leave the hole with 10 psi already there, no lag between shifts and constant boost unlike manual tranny. I just bought another 87 tranny from Japan with 16,000 miles on it for $80.00 great deal or what? It came with a turboII engine that my friend bought.

 

You want boost off the line?&nbsp Just run a retard/rev limiter on the manual...



-Ted

 

We use a G-Force tranny for the Drag RX-7. It's almost like running on an auto tranny (no lag between shifts) just move the stick back and forth. I know it is not the same as an auto tranny but it is the same principle (no clutch pressing between shifts). I like manual trannys but I got to give it to the auto tranny when it comes to eliminating turbo lag.

 

RETed: The top cars do not HAVE transmissions, the only "transmission" they have is the reverser so they can back up after a burnout. They launch entirely off of a timed and calculated clutch slip, and the clutch doesn't "lock up" until half track. They never shift.

Angel Guard: That's what I'm talking about.. a nice manual valvebody transmission. I used to run one in my Ford and it just KICKED *** - brake torque it at the line, launch it, hold your right foot down and never let off, just keep grabbing gears. I'm going to look into getting a transbrake, that's supposed to make launching a lot better. Lots more $$$, though...

My street cars will always have manuals... but an automatic is so much better at the strip.

 

G-FORCE are the ultimate just be reddy to fork over some dough

 

You gotta be ******* kidding me...
This debate is stupid unless you dumbasses are going to do a write-up on a Turbohydro converion on a rotary engine or some cheap way of beefing up the automatic transmission from a stock RX-7 where it can take over 500lb/ft of torque.

It's useless arguing this point cause it's either going to take a lot of fabrication skills or a lot of money.&nbsp Last time I checked, this was a 2ND GENERATION RX-7 FORUM, and your talking about drag auto transmissions are NOT even close to what is proper in here.

Show me a "cheap and easy" automatic transmission for the 13B, and I'll shut my mouth.&nbsp Last time I checked, the NA (and J-spec autos) were CRAPPY options to go drag racing with.

I don't wanna build some crappy V8 bracket racer with an auto trans so I can be consistent.&nbsp In my book bracket racers are racers who don't have the know-how or the money to afford going heads-up.&nbsp I call it sissy racing and not fun to watch...




-Ted

 

I asked a legitimate question, and wanted a legitimate answer. That's all.

This is not some "crappy V8 bracket racer" as you put it. It's for the FC that I'm thinking about stripping out and turning into a dedicated drag racer. (Still in the thought stage, and the best time to ask questions is before you even turn a wrench, so all progress is forwards)

I feel that an automatic would be greatly beneficial to drag racing a rotary. I already outlined why, above. I know there are people somewhat SUCCESSFULLY drag racing with the old 3-speed automatics, (9-10 second range) and I wanted to know if the 4-speed unit was similarly strong. I guess not.

Consistency in shifting isn't my main concern, although it is a nice bonus. My main worry is LAUNCHING. Did you know that FWD Dodges, on street tires, with AUTOMATICS, can launch in the 1.7sec 60' range? IN fact one of the first things they do with a 5-speed car is convert it to automatic. Not just for bracket racing, for ANY type of racing. If you launch harder, you get lower ETs. Getting lower ETs is the goal of drag racing.

I'm sorry if my line of thinking gets a hair across your ***. I know "paradigm shifts" are difficult for everyone. Maybe my project will get stalled from the immense cost of a 6000rpm stall torque converter for a C4. (More than the cost of the car, really) Maybe with a more reliable transmission, I'll start snapping rearends and axles left and right, and have to go solid axle. I do know that it is far too "fun" to try to get a car with a peaky engine to hook just enough to get moving, but not so much that it bogs, 'cos either way is the slow way to launch.

 

In a rotary?&nbsp I'd like to see proof...

You talking about the Phatridz/Forward Motion Neon?

That already goes above and beyond the capabilities (and needs) of 99.99% of the people on here.

I took offense of your comment - "Drag racing means automatic transmission." - which is total bullshit.&nbsp There are numerous rotaries going deep into the 9's on basically a stock FC turbo transmission.&nbsp The fastest rotaries are running dog-gear boxes.&nbsp I don't see a single FAST rotary engine vehicle running an auto transmission; "FAST" meaning 7's down the 1/4-mile.

As for your comment on the LENCO, you better go check one out.&nbsp It still uses manually shifted levers with a "clutch".&nbsp It's more manual transmission that automatic...



-Ted

 

What I don't understand is your choice of a C-4 ford auto 3 speed. The ford boys only run these because they bolt right in. Many of the really fast bracket racers run Powerglides. C-4 is a great transmission, but a few mechanics of it don't make it as suitable as the powerglide. If the C4 was so great, why do they offer a C$ to powerglide conversion plate? Why don't they offer a powergilde to C4 plate? If you have to go to all that work, why not go with a better transmission?

Indeed, many of the serious drag racers swap out their stick trannies for auto's. They do this for more consistency in shifting and better launches. Do they run faster than with stick cars? Not with good drivers
Will you be faster with a auto car? No.
Will you be more consistent? Yes.
Sean Cathcart

 

These 2 and 3 speed autos were meant for big torque motors.&nbsp This is a bad application for a rotary (even a turbo one).&nbsp I dunno what's with peejay's fascination with them...



-Ted

 

*sigh* No, I don't mean Neons, I mean all the Shelby-Dodges out there running very quickly for next to no money. Shelby-Dodges as in anything with a turbo 2.2/2.5 engine in it: Lancers, Omnis, Spirits, Shadows, Caravans, etc.

I don't plan on having enough power to warrant a 2-speed... in fact, people recommend you stick with a 3-speed for heavier cars or cars with smaller engines. This is the last time I'll explain it... a drag race is won or lost in the first 60 feet - if you launch like crap, you need an extreme amount of power to make it up on the rest of the track, compared to your competitor. Automatics have inherent advantages off the line, due to the torque converter allowing the engine to "flash" up to its powerband while at the same time MULTIPLYING torque. It's like having another set of gears. If my engine makes 200lb-ft of torque at X rpm, and the torque converter multiplies that by two, that's 400lb-ft at the transmission input shaft. Meanwhile with a manual transmission, you are slipping the tires or the clutch, and putting down less than the engine's torque output. (Meanwhile the automatic car is putting down roughly DOUBLE the engine's peak torque)

I never mentioned Lencos, by the way. I am aware how they work...

 

Multiplying torque is the same as changing our rear end ratio or the gears in your transmission.&nbsp Big deal.&nbsp Having too high of a ratio isn't going to help you anyways.&nbsp it's a balance of engine power and gearing to get you efficiently down the 1/4-mile.



-Ted

 

The FC auto trans only has a 2.841 low gear compared to the 3.475 for the 5 speed. I dunno what kind of stall converters are available for it either.

Ford C-series are 2.46 low gears, but they most likely have a much better stall converter selection.

Ted, I guess you've never seen Mazfix's 20B FD that runs low 8's with a Powerglide?