who knows about these boxes?

I am thinking about a race prepared one (big dollar unit) but I need to know specifics especially the ratios 1st, 2nd, 3rd... so I can do an analysis on it.

Does anyone know about these or know where to point me too?

Thanks

 

Are you drag racing now?

http://www.gearvendors.com/hrfordratios.html

Why would you consider using this specific tranny?

 

All I know is they were used in '79 Mustangs.

 

i'm working on that adapter right now. i am presently setting up for a th350 setup. turbostreetfighter pointed me to a torque converter manufacturer. th350 way easier than c4.

 

Are you working on a kit for this auto and will be able to sell it to other FD owners?

 

As i remember, the C4 uses much more HP to drive than the more popular turbo 350...Carter

 

Thank you sooooo much for that link ! I love you guys

me into drag racing.....never

You will see soon enough

 

hmm.... yeah.... asking about a auto trans, running big turbo, hmm.... ok I'll believe you

like the other guys said, check out the TH350 also. It's a proven transmission. I think the ratio on it is 2.52:1, 1.52:1, 1:1

 

Also I remember reading somewhere that a TH350 took 36 LESS HP to run vs a TH400 on the same setup. Assuming they did the test on a muscle car with a V8.

 

I am also a very firm believer that an auto transmission car with a transbrake is a much better choice for a big turbo car. It makes it very consistant ,and much more reliable than the manual transmission, not to mention an auto with a transbrake leaves HARD on boost. Also I agree that the TH350 is probabably the best auto transmission for a RX7 drag car due to it's minimal parasitic drag compared to other automatic transmissions.

 

i'll post a pick of how ridiculusly big the th350 looks bolted to my motor. i was able to fit the engine and tranny under the stock tunnel in my second gen.

 

I have a fully built 4L80E with a 3k stall mated to a 20B for a street TII!
The tranny came with a lifetime warranty.
I also got a 200R4 out of the Buick GN for the same setup.

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs
un-tubbed

 

Well after doing a comprehensive computer simulation, there is not much in it.

For those interested

Test sample is for a "car" with peak 1000bhp and a typical rotary side port power cuve. (no not mine!!!)

2 speed glide
8.29sec 167mph

3 speed C4
8.06sec 170mph

6 speed C4 GV
7.93sec 171mph

6 speed race manual (custom ratios)
7.85sec 173mph
BIG DOLLARS!!!!!! Un streetable


These are all with optimised rear end ratios and in the "6 speed" C4 case not using all the gears as it was slower due to the extra time spent changing gear and the assosiated loss of drive & performance.

realy realy good option though in regards to gearing and cruising the car when equiped with the GV kit, I tried to take into account as many variables for the individual tansmissions as I could get my hands on too so i think the final result are very indicative of what to expect from either option. The GV kit looks realy attractive for a car that will be used on the street and track got to love those gearing options !

 

Can a fully race prepared TH350 take over 1150bhp in a 2500lb car? has anyone used one or know of someone who can verify this for me, interested in people who have run them for season after season and have a maintenance history ?

Also some links of reputable shops who specialize in building these transmissions would be appreciated, what is the percentage difference in favour of the TH350 over the C4, I am guessing it is less than 3 to 4% ? Please note power handling capacity is my main issue and 100% reliability, I don't care about loosing a little bit more power thru the trans to gain ALOT of extra trans life

That GV kit has got the OK, just need to finalize the trans choice.........so fire away

 

did you let your subscription to hot rod lapse?
try hmm tci (no website, 662-224-8972)
www.shiftworks.com
hmm ok hot rods a little thin this month, maybe you dont need it

mike

 

I fully race prepped TH350 can take WELL over anything a rotary could throw at it. It has been used in MUCH heavier cars, making MUCH more power.

 

This is very true, even Paul Efantis runs a TH350 in his Supra, and his car is making over 1000RWHP at about 2900-3000pounds.

 

So what percentage less power will a TH350 require? Compared to a C4...

 

8-10% depending on the convertor, it is my understanding that something actually spins in reverse on teh C4's causing DT loss!!! BTW i have a race prepped th350 for sale with adapter , wicked 6k convertor,starter, cheetah pro shifter ,flywheel and starter. they also make a bellhousing for the C4 that bolts to a chevy engine. try Trans king in galveston for exact numbers,talk to a guy named Gilbert. the convertors that i use only lose a maximum of 5% loss compared to the normal 13-20% you usually see on a dyno.


MWW

 

why are you selling out and how much you asking

 

Rice, the 350 used to have problems with the intermediate sprag clutch on 400+hp applications in a heavy car. Now of course I understand you are talking far, far lower weight than most cars I saw break the int. sprag, but you are going to be revving a hell of a lot higher and making more power. I would be somewhat concerned about the 350 holding up to that well. I have seen C-4's behind pretty impressive cars and it always amazed me to see that little unit hold up. At the place I used to work at (J.W. performance transmission) I once saw the guts for a C-4 put inside a c-6 case for a bracket racing big block car. It picked up, I think .3 seconds which started a round of protests about illegal engine mods. After the 4th protest they tore down the trans. oops, how did those c-4 guts get in there. The moral is the c-4 is a small, light compact and relitivly durable unit. I would look into it. And with removable bell housings adapting would be easier.
Jay

 

what he said!

 

TH400 <--stronger than TH350, with same dimensions, I think

 

A TH400 is stronger, BUT it's less efficient than a TH350, and like I said before Paul Efantis Supra is making over 1100RWHP, and it's not breaking it, a properly prepped TH350 should be enough for a rotary.

 

i am selling my tranny setup because i have ditched my race car, the 350 can withstand up to 1000 ft/lbs of torque on a light car ( my car was only 2300 lbs) and is more effecient than the 400 ,PG and the C4.

MWW