Who's running a automatic. c4

[RACERAL]

Thanks Tom... good info. I am planning on my first BB build, the 390 to 445 thing. C6 or C4 it doesn't matter to me. Street use only with maybe 2 or 3 runs down the 1/8 just to see what it will do. I'm hearing about 3600 stall speed for such a ligh weight car. I'm still early in my planning stages, I have had one other roadster, but sold it 3 years ago, and have the itch.

Must be a BB this time... Thanks for the comments guys.

David, I met you one time at VIR , the Club Cranky gang was there.

[DAVID GAGNARD]

Al;
yep I remember VIR very well.......

While not up on automatics and stall speeds,I would have thought you'd need less stall speed for a lightweight Cobra, maybe in the 2000 to 2200 rpm range,I thought the higher stall speed (3000+ rpms) were needed for those big heavy cars like the old Galaxies....

Unless I have things backwards,which wouldn't be out of the norm for me...

David

[avanti-176]

Al,
I have a good C6 that came off a 428 I bought, I was just getting ready to put it on Craigslist. PM me if you are interested, I would just as soon it went to a member here. I will also be passing through NC in mid April and would be willing to bring it along to save on shipping if you would like.

Dan

[mr bruce]

FE Big block Ford to C4 Automatic Transmission Bellhousing

[dallas_]

Originally Posted by DAVID GAGNARD

While not up on automatics and stall speeds,I would have thought you'd need less stall speed for a lightweight Cobra, maybe in the 2000 to 2200 rpm range,

Originally Posted by Tom Wells

As of now I use a nice big trans cooler ( about a square foot with its own fan ), a torque converter with a 1600 rpm stall speed

I've got a 2800 now in a street Cobra and want to change it for something lower. How does that 1600 do on the street?

Thanks!

(sorry if this is a hijack)

[Tom Wells]

dallas_,

Torque converter stall speed is a bit of science with maybe a pinch of voodoo

My engine produces probably 350-400 ft-lbs of torque at 2000 rpm, the car weighs 3100 pounds and it has a 2.88 rear axle ratio. It can spin the tires if I twitch my right foot at any speed up to and over 100 mph, using 200 wear rating tires which are pretty sticky -> Nitto NT05s.

The engine idles at 650 rpm so a low stall converter doesn't make the car try to go forward at stoplights very much at all.

So I guess the answer - as usual - for your case is: it depends.

You need to consider the low speed torque characteristic of your particular engine combo, the vehicle weight, whether the trans is 1:1 in top gear or has an overdrive, and its rear axle ratio.

I remember using a 3.55 behind a similar combo to mine; recall the top gear in a C6 is not an overdrive. It was awful - the tires spun at low speeds and the engine was buzzed up way too high at 70 mph. I switched that car to a 2.73 and it is a delight on the street and on the track.

A friend uses an AOD with an overdrive top gear (not sure of the ratio but it's common to almost all AODs) and a 3.55 and it works very well with a stock stall converter behind a 408 stroker small block with a moderate cam.

Look at some of the converter maker's web sites to see more considerations. Realize, too, that they may not understand exactly what you want, especially if they are drag race oriented. I kinda had to browbeat FTI a little to get them to make the stall as low as I wanted but I'm very happy with the result!

A high stall converter is needed for drag racing but not much else, unless you have a very small engine with almost no low speed torque. Driving such an engine on the street isn't my idea of fun, at least in a daily driver...

Have fun learning about this technology,

Tom

[Hotfingrs]

Originally Posted by RACERAL

Thanks Tom... good info. I am planning on my first BB build, the 390 to 445 thing. C6 or C4 it doesn't matter to me. Street use only with maybe 2 or 3 runs down the 1/8 just to see what it will do. I'm hearing about 3600 stall speed for such a ligh weight car. I'm still early in my planning stages, I have had one other roadster, but sold it 3 years ago, and have the itch.

Must be a BB this time... Thanks for the comments guys.

David, I met you one time at VIR , the Club Cranky gang was there.

Al, The higher the stall, the more heat you're going to build. Mostly street driven doesn't need 3600 stall, I'd stay with something in the low 2000's.