Dabesiv

iTrader: (1)

So I'm preparing to finally convert over to a 700r4 from the 200c, I was going between a 3.73 or 4.10 posi but since this is a daily driver with high speed weekends it didn't seem smart on fuel to do a 4.10. The guy that's building the trany for me talked about doing a 3500 torque converter which I think is too high as the goodwrench has peak torque at around 3700. From my reading I should probably do a 3000, correct?

My 200c has what I believe is a 2000 true stall as the engine won't budge past that with brakes on. I cant even chirp the tires with this which bothers me as the engine should have more than enough torque to burn tires (I believe its 350 lbs). I want something performance based but still reasonable on the street. Is this possible with what I'm thinking, all info is helpful as I barely know anything about tranys, onlu what I have read and comprehend.

Also, will a higher tc mean a higher true stall?

92droptopws6

iTrader: (10)

The minimum I would put in ANY car would be a 2600 stall... if for instance you have a cam that starts its powerband at 1600rpm you should have 1000 rpm more in your converter. Don't skimp in this area, contact a reputable company like YANK,PRECISION INDUSTRIES,CIRCLE D,REVMAXX etc. Let them explain to you what your setup really requires to give you the most for your hard earned cash.....
Be kind to both your transmission and converter USE the largest external cooler you can find HEAT KILLS transmissions..

Dabesiv

iTrader: (1)

Alright! Will give one or more of them a call. Do you know about if a true stall changes with a mew tc?

fireturd350

iTrader: (8)

The high dollar companies should take down all your specs and design it directly for you. If you request a 3000 RPM that's what it should be. Also some allow you to mail the converter back in within a lot time period like 2 years to have your stall changed again. That day if your combo changes or you don't like the stall speed you are not stuck with a $450-$800 converter.


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Reid Fleming

iTrader: (2)

http://www.circledspecialties.com/p-...converter.aspx

With your setup, I'd go with a 2C or possibly a 3C from Circle D. But give Chris a call there and run your specs by him. He'll set you up real good.

And don't bother with 4.10 gears. With the 3.06 first gear ratio on the 700 R4, it's just too much axle ratio. (No traction, especially with a converter) Never mind that it makes highway driving miserable. 3.73 is plenty for the 700R4.

Dabesiv

iTrader: (1)

Will do, I guess none of those shops are open on weekends so I have been anxious to call.
Do you think the 3.73 will still break loose pretty well, less traction = more fun on cruise nights but there is a limit. and I have seen what a 4.10 will do with a 700R4 and a 350ci, smoked tires till 3rd which sounds like fun but I can't be replacing tires every few months

freaky

i spin at will up to a 30 mph roll with my mods an 2.73 rear gear .

Dabesiv

iTrader: (1)

Well Chris was a big help. My car never breaks the tires lose most likely due to a low TC keeping the brake stall working. I was right about the 3000 TC for my engine which is nice to know I comprehended what all I read. I didn't realize that the 4.10 and 3.73 overdrive were so close in RPMs until talking to him, 3.73 is gonna be around 2000 and 4.10 are around 2300 either is gonna be a lot lower than my stock setup.

While I have your guys attention. Is it worth it to get a B & M mega shifter put in with the transmission? It would take me ages to figure out how to and then actually install a new transmission as I have no clue what to do, for now. So it seems like it would be easy to just have the mechanic install the shifter with the transmission, I will need a new shifter anyways so maybe kill two birds with one stone and not buy a second shifter later down the road. Or should I just stray away from the mega shifter.

I already do the "manual" shifting with my automatic because my shift kit is a little too rough on the shifts otherwise. I love the look too but is it practical?
I talked myself into "needing" it so just wondering if I should rethink it or not.

Reid Fleming

iTrader: (2)

What speeds are you planning on driving? My car with the 3.27 axle does 2000 RPM at 60 mph and 2300 at 75 mph. (2500 = 85 mph). These are my cruising speeds.

My wife used to have a 4th gen LT1 with 3.73 gears and a Vigilante 2800. It had a lot of pep when you stood on the gas. You were in the power zone right now. But with headers, high flow cats, and Flowmasters, the car was annoying on long highway drives. Just way too loud. Pulling 2600-3000 RPM on the highway in overdrive gets old real fast with headers and catback.

The ONLY way you're going to get traction in 1st gear with 3.73 and converter is with drag slicks. With 4.10 gears, forget it. The 4.10 gears are popular with 6 speed people. But you have to remember that 4.10 with a 6 speed is the same ratio in 1st gear as a 700R4 with a 3.56 axle. And then the 6 speed people have the benefit of the ultra tall 6th gear to keep the revs down on the highway.

I would say no to the B&M Megashifter. A lot of people here don't like them. And with a converter in the car, it's going to shift softer than it does with the stock converter in there right now.

The converter in my opinion is so much better than aftermarket gears. You get a huge performance boost (wife took 5 tenths off her 1/4 mile time with the 2800 stall alone), you get instant power right now, yet once you're on the highway it locks up and acts 100% stock with quiet performance and good gas mileage. Aftermarket gears on the other hand are loud on the highway, get bad gas mileage 100% of the time, and don't gain much of anything at the track. Maybe a tenth or two.

Reid Fleming

iTrader: (2)

The other thing to remember is that the drop between 1st and 2nd gear with the 700R4 is a big ultra wide gear change. With the 3.73 axle, you blow through 1st gear just about instantaneously. Why not spend more time in 1st gear by going with a taller axle ratio, but then combine that with the converter. A lot of fast cars at the track use a 2.73 axle with a great big stall. That way you get traction on the line, have that midrange power from 70-100 mph in 2nd gear (especially with the stall), all the while retaining low RPM cruising on the highway. (2100 RPM at 100 mph)

I've driven 2.73, 3.27, 3.42, and 3.73 with the 700R4 transmission. I like 3.27 and 3.42 the best.

Dabesiv

iTrader: (1)

well my car is mostly a city driven car, with the occasional highway driving, with my exhaust cutout as loud as it is the highway can be fairly annoying with noise, like a constant yelling in the ear, and I am at around 3500 RPMs at 65 which is horrid on gas.

Thanks for the advice on gear ratio as I never would have known that 3.73 wouldn't grip in first. I knew the 4.10 wouldn't grip at all for first and maybe 2nd. I will look into the 3.56 as I want performance and speed but with practicality. The shop I was going to take it to said it would be a pain to setup a lockup on my car and it wouldn't be all that important which I was hesitant to agree with, I wouldn't mind just doing a toggle switch lockup either if it's easier.

Dabesiv

iTrader: (1)

I never would have imagined anything below 3.23 would be that great as I have seen the 3.23 on a 700R4 with a thirdgen locally and from a dig, I would have him almost every time. but he does have stock stall if I remember right.

Reid Fleming

iTrader: (2)

Which stall did Chris recommend?

There isn't a 3.56 axle ratio available. I'm just saying that mathematically a 700R4 1st gear (3.06) x 3.56 axle = 10.89

10.89 divided by 2.66 (1st gear in a 6 speed) = 4.10 axle.

A 2.73 rear end by itself is pretty sluggish. 0-60 is not particularly fun. It's only when you're on the highway that you can floor it and get that looooooong 2nd gear that sends you up to triple digit speed. A 2.73 axle with a big bad torque converter brings back the low speed power and continues it as long as you hold onto the gas.

The downside is that a 2.73 axle ratio with a big torque converter takes more gas pedal to get going than the same car with a shorter axle ratio.

3.27 is a nice axle for just about everything. Quick off the line. Doesn't rev too high on the highway. Doesn't feel bogged down at any area. Handles the TPI torque nicely.

3.42 is basically a quicker version of the 3.27.....The RPM's are about 200 RPM more at any given time. I wouldn't change out a 3.27 to a 3.42. But if you did have a 2.73 and were thinking of changing to something else, THEN I'd recommend the 3.42

3.73 I personally feel is too much for a TPI. On an LT1, they're a bit handier. And they're fine for an LS1. But even then you've still got the high RPM highway driving.

Dabesiv

iTrader: (1)

Chris said the 3000 stall would be perfect for my setup, I didn't realize it until I went to call them, but I am about an hour and a half from their shop so I can easily go down there too and talk with him more and show him exactly what my setup is.

Now how might the 3.73 run on a Q-jet carb, since they are usually lower power than TPI from what I understand. Eventually, I want to do a super ram TPI but by then I can change out the rear gears if needed.

Reid Fleming

iTrader: (2)

We're talking about the same Chris right? Chris at Circle D? If so, that's going to be a lot longer than an hour and a half from Colorado Springs to Houston. I drove through Colorado Springs when I was moving to Houston. A fun drive for sure. But a long drive.

With a carb? The 3.73 should be fun. But let's not forget that a torque converter will give you some serious midrange power. Check out this chart for an example:

http://www.eecis.udel.edu/~davis/z28...age011026.html

Dabesiv

iTrader: (1)

Maybe I'm wrong but I was pretty sure the area code I called was for Pueblo haha which feels like Texas but I guess I'll double check that location.

Reid Fleming

iTrader: (2)

Circle D is in north Houston.

Janefer

As you have received a lot of suggestions and some of them are just brilliant. As per reading of them you can just upgrade to your vehicle as you required and surely there'll be no problem

Dabesiv

iTrader: (1)

Don't know how I messed up the area code but I did

Anyways, I think I have most of my ducks in a row. I'm gonna be checking the local wreckers for a driveshaft and 26 spline 3 series posi to put in the differential. I found my transmission, and am now contemplating just installing it myself as after reading quite a few posts here and elsewhere it doesn't come off as too difficult and it will save me a few bucks by far.