68s

Im getting ready to order a 2004r. 68 cutlass mild 350. 10 bolt 3.73


So my ? is for a daily driver mostly around the city what should i go with? It might see the freeway here and there but mostly around town.

Lock up or non lockup?

svnt442

AFAIK they are all lock up transmissions. I wouldn't want to run it without the lock up feature due to overheating.

jag1886

The builder can convert it to a non lockup, that's what I did, makes for a very easy install and you also end up with full oil flow to the cooler all the time. I vote for non.

DoubleV

I think it's a toss up since you're going to be driving around the city more often than highway, but since it's a street car my vote is lockup, but I don't think it's going to make a huge difference in your case IMO.

rustyroger

Why would you want to delete the lockup?. It's a useful fuel saving device, even if your driving habits mean it isn't used much.
What will you gain from deleting it?, the transmission was designed to work with lockup and seems to do a fine job judging by its popularity.

I say leave well alone.

Roger.

Redog

I think why he wants to know is because the lockup was contorled by a computer. Once the car hit a certain speed in 4th, it would lock the converter. In 68, they did not have the computer.

I vote for the lock up. There are plenty of kits that are made for this. It can make the lock up vacuum controlled, speedo controlled, or electronicly controlled both inside the pan and out. Prices are different based on which kit you want.

I want the kit inside the pan

68s

I called ck performance n was always put on hold. Called extreme auto n he referred a non lockup. Spoke with raptor this morning n he recommended a level 3 with billet convertor.

My 355 will be short of 400hp I believe but I plan on beating the crap out of it.

gearhead1218

http://cpttransmission.com/pdfs/carcraft2009.pdf

Read this article from the CPT website.
IMHO Art Carr knows a thing or two about the 200-4R

DoubleV

The only good reason to delete it is so you can run a non-lockup converter which is more efficient than an unlocked lockup converter. Better for track use and the more efficient non-lockup converter is still almost as good as a locked up lockup converter.

The other reason to go non-lockup is that you don't have to mess around with aftermarket lockup kits that can sometimes be frustrating to get to work the way you want them to.

With that said though, I run a lockup on my car and always plan to as I feel it's the better choice on a street car, especially one that sees the highway alot.

jag1886

The other reason to go non-lockup is that you don't have to mess around with aftermarket lockup kits that can sometimes be frustrating to get to work the way you want them to.

I can't agree with this more I spent a fortune trying to get that lockup to work properly and it just wouldn't, if I lived out on the flats of Nebraska I could have gotten it to work somewhat OK but I live in the mountains and it just wouldn't kick in and out like it should.

68conv455

I recommend a lock-up.
I have a 2004R with lockup from CK perform. A 12 volt power source (switch) locks or unlocks it in 4th. I have a 3.55 rear. I typically lock it at 40 mph or above.
With the 3.73, I would think you will lock it frequently. Better gas milage when cruising too. CK told me never lock it at WOT.

Vistabrat72

By all means go with the lockup, the purpose of these transmission conversions in most cases is to get better fuel mileage AND a sight performance boost due to the lower 1st gear and the smaller power losses needed to work the transmission versus the THM350/400. Yes, there are a few things to overcome when hooking up all the lockup gadgets, I had my own story involving this, but I will say the lockup is nice to have on the highway and around town at higher speed levels. Howie.

68s

Im not too concerned about gas mileage. I hear about a lot of headaches with the lockup, 300 rpm difference isnt much for me since i will rarely hit the highway. If i do it will be 10-15 min. I dont plan on traveling with the car more of a town car. Im pretty much just gonna beat on it when i drive it around town. no cruising involved.

There are different ways for the converter to lockup right?

1 shop said its internal.
Most that i read about have a switch.

I just dont want the headache like everyone else.

If i do go lockup whats a good Convertor?

Whats the worst that can happen with a non lockup? Heat, durability? slippage?

rustyroger

If you are just going to beat on the car round town and aren't worried about gas mileage why not use a 350 transmission?.
I think it would be easier (and cheaper) to build one to handle 400hp than a 200R4.

Roger.

1970-W30

Like Rusty said, why bother with a 200-4R if you don't care about mileage and are just going to be running around town only, save a bunch of money and stick with a 350Turbo trans.......

68s

Right now I have a 2spd tranny. I could get a 350 or th400 locally but for a few hundred more why not a 4spd?

If I do go on the freeway dont want to be in the 3k range with 3.73s .

Motor should be done soon...... tranny is the last thing I need.

jag1886

Think you just answered your own question. That 200R4 has a nice low first gear, will help out the gas milage and knock down the RPM's at highway speeds. I don't think any of the above mentioned transmission will help with
all 3 of these.

68s

Im mostly concerned with the lock up convertor.... 3 different vendors 3 diff answers.

Non lockup seems to be the most simple.
What are the cons?

rustyroger

You will need a suitable converter and an aftermarket transmission cooler if you go non lockup.
Every transmission builder has their own idea of what is best, a good one will be able to explain why his idea works. If you come across one who can't explain why his way works in a way that makes sense to you look elsewhere.

Roger.

Lee_A

What is the stall speed you are targeting? In my Cutlass, with a 700R4, the stall was about 2800rpm, and the lock-up made a noticeable - but not huge - difference when it locked.

In contrast, my Falcon station wagon has a converter that stalls closer to 4000. With it, the lock-up makes a HUGE difference!

POINTS:
1. A lock-up costs more money than a non-lock-up converter
2. If you want a lock-up converter that can handle being locked under full-throttle with a stout motor, then it will cost MUCH more money (I've bought two different converters for my Falcon, they cost right at a grand for each of them).
3. A heavy-duty lock-up converter is HEAVY (more mass for the motor to turn).
4. If you are using a stock stall speed, or maybe just 2000rpm or so, then the lock-up isn't going to really alter your mpgs or engine speed a whole heck of a lot.

jag1886

The main thing I like about the non-lock up is you just put it in and it works pretty much like the transmission you took out.
I talked with several different transmission guys and they all seemed to agree that the lockup only changes the RPM's at cruise speed by about 200 RPM's and that's good for about 1-2 MPG difference at best (I'm just repeating when they told me).

matt69olds

My opinion is a lock-up converter is the best of both worlds. Get a converter loose enough to really make the car move, then lock it up on the highway. The hot ticket for the Grand National guys is to lock the converter once the turbo is spooled up and the car is already accelerating. The problem is it takes deep pockets to afford a converter with the modifications to hold at wide open throttle. Obviously, that isn't what your trying to do. As long as you get a good quality converter built for your application and understand what it was built to do you wont be disappointed.

odddoylerules

with 3.73s you dont need a loose converter to launch though right? in first you gotta be traction limited as it is!

cdrod

I talked with Jake of Jakes Performance in Sanger, TX. He recommended I skip the lock up feature for my build: 350ci 300HP/350TQ, TH200-4r with 3.42 gear. I plan to run a low stall convertor (1700-1800) so the lock up won't really make a hugh difference. The lock-up convertor is heavier and will steal more HP on the way to the rear wheels.

Running a 3.73 rear gear with the TH200-4r, 1st gear is almost the same ratio as 4.11s with a TH350. TH200-4r=10.22:1; TH350=10.36:1. Traction could be a problem!

odddoylerules

yeah so a similar setup to yours would be great, with a soft hit and low highway slippage

Lee_A

Acceleration = mass divided by force.

Mass doesn't change. To simplify the discussion, let's say that torque is the "force". Now, look at a graph of your engine's torque curve. To maximize acceleration off the line, you want your stall speed to be just under the rpm where your torque peaks.

A proper torque converter will do that for you, gears don't change that at all.

Gears rarely change performance more than a hundredths of a second, maybe two-tenths in extreme examples.

I've seen a car run mid-16's with a stock converter, then run 14.9's with a converter that stalled just under 3000 - no other changes.

As for the weight of the converter, I've tested a very light 8" converter against my monster multi-disc lock-up converter, and the light-weight converter offered no improvement.

odddoylerules

agreed, but with steep gears and a strong hit off the converter you are just gonna blow the tires off.

going from 2.76 to 3.42 or 3.55 usually is worth more than a tenth though, cant agree there

rustyroger

If it isn't locked it will act like a high stall converter, if it is locked it will steal LESS hp.
What it will do being heavier is make the engine less responsive to throttle input. It will be hardly noticeable and not really an issue unless you are using stick shift on a bendy circuit.


Roger.

matt69olds

And the few pounds of extra weight probably wont be noticed. It MIGHT show up on a timeslip (but I doubt very much) but my opinion would be the extra mileage benefit would far outweigh any downside.

TexasT

Once you have the converter spinning, it tends to stay spinning. The stall part gets your engine to an rpm that makes power(torque) so chose one that stalls at max torque(or at the base of your torque curve)rpm and you get a lot of acceleration, especially if the converter is multiplying.
Rear gears do the same so chose with the knowledgeof what your first gear ratio will be. This get you an optimum formula for acceleration.

MXman112

I am running the 200r4 with lockup behind my 403. I tried the kits but didn't like the way they worked on my combo. What I did was direct wire the lockup circuit to the cruise control on and off switch. When I want it locked, flip the switch, locked.

One thing that needs to be understood when doing this is that when you apply the brakes it doesn't automatically unlock like stock or the kits. If you have to jam on the brakes hard to prevent a collision the car could stall.

Works fine for me.

matt69olds

Its pretty easy to wire it in to go through the brake switch so it will unlock when you push the brake pedal. If the car had cruise control, its even easier and free. There should be extra set of wires on the brake switch, I'm almost positive one if the wires is purple. Those contacts will show continuity with the pedal at rest, and show a open circuit when pushing the brakes.