zelement

After killing my 700R-4 at the track on Saturday, I have decided to have "the real" Art Carr redo my tranny with the extreme duty 700R-4 that is able to handle 700+hp and 650+tq.

Steve over at Art Carr also recommended me their 9" NON-lockup converter, and a huge transmission cooler.

I have never been in a car with non-lockup converter so I don't know what it is like but from what I have heard is that a non-lockup converter is not recommended for the street. Because of the extra heat it creates and the poor gas milage it produces. However, the guys over at Art Carr all said that their non-lockup converter actually creates less heat than other lockup type converters, because a non-lockup is clutchless,and the driveablility is as good as a lockup type. They also told me that if I go with their non-lockup converter I will pick up around 50 rwhp on the dyno.

I am just confused about the whole lockup vs. non-lockup debate. If anyone has a non-lockup driver on the street please share your thoughts.

BTW: They are not trying to make money on the converter because a lockup actually cost a lot more.

Thanks,

Paul

GlockLT4

:eek: :eek: :eek: :eek: :eek:


[Modified by Glock'94, 12:55 AM 6/6/2002]

nsimmons

how could that be..a slipping converter wastes power..thats why many people force lockup for 1/4 mile runs

i cruise all the time with mine unlocked.i much prefer it, a slight nudge of the gas brings the rpms right up into the power band, which aids part throttle What i dont like is the mushy feeling it gives the car as its always slipping, you dont have fine throttle control.

Also they recommend a huge cooler because a high stall non lockup converter will make alot of heat, especially on the highway. I'd stick with a lockup.


[Modified by nsimmons, 11:09 PM 6/5/2002]

Red94Vette

I'm headed to work in my C4 (only reason I bother going to work is the drive). When I get there I will tell you about my experience with a 3500 RPM stall non-lockup in my 86 maro (low 11 second machine) on the street.

Red94Vette

I ran across a heavily modded F4 maro SS on the way to work. Traffic was too bad to play but I can tell you I would of lost, and lost BADDLY. He has heads/cam/12 bolt rear end/ aftermarket intake, long tube headers.. etc on his LS1 SS.

But, I'm not one to back down from a race, it's supposed to be fun right?

I plan on running that car after the AFRs, hotcam, and headers though.

Red94Vette

Your drivability should be the same when the lock-up is unlocked. It only locks after you get up to speed or when the computer tells it to. I can't see why you would get 50 more HP at the RW. I don't believe that.

Ok, non-lockup converter.

I have a 3500 RPM stall (this is what it flashes to in 3rd at a slow cruise). I can't stall it up that high stopped because my rear brakes suck on my 86 maro.

The advantages of a 3500 stall is.. your motor will flash to the hook-up RPM and give you all the torque at that RPM even though your are traveling slower. Also, since your engines RPM is constant at this time you are getting your full BRAKE HORSEPOWER. You are not losing any power to the weight of the rotating assembly of the engine. You only lose power if something is accelerating, and since it's not you are getting the full power of the engine. That's why converters give you more torque when it is stalling.

Ok the dissadvantages. One is heat. When a converter is slipping it makes a lot of heat. I had idleing trouble when my camaro was still a TPI. I had to idle it high to keep it from dying. So, at a redlight with the brakes on the converter would be making some major heat while it was slipping. I ended up burning up two TH-350 stage III trannies.

Two is traction problems. The higher stall kind of acted like an "on - off" switch for power. I didn't have as fine control and I spun more than having a tight converter.

Third, car was a lot louder. When I would take off from a redlight it would slip up to 2800-3000 RPM while I was just starting to move. And same with highway cruise.

I don't have any experience with a lockup converter because I broke my 700R4/verter on my 2nd pass on the car.

If you like to drive this car a lot I would get a lock-up. If you are going for max power viper killing machine only I would get non-lockup.

But I can you Art Carr knows their stuff. I would listen to them.


[Modified by Red94Vette, 7:45 AM 6/6/2002]

zelement

Just talked to steve at Art Carr, he said that as soon as a converter locks up you loose the torque mulitiplications that a converter is intended for.

I am still deciding so keep the comments coming!

nsimmons

yes thats true, but when you mat the gas the torque converter unlocks and you get your multiplication..when you cruise it locks which is good for milage and less heat. so its a mute point..the thing wont be locked when driving aggresively

Red94Vette

I think the point Steve is trying to make is the lock-up converter will be heavier, thus it would take more HP to accelerate.

Red94Vette

Zelement,

here is one thing I thought of. WHen you have a loose stall your RPMS are a little higher than your trans input shaft (converter slip).

This means you are higher up your torque curve (compared to a standard).

Now this is good if you are below your torque peak because the torque is getting higher with more RPM. Once you are past your torque peak any slip you have will hurt you because you are now on the downhill side of your torque curve and the slip causes you to be farther down torque curve (higher RPM) then compared to zero slip.

I think this is why some people tell you they run faster locked up on the big end.


[Modified by Red94Vette, 3:15 PM 6/6/2002]

zelement

I am now more confused than before? So why do drag racers (non-drivers) all run non-lockup converters? Why is the advantages of a non lockup if people are running faster with a lockup?

nsimmons

like red said, lockups are heavier and you dont need to cruise on the highway with a drag car. for a street car the lockup is the better choice

you want to be cruising on the highway with your converter slipping at 3000rpm or locked at 1800rpm

J Z06

I can't imagine a NON-locked convertor. I think all of the auto 700R's locked at 41 mph or close by. You're actually losing power by keeping it un-locked. I think when I do 1/4 runs...mine locks just after hitting third. A friends car with the convertor locked will make much more power than with it loose. Keep it a lock up convertor though many opinions will come along and make it confusing. It really depends on your application for the car...

JD

Raysur

What size cooler are you getting? I got a B&M stacked 24,000GVR today.

GlockLT4

I got a 22,000 ... works very well.

zelement

I have the biggest B&M cooler on my car right now, obviously it doesn't do the job.

The cooler that I am getting now is twice the size of the B&M.

Red94, Tell me more about the driveability of your non-lockup converter. Was it a pain to drive? Please describe the characteristics of the converter, thanks.

YorkL8apex

Glock

Where did you get your cooler and where did you mount it. Looking to add one to my 91 but want to use something that works. :seeya


[Modified by York67vette, 8:41 AM 6/7/2002]

Raysur

Paul,
When I bought my cooler I checked out the biggest B&M available (28,000 gvr race version) and my 24,000 gvr street version. There are three differences, the race kit is obviously bigger, the race kit didn't come with mounting hardware and the race kit doesn't have the street versions "low pressure drop" feature that protects against lube failure. I'm wondering if you bought the race version because that could be your problem right there.

corvette1990

Since my new engine last year, and new chip, I have had NO lockup. I have burned up 3 transmissions (2 bullet proof) due to heat!!! The trans guy says that every torque convertor that has been put in is a lockup convertor, but it isn't lockin due to the chip. The chip people say the chip is supposed to lockupat 50 mph at from vss, but I never go to ground on pin D. bottom line is for over a year, I have driven nonlocked up. here is what it feels like. Engine revs easily with 2200 stall convertor. Car shifts sorta normal thorugh the gears. once in overdrive is where you notice it. come to a hill and you must give more gas (rpms) to keep constant speed. go down a hill you have to let off gas alot to maintain speed. flat ground I get similar gas mileage as I did with lockup convertor. Non-lockup heats more. My cooler is in front of my A/C cooler, some put it in front of the power steering cooler. But get a trans cooler, and use it in tandem with one in radiator.

MCAF84

I have been running a non-lockup TC for about a year on the street.
I was leery when the trans. shop sold it to me. I had run a 408 sb now run a 500+ hp 383. The trans acts the same in the first three gears whether it lockup or not. you do gain 200 rpm on cruising speed. I have put 5000 miles on this trans. and like it better. the car is used for driver events and some drag racing. I have a 2500 stall and wish I had 3000 to 3500. oh well.