Hi All,

I need help and verification on selection of Torque converter for my 1982 Firebird.

First Off! I do not drag race, I don’t street race either! I enjoy driving my car and due to recent fuel cost increase I wish to make it more fuel-efficient.

Next Some History,
I purchased my 1982 Firebird new in Jan, 1982. It came with LG4 engine, 200c transmission, 2.73 rear end, AC, power windows, cruise, tilt wheel, and gauges. In April 1982 I added the wing. A year later I changed out the wheels for some Keystone Classics, etc.

In 1992, The 200c transmission was rebuilt by Aamco with full life-time warranty.
In 1996, the car was stripped and completed painted.
In 1998, The engine was replaced with 350 crate and TPI fuel injection system, with electric fans, etc using all new components. I also added delay windshield wipers using OEM original new parts.
In 2000, The seats were replace with some custom leather seats, the front seats are low back buckets

In Nov 2002, a nice lady in a van ran a stop sign and smashed into the front right side of the Firebird.

During the rebuild the suspension was completely replaced with all new components, I added SFC, STB, Wonder-Bar, tubular LCAs and track bar, LCA brackets, Eibach Pro springs, new 16 wheels and 245/50vr16 tires. I have replaced the headliner and other parts to bring the car to a near mint condition. Too many miles to call it Mint. And I added power driver seat base, and power door locks with a new alarm system. The car has a custom 12 speaker sound system.

So here it is 2005 and the Gas prices have soared. Before the accident in 2002, the Firebird was my daily driver. I got 18 MPG around town and about 25 on the highway. With the work that was done in 2003, some of the exhaust components were replaced and I went with the wider tires. The effect of these new wheels, tires and exhaust components changes has caused the gas mileage to drop. I now get around 16 MPG in town and about 18 on the highway.

Now we are up to date.
So in order to get my MPG back I will be swapping out the 200c for the 700r4 overdrive.
My current Torque Converter has a stall of 1600 RPMs. This is brake stall, hold the brake and give it gas. This is too low for the current configuration.
Also my power band has gone up due to the exhaust system changes which consisted of;
1) going from a 2.5 inch converter to 3 inch converter,
2) Stock Y-pipe to SLP y-pipe.
I already had the SLP catback system (two outlets on driver side).

The power band ran form something like 2000 to about 4600 RPM.
Now the power-band is more like 25/2600 to 5500 RPM. Nothing else has changed on the engine.
Please note I’ will be keeping the 2.73 rear gears.

So I need to pick a STALL the will get me back into the power band, but will not cause problems with TCC lock-up. Due to gearing the cruise RPMs will be very low. Please see chart. Do to low RPMs, I most likely will not using Overdrive for in-town driving. If I pick a too high of a STALL then I will get a nice load CLUNK every-time the TCC Lockup engages. I do not think the load CLUNK will be very good for the converter.
s
For example
MPH 200c 700r4 in Overdrive
---------------------------------------------
50 1789 1252
60 2147 1500
70 2505 1750
80 2863 2004

So I am thinking of going with a 2200 Stall or 2400 Stall converter.
So what do you guys think?

Sincerely
Bruce in Cary NC

 

Bump please comments!

 

Keeping the highway gears in the diff will only drag down any performance enhancments you do with the engine or tranny. Any converter in the low 2000 range should work fine.

 

My car came with a 2,500 RPM stall in it. No clunk when it locks up. I like it, because my cars not a daily driver, and i plan to someday race it. But i think if i where driving it in town everyday, it would be a little high.

 

I'm 51, and the car can get me into trouble easly. The 700r4 has taller 1st and 2nd gears then the 200c, so the acceleration of the car will increase. Might be highway gears, but the highway is where I drive it. I was thinking about 2200 STALL convertor.

Thanks

 

When I first built my GTA, I installed a 2400 converter. Didn't like it at all. Went back to the trans shop and talked to a fellow I knew there. Ended up with a rebuilt converter for a 4.3 Astro van. It works great, and only cost me 120.00. Been running it for 3 years no problems.

 

What kind of stall do you think that has?

What didn't you like about the 2400 stall specifically?

 

I think you should change the rear end gear to a 3:23 and dont mess with the converter, because that tall of a gear you have to keep your foot in it all the time so you are constintly not in your tq range and that is your problem with mpg. If you had a lower gear you would be more likley to stay at say a constant RMP and therfore not have to constintly add more fuel. I have a friend that had a set of 3:08s and swaped to a 12 bolt with 3:55s and the car had more pick up and got about 1-1/2-2 mpg better.GOOD LUCK

 

I as said I'm not changing the rear gears. I been though one rear end build but was able to keep the orginal ring and pinion. The dealer who did the rear end commented that the ring and pinon was like brand new.

I been though a lot of web sites to different companies who sell rebuild 700r4s. There requirements for the warrenties are tough to meet. I thinking of going back to the dealer who installed my engine to get the 200c to 700r4 conversion done. Then I should not have any problems with warrenties.

GM now sells a 4L60 – Automatic transimmsion which is the same as the 700r4. Has anyone here used one of the 4L60 transmissions? The 4l60 transmission comes with a 36 month 100,000 mile warrenty.

 

I have the SLP 2400 stall converter in my 82 Z28. Looking back on it now I wish I had gone bigger for like a 2800 or so.
I swapped in the Pro-Built 700r4 about 2 yrs ago to replace my 200c because I wanted overdrive

Car info: 305 - full exhaust, ported heads, comp xe262 cam, performer intake, holley 670cfm carb, dui distributor. 3.73 gears out back.

 

Thanks!
You have a much healthyer cam in that 305 then I do my 350. My 350 still has its standard cam. Made absolutly no changes to it except for external componants. I going to get the specs for the motor and see if TCI will give me a decent sugguestion.
I have also decided that I going to get Chavy dealer that install the engine to do the transmissions. Most likely I getting the overcounter 4L60 transmission. I believe it already comes with the proper STALL convertor for the chavy small block.

 

SORRY BRUCE, I thought you question and or problem was you wanted to increase you gas mileage, and so you said you dont drag race or street race why would you want to install a stall converter or change the trans, if all you want to do is return the car to mint condition you should just put a stock rebuild in it, especially if your not looking to make any power. I just suggested the rear gear swap to pick you up some mileage because that seemed to be your question while trying to save you some money on not having to put a converter in the car. Because of the exaust change and bigger tires/wheels combo your gear seems to be to high therfore that is another reason to lower your gear ratio so you will be back in the power range of you engine and not try to just patch it up with a converter, THANKS

 

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I'd say the astro converter stalls about 2000 rpm. behind my 355. The 2400 was way too loose for me. This is a street car not a race car. I'd have to rev it up to engage the gear. would have been ok for a drag car. I'm running 4.10 gears too. That 2400 was looser than the 3400 I have in one of my race cars.

 

If you want efficiency for fuel milage, the lowest stall you can find that will keep the engine idling and one that has the highest torque multiplication possible.

I don't know what that is, but it's fairly obvious the reponses you've
gotten here about going with a higher stall than stock, aren't going to get you the answers you seek

 

I don't think know one really knows. I decided that I am going with the over the counter 4L60 transmission with stock convertor ffrom GM Parts. That will will give the overdrive which will increase my MPG on the highway. Around town I don't expect much increase in MPG.

 

GOOD DECISION BRUCE.....

 

Here is some interesting information.
I went over to www.700r4.com and used there calculator.

With the original tire size of 195/75-14 the RPMs @ 60MPH is 2,158.

With the new tire size of 245/50-16 the RPMs @ 60MPH is 2,147.

That an 0.5 % drifferance in RPMs. The calculator for both tires calls the same speedmeter gears.

So tire size really has nothing to do with any of my Gas Millage issues. It the big motor, she needs overdrive!