[Matts39]

Looking for a torque converter for my 99 ZR2 s10 with a 350 Vortec and LT4 Hot cam. Stock 4L60E trans from the 4.3 (298mm shaft, 10.75 bolt circle, 12inch converter)
Trans bit the dust and since it’s being rebuilt, I may as well put a better torque converter in. The stock L35 converter done great behind the 350, but I’m not sure how long it would last if I was to buy a reman unit.
I’ve also looked at aftermarket converters from TCI, Hughes, Boss Hogg, and many others. My price range is less than $500. I was thinking of going with the TCI Breakaway with an estimated stall of 2400-2600. But I’ve read bad reviews of converters from not only TCI, but many other brands in the less than $500 range.
Any input on which converter is best is greatly appreciated!!

 

[Gen210]

Circle D Specialties
Houston Tx.

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www.circledspecialties.com

 

[Tranzman]

Circle D is what I recommend to my customers...

 

[Matts39]

Thanks guys! Just placed an order for a Circle D 2200-2400 stall. Sucks that it’ll be 3-4 weeks before it comes in but good things come to those who wait

 

[twws]

PTC or atlantic coast

 

[EZA]

Circle D is what I recommend to my customers...

Not to put you on the spot but didn't you say that the Trailblazer 6 cyl torque converter BU51 was a cheap stall upgrade for a 5.3 engine using the 4L60-65E transmission, for street driving not the drag strip.

 

[Ironduker]

I am old, we used to use stock Vega stalls, they were smaller and gave you 2500-2700 rpm stall in a TH350 for CHEAP, lol.

 

[Tranzman]

Not to put you on the spot but didn't you say that the Trailblazer 6 cyl torque converter BU51 was a cheap stall upgrade for a 5.3 engine using the 4L60-65E transmission, for street driving not the drag strip.

Yes that is correct, it's a 1800-2000 stall rating for the 4.2L. usually put's at the 2000 range for a 5.3L engine

 

[Tranzman]

I am old, we used to use stock Vega stalls, they were smaller and gave you 2500-2700 rpm stall in a TH350 for CHEAP, lol.

Exactly!!! I was one of the first to have a high stall in my area. 1969 Impala 327 10.1, headers, Edelbrock intake, 780 Holley, Accel dual-point/super-coil, 350 turbo, 10" vega (3500 stall) and 4:10 gears/posi... Mid 13's in a lead sled!
everyone wanted a ride!!!

 

[Gen210]

I am old, we used to use stock Vega stalls, they were smaller and gave you 2500-2700 rpm stall in a TH350 for CHEAP, lol.

You always knew when the vega converters were going bad because the stall speed would become irratic and inconsistent.

 

[Briglicon]

Precision of new hampton is all i run in everything. They will build whatever you desire, but for most common stall speeds they are on the shelf in many warehouses around the country. I've been using then for 18 years and can count on one hand the number of failures I've had from them. Circle D does makes a fine performance converter, as well. But i can tell you from personal dealings with their converter shop, if it's not something "cool" they don't care.

 

[EZA]

Thanks Tranzman, Enginetech also list a BU51HS 2200-2500 or is this a little much for everyday street driving? I don't have any experience with stall converters.

 

[Tranzman]

Thanks Tranzman, Enginetech also list a BU51HS 2200-2500 or is this a little much for everyday street driving? I don't have any experience with stall converters.

Are you installing a mild cam? If you are look at RPM range for the cam an use a converter that is approximately 200 more RPM stall than the bottom of the range. I.e. 2000-6000 a 2200 stall is nice. That is the spec on my cam and I'll be using the BU51HS myself. The stall is a flash or power brake stall. Under mild driving conditions the truck will start to move at a lower RPM. When I was younger and had a 3500 stall it would start to move at 2300-2500.

 

[EZA]

LS3 factory cam .204 / .211 .551 / .525 117

 

[Tranzman]

To my knowledge all the factory LS cams had a TMBX converter behind them. That converter had a 1400-1600 stall. A BU51 stock Trailblazer 4.2L converter with a 1800-2000 stall would be a nice upgrade. A couple of hundred increase will add to the launch feel and still not kill fuel mileage. That is the one I do for a lot of people and haven't had any complaints yet.
Yee hawww!!!

 

[EZA]

Have you heard of Pro-King? I can get one 1800-2200 one year warranty, can get one very reasonable.

 

[Gen210]

Be sure to have a very good transcooler no matter the amount of stall you have. Bypass the radiator completely...

 

[EZA]

Be sure to have a very good transcooler no matter the amount of stall you have. Bypass the radiator completely...

Thanks, will do !!!

 

[Briglicon]

Thanks, will do !!!

Don't bypass the radiator. Run the external cooler in series after the radiator. Air contact will never, ever, under any circumstances cool better than water contact. If the radiator cooler is clogged or dirty, replace the radiator. Never bypass the radiator cooler... EVER... under any circumstances. For the love of God, don't!

 

[Tranzman]

Bypass coolers are a way of life in the transmission trade. However I always used a plate style cooler. They are similar to the OE auxiliary coolers and are much more efficient than the tube & fin coolers. Personally I don't like to do the bypass thing, so I agree with @Briglicon. The aftermarket/auxiliary cooler set up in as bypass cooler may actually make it to cool. I run the cooler in series with it as the first cooler then into the radiator. If the auxiliary cooler is to big or cools to well the radiator will warm it to an ideal temperature before returning to the transmission. Ideally a transmission should run from 175-200 degrees. Less than 175 the fluid is slightly thicker than it should be and puts extra strain on the trans pump and other components. Higher than 210 the fluid looses it ability to lubricate bearings and bushings. My opinion is based on the fact that I live in the mid-west where it does get cold. If in sunny California or Florida it may be better to run it after the radiator.