Author Topic: Torque Converter Selection  (Read 671 times)

Offline lake_harley

  • Full Member
  • ***
  • Posts: 204
    • View Profile
  • Your Best Time: none
  • Your Engine: 305 Chevy
  • Your Track: hope to race at Sikeston, MO
  • Your Vehicle: Building a FED
  • General Location: SE Missouri
Torque Converter Selection
« on: April 12, 2022, 07:19:33 AM »
I'm building a FED for bracket racing and I'm getting ready to buy a torque converter for the Powerglide. I expect the car to be about 1650# with driver, HP of the carbureted 305 Chevy I expect to be about 250-270, rearend gear I have is a 3.23 and I plan to run 1/8 mi tracks. Also, I plan to foot-brake the car rather than running a trans brake.

I had been thinking about a 9 to 10" converter that would stall at about 2400-2800 RPM up to this point. Yesterday I called a company nearby, BuiltRite Converters, who suggested a 8" converter that he typically would consider a 5000 stall but with my low HP he thought it would stall at about 3000. He's used to building converters for some big HP engines. The price of what I had been looking at is ~$400 for an off-the-shelf converter would go up to about $850 for the 8" unit from BuiltRite.

I think what he's telling me makes sense, that I need higher stall to come off the line, but I know that my little 305 is going to be running out of steam at 5500-ish RPM. The Elgin cam I'm running had a useable RPM range of 2200-5200 if my memory serves correctly. I'm completely new to this and can certainly spend money to do the right thing, but I only want to spend it one time.

Input and advice appreciated. If I'm missing info needed to make suggestions, please let me know.

Thanks

Lynn
« Last Edit: April 12, 2022, 07:22:39 AM by lake_harley »

Offline wideopen231

  • Hero Member
  • *****
  • Posts: 1849
    • View Profile
  • Your Best Time: 1/8 3.70@ 198 1/4 5.78@245
  • Your Engine: Hemi 526 ci alcohol
  • Your Track: Piedmont
  • Your Vehicle: 225 CMC FED
  • General Location: NORTH CAROLINA
Re: Torque Converter Selection
« Reply #1 on: April 12, 2022, 07:38:04 AM »
If cams power band is 2200 then I would think the 2400 range would work. My only question is why a 305? Other than pistons and rings everything will fit in 350 block and that extra .250 bore will give lot more usable engine,breathe lot better and allow upgrades later.

  While you can build 270 in the 305 it will be easier and cheaper to build little more in the 350. I know not question related but had to ask why 305"

 A stock converter will actually work pretty well. I am not crazy about the reargear with glide. High gear with medium low in glide(1.76?) will have it leaving unreal soft. I ran 3.73's with 700R4 with 3.27:1 first gear on the street. in 3200 lbs car. Yes you are half weight.

No matter my thoughts on combo have fun with it is important thing.
Relecting obama is like shooting right foot because it did not hurt enough when you shot left foot

Offline lake_harley

  • Full Member
  • ***
  • Posts: 204
    • View Profile
  • Your Best Time: none
  • Your Engine: 305 Chevy
  • Your Track: hope to race at Sikeston, MO
  • Your Vehicle: Building a FED
  • General Location: SE Missouri
Re: Torque Converter Selection
« Reply #2 on: April 12, 2022, 09:46:33 AM »
Sounds contrary to the idea of racing, but I don't want to get the car too quick, so opted for a smaller displacement engine. Building to bracket race, so 6.80 vs 7.00 vs 7.20 it's all dial in. Making the car consistent will likely be the biggest challenge.

I'd use a stock converter, but plan to "lap" the car and the cam I have has a pretty substantial lope in the little 305, so want it to have decent manners going to staging and returning after a run. My thought is that a stock converter will try to drag the car around too much at idle and bog the engine down a lot. Maybe my thinking is all screwy, and I'm not too proud to admit it.

Thanks for the quick reply.

Lynn

Offline tcoupekyle

  • Sr. Member
  • ****
  • Posts: 332
    • View Profile
  • Your Best Time: 4.70 1/8
  • Your Track: Houston Motorsport park
  • Your Vehicle: 225" slip joint FED
  • General Location: Houston
Re: Torque Converter Selection
« Reply #3 on: April 13, 2022, 06:06:32 AM »
Yeah, I would definitely look at a 2500-3500 converter namely because of the weight of the car and the torque or lack of torque with the motor.