I am a big fan of the PTC Converters. Great bang for the buck. They do quite well in the heads up classes. Have never had one that didn't do exactly what I wanted it to do. I have them in 6 second turbo cars, 12 second street cars and literally everything in between. I have a 9 inch in a pump gas 500 inch mopar that runs in the nines with Edelbrock Perfomer heads. 60' times in the mid 1.30's and about 5% slip out the back. Exceptional. Lenny from UCC makes an excellent converter as well, and a great guy to deal with. Known him close to 20 years and never been unhappy with one of his units either. SB
Steve, Generally speaking a smaller diameter torque converter will be more efficient down track. Looks like they have optimized that 10" for launch, but your paying the price later. So yes, typically a smaller converter will give you the best of both worlds. JW
I found a nice 10" 3000-3200 stall ATI that a board member offered me for sale. Thanks for the input guys.
I realize this is from 2011. Are these modern switch pitch torque converters different from the original ones? I have been rather unimpressed with the S/P converter in my '66 Toronado. After messing with the switch quite a bit, I find that it's better to leave it in low stall all the time. During normal driving, car gets moving a lot easier in low stall. High stall just gives me slippage and no noticeable torque multiplication. This is with a mild Olds 455. Thanks.
The stock 13" SP converters were like 2100/1100 stall speeds. The trick back in the day was to install the 12" SP converter that came behind the small v8 and ST300 transmission. That gave you more stall speed in hi and low. In addition, there were modified SP converters by PAE that were not very good or efficient. The question is, do you know what converter you have? If it's a PAE, they were notorious for being too loose. Jim's (TSP) converters were way better. I had one of his 12" converters in my GS up until about 5 years ago when I went to a fixed pitch converter. My experience with the 12" converter was it was the high stall was just a bit too loose for taking off in normal traffic. It worked great at the track giving me a best 60' of 1.62. My solution was to use a control box that mimicked the original stock Buick control of the stall speeds. Stock control was hi stall at idle stopped. Off idle went to lo stall immediately and at 60% throttle to full throttle, back to hi stall. The box I used had a vacuum switch and 3 timer circuits to fully control the stall speeds. The vacuum switch put it back into hi stall at below 4.5" of vacuum. It really made the car go, would break the tires loose at speed.
Larry, I am looking at putting a st400 with st 300 converter in my ‘60 LeSabre 364 nailhead to help move the big ol’ boy more swiftly than the dynaflow Is this “control box” still something available currently? If so do you know of a source? I was otherwise just going to manually control the high/low stall with a second headlight floor switch.
Cool info Larry. JW rebuilt my ST-400 and my ST-300 converter. It is going behind the 430 I am putting together and be stuffed into my '68 'lark with 3.42 8.5 from Jim at JD Race. I think I'm going to want "the box™". Maybe get a "group order" to Bruce and make the effort worthwhile.
If you do buy the box, ask Bruce about modifying it like he did mine. The brake timer was adjustable, but only down to 3 seconds or so. That way, just taking off from a traffic light on the street, you'd be in hi stall for no less than 3 seconds. My experience was the hi stall was a bit too loose, so it made the car feel lazy coming off a dead stop at light throttle. I had Bruce modify the box so as soon as you came off the brake, the converter would go to lo stall. There was a separate drag race timer that let you adjust converter hi stall time. It worked off the kick down switch, but you can also wire it to 12 volts via a toggle switch to select drag race mode. The drag race timer overrides the other timers.
Hi Larry, As far as I know it's a stock converter from 1966. Looks like next time the engine or transmission are out, I'll be calling Jim. Thank you.
The control box is the key IMHO. The box that Bruce Roe makes really lets you make the best of the Switch Pitch. Like I said, high stall is not meant for leisurely take offs in normal traffic. You want hi stall when your standing still with your foot on the brake, especially if you have a larger cam, smooths out the idle and lets the engine idle easier. Off the brake, it should immediately go to lo stall. At the track, you want the hi stall on until the 60' to 100' mark, then lo stall. I once wired my SP to stay in hi stall for the whole pass, the result was my best ET, but I lost MPH, presumably because the converter wasn't coupled as well at the top end. Bruce's box lets you adjust all that with 3 timers and a vacuum switch. I really liked the vacuum switch, it put the converter in hi stall when you needed it most. The box had other options as well to adjust how long it stayed in hi stall with low vacuum and other options. Like I said, the only fault I found was that I could not adjust the timer for brake on hi stall to off brake lo stall lower than 3.1 seconds. Bruce modified the box for me to make it go to lo stall immediately upon brake release. More information here, http://www.v8buick.com/index.php?threads/s-p-st-300-bruce-roes-electronic-controller.190075/ Here is the way the box works,
