PTC 10" TH400 Converter & 2.73 Gears
02-24-2019, 09:33 PM
#1
PTC 10" TH400 Converter & 2.73 Gears I know higher gears (numerically lower) isn't ideal, but I'm putting together the car in my sig for 80% street/highway cruising, 10% 1/4 mile drag racing, and 10% autox (for fun, not competitively/class racing).
Combo is a 10:1 L33 5.3, stock 799s, 220/224 .575/.575 112+4 cam, ls6 intake, 78/75 billet turbo, huron speed v3 ac T4 kit, TH400, 10" PTC converter, and a fabbed 8.8 in a 3550 race weight car. Goal is 700+rwhp thru the unlocked TH400.
I really want to keep the RPMs down as much as possible for highway cruising, but wasn't sure if a 10" converter would work alright or slip too much with a 2.73 rear gear. Dusty at PTC mentioned that I may be better off with the 9.5" with a 2.73 gear (that I'd like to run for the highway). But the uncertainties are if the 5.3 would make enough power to not feel sluggish out of boost just normal driving with a 9.5" converter compared to the 10", and if I would make enough power to justify the 9.5" vs the 10". I'd obviously rather keep the 10" since I already bought it, but that was also with a 3.27 rear gear in mind with a 26" tire on the street and a 28" at the strip. Thinking more and more about what I'll do with the car, 70mph sounds a lot more comfortable at 2500rpm vs 3000rpm with the 26" tires on the highway for cruises etc.
Anyone have any real world input on this? TIA
Combo is a 10:1 L33 5.3, stock 799s, 220/224 .575/.575 112+4 cam, ls6 intake, 78/75 billet turbo, huron speed v3 ac T4 kit, TH400, 10" PTC converter, and a fabbed 8.8 in a 3550 race weight car. Goal is 700+rwhp thru the unlocked TH400.
I really want to keep the RPMs down as much as possible for highway cruising, but wasn't sure if a 10" converter would work alright or slip too much with a 2.73 rear gear. Dusty at PTC mentioned that I may be better off with the 9.5" with a 2.73 gear (that I'd like to run for the highway). But the uncertainties are if the 5.3 would make enough power to not feel sluggish out of boost just normal driving with a 9.5" converter compared to the 10", and if I would make enough power to justify the 9.5" vs the 10". I'd obviously rather keep the 10" since I already bought it, but that was also with a 3.27 rear gear in mind with a 26" tire on the street and a 28" at the strip. Thinking more and more about what I'll do with the car, 70mph sounds a lot more comfortable at 2500rpm vs 3000rpm with the 26" tires on the highway for cruises etc.
Anyone have any real world input on this? TIA
02-24-2019, 11:06 PM
#2
I had a 10” PTC with a 3.08 and 3.31 gear and a 275/60 tire and it cruised 70-75 mph at 3000-3100 RPMs. That converter isn’t going to be as tight as you think on the highway. RPMs are gonna be up and it’s gonna sit on the converter the whole time and do nothing but build heat, especially with the 2.73. I’ve since changed to the 9.5” and while I haven’t driven it yet (due to weather) it’s night and day. The 10” would only go to 3400 on the brake and make about 7-8psi. The 9.5” goes 5000 and makes 19 psi in under 2 seconds (I’ll show you the datalog). I went to the 9.5” based on experience from buddies that have em and can’t believe how they tighten up on the big end and during cruise. You really cant compare the two as the diameter isn’t the only difference. It’s the internals that make it a totally different animal.
02-24-2019, 11:39 PM
#3
Never used the 10 inch, but I do have the 9.5 14 stator (I think). I also use 2:73, car cruises nicely, and doesn't cook the fluid either. Don't have any data, but the converter seems to couple up hard up top, on the transbrake it will go 5200 and 20psi pretty quick. Car is also on a 26 inch tire, and makes 740whp.
https://youtu.be/zG4N59Zw4Eg
https://youtu.be/tRTkZcQLj50
https://youtu.be/ZLom9yRmZRo
https://youtu.be/zG4N59Zw4Eg
https://youtu.be/tRTkZcQLj50
https://youtu.be/ZLom9yRmZRo
02-25-2019, 04:42 AM
#5
I run a ptc specked 10" converter. I think a 3.08 whould work well but im sure the 273 will work as well . I have ran mine with a powerglide and 3.23 gear and it is a little doggy out of boost but not bad at all. but I ran 9.90s with it at 3510 lbs street car.
