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#1
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Loose vs Tight Torque Convertor
What is the difference between a "Loose" and a "Tight" torque convertor. I see those terms used but not sure what they mean.
Thanks
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65 Catalina sedan. Allen Thomas Performance 495. KRE Heads at 310cfm ported by SD Performance, ProSystems Dominator carb on ported Victor intake, P-Dude custom grind hydraulic roller, MSD ignition, 3.50 Moser/Ford rear. F-Glass front bumper by son Rob, rear by the old man and joint effort for trunk lid. 3950# w/driver. Best of 9.5761/139 on 175 shot, 6.01 /114 in 1/8. |
#2
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Me too would like to know!!!!
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#3
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Tight means the engine is more tightly, or closely coupled with the trans. Loose means just the opposite. Think of the torque converter as a fluid coupling. Imagine a fan, with another fan a few inches away from it...now imagine the first fan spinning under a motor's power. What happens to the second, non-motor powered fan? Yep...it's gonna turn. Same principle with the converter, only it uses fluid. By changing the fins, you can change the coupling properties. People often choose converters based on the motors power band... cam choice and rear gear also play a huge part. You'd not want a really loose converter on the street because each time you pulled away, your motor may go to 3000+ RPM's before the car really started to move.
At least that's the way I understand it! Hope that helped you some!
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Darin '64 Bonneville Wagon (sold) 69 Lemans-All motor (sold) 9.81 @ 136.39MPH |
#4
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Jagtec1 - thanks for the explanation - that's kinda what I thought. So if you had a convertor that was a 2500 stall and it was "loose" it would flash quicker as opposed to a 2500 stall that was "tight" ?
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65 Catalina sedan. Allen Thomas Performance 495. KRE Heads at 310cfm ported by SD Performance, ProSystems Dominator carb on ported Victor intake, P-Dude custom grind hydraulic roller, MSD ignition, 3.50 Moser/Ford rear. F-Glass front bumper by son Rob, rear by the old man and joint effort for trunk lid. 3950# w/driver. Best of 9.5761/139 on 175 shot, 6.01 /114 in 1/8. |
#5
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In theory, 2500 vs. 2500 would be the same. A 3000 would be more loose. It all depends on the torque of the motor also. A 3500 stall converter in a SBC would be tighter than a 3500 in a 455 Pontiac. Ask me how I know!! I had an off the shelf Trans Specialties 3400 I borrowed from a friend...wow! My motor blew right thru it. WAY too loose.
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Darin '64 Bonneville Wagon (sold) 69 Lemans-All motor (sold) 9.81 @ 136.39MPH |
#6
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Jagtec1 - thanks for the answers, think I have a much better understanding.
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65 Catalina sedan. Allen Thomas Performance 495. KRE Heads at 310cfm ported by SD Performance, ProSystems Dominator carb on ported Victor intake, P-Dude custom grind hydraulic roller, MSD ignition, 3.50 Moser/Ford rear. F-Glass front bumper by son Rob, rear by the old man and joint effort for trunk lid. 3950# w/driver. Best of 9.5761/139 on 175 shot, 6.01 /114 in 1/8. |
#7
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tight and loose IMO would refer more to top end rather than stall speed....for example I had 2 convertors one 8" and a 9" both stalled to 5000 rpm, both would drive just fine on the street, you could let off of the brake at idle and the car will move just like a stock convertor....well anyway the 8" was loose on topend 12% slippage, the 9" was much tighter @ 5% slippage, best run with the 8" was 1.37 60' 9.91 @ 134.33 best run for the 9" 1.34 60' 9.75 @ 137.89...the only change was going to a convertor that was "tighter" on top end In my case the tighter convertor worked better for me since it waisted less power (less slippage) ...
Chad
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3500lb 10.5" tire. 5.34@134.4 with a poor 60' |
#8
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I suppose tight and loose could refer to either stall speed or slippage, because I know that my 8" was called a "tight" 8" it was a TCI 300+ 8" in fact it was so tight that they said they really could not tighten it anymore to reduce slippage... who knows....
Chad
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3500lb 10.5" tire. 5.34@134.4 with a poor 60' |
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