Choosing a stall converter
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seconds, then do a gentle drive afterward. Assuming you didn't just shred the tires, that was your "foot-brake | seconds, then do a gentle drive afterward. Assuming you didn't just shred the tires, that was your "foot-brake | ||
stall". | stall". | ||
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Now that I'm started, there's so much to cover that I'm not sure how to proceed without making it confusing. ( I do | Now that I'm started, there's so much to cover that I'm not sure how to proceed without making it confusing. ( I do | ||
have A.D.D.) It all inter-relates. I want to make it fascinating and educational. | have A.D.D.) It all inter-relates. I want to make it fascinating and educational. | ||
Anyway, back to stall. | Anyway, back to stall. | ||
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You can find all sort of descriptions and explanations, but your first interest is in what your stall does for your | You can find all sort of descriptions and explanations, but your first interest is in what your stall does for your | ||
car. | car. | ||
Need mostly centers on your camshaft, heads, compression, gearing, and expectations. Tuning and fuel quality are | Need mostly centers on your camshaft, heads, compression, gearing, and expectations. Tuning and fuel quality are | ||
your responsibility. For this thread we must assume you got the tune right and run enough octane. | your responsibility. For this thread we must assume you got the tune right and run enough octane. | ||
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I guess the best way to proceed is to detail 5 different combos I've owned and driven, that really stand out in my | I guess the best way to proceed is to detail 5 different combos I've owned and driven, that really stand out in my | ||
recollections: | recollections: | ||
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Trying to keep this in chronological order, the first combo is a '79 Firebird. 150-HP 301 with a slightly leaky | Trying to keep this in chronological order, the first combo is a '79 Firebird. 150-HP 301 with a slightly leaky | ||
Q-Jet hurting MPG but not driveability, backed by a TH350, a 2.73:1 axle, and on new Firestone 215/75R15 tires. I | Q-Jet hurting MPG but not driveability, backed by a TH350, a 2.73:1 axle, and on new Firestone 215/75R15 tires. I | ||
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of slippage? I lifted off. Yes, a total slip at WOT of 400 RPM. Again, fairly typical it turns out. | of slippage? I lifted off. Yes, a total slip at WOT of 400 RPM. Again, fairly typical it turns out. | ||
[b]Lesson learned[/b]: normal slip of torque converters. Also applies to lockup style when not locked. | [b]Lesson learned[/b]: normal slip of torque converters. Also applies to lockup style when not locked. | ||
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Combo 2: '78 Camaro LG3 ( 145-HP 305 ) TH350, swapped stock 1200-stall for B&M TorkMaster 2000 converter, 3.08:1 | Combo 2: '78 Camaro LG3 ( 145-HP 305 ) TH350, swapped stock 1200-stall for B&M TorkMaster 2000 converter, 3.08:1 | ||
axle, 235/70R15 tires. | axle, 235/70R15 tires. | ||
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/ 205-75R14 Camaro did 23 MPG with a best of 26. | / 205-75R14 Camaro did 23 MPG with a best of 26. | ||
I can't say the 2000-stall drove better than the 1200-stall in the snow, but I can say it wasn't any worse. | I can't say the 2000-stall drove better than the 1200-stall in the snow, but I can say it wasn't any worse. | ||
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Combo 3 was a friend's '65 Mustang. It had an 8.3:1 302 with Roush 200 heads, a Comp Magnum 292 cam, headers, | Combo 3 was a friend's '65 Mustang. It had an 8.3:1 302 with Roush 200 heads, a Comp Magnum 292 cam, headers, | ||
intake, carb, 3500-stall, C4, 3.80:1 spool. Tires were 25" diameter. | intake, carb, 3500-stall, C4, 3.80:1 spool. Tires were 25" diameter. | ||
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First experiences are always more vivid than follow-ups, and that's the case here. This wasn't to be my last | First experiences are always more vivid than follow-ups, and that's the case here. This wasn't to be my last | ||
experience with race converters, but it was an eye-opener. | experience with race converters, but it was an eye-opener. | ||
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Following that, I was playing with an '85 Camaro with a mildly modified L69, 700R-4, 3.42:1, and sticky 215/60R15s. I decided on a B&M TorkMaster 2400. It drove pretty stock, until I swapped the heads. Finally it all came together: | Following that, I was playing with an '85 Camaro with a mildly modified L69, 700R-4, 3.42:1, and sticky 215/60R15s. I decided on a B&M TorkMaster 2400. It drove pretty stock, until I swapped the heads. Finally it all came together: | ||
No traction in first gear, very very fun! | No traction in first gear, very very fun! | ||
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Great converter for playing, needs some rear gear. | Great converter for playing, needs some rear gear. | ||
Great tragedy I never tried it in any snow, in either car. | Great tragedy I never tried it in any snow, in either car. | ||
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So, the combo is everything. | So, the combo is everything. | ||
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If you're studying the COMP CAMS catalog, for example, you'll note that once you look past the smallest cams, they | If you're studying the COMP CAMS catalog, for example, you'll note that once you look past the smallest cams, they | ||
begin noting stall speeds. But as with all things camshaft, these are for the popular engine. | begin noting stall speeds. But as with all things camshaft, these are for the popular engine. | ||
If you're gonna pick a cam for a lesser-displacement version, read the notes for the next larger cam. | If you're gonna pick a cam for a lesser-displacement version, read the notes for the next larger cam. | ||
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For racing, you want a stall about 500 RPM below the RPM at which your engine makes peak torque. For most mild | For racing, you want a stall about 500 RPM below the RPM at which your engine makes peak torque. For most mild | ||
SBC 350s, torque peak is typically 3500 RPM. With Vortec heads and such, 4000 is more like it. AFR heads should | SBC 350s, torque peak is typically 3500 RPM. With Vortec heads and such, 4000 is more like it. AFR heads should | ||
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reduce detonation. Way low, it covers the soggy off-idle. And a cam that's way too big is the same soggy feel as | reduce detonation. Way low, it covers the soggy off-idle. And a cam that's way too big is the same soggy feel as | ||
way low compression. | way low compression. | ||
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[b]Efficiency[/b]: This is difficult to discuss. Look back at my '78 Camaro. The TM2k was much more efficient than | [b]Efficiency[/b]: This is difficult to discuss. Look back at my '78 Camaro. The TM2k was much more efficient than | ||
the stock converter it replaced, and was also more efficient than what was in my '79 Firebird. | the stock converter it replaced, and was also more efficient than what was in my '79 Firebird. | ||
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More gear reduces the load that the converter feels. Same with taking weight out of the car. But not only that, | More gear reduces the load that the converter feels. Same with taking weight out of the car. But not only that, | ||
having more gear also takes load off the transmission, helping it survive stoplight antics. | having more gear also takes load off the transmission, helping it survive stoplight antics. | ||
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[b]When to buy what[/b]? | [b]When to buy what[/b]? | ||
Should this be an early mod? Or later, after everything else? | Should this be an early mod? Or later, after everything else? | ||
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