Choosing a stall converter

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(Flash stall)
(Examples of different applications)
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=Examples of different applications=
 
=Examples of different applications=
 
Details of  5 different combinations:
 
 
*Combination 1: 1979 Firebird. 150-HP 301 with a slightly leaky Q-Jet hurting MPG but not driveability, backed by a T-350, a 2.73:1 axle, and on new Firestone 215/75R15 tires.
 
The converter was an 1800-stall. I could, occasionally, chirp a tire from a dead stop. But i soon got curious about the converter slippage: Cruising along at 55 MPH, lift off the throttle, the RPM instantly dropped 200 RPM. Ease back into it, it came back up by 200 RPM. In later years, I came to learn that this is typical of most stock GM converters, though I doubted, and still doubt, that that converter was stock.
 
But then I tried it the other way: stomping the gas, RPM climbed another 200 RPM. Did that mean a total of 400 RPM of slippage?  Yes, a total slip at WOT of 400 RPM.
 
 
Lesson learned: normal slip of torque converters. Also applies to lockup style when not locked.
 
 
*Combination 2: 1978 Camaro LG3 ( 145-HP 305 ) TH350, swapped stock 1200-stall for B&M TorkMaster 2000 converter, 3.08:1
 
axle, 235/70R15 tires. This converter was stock, it was 1200 RPM flash stall.
 
 
A change to a  B&M converter gave my combo a 1700 RPM flash stall. It felt like I had swapped to a 350, when launching. And by launching, I mean flooring the gas the instant the light went from red to green. It pushed me into the seat noticeably more, and I loved it.  But I was in for another surprise. I finally stopped playing in traffic and got on the highway. I was so stunned to discover my slippage wasn't 200 RPM. It was just 50 RPM! So I stomped the go pedal, the RPM shot up by another 350, for a total of 400. After all, my previous 1978 / LG3 / TH350 / 1200 / 2.41:1
 
/ 205-75R14 Camaro did 23 MPG with a best of 26.
 
 
*Combination 3 : A 1965 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.
 
That thing needed 10.5:1 compression, but a full summer of tuning got it driveable. To the point that he swapped
 
street radials for drag tires. Then we went out to the exact center of nowhere, did up the 5-point race harnesses,
 
and he let it fly.
 
If you've ever felt a jet plane on takeoff, this puts them all to shame. Nothing you've ever experienced at any
 
amusement park even comes close, either. This was like God's own pillow-covered sledgehammer to the heiney.
 
First experiences are always more vivid than follow-ups, and that's the case here.
 
 
*Combination 4: A 1985 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. No traction in first gear, very very fun!
 
 
 
*Combination 5: A 1995 Camaro Z28 convertible with the LT1, 4L60E, 2.73:1, and 235/55R16s.  My flash stall was now 2400, twin black stripes became effortless, from a rolling 5 MPH start, and even starting with the 4-wheel-disc-brakes applied enough to keep the car stopped, getting both tires
 
turning took like half throttle.
 
But the driveability? It was hell. My slippage was always 1200, maybe because someone or something had caused it
 
to fall off a workbench some weeks prior. But no denting was found. Still, lockup no longer worked. I replaced the trans, and still no lockup.
 
Great converter for playing, needs some rear gear.
 
  
 
=Choosing a Stall Converter=
 
=Choosing a Stall Converter=

Revision as of 10:28, 1 January 2012

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