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driveshaft rpm vs engine rpm
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per my data logger at the end of a run (1/8) mile my driveshaft rpm is still 1300 rpm slower than engine rpm......do I have a converter problem


JRP
 
Posts: 3 | Location: indiana | Registered: August 30, 2017Reply With QuoteReport This Post
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quote:
Originally posted by rzlwkj:
per my data logger at the end of a run (1/8) mile my driveshaft rpm is still 1300 rpm slower than engine rpm......do I have a converter problem


No the converter is slipping 18% (if your crossing 7000 rpm).
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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quote:
Originally posted by Mike Rietow:
quote:
Originally posted by rzlwkj:
per my data logger at the end of a run (1/8) mile my driveshaft rpm is still 1300 rpm slower than engine rpm......do I have a converter problem


No the converter is slipping 18% (if your crossing 7000 rpm).


Thank You.
may i ask what is acceptable range of converter slippage?


JRP
 
Posts: 3 | Location: indiana | Registered: August 30, 2017Reply With QuoteReport This Post
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1/8 mile for me on a 5.80 pass was 6773 and 5907 just for a reference. 4.88 gear 14 x 32

Don't know if it helps you or not.



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Posts: 2897 | Location: KIEFER, OK. | Registered: August 17, 2007Reply With QuoteReport This Post
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quote:
Originally posted by rzlwkj:
quote:
Originally posted by Mike Rietow:
quote:
Originally posted by rzlwkj:
per my data logger at the end of a run (1/8) mile my driveshaft rpm is still 1300 rpm slower than engine rpm......do I have a converter problem


No the converter is slipping 18% (if your crossing 7000 rpm).


Thank You.
may i ask what is acceptable range of converter slippage?


You're welcome. I won seven Super Pro championships in ten years at a track in Florida 33 and 41 race seasons, with a street car on a 10" tire slipping 21%.

Hypothetically speaking, Lets say you're on gasoline and my guess you cross at 7000 rpm is correct and you shift at 7800 rpm. In this case you'd want a lot more gear in order to cross close or a hair above your shift rpm. Spinning the converter 7800 rpm at the stripe, will result in the same converter being quite a bit more efficient, as well as the car, according to the engines latent potential for rpm.

Same scenerio shifting 6800-7000rpm and crossing 7000 rpms, I'd say it's perfect for the converter in the car currently to slip 18%.

You'd have to describe what you have in detail, in order for me to be more specific.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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I wouldn’t spend a lot of time or money chasing converter slippage if it were me.. I haven’t seen much gain or loss either way


J.R. Baxter

""Fathom the hypocrisy of a Government that requires every citizen to prove they are insured ..but not everyone must prove they are a citizen."

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Posts: 1510 | Location: Waxahachie | Registered: July 04, 2005Reply With QuoteReport This Post
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posted Hide Post
quote:
Originally posted by Mike Rietow:
quote:
Originally posted by rzlwkj:
quote:
Originally posted by Mike Rietow:
quote:
Originally posted by rzlwkj:
per my data logger at the end of a run (1/8) mile my driveshaft rpm is still 1300 rpm slower than engine rpm......do I have a converter problem


running a super pro dragster , sbc 383...shifting at 6800 drops back to 6300 after shift and crossing the line at 6900rpm

No the converter is slipping 18% (if your crossing 7000 rpm).


Thank You.
may i ask what is acceptable range of converter slippage?


You're welcome. I won seven Super Pro championships in ten years at a track in Florida 33 and 41 race seasons, with a street car on a 10" tire slipping 21%.

Hypothetically speaking, Lets say you're on gasoline and my guess you cross at 7000 rpm is correct and you shift at 7800 rpm. In this case you'd want a lot more gear in order to cross close or a hair above your shift rpm. Spinning the converter 7800 rpm at the stripe, will result in the same converter being quite a bit more efficient, as well as the car, according to the engines latent potential for rpm.

Same scenerio shifting 6800-7000rpm and crossing 7000 rpms, I'd say it's perfect for the converter in the car currently to slip 18%.

You'd have to describe what you have in detail, in order for me to be more specific.


running a super pro dragster , sbc 383...shifting at 6800 drops back to 6300 after shift and crossing the line at 6900rpm


JRP
 
Posts: 3 | Location: indiana | Registered: August 30, 2017Reply With QuoteReport This Post



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posted Hide Post
quote:
Originally posted by rzlwkj:
quote:
Originally posted by Mike Rietow:
quote:
Originally posted by rzlwkj:
quote:
Originally posted by Mike Rietow:
quote:
Originally posted by rzlwkj:
per my data logger at the end of a run (1/8) mile my driveshaft rpm is still 1300 rpm slower than engine rpm......do I have a converter problem


running a super pro dragster , sbc 383...shifting at 6800 drops back to 6300 after shift and crossing the line at 6900rpm

No the converter is slipping 18% (if your crossing 7000 rpm).


Thank You.
may i ask what is acceptable range of converter slippage?


You're welcome. I won seven Super Pro championships in ten years at a track in Florida 33 and 41 race seasons, with a street car on a 10" tire slipping 21%.

Hypothetically speaking, Lets say you're on gasoline and my guess you cross at 7000 rpm is correct and you shift at 7800 rpm. In this case you'd want a lot more gear in order to cross close or a hair above your shift rpm. Spinning the converter 7800 rpm at the stripe, will result in the same converter being quite a bit more efficient, as well as the car, according to the engines latent potential for rpm.

Same scenerio shifting 6800-7000rpm and crossing 7000 rpms, I'd say it's perfect for the converter in the car currently to slip 18%.

You'd have to describe what you have in detail, in order for me to be more specific.


running a super pro dragster , sbc 383...shifting at 6800 drops back to 6300 after shift and crossing the line at 6900rpm


What gear and what size tire?
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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The converter sounds pretty good to me. I'd imagine you're trying to figure out how to go quicker with 500 hp pulling 1800 - 1900 lbs. You're on the right track thinking if you could get the driveshaft turning close to the same rpm as the engine, it would go faster. Only thing is you're gonna need more power for it to do that.

The converter flashes probably 6000 now at the hit, peak torque is probably around 5500 - 5600-5700. That gets it going about as good, as it's gonna to the 60ft. The difference in torque at 6300 isn't gonna be much from 5900 if you did have the converter tightened, and if you did, it wouldn't 60ft as well most likely. The only way it would pickup lower stall is if you're operating the engine above it's capacity (compression, cylinder head and cam) for the rpm you're operating it now (shift and finish line rpm).

Sounds pretty good to me as it is now. Ya need to work on power - compression, cylinder heads and cam.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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