down sides of high stall speeds?
07-08-2005, 10:59 AM
#4
They build excessive heat. Also, how high are you thinking? For me a high stall is 4500+ and to reach that, you would need a 9.5" core (which could become very inefficient) or use an 8". The 8" won't be able to use a lock up feature.
07-08-2005, 11:08 AM
#5
Well, I'd like my setup to hit full boost between 3500 and 4000 RPMs, and start building between 2000 and 2500... I am sure I will have to compromise on one of those numbers, but that's what I'm shooting for. I guess my ideal stall would be between 3000 and 4000 then, huh?
Seems to me like if it's stalling at higher speeds, normal daily-driver starts would be soft and mushy, or require excessively high RPM's and be impractical. Do you guys see any of that?
Seems to me like if it's stalling at higher speeds, normal daily-driver starts would be soft and mushy, or require excessively high RPM's and be impractical. Do you guys see any of that?
Originally Posted by Flame Throwing SS
They build excessive heat. Also, how high are you thinking? For me a high stall is 4500+ and to reach that, you would need a 9.5" core (which could become very inefficient) or use an 8". The 8" won't be able to use a lock up feature.
07-08-2005, 11:21 AM
#6
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The higher the stall, the more pedal you're going to have to use and the more RPMs you'll be turning to accelerate from a stop. Once you're at speed you've got lockup so it's no big deal. As long as you have a tranny cooler I dont see heat being a big deal either (it gets mid 90s here in TN and with my 4000 stall and B&M 24gvw cooler I rarely see over 170 degrees in the tranny, maybe 185 if I'm doing alot of stopping and going or WOT runs).
Really the looseness is the only downside I see. The bigger the stall the looser it is. This can be compensated for by gearing and weight reduction. Lighter cars feel tighter and cars with lower gears (numerically higher) feel tighter. My 4000 stall with 3.42 gears in a stock weight T/A (3600-3700) is fairly loose, but not excessive enough to really bother me.
Really the looseness is the only downside I see. The bigger the stall the looser it is. This can be compensated for by gearing and weight reduction. Lighter cars feel tighter and cars with lower gears (numerically higher) feel tighter. My 4000 stall with 3.42 gears in a stock weight T/A (3600-3700) is fairly loose, but not excessive enough to really bother me.
07-08-2005, 02:47 PM
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I agree with you Josh. It's probably just the looseness. I think everyone with a converter, even if it's a 2,800 or 3000, should get a B&M 24,000 cooler. It just makes sense to keep it cooled off as much as possible (within reason). So the heat isn't a problem, but you will get used to it.
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07-09-2005, 04:31 AM
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Originally Posted by Scotty-Z
I agree with you Josh. It's probably just the looseness. I think everyone with a converter, even if it's a 2,800 or 3000, should get a B&M 24,000 cooler. It just makes sense to keep it cooled off as much as possible (within reason). So the heat isn't a problem, but you will get used to it.
07-09-2005, 09:55 AM
#12
The first high stall converter I used was great.
Until I was just cruising down a wet highway at 65-70 mph, right around the stall speed it was starting to spin the tires and get loose. If I wasn't paying attention I could have lost it.
After reading your post about the stock converter in a 4L80E you might also want to think about the downsides of a stock stall speed.
Like stalling (engine shutting off) at idle with a bigger than stock cam, sluggish performance up to the power peak, etc.
Until I was just cruising down a wet highway at 65-70 mph, right around the stall speed it was starting to spin the tires and get loose. If I wasn't paying attention I could have lost it.
After reading your post about the stock converter in a 4L80E you might also want to think about the downsides of a stock stall speed.
Like stalling (engine shutting off) at idle with a bigger than stock cam, sluggish performance up to the power peak, etc.
07-09-2005, 10:41 AM
#14
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Downsides are far outweighed by the benefits, IMO. I daily drive a TCI SSF4000. Only things that ever bother me are how it often sounds like I'm giving it more gas than I am and increased gas conumption around town. The first one isn't a big deal at all, and I can live with decreased city mileage. One of the things you must deal with when buliding a high powered, go fast car is gas consumption.
07-11-2005, 05:16 PM
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Originally Posted by jlrz28
I had a higher stall converter and of course it spun up alot more and had a hard time keeping alternators on the car, and my AC compressor started to make some funny noises too.
07-12-2005, 02:57 PM
#19
True, but I think it only locks up after the two pieces of the converter (pump and turbine?) are moving at close to a 1:1 ratio. That's frequently on the highway or when you are at a cruise speed. It's everything that happens before that.... getting close to the 1:1 ratio.... that's the tricky part.
Originally Posted by SteveC
My understanding is once lockup (1:1) is achieved, the converts work is done until it unlocks.
SteveC
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07-12-2005, 04:04 PM
#20
Originally Posted by FastKat
True, but I think it only locks up after the two pieces of the converter (pump and turbine?) are moving at close to a 1:1 ratio. That's frequently on the highway or when you are at a cruise speed. It's everything that happens before that.... getting close to the 1:1 ratio.... that's the tricky part.
Pump and Turbine speed have nothing to do with lock up.