Another "which stall speed conv" thread!

crazypete · 10-08-2003, 10:46 PM

So my t-5 is totally on it's way out. I said "lets try the world of automatics". I love acceleration and performance but, man, I just love the way an automatic WANTS to go forward and it does it with one pedal and takes only 1 arm to drive the car. I know, I'm a wuss. I got a full stock AOD "kit" from a part out off ebay for $300 (see? and it's DIRT cheap) complete with stock EVERYTHING. Now I hear the stock converter is a 1500 rpm stall. I gathered from reading a few posts that you need to select a converter stall for where you want the cruising speed to be. If I want to launch like on my t5 at 2400 rpms and cruise at the same then a 2400 rpm converter is the right choice? What diameter should I go for?

I'm 400 lbs lighter (how much more does an AOD weigh than a t5?), running 3.73's and a full carb conversion.

Thanks guys!

stang_racer20 · 10-09-2003, 02:35 AM

probably about 40 lbs heavier. ive got a b&m 2000 rpm stall sittin round if your interested

crazypete · 10-09-2003, 09:43 AM

Will the 2000 put me where I want to be? (2300-2400 launch and lockup on the highway cruising at 2400). If so, what are you looking to get for it?

crazypete · 10-09-2003, 12:38 PM

Whats a good shift kit for an AOD? I've been eyeing the transgo.

silver_pilate · 10-09-2003, 12:54 PM

Transgo's are OK, but if I had it all to do over again, I'd skip the shift kits and go straight for a valve body. Lentech rocks.

As for the torque converter, you're correct, the stock converter stalls arou8nd 1500. I'd recommend a minimum of 2500 rpm. Most of the higher end converters are a little pricey, but you get what you pay for in this case. With a 2800 rpm non-lock up and 3.73's, I cruise 70 mph at 2500. 4.10's will raise the cruise up a couple of hundred rpm, but the car will perform better.

I'd say a 2800-3200 rpm lock up converter with a Lentech VB and a set of 4.10's and that thing will FLY!!

One thing about converters, if you're running an aftermarket cam, it's a good idea to talk to the converter folks to see what stall they recommend and power bands vary widely. The main thing is that you want the converter to allow you to reach your power band as quickly as possible. If your power comes on at 2700 rpm, a 2800 rpm will put you right there. Another thing to consider is that a converter that stalls around 2800 rpm on a stock motor may stall a bit higher on a modified car. Call up Precision Industries and talk with their tech people. They can give you good advice.

--nathan

crazypete · 10-09-2003, 02:12 PM

I know the term gas milage has no place on a performance enthusiast board but I DO have to drive this thing from boston to woods hole or portland on a fairly regular basis, so how much of an impact would a 2500 rpm non lockup have on milage compared to it's lockup cousin?

What exactly is inside one of these shift kits anyway?

silver_pilate · 10-09-2003, 03:10 PM

Just a little FYI on converters. A converter uses fluid dynamics to couple the flywheel to the tranny in the same way that the friction plates on a clutch does. At lower speeds, the converter can "slip," meaning that the engine and tranny aren't directly coupled. It's analogous to feathering/slipping the clutch and it allows the engine to rev faster, in essence, almost free-reving until the resistance of the tranny fluid against the stators is enough to overcome the resistance of turning the transmission/driveshaft/axles/wheels. This occurs over a continuum, with the converter coupling more and more with increasing rpm. Eventually, the fluid dynamics creates a resistance enough to basically lock the converter into one solid peice, thus directly coupling the engine and transmission as long as that rpm or higher is attained. This, in very rough terms, is considered the "stall" speed of a converter: the point at which the converter no longer slips.

When I bought my converter, I decided to go with a non-lockup. This means that the converter slips in all gears up to its stall speed. A lock-up converter will directly couple the tranny to the engine (ie. not slip) in third and fourth gears. Looking back, I should have gone with a lock-up converter. For one, anytime the converter is slipping, it's creating heat (the number one enemy of AOD's). This means that a non-lockup cruising at 65 mph is still slipping some (~2000 rpm @ 60 mph vs. a stall speed of 2800 rpm) and thus is creating extra heat. A lock-up converter, on the other hand, will directly couple the engine to the transmission in third and fourth. This means a little bit of performance loss at low speeds in thrid gear, but not much. And when you think about it, when racing, you will be going all out and shifting at a fairly high rpm. When the tranny shifts, the rpms will not drop below say 3500-4000 rpm (which is higher than the 2800 rpm stall speed of the converter). This means that a non-lockup converter is not slipping anyway.

So, after all that verbage, a lock-up converter will give you better gas mileage while cruising in third and fourth gears and the same performance off the line in first and second gear as a non-lockup. Also, with a converter that locks up in third and fourth, you decrease the amount of heat created. When I send my PI back for reconditioning (had some junk from a blown tranny wash through the converter and it's not working right anymore), I'm going to have them convert it to a lock-up and raise my stall speed to around 3200. This won't effect my highway cruising, as the converter will lock-up in fourth gear anyway, but will drastically improve my launches (while maybe costing me a couple mpg in town).

Unfortunately, because my converter is malfunctioning, I can't really give you an estimate of what my gas mileage is. I can tell you that with any higher stalling converter, you will burn quite a bit more gas when just cruising around town. Thus the reason that Ford chose a 1500 rpm stall. However, if you're cruising on the highway for your commutes, a lock-up converter will likely give you better fuel economy to the tune of 2-3 mpg.

As for shift kits. The Transgo kit comes with a video for install. Basically, you just swap out a few valves in the valve body and a number of springs. This will allow higher fluid pressures in the transmission and thus firmer/faster shifts. Also, you have to drill or enlarge a few holes in the converter and seperation plate.

The Lentech valve body, on the other had, is reworked so as to change the shift pattern from the annoying 1-2/3-OD pattern that we all hate. This shift pattern means that you have to do the 1-D-1 shuffle to hold second gear, and shifts are often inconsistant as to when the tranny shifts in relation to when you tell it to. Mine would sometimes lag behind: I would throw the lever at the same point every time, but sometimes the tranny would hold the gear for a while longer and bounce the rev limiter before shifting. The Lentech valve body changes the pattern to 1-2-3/electric OD. This means you can completely control the tranny with manual shifting, and OD is accessed with the flip of a rocker switch. Shifts are fast (all the time), hard (when at full throttle), and superbly consistant (all the time).

Sooo...after that little mini-novel, maybe you can make some decisions. Let me know if you have any other questions/concerns.

--nathan

crazypete · 10-09-2003, 04:24 PM

In that case, a 2500 rpm lock up converter would be a perfect choice for me! Gives me the best of both worlds. I'd love the lentech, but it's crazy $$$ and the transgo is roughly 100 bucks.

What do you guys think of these?

http://cgi.ebay.com/ebaymotors/ws/eB...category=33727

This guy is obviously selling from his house cause you can see the furniture in the background.

stang_racer20 · 10-10-2003, 02:45 AM

Quote:

Originally posted by crazypete
In that case, a 2500 rpm lock up converter would be a perfect choice for me! Gives me the best of both worlds. I'd love the lentech, but it's crazy $$$ and the transgo is roughly 100 bucks.

What do you guys think of these?

http://cgi.ebay.com/ebaymotors/ws/eB...category=33727

This guy is obviously selling from his house cause you can see the furniture in the background.

It actually sound like a great deal, its a 2300 then im guessing. ask the seller what brand it is though before you buy it and post back!

10-08-2003, 10:46 PM	#1
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	Another "which stall speed conv" thread! So my t-5 is totally on it's way out. I said "lets try the world of automatics". I love acceleration and performance but, man, I just love the way an automatic WANTS to go forward and it does it with one pedal and takes only 1 arm to drive the car. I know, I'm a wuss. I got a full stock AOD "kit" from a part out off ebay for $300 (see? and it's DIRT cheap) complete with stock EVERYTHING. Now I hear the stock converter is a 1500 rpm stall. I gathered from reading a few posts that you need to select a converter stall for where you want the cruising speed to be. If I want to launch like on my t5 at 2400 rpms and cruise at the same then a 2400 rpm converter is the right choice? What diameter should I go for? I'm 400 lbs lighter (how much more does an AOD weigh than a t5?), running 3.73's and a full carb conversion. Thanks guys! __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

10-09-2003, 02:35 AM	#2
stang_racer20 Registered Member Join Date: Jun 2003 Location: Wisconsin Posts: 348	probably about 40 lbs heavier. ive got a b&m 2000 rpm stall sittin round if your interested __________________ 92 Mustang GT, 347 Stroker(Forged Steel Crank/Rods-Balanced, Forged Aluminum Dished Pistons), Trick Flow Track Heat Intake, Trick Flow Twisted Wedge Heads w/ Stage 3 port/polish, 80mm C&L MAF, FMS 30# Inj., BBK AFPR, Trick Flow Stage 2 Cam, Trick Flow 1.6R Rockers, BBK E.L. Headers, Flowmaster Cat-Back, MAC CAI, FMS Pulleys, Griffin Alum. Radiator, MSD Pro-Billet Distributor; AOD, Dynamic 3300 Lockup Converter, B & M Super Cooler, B&M Ratchet Shifter; 3:73 gears.

10-09-2003, 09:43 AM	#3
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	Will the 2000 put me where I want to be? (2300-2400 launch and lockup on the highway cruising at 2400). If so, what are you looking to get for it? __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

10-09-2003, 12:38 PM	#4
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	Whats a good shift kit for an AOD? I've been eyeing the transgo. __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

10-09-2003, 12:54 PM	#5
silver_pilate DURKA DURKA!! Join Date: Sep 1997 Location: Lubbock, TX...(TX panhandle) Posts: 1,418	Transgo's are OK, but if I had it all to do over again, I'd skip the shift kits and go straight for a valve body. Lentech rocks. As for the torque converter, you're correct, the stock converter stalls arou8nd 1500. I'd recommend a minimum of 2500 rpm. Most of the higher end converters are a little pricey, but you get what you pay for in this case. With a 2800 rpm non-lock up and 3.73's, I cruise 70 mph at 2500. 4.10's will raise the cruise up a couple of hundred rpm, but the car will perform better. I'd say a 2800-3200 rpm lock up converter with a Lentech VB and a set of 4.10's and that thing will FLY!! One thing about converters, if you're running an aftermarket cam, it's a good idea to talk to the converter folks to see what stall they recommend and power bands vary widely. The main thing is that you want the converter to allow you to reach your power band as quickly as possible. If your power comes on at 2700 rpm, a 2800 rpm will put you right there. Another thing to consider is that a converter that stalls around 2800 rpm on a stock motor may stall a bit higher on a modified car. Call up Precision Industries and talk with their tech people. They can give you good advice. --nathan __________________ '91 GT, Coast 347, 9.5:1 compression, full intake, Wolverine 1087 cam, exhaust, Keith Craft ported Windsor Jr. Irons (235 cfm intake, 195 cfm exhaust), AOD, PI 3500 converter, Lentech valve body, 3.73's (4.10's in the works), and Yokohama ES100's out back. Daily Car: '04 Infiniti G35 Sedan 6MT

10-09-2003, 02:12 PM	#6
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	I know the term gas milage has no place on a performance enthusiast board but I DO have to drive this thing from boston to woods hole or portland on a fairly regular basis, so how much of an impact would a 2500 rpm non lockup have on milage compared to it's lockup cousin? What exactly is inside one of these shift kits anyway? __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

10-09-2003, 03:10 PM	#7
silver_pilate DURKA DURKA!! Join Date: Sep 1997 Location: Lubbock, TX...(TX panhandle) Posts: 1,418	Just a little FYI on converters. A converter uses fluid dynamics to couple the flywheel to the tranny in the same way that the friction plates on a clutch does. At lower speeds, the converter can "slip," meaning that the engine and tranny aren't directly coupled. It's analogous to feathering/slipping the clutch and it allows the engine to rev faster, in essence, almost free-reving until the resistance of the tranny fluid against the stators is enough to overcome the resistance of turning the transmission/driveshaft/axles/wheels. This occurs over a continuum, with the converter coupling more and more with increasing rpm. Eventually, the fluid dynamics creates a resistance enough to basically lock the converter into one solid peice, thus directly coupling the engine and transmission as long as that rpm or higher is attained. This, in very rough terms, is considered the "stall" speed of a converter: the point at which the converter no longer slips. When I bought my converter, I decided to go with a non-lockup. This means that the converter slips in all gears up to its stall speed. A lock-up converter will directly couple the tranny to the engine (ie. not slip) in third and fourth gears. Looking back, I should have gone with a lock-up converter. For one, anytime the converter is slipping, it's creating heat (the number one enemy of AOD's). This means that a non-lockup cruising at 65 mph is still slipping some (~2000 rpm @ 60 mph vs. a stall speed of 2800 rpm) and thus is creating extra heat. A lock-up converter, on the other hand, will directly couple the engine to the transmission in third and fourth. This means a little bit of performance loss at low speeds in thrid gear, but not much. And when you think about it, when racing, you will be going all out and shifting at a fairly high rpm. When the tranny shifts, the rpms will not drop below say 3500-4000 rpm (which is higher than the 2800 rpm stall speed of the converter). This means that a non-lockup converter is not slipping anyway. So, after all that verbage, a lock-up converter will give you better gas mileage while cruising in third and fourth gears and the same performance off the line in first and second gear as a non-lockup. Also, with a converter that locks up in third and fourth, you decrease the amount of heat created. When I send my PI back for reconditioning (had some junk from a blown tranny wash through the converter and it's not working right anymore), I'm going to have them convert it to a lock-up and raise my stall speed to around 3200. This won't effect my highway cruising, as the converter will lock-up in fourth gear anyway, but will drastically improve my launches (while maybe costing me a couple mpg in town). Unfortunately, because my converter is malfunctioning, I can't really give you an estimate of what my gas mileage is. I can tell you that with any higher stalling converter, you will burn quite a bit more gas when just cruising around town. Thus the reason that Ford chose a 1500 rpm stall. However, if you're cruising on the highway for your commutes, a lock-up converter will likely give you better fuel economy to the tune of 2-3 mpg. As for shift kits. The Transgo kit comes with a video for install. Basically, you just swap out a few valves in the valve body and a number of springs. This will allow higher fluid pressures in the transmission and thus firmer/faster shifts. Also, you have to drill or enlarge a few holes in the converter and seperation plate. The Lentech valve body, on the other had, is reworked so as to change the shift pattern from the annoying 1-2/3-OD pattern that we all hate. This shift pattern means that you have to do the 1-D-1 shuffle to hold second gear, and shifts are often inconsistant as to when the tranny shifts in relation to when you tell it to. Mine would sometimes lag behind: I would throw the lever at the same point every time, but sometimes the tranny would hold the gear for a while longer and bounce the rev limiter before shifting. The Lentech valve body changes the pattern to 1-2-3/electric OD. This means you can completely control the tranny with manual shifting, and OD is accessed with the flip of a rocker switch. Shifts are fast (all the time), hard (when at full throttle), and superbly consistant (all the time). Sooo...after that little mini-novel, maybe you can make some decisions. Let me know if you have any other questions/concerns. --nathan __________________ '91 GT, Coast 347, 9.5:1 compression, full intake, Wolverine 1087 cam, exhaust, Keith Craft ported Windsor Jr. Irons (235 cfm intake, 195 cfm exhaust), AOD, PI 3500 converter, Lentech valve body, 3.73's (4.10's in the works), and Yokohama ES100's out back. Daily Car: '04 Infiniti G35 Sedan 6MT

10-09-2003, 04:24 PM	#8
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	In that case, a 2500 rpm lock up converter would be a perfect choice for me! Gives me the best of both worlds. I'd love the lentech, but it's crazy $$$ and the transgo is roughly 100 bucks. What do you guys think of these? http://cgi.ebay.com/ebaymotors/ws/eB...category=33727 This guy is obviously selling from his house cause you can see the furniture in the background. __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

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