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Discussion Starter #1
Hey guys,

I'm trying to figure out what's the best way to shift and when/if i should use lockup or not?

Have a Freddy Brown Manual VB with a Circle D Converter and a TCI Shifter behind a 2V. New to the automatics, so any help or advice would be great.

Need any more information let me know.

Thanks guys
 

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What's your setup? Stock or built trans?
 

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Power? Dyno graph? Is it tuned? If so, tuner didn't recommend where to lock it and where to shift? I'm assuming you're talking about WOT lockup and shifting not street driving?
 

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Discussion Starter #5
Power? Dyno graph? Is it tuned? If so, tuner didn't recommend where to lock it and where to shift? I'm assuming you're talking about WOT lockup and shifting not street driving?

Nope never said a word. I know when to shift I just don't know if lockup is worth it, should I put it in OD before I use lock up? These are the things I don't know.

On my phone currently I cant upload my Dyno graph is a bit.

Phone is acting up didn't mean to double post. Thanks man
 

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Power? Dyno graph? Is it tuned? If so, tuner didn't recommend where to lock it and where to shift? I'm assuming you're talking about WOT lockup and shifting not street driving?

Nope never said a word. I know when to shift I just don't know if lockup is worth it, should I put it in OD before I use lock up? These are the things I don't know.

On my phone currently I cant upload my Dyno graph is a bit.

Phone is acting up didn't mean to double post. Thanks man
So WOT lockup or lockup during cruising? Sounds like you're talking about cruising lockup.
 

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Discussion Starter #7
Power? Dyno graph? Is it tuned? If so, tuner didn't recommend where to lock it and where to shift? I'm assuming you're talking about WOT lockup and shifting not street driving?

Nope never said a word. I know when to shift I just don't know if lockup is worth it, should I put it in OD before I use lock up? These are the things I don't know.

On my phone currently I cant upload my Dyno graph is a bit.

Phone is acting up didn't mean to double post. Thanks man
So WOT lockup or lockup during cruising? Sounds like you're talking about cruising lockup.
No I'm talking about WOT. I know when it's needed for cruising.
 

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I'm really surprised your tuner didn't say anything. Was the car tuned with the converter locked or unlocked? You're able to manually force lockup? You never should hit overdrive when you're at WOT. Usually guys will lockup towards the top of 3rd around 5k rpm, but some are locking up in 2nd and 3rd.

You're not looking at huge gains by locking it. .1-.2 and a few Mph. I'd run it unlocked to start. I've got a single disk so I run unlocked. Circle D told me I'm looking at minimal if any gains by locking so they recommended the single over triple disk for my setup.
 

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Discussion Starter #10
I'm really surprised your tuner didn't say anything. Was the car tuned with the converter locked or unlocked? You're able to manually force lockup? You never should hit overdrive when you're at WOT. Usually guys will lockup towards the top of 3rd around 5k rpm, but some are locking up in 2nd and 3rd.

You're not looking at huge gains by locking it. .1-.2 and a few Mph. I'd run it unlocked to start. I've got a single disk so I run unlocked. Circle D told me I'm looking at minimal if any gains by locking so they recommended the single over triple disk for my setup.
Car was tuned with converter unlocked. Yes im able to manually lock up. Yeah id never hit it WOT. My car pulls like a freight train in 3rd so haven't even considered locking up. Only time i use overdrive and lock up is when i'm on the highway around 70-80 mph cruising. If i got WOT i turn em off, down shift and punch it.
 

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When cruising IDE go into OD then LU if you do that in reverse you will hear some noise that the car doesn't like.

During a WOT pull you can go into LU any time your in third gear however you would have to be on the dyno and get some graphs on the exact RPM you will want to engage LU to get the optimal power and Speed out of it.

Obviously using LU to early will actually BOG you down for a brief point until the converter and motor are married up right and back to spinning up that RPM.
 

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Discussion Starter #12
When cruising IDE go into OD then LU if you do that in reverse you will hear some noise that the car doesn't like.

During a WOT pull you can go into LU any time your in third gear however you would have to be on the dyno and get some graphs on the exact RPM you will want to engage LU to get the optimal power and Speed out of it.

Obviously using LU to early will actually BOG you down for a brief point until the converter and motor are married up right and back to spinning up that RPM.
Awesome. Thanks for the tips and advice guys.
 

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Based on that curve, your ideal shift point will be basically as late as you can. To go as fast as possible, you want the horsepower to be has high as possible. Your power is basically flat from 5400-6800 (which is excellent), but a shift at 6800 is going to drop the rpm lower than 5400, which will reduce the average horsepower output. So the further out your shift point is, the better.

NEVER, under any circumstances, shift into overdrive at WOT with that kind of power. At 700+ horsepower, once incident will likely grenade the OD band. So don't do it.

As for locked vs. unlocked at WOT, the principle is exactly the same as the shift points. You want to maximize horsepower output, to the tires. An unlocked converter is essentially the same thing as another higher gear ratio (numerically lower). In other words, at the same vehicle speed, the rpm will be higher. However, this "extra gear" comes at the expense of efficiency. While the converter is 100% efficient locked, it's some amount less than that unlocked. It depends on a myriad of factors, such as stall speed, build design & quality, etc., but on a good Circle D like you have, you're probably talking 95% efficient. That means that your rpm will be 5% higher unlocked than locked.

To answer locked versus unlocked, the question is whether or not a 5% increase in engine rpm (at a given vehicle speed) increases the power output enough to overcome the 95% efficiency. If not, then the power output through the converter / transmission and to the tires will be less, and thus will be slower. If the answer is yes, then it will be faster.

For example, big block NA, roots blown, and properly-set-up turbo builds have a fairly flat power curve once well up into the band (where you're actually racing at). So if you're up in the band, and unlock the converter, you'll lose 5% efficiency, which gains you 5% more rpm, but since the curve is flat, you don't gain any more power from that extra 5% rpm. This gives you a net -5% loss of power transmitted through the converter, and thus you'll be slower. My old SVO setup fell into this category. Unlocked was several mph and tenths slower than locked.

On the flip side, a small block NA or centri blower or improperly built turbo setup may have a very linear power curve, where it's increasing fairly rapidly with rpm. In this case, unlocking it loses 5% efficiency, gains 5% rpm, and maybe that 5% more rpm gets you 9% more power. Therefore, with this example, the net would be a 4% gain of power transmitted through the converter by unlocking it. There were several members around here with centri blower setups that documented significant mph gain by unlocking the converter for as long as they could down the 1/4.

In your case, the power curve is nice and flat once it gets up in the band (which is good). I'll almost guarantee that your setup will go a significant amount faster in the 1/4 if you lock the converter as soon as you can. Once you get to ~5500 rpm, any gain in rpm from unlocking the converter doesn't result in any significant amount more horsepower, so I'd bet the net change would almost definitely be less if you kept it unlocked.

To illustrate, let's look at your car at 5800 rpm in say 2nd gear, with the converter locked. Depends on the tire and gear setup, but that's going to be 70ish mph. At 70 mph, your motor is making exactly 700 horsepower, and since the converter is 100% efficient when locked, means that 700 horsepower is making it to the transmission. Now, let's say you unlocked the converter at 70 mph, and it's 95% efficient. That means that your rpm is now 5% higher, or about 6100 rpm, at 70 mph. At 6100 rpm, you're making ~710 horsepower, BUT, the converter is only transmitting 95% of that to the transmission. So 710 * 95% = 675 horsepower that's actually making it to the transmission. This is 25 horsepower less than the 700 with the converter locked, and thus you'll be slower by 25 horsepower. It also means that you've got 25 horsepowers worth of HEAT that's being generated that has to go somewhere (i.e. the transmission fluid). That is a LOT of heat. Keep that in mind.

Imagine doing that comparison across the powerband that you're racing in, and taking the average of the whole thing. Whichever is higher is the answer to the question of locked vs. unlocked.

Here's a video of my old SVO setup with it locking after it shifts into 2nd gear. I found that if I locked it at the exact same time it shifted to 2nd, that it was a little bit too much of an rpm drop all at once, and it would kinda "hiccup" a bit as I did it. So I delayed it just a bit after the shift. The car ran .2-.3 faster with it locked, and 4-5 mph faster.

All of this is completely irrelevant if you don't have a triple plate converter. A single plate won't even come close to locking up that kind of power.


 

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Discussion Starter #14
Based on that curve, your ideal shift point will be basically as late as you can. To go as fast as possible, you want the horsepower to be has high as possible. Your power is basically flat from 5400-6800 (which is excellent), but a shift at 6800 is going to drop the rpm lower than 5400, which will reduce the average horsepower output. So the further out your shift point is, the better.

NEVER, under any circumstances, shift into overdrive at WOT with that kind of power. At 700+ horsepower, once incident will likely grenade the OD band. So don't do it.

As for locked vs. unlocked at WOT, the principle is exactly the same as the shift points. You want to maximize horsepower output, to the tires. An unlocked converter is essentially the same thing as another higher gear ratio (numerically lower). In other words, at the same vehicle speed, the rpm will be higher. However, this "extra gear" comes at the expense of efficiency. While the converter is 100% efficient locked, it's some amount less than that unlocked. It depends on a myriad of factors, such as stall speed, build design & quality, etc., but on a good Circle D like you have, you're probably talking 95% efficient. That means that your rpm will be 5% higher unlocked than locked.

To answer locked versus unlocked, the question is whether or not a 5% increase in engine rpm (at a given vehicle speed) increases the power output enough to overcome the 95% efficiency. If not, then the power output through the converter / transmission and to the tires will be less, and thus will be slower. If the answer is yes, then it will be faster.

For example, big block NA, roots blown, and properly-set-up turbo builds have a fairly flat power curve once well up into the band (where you're actually racing at). So if you're up in the band, and unlock the converter, you'll lose 5% efficiency, which gains you 5% more rpm, but since the curve is flat, you don't gain any more power from that extra 5% rpm. This gives you a net -5% loss of power transmitted through the converter, and thus you'll be slower. My old SVO setup fell into this category. Unlocked was several mph and tenths slower than locked.

On the flip side, a small block NA or centri blower or improperly built turbo setup may have a very linear power curve, where it's increasing fairly rapidly with rpm. In this case, unlocking it loses 5% efficiency, gains 5% rpm, and maybe that 5% more rpm gets you 9% more power. Therefore, with this example, the net would be a 4% gain of power transmitted through the converter by unlocking it. There were several members around here with centri blower setups that documented significant mph gain by unlocking the converter for as long as they could down the 1/4.

In your case, the power curve is nice and flat once it gets up in the band (which is good). I'll almost guarantee that your setup will go a significant amount faster in the 1/4 if you lock the converter as soon as you can. Once you get to ~5500 rpm, any gain in rpm from unlocking the converter doesn't result in any significant amount more horsepower, so I'd bet the net change would almost definitely be less if you kept it unlocked.

To illustrate, let's look at your car at 5800 rpm in say 2nd gear, with the converter locked. Depends on the tire and gear setup, but that's going to be 70ish mph. At 70 mph, your motor is making exactly 700 horsepower, and since the converter is 100% efficient when locked, means that 700 horsepower is making it to the transmission. Now, let's say you unlocked the converter at 70 mph, and it's 95% efficient. That means that your rpm is now 5% higher, or about 6100 rpm, at 70 mph. At 6100 rpm, you're making ~710 horsepower, BUT, the converter is only transmitting 95% of that to the transmission. So 710 * 95% = 675 horsepower that's actually making it to the transmission. This is 25 horsepower less than the 700 with the converter locked, and thus you'll be slower by 25 horsepower. It also means that you've got 25 horsepowers worth of HEAT that's being generated that has to go somewhere (i.e. the transmission fluid). That is a LOT of heat. Keep that in mind.

Imagine doing that comparison across the powerband that you're racing in, and taking the average of the whole thing. Whichever is higher is the answer to the question of locked vs. unlocked.

Here's a video of my old SVO setup with it locking after it shifts into 2nd gear. I found that if I locked it at the exact same time it shifted to 2nd, that it was a little bit too much of an rpm drop all at once, and it would kinda "hiccup" a bit as I did it. So I delayed it just a bit after the shift. The car ran .2-.3 faster with it locked, and 4-5 mph faster.

All of this is completely irrelevant if you don't have a triple plate converter. A single plate won't even come close to locking up that kind of power.


Supercharged Mustang 0-125 mph (Mid-11 Second Pass) - YouTube
Awesome man, this is very useful. Ill go play around and see how to works for me when i go to the track. Replacing my fuel tank this weekend and if i got time i may go out and try.

Thanks again sneaky.
 
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