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Isn't that the entire point of doing a stall speed higher than stock in the first place? The engine is stock, so why not just use a factory converter if absolute best economy is desired? No higher stall speed is required for a stock cam.
Understand that 2800 or even 2400 is not going to deliver best economy, if that's the #1 goal. Better to stick with stock stall speed for a stock engine then.
How about finding a balance? High quality converters in the ~3500 stall speed range tend to best represent said balance for LS1/4L60E combos for most enthusiasts. They certainly won't deliver the best possible performance, and they certainly won't deliver the best possible economy, but they are a better balance of these two aspects than a 2400 OR a 4400. For most of us, myself included, a ~3500 stall speed (LS1/4L60E) feels almost like stock after about a week of driving; totally daily driveable for the average enthusiast (which the OP seems to be as he's interested in improving performance.)
It seems that you're only looking at one aspect - economy. If so, stick with stock for a stock engine and don't worry about anything else.
NOW you are thinking along the same lines, exactly the question we should be asking ourselves, where is the balance? If a motor is to stay stock forever and economy is essential you use the low stall speed, and it goes up from there.
Why not use an OEM converter?IS a good question, with a good answer: OEM converters are not as efficient as their 9.5" Counterparts. All else equal, a 9.5" will give better economy, if for no other reason than its reduced weight. So we CHOOSE the light, efficient converter, as if it were a lightweight flywheel, regardless of performance aspect (in an auto app, you don't generally have to worry about having too light of a rotating mass in the flywheel regions). And from that point, you dial up performance at the expensive of economy as the owner can afford to spend $$ on fuel or not (we would want to calculate miles/year vs miles per gallon, something like that) and make the call.
It wasn't an argument I was making, or a point, it was an observation.
...exactly the question we should be asking ourselves, where is the balance?
As mentioned above, about ~3500rpm stall speed is a good balance between performance improvement and economy/drivability for a 4L60E/LS1 combo. Most folks who have experienced this combo are very happy with it on the street.
Originally Posted by kingtal0n
Why not use an OEM converter?IS a good question, with a good answer: OEM converters are not as efficient as their 9.5" Counterparts. All else equal, a 9.5" will give better economy, if for no other reason than its reduced weight.
However, all else is NOT equal, unless you somehow have a custom 9.5" unit built with stock stall speed. The cost of this would be well beyond what you'd make back in MPG savings over any reasonable period of time. Just no point in even considering this.
If you don't want to improve performance, and you prioritize economy over everything else, just stick with stock.
However, all else is NOT equal, unless you somehow have a custom 9.5" unit built with stock stall speed. The cost of this would be well beyond what you'd make back in MPG savings over any reasonable period of time. Just no point in even considering this.
If you don't want to improve performance, and you prioritize economy over everything else, just stick with stock.
When I say efficiency, it means more power also. I refer to economy as to point it out- I don't mention power because I expect you to know that already. If I have to spell it out for you, sorry you missed it, the smaller diameter converter is more efficient in both terms of drivetrain losses (cough fuel economy) and drivetrain losses (cough more power to the rear wheels). It is the same result either way. Furthermore, I do not know if it is even possible to create a stock stall 9.5" converter. I asked edge racing years ago if they could do that and Andre (owner) told me no, because of something to do with it's size I think.
And yes behind a couple F-body cars, 2800~ stall. I remember the 2.73 rear gear TPI engine enjoying the 2800 9.5" stall both with and without turbochargers, and the 2.77 rear gear TH350 10" 3800 Fbody carb'd @ 350tq/350hp was terrible, just turrible. There is a way more stall can hurt the combo, that is for sure. Numerically low rear gear + heavy vehicle + high stall seems like the worst thing you can do, in my experience.
When I say efficiency, it means more power also. I refer to economy as to point it out- I don't mention power because I expect you to know that already. If I have to spell it out for you, sorry you missed it, the smaller diameter converter is more efficient in both terms of drivetrain losses (cough fuel economy) and drivetrain losses (cough more power to the rear wheels). It is the same result either way.
I didn't miss anything at all, but perhaps I need to spell something out for you: I simply don't think there would be enough gain (power OR MPG) to justify the cost of doing this in the first place. The actual rear-wheel power/efficiency gains are speculative; I don't disagree in principle but I don't know of any before/after hard evidence nor do I even know if anyone has ever produced such a small diameter converter with a stock stall speed. If the option doesn't even exist, and/or isn't remotely cost effective, then you're making a pointless argument.
I didn't miss anything at all, but perhaps I need to spell something out for you: I simply don't think there would be enough gain (power OR MPG) to justify the cost of doing this in the first place. The actual rear-wheel power/efficiency gains are speculative; I don't disagree in principle but I don't know of any before/after hard evidence nor do I even know if anyone has ever produced such a small diameter converter with a stock stall speed. If the option doesn't even exist, and/or isn't remotely cost effective, then you're making a pointless argument.
Enough gain? Some spend $999 to gain 2 horsepower. It has happened. The slew of aftermarket parts available cost $0.02 to $999999+ and some of them will decrease performance, regardless of money spent. So we can never say "does not justify the gain" because you can always say that, it applies to every part in existence. You see a head/cam swap and can always say "It doesn't justify the gain, instead add nitrous/turbo/bigger engine/etc" There is always another way to gain.
The observation is not an argument. Imagine a scroll bar. On the left side, is economy. On the right side, performance. Applies to a majority of situations, left is low stall, right is high stall. There is no bell curve for each individual attribute, however when you put the two together you find a peak in the center where they meet. A theoretical peak, since nobody is measuring economy or efficiency of torque converters and posting the results on the myriad of engine combinations possible.
Also I apologize if I sounded rude, I should have proof read that. Was never my intention to be rude. You pretend to miss an efficiency point so I made it clear. To put this another way, some parts are a guess, and some are certain. Nitrous seems like it always works, but custom cam grinds don't always work. The high efficiency of modern well designed converters is nearly guaranteed, it is a good investment regardless of what engine you own, most of the time, at any stall speed.
Your observation is purely theoretical since there is no known real world before/after data on the performance (or economy) enhancements of a small diameter stock stall speed converter in this application (at least not to my knowledge, but if you have such data I'm certainly open to seeing said results.)
Originally Posted by kingtal0n
Enough gain? Some spend $999 to gain 2 horsepower.....
There are two primary groups who will buy aftermarket torque converters:
- Those looking for max performance
- Those looking for a good street balance
Neither group would be interested in a small diameter stock stall speed as it would be a poor match for either goal. THAT is when "justifiable" stops being just an opinion - when an item has no target audience (other than perhaps you. ) Anyone looking for stock stall speed/stock economy will simply retain the stock converter, and anyone looking for performance enhancement will want an increased stall speed that is idealized for their combo. For the latter group, "idealized" becomes a subjective matter depending on goals and tolerance, hence this thread and the recommendations within. Most of us feel that a mid-3k stall speed range, with a high quality unit, meets that balance for a 4L60E/LS1 combo. You don't seem to agree, and that's fine, but we've now gotten way off track with discussion about an item that doesn't seem to even exist. Theoretical discussion can be interesting and lead to some new ideas, but in this case it's an item that would appeal to almost nobody even if it were available/able to be produced - and it certainly wouldn't be best for the OP based on the sort of balance that he seems to be interested in.
Originally Posted by kingtal0n
To put this another way, some parts are a guess, and some are certain.
When folks go outside the box and take a "guess" on an upgrade, it's usually because proven combos aren't yet established for the setup in question, or they are trying to overcome some obstacle/barrier/record/behavior that hasn't yet been overcome to their satisfaction. I don't see that either case applies to this thread/the setup in question.
So you have to ask yourself, what do you want to do with the car.
If you daily drive the car in a lot of stop and go traffic, a loose stall is not that fun. It generates a lot of heat because it is not converting engine speed to tire movement, is terribly inefficient at part throttle causing RPMs to shoot up to stay with traffic, and if you never get to a cruising speed where lockup can happen, then you're always driving a sluggish, loud, and poorly performing car in that scenario.
However, at the track or on the open road, the more throttle you give it and the faster you get the RPMs up, the better the converter responds.
But that's just because of the efficiency of a loose converter. Or lack of efficiency down low. Where it gains efficiency is at the top of the power curve.
So let's take a step back for a moment and look at this little picture I drew:
Let's compare a couple of Yank Converters to show how even with the same stall speed, they behave differently. A tighter stall with a higher STR needs less throttle to move under their stall speed. An SS4000 is tighter than a PT4000. Both flash to 4000 RPM, meaning that if you drop the hammer (or could brake stall it that high), it's where the RPMs will jump on a WOT run. Now, beyond that, they do perform differently. The SS4000 is less efficient up top and couples slower. It does however produce more midrange torque multiplication. The PT4000 on the other hand couples up faster, produces less torque multiplication, but is far more efficient up top.
But what do I mean by efficient? I mean the PT4000 is eating roughly 5% of the speed of the engine and translating about 95% of it to the wheels. Say you're gearing/tire combo is 100mph top of second locked up or with a 6-speed. The PT4000 will get you to 95mph. The SS4000 is usually 12-15% inefficient so you'd see 85-88mph with it. But it accelerates harder and dissipates energy in the form of added heat and slip in that 4500-5500 range a little better. So for most LS1s that spin to 6500, the SS4000 is a better converter and does well at the track and on the street. The PT4000 is once you start making more power NA and spinning higher, the converter allows you to put more power to the ground and makes you faster, bypassing a lot of the 5000 rpm range altogether.
But that slip uptop means it's less inefficient driving around town. It may need only 2500rpm with the same rear gear and motor to drive in traffic at 8-10% TPS input. Whereas the PT4000 may give you 3000rpm with the same input.
So it's not just stall speed but the design of the stator and positioning of the stators that makes a difference as well.
So you have to ask yourself, what do you want to do with the car.
If you daily drive the car in a lot of stop and go traffic, a loose stall is not that fun. It generates a lot of heat because it is not converting engine speed to tire movement, is terribly inefficient at part throttle causing RPMs to shoot up to stay with traffic, and if you never get to a cruising speed where lockup can happen, then you're always driving a sluggish, loud, and poorly performing car in that scenario.
Hold on. Yes I will be driving in a lot, and I mean A LOT of stop and go traffic. And heat is an extremely big problem in where I live (it's what killed my trans in the first place).
If a loose stall will create problems with heat, then I would seriously prefer to be safe than have performance gains.
Hold on. Yes I will be driving in a lot, and I mean A LOT of stop and go traffic. And heat is an extremely big problem in where I live (it's what killed my trans in the first place).
If a loose stall will create problems with heat, then I would seriously prefer to be safe than have performance gains.
Spend the money on a good cooler and you will be fine. Or if you are REALLY paranoid about heat, put two coolers in series.... both with fans.
Spend the money on a good cooler and you will be fine. Or if you are REALLY paranoid about heat, put two coolers in series.... both with fans.
Yes I because extremely paranoid about transmissions. Because when my tranny went out, I was 200 miles away from home, penniless, and on a non used highway with no cars passing by, at 2 O'Clock in the morning. It made me despise the 4L60E and love the LS1 more. The motor didn't disappoint one bit as I was downshifting my way to home (imagine having 2 gears only, not knowing if they'll even hold while downshifting for 200 miles).
That being said, I would love to install two of the biggest coolers on the market, and add fans on them, if they can fit that is...
You get used to it to some degree. But because you're in that inefficient range below 2500rpm with a 3500+ converter, you lose throttle resolution. And to me, that's the worst part of it. With a stock 1600-1800 stall, you're in that like 4500 range you see in that above chart with it at 2k RPM and a little bit of throttle translates into immediate forward movement. Because it couples up fast and basically as you provide throttle, the car responds.
With a big stall, if you give it 30% throttle, you will go. Much faster than stock. But at 10%, it's just not doing much. And in traffic, it's hard to open it up. I fall behind traffic a lot in stop and go.
I liken a big stall to like winding up a slingshot. The more throttle the more you are pulling back on the slingshot and once you hit a certain amount of throttle, you slingshot forward.
You get used to it to some degree. But because you're in that inefficient range below 2500rpm with a 3500+ converter, you lose throttle resolution. And to me, that's the worst part of it. With a stock 1600-1800 stall, you're in that like 4500 range you see in that above chart with it at 2k RPM and a little bit of throttle translates into immediate forward movement. Because it couples up fast and basically as you provide throttle, the car responds.
With a big stall, if you give it 30% throttle, you will go. Much faster than stock. But at 10%, it's just not doing much. And in traffic, it's hard to open it up. I fall behind traffic a lot in stop and go.
I liken a big stall to like winding up a slingshot. The more throttle the more you are pulling back on the slingshot and once you hit a certain amount of throttle, you slingshot forward.
If the throttle in stop and go traffic is something that I can get used to, then it's fine. I will eventually find the right amount of throttle to put down and keep up with the traffic.
So far, the choices I have are between a Yank SS3600, or a CircleD HP 3200 (if I couldn't pay for the Yank, I think that's the second best?).
I also want to install the Derale 15950 cooler, a Magnefine filter, and the Derale cooling pan #14204.
I know I'm probably going overkill with transmission that'll sit behind a stock LS1 (bought the most expensive kit from Dana, Pro Street Elite), but I don't have money to get a new car in the near future, and I don't want to get a used crap like Toyota or Honda. So all I can do is fix what I have right now and live with it for a while.
word of caution about that Derale cooling pan #14204. If it hangs too low,could be catastrophic if it gets damaged and all the fluid comes out. happened to me with a cast aluminum deep pan,touched a speed bump(I'm not lowered) and fractured,wasn't catastrophic,just started leaking thru the fractures.
word of caution about that Derale cooling pan #14204. If it hangs too low,could be catastrophic if it gets damaged and all the fluid comes out. happened to me with a cast aluminum deep pan,touched a speed bump(I'm not lowered) and fractured,wasn't catastrophic,just started leaking thru the fractures.
I'll scratch that. The bottom of the car is already not even from how terrible the roads are here. I'll just add two coolers then.
05-17-2017, 09:51 PM
) Anyone looking for stock stall speed/stock economy will simply retain the stock converter, and anyone looking for performance enhancement will want an increased stall speed that is idealized for their combo. For the latter group, "idealized" becomes a subjective matter depending on goals and tolerance, hence this thread and the recommendations within. Most of us feel that a mid-3k stall speed range, with a high quality unit, meets that balance for a 4L60E/LS1 combo. You don't seem to agree, and that's fine, but we've now gotten way off track with discussion about an item that doesn't seem to even exist. Theoretical discussion can be interesting and lead to some new ideas, but in this case it's an item that would appeal to almost nobody even if it were available/able to be produced - and it certainly wouldn't be best for the OP based on the sort of balance that he seems to be interested in.
