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About to get a PT4000; reassure me or talk me out of it!!

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Old 05-23-2004, 07:08 PM
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JNorris, What is the efficentcy and str on the TCI 4000, 4200, and 4400? Ive considerd this route and know I would save $100s.
Old 05-23-2004, 08:25 PM
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According to the data from Texas Speed and Performance group purchase post the STR for the TCI Competition converters are as follows:

2-242933: Competition 3800, 2.6:1 STR
2-242934: Competition 4400, 2.8:1 STR
2-242933C: Competition 4000, 2.8:1 STR

As far as efficiency goes my TCI 4000 is FAR more efficient than my Yank PT4000.

TCI 4000 - ~94% at 5500 rpm
Yank PT4000 -~83% at 5500 rpm

The efficiencies above are from my 98 Z28. I am sure Kevin at TCI could provide you with the TCI spec.

I think your main concern with buying a Yank converter should not be the performance of the converter but the total lack of customer support.
IMO performance of the TCI and Yank converters are on par with each other for the most part. However TCI kicks Yank’s butt in the customer service and support after the sale area.

John
Old 05-24-2004, 10:08 AM
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It's important to note that my friend JNorris seems to calculate his efficiencies based strictly on slippage rather than HP loss from input to output. I'm not going to debate which way these things should be rated. That's up to the individual mind. I know what's important to me. However, if you're inclined to judge efficiency on slippage alone then consider a few things...

1. When sitting on the starting line and stalled up, your efficiency would be ZERO if you did it by slippage since your slippage is 100%. But yet, the input shaft of the tranny is indeed seeing ALOT of power (elsewise your car wouldn't be straining to move while being held back by your brakes.)

2. Consider that at 5500 RPM, for example, your slippage is going to be more and more the higher and higher you go in stall speed (and that is desired! It's called TQ mulitiplication. It's part of the reason that you WANT a higher stalling converter in the first place.)

3. Consider shift extension. Let's say our shift extension on a given converter is 5500 (that would be about right for a PT4000 stall.) Make no mistake shift extension is GOOD. It keeps us in our best power range better. Now, take another converter *with less slippage* and your shift extension might be only 5200.....is this a good thing? I mean, there's less slippage and that means it's more efficient, right? NO. It simply means that we're dropping farther out of our best power range on the shifts and therefore we're getting down the track slower.

So, IMO, slippage at 4500, 5500, or even 6500 has nothing directly to do with efficiency (it IS partly a result of efficiency, however and this is where the confusion lies.) HP out v/s HP in is what your tranny sees...and it's what moves you down the track.

FWIW, both my TP 4600 and my TP 4000 lost only 10 RWHP on the dyno when unlocked v/s locked. Not THAT'S efficient in my book! Both of these converters broke NA track records of the day.

John's experience with his Yank converter may have been a rare case of a faulty Yank converter. These things happen with ANY company occasionally. Or, it may have been partly, or in whole, a case of a bad tranny. I don't know. What I do know is that Yank makes some of THE MOST efficient converters in the world. This has been proven many countless times on dynos across the nation and at tracks around the world.

Last edited by Colonel; 05-24-2004 at 10:13 AM.
Old 05-24-2004, 11:04 AM
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Colonel, what do you think about the SS4000 or the SS4200 for my set up? I dont mind a loose verter and I want it to perform at the track. I want low 1.5s or high 1.4s.
Old 05-24-2004, 11:17 AM
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If you really don't care about looseness then the PT will be the better converter. The SS converter shines at being the best compromise between a street/strip converter.

Either could get you the 60ft times that you're talking about.

As for the SS4200, I believe that the SS line starts to loose just a little too much efficiency after 4000. Now that doesn't mean I wouldn't want that converter for some applications. If I really needed a 5500 shift extension (studying your dynograph will tell) while retaining descent streetability then I'd go for it. In my case I determined that I needed a SE of about 5300 so the 4000 was my choice.
Old 05-24-2004, 11:29 AM
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What size PT, 4000 or 4200? Really not looking at 4400. Is there a performance differance between the three if so I would think it is minimal. My wife needs to drive this car every day and she's used to the VIG3600. The Vig bothers me cuz if I have a good 60' with it the mph is down and worse 60' the mph is better. My 3200was the same way. I want a little more concistantcy.
Old 05-24-2004, 11:38 AM
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Your Vig "3600" is actually a 4300 so I don't think you'de have any trouble driving a PT4200 if that's what you're used to.
Old 05-24-2004, 12:04 PM
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Thats what I wanted to hear. What about the performance and shift extension differance between the PT4000, 4200, 4400. Thanks for you time and info.
Old 05-24-2004, 12:43 PM
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Originally Posted by J2KSS
Ragtop 99, you said you cannot tell a differance daily driving between the 4000 & 4200. How were they at the track?
I could not measure any change as I had also changed some motor components at the time I swapped. If the car hadn't been apart, I would not have bothered to switch.

Overall, I think the 4200 is the best application. I would choose the 4000 only if you highway race and run to redline in 3rd gear.
Old 05-24-2004, 01:32 PM
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Originally Posted by Colonel
It's important to note that my friend JNorris seems to calculate his efficiencies based strictly on slippage rather than HP loss from input to output. I'm not going to debate which way these things should be rated. That's up to the individual mind. I know what's important to me. However, if you're inclined to judge efficiency on slippage alone then consider a few things...

1. When sitting on the starting line and stalled up, your efficiency would be ZERO if you did it by slippage since your slippage is 100%. But yet, the input shaft of the tranny is indeed seeing ALOT of power (elsewise your car wouldn't be straining to move while being held back by your brakes.)

2. Consider that at 5500 RPM, for example, your slippage is going to be more and more the higher and higher you go in stall speed (and that is desired! It's called TQ mulitiplication. It's part of the reason that you WANT a higher stalling converter in the first place.)

3. Consider shift extension. Let's say our shift extension on a given converter is 5500 (that would be about right for a PT4000 stall.) Make no mistake shift extension is GOOD. It keeps us in our best power range better. Now, take another converter *with less slippage* and your shift extension might be only 5200.....is this a good thing? I mean, there's less slippage and that means it's more efficient, right? NO. It simply means that we're dropping farther out of our best power range on the shifts and therefore we're getting down the track slower.

So, IMO, slippage at 4500, 5500, or even 6500 has nothing directly to do with efficiency (it IS partly a result of efficiency, however and this is where the confusion lies.) HP out v/s HP in is what your tranny sees...and it's what moves you down the track.

FWIW, both my TP 4600 and my TP 4000 lost only 10 RWHP on the dyno when unlocked v/s locked. Not THAT'S efficient in my book! Both of these converters broke NA track records of the day.

John's experience with his Yank converter may have been a rare case of a faulty Yank converter. These things happen with ANY company occasionally. Or, it may have been partly, or in whole, a case of a bad tranny. I don't know. What I do know is that Yank makes some of THE MOST efficient converters in the world. This has been proven many countless times on dynos across the nation and at tracks around the world.

I agree that my method of measuring TC efficiency is not as valid as using a dyno.
After the RPM at which the converter becomes hydraulically coupled efficiency can be measured that is why I quote my numbers at 5500rpm, which is a point that a true 4000 stall SHOULD be coupled. The fact is the efficiency of my PT4000 was poor. Are all PT4000s that poor? No.

In my previous post I did not call into question Yank’s performance. I believe that it is on par with TCI.
I did however say that their customer service was poor.

IMO most of the great Yank converter accomplishments are history. It is easy to say you are “the best” or “number one” when there were are only a few (2) companies making a high stall converter for an LS1-4L60E. Now there are many more and things are changing.

In the event that I want a converter that is $200 more than an equally performing converter and want to buy it from a company that does not answer the phone or return calls or email and that you have to beg to take your money then I will call Yank.
Until that day comes I will stick with TCI or Precision industries (Vigilante). I have owned all of them; some more than once and nothing I have seen from Yank (at the current time) will motivate me to buy another one or make me believe that their converters are any better than the others are now.


Good luck with your converter selection.
Remember that there are many factors that contribute to being the “Best”. Choose wisely.


John

Last edited by JNorris; 05-24-2004 at 07:24 PM.
Old 05-24-2004, 03:25 PM
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John, you don't really see me sticking up for Yank's customer service in any of these threads. However, when their quality or performance is questioned, attacked, or even so much as doubted, I do stick up for them because truth is truth. They perform and perform well consistently.

Now back to tech...

"After the RPM at which the converter becomes hydraulically coupled efficiency can be measured that is why I quote my numbers at 5500rpm, which is a point that a true 4000 stall SHOULD be coupled."

I think you have the wrong idea here. Shift extension and the so-called coupling point (I say so-called because it's a gradual thing that NEVER reaches 100% so there is in fact no definable coupling RPM with ANY converter) are two different things. Also, neither is necessarily effected in a 1:1 ratio by a change in stall speed. They are effected by many factors. You can have three different converters all with the same TRUE stall speed of 4000. One may have an SE of 5200, another an SE of 5400, and another with an SE of 5600....and all three may have an efficiency of 94%, for example. Again, I'm talking about with THE SAME true stall speed of 4000.

I believe that measuring efficiency should ONLY be done on a chassis dyno where you can actually see what is getting to the ground and if you want to really do it right, all RPMs that pertain to our combination, usage, and goals should be considered. One converter may be more efficient at 5500 than another converter that is more efficient at 6500, for example. From simple slippage measurements we can only speculate of efficiency and overall effectiveness...and our conclusions (if we dare make any with this limited information) very well may have our thinking awry.
Old 05-24-2004, 04:25 PM
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Hey Colonel!How do you determine Shift Extension from your dyno graph ?I mean How do I pick a converter?I went with X1 cam and MTI S2 Heads.I am in the same boat
Thanks!
Old 05-24-2004, 04:36 PM
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Ok, we'll look at my dynograph for example...



You can see that my power climbs very rapidly until about 5400. After this point it rises slower. In my case I was looking to make good use of my power without having a converter that was too loose for daily driving. I picked the SS4000 which gives me a SE of about 5350-5400 putting me right up where my power isn't very far off from what it is at it's peak. It's important to note that I could have gotten even better performance with a higher SE (my HP peak isn't until 5900) but I would have had to use a looser converter to do it...which isn't what I wanted for a daily driver. If this were a track ONLY car then I'd use a converter with a 5800-5900 SE. It isn't, so I picked the best compromise for my tastes.
Old 05-24-2004, 04:45 PM
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Ok Thanks Colonel,I will be studing my graphs tonight
Scott
Old 05-24-2004, 05:28 PM
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Colonel I enjoy your posts because of the helpful information you provide. When you write in details I understand the topic fairly well. You must have spend alot of times with these fast cars. Thanks for the understandable information. cheers............................................ ...........
Old 05-24-2004, 08:06 PM
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“there is in fact no definable coupling RPM with ANY converter”

Sure there is. It is the point at which the fluid is being pushed by rotation (RPM) from the engine side of the converter to the transmission side of the converter at a rate that that almost simulates a direct connection. The hydraulic coupling of the converter will rarely exceed 96%. You are correct in that the exact RPM this happens is not completely definable because of all the variables that come into play.

Mike @ Yank told me that a good rule of thumb is the stall speed plus 1200-1500 RPM is the point that a converter starts to become hydraulically coupled. That is where I got my 5500 rpm number.

Mike @ Yank also told me that the efficiency of ANY of the Yank PT series converters would be “dismal” when used with 3.23 gears. I am not sure that the 83% efficiency I had with my PT4000 converter should be considered dismal but it sure was not very good!
BTW using my method of determining converter efficiency my Vig3200 came in at 94% which is what the Yank web site said Vig3200 efficiency is.

“You can have three different converters all with the same TRUE stall speed of 4000. One may have an SE of 5200, another an SE of 5400, and another with an SE of 5600....and all three may have an efficiency of 94%, for example. Again, I'm talking about with THE SAME true stall speed of 4000.”

If in your above example nothing else on the car was changed except the converter then you are way way off base unless the converter in question is a variable pitch converter of some sorts. I will leave my commits at that.

Good catch on the shift extension statement. I mistyped. I corrected my post.

John

Last edited by JNorris; 05-24-2004 at 10:42 PM.
Old 05-24-2004, 10:22 PM
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Colonel,I know you deal alot with MTI ,and I now too.I ordered a SS4000 from Jayson TodayHe said with my combo the SS4000 would be better for performance.Will this thing be hard out of the hole?I had a SY3500 in my car with Stock internals,I hated it,so I went to the Vig 3200 and It was alot faster out of the hole on the street.With my X1 cam and S2 Heads,Mine was dyno tuned on a Mustang Dyno.So where They have got my power starting is 230rwhp@4200 and it Climbs steadly up to 375 rwhp@6700 So I dont have a real point to pickI hope I made the right Desision going SS4000 Instead of the SS3600.
Old 05-24-2004, 11:35 PM
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"“You can have three different converters all with the same TRUE stall speed of 4000. One may have an SE of 5200, another an SE of 5400, and another with an SE of 5600....and all three may have an efficiency of 94%, for example. Again, I'm talking about with THE SAME true stall speed of 4000.”

If in your above example nothing else on the car was changed except the converter then you are way way off base unless the converter in question is a variable pitch converter of some sorts. I will leave my commits at that."

Perhaps you didn't notice that I said THREE DIFFERENT CONVERTERS? I wasn't speaking of one converter therfore there is no variable pitch needed. If you do understand this then I'm confused as to why you say I'm way off base. What I said is perfectly feasable.

As to the coupling, again you never reach 100% (as you mentioned about the almost simulates a direct connection) at any RPM so there is no definable true coupling RPM. (As an aside, if we could truly reach a direct coupling then there would be no point of locking a converter at WOT.) There is of course what people refer to as an general coupling but it can't be defined as an exact RPM since it's a matter of opinion as to how close to 100% is close enough. That's all I was saying.

"Mike @ Yank told me that a good rule of thumb is the stall speed plus 1200-1500 RPM is the point that a converter starts to become hydraulically coupled."

Right, it's a rule of thumb with a range. I understand what people mean when they say "becomes hydraulically coupled." I also understand that this doesn't literally happen with an unlocked converter.

"Mike @ Yank also told me that the efficiency of ANY of the Yank PT series converters would be “dismal” when used with 3.23 gears."

And we can easily understand what is meant by this. The efficiency of the converter doesn't actually change when using 3.23 gears (ask Mike)...but the RPMs used in 3rd, and therefore the slippage of the converter DOES. If you're crossing the line at only 5000 with a converter that has a shift extension of 5600 then there is going to be alot of slippage going on. This would be the case with ANY completely unlocked converter of this loosness...not just a Yank.

Ok, one last example. Let's assume that we have 3.23 gears and are crossing the line at 5000 RPM with one converter. Let's say that we have only 6% slippage at this RPM. Now, let's say that we change converters and now we're crossing the line at 5600 RPM. Which would you rather have? At first glance we might say the one with less slippage. I mean, afterall, it appears to be more efficient, right? UNTIL we take into consideration just how much more HP the engine is making at 5600 than at 5000. Despite the slippage we're seeing more HP to the ground across the line. Also consider than the shift extension of the second converter is going to be alot better than the tighter converter. We're going to stay closer to our HP peak after the shifts. Again, more HP is seeing the ground on the average. I'll take the second converter...absolutely no doubt about it.
Old 05-24-2004, 11:46 PM
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Pro Mouse, you certainly made a good decision going with the 4000 over the SS3600 if better track times are your goal. The SS line of converters has low shift extensions for their stall speed and not surprisingly, better drivability for their stall speeds than 18-blade type converters. I bet your Vig 3200 (which is actually a 3800) had a shift extension of about 5100-5200...am I right? Your new converter will have a SE of about 5300-5400. It should feel very similar to the Vig 3200 in daily driving. Your 60ft should be low 1.5s-high 1.4s (depending on weight) with your gearing if you can hook perfectly.
Old 05-24-2004, 11:47 PM
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"Colonel I enjoy your posts because of the helpful information you provide. When you write in details I understand the topic fairly well. You must have spend alot of times with these fast cars. Thanks for the understandable information. cheers............................................ ..........."

Hey, THANKS! Glad I can help.



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