Vigilante LU Converter vs Non-LU converter

[KEVINS]

Why would someone choose a Non-LU coverter over a Vigilante LU? It seems to me that a LU would be much better on the topend since you can lock it up.

I did read things about the stall not being as high with a Vigilante LU. How much stall can Precision get out of one of these units?

KS

 

[bison]

The reason I wouldnt use one is because unlocked the precision industries converters can't come close to coupling the power a low revving 500+hp turbocharged engine can produce. The higher the advertised stall the more they slip unlocked and get even worse the more power thrown at them. The only time you benefit from lockup is when it's locked and locking too soon could hurt e.t. by dragging the engine down too far even though you might see a higher mph locked. A proper non locking converter like the ones I use will couple in every gear and produce the most useable road horsepower over the quarter mile. Cruising slip is so slow it's almost not worth mentioning. Like less than 5% on level ground. Also the cooling circuit in a lockup configuration is compromised when the converter isn't locked. If you have driven or remember the factory calibration the factory locks the converter early in 4th gear. The reason they do it is so that the oil flow is directed through the cooler.

 

[Pittsburghkid]

The reason I wouldnt use one is because unlocked the precision industries converters can't come close to coupling the power a low revving 500+hp turbocharged engine can produce. The higher the advertised stall the more they slip unlocked and get even worse the more power thrown at them. The only time you benefit from lockup is when it's locked and locking too soon could hurt e.t. by dragging the engine down too far even though you might see a higher mph locked. A proper non locking converter like the ones I use will couple in every gear and produce the most useable road horsepower over the quarter mile. Cruising slip is so slow it's almost not worth mentioning. Like less than 5% on level ground. Also the cooling circuit in a lockup configuration is compromised when the converter isn't locked. If you have driven or remember the factory calibration the factory locks the converter early in 4th gear. The reason they do it is so that the oil flow is directed through the cooler.

Any recommendations on a good NLU on the round about specs you mentioned?

 

[fastblackracing]

A mostly stock trans and converter locked up at the track worked well until you go quicker/faster than 11.70- 114 mph, at that point reliability will fall like a rock. The purple lock up converter can work well on The faster cars but if the guys that run these are honest they usually have the trans played with quite a few times before they lock up like they should. I know from personal experience, and like bison said if they dont lock up they slip a good bit. Also the lock up converter is harder on the trans than a non lock up. If you want to go fast and use a lock up you will end up being one your tranny guys best customers.

 

[BEATAV8]

The WOT RPM trace from a multi-disc lock-up vs a good non-lock shows the differences.

A lock up comes out of the hole and the engine RPM goes right to the ceiling. Gear changes are barely noticeable, only a couple hundred RPM drop. The whole time the engine is screaming near it's limit, mostly over the top of it's power band. Then comes the lock-up which pulls the RPM way way down to the basement, usually below the power band. Through the traps at 0% or 1% slip. If left unlocked, slip is usually around 20% or even more.

A good non-lock looks totally different. Each gear change is well defined, running the engine up near its peak and then pulling it down 700 or 900 RPM, keeping the engine in the meat of it's power band the whole time. Each shift occurrs at a much higher MPH compared to the lock up due to the stronger coupling, putting each revolution of the engine to the tires which much better efficiency. Through the traps at 3% to 8% slip typical.

I have a PTC which is on the loose side of it's spec, 7.7% slip through the traps. It spools my combo extremely fast.

 

[jasjamz]

Come on gents! The Precision converter are great for 12 second street drivers with bolt on performance parts. I'm talking about the single disk at the moment. It will spool anything from stock all the way up to a 6262 or PT-51 Turbo on a stock motor. The come in at 2800@0-1 on a healthy engine and 3200@5 psi. This is for the one rated at 3200 stall. They will start showing sights of weakness in the 11's but when these came out for these cars an 11.50-11.0 TR was a bad boy with big bad parts and had a race type converter anyway. The multiple disk unit was an option but cost like $400+ more and rattled at idle like the bottom end had an issue. However you could lock it in 2nd or 3rd and push the power to it and still cruise the highway like a sticker as opposed to the Art Carr non lock screamer. The multiple disk were good to mid tens and could be serviced to bring the back to life after tons of passes locked on 11 second street strip cars. Locking single disk converters is not a good idea while WOT. If you have a multi disk and plan to lock it you already have a powerful engine and better have a worthy transmission in to handle it all so the stress it caused is not a huge concern. I see most damage when the chip commands it to lock at a predetermined MPH and it happens in the burnout box to sticky track rollout on a high speed burnout.

 

[KEVINS]

So a multidisc Vigilante LU Converter slips a lot, like in 1st and 2nd gear until it gets locked up in high gear? Is this typical?

ks

 

[bison]

So a multidisc Vigilante LU Converter slips a lot, like in 1st and 2nd gear until it gets locked up in high gear? Is this typical?

ks

If you're making any power it is.

 

[jasjamz]

Kevins, Look up Sweet6 on here. He has a 10 second car with one.

 

[BEATAV8]

The vigilante single disc in my wife's 87T slips 22% at the top of 3rd.

 

[jasjamz]

The vigilante single disc in my wife's 87T slips 22% at the top of 3rd.

Put a used Art Carr in it. Or $$$$

 

[Pronto]

[quote="BEATAV8, post: 3126557, member: 5122] A good non-lock looks totally different. Each gear change is well defined, running the engine up near its peak and then pulling it down 700 or 900 RPM, keeping the engine in the meat of it's power band the whole time. Each shift occurrs at a much higher MPH compared to the lock up due to the stronger coupling, putting each revolution of the engine to the tires which much better efficiency. [/quote]

I've got a question on that. How do you determine what your shift point should be? I know a bigger cam raises the engine power band and better heads allow more air to flow at that higher rpm. Is there a typical shift point that the usual combos like ie; ported irons/206 roller, ported irons/212, aluminums/ 212, aluminum/ 218 with a 28" tire?

 

[BEATAV8]

Put a used Art Carr in it. Or $$$$

it's too fast for me already!

 

[BEATAV8]

I've got a question on that. How do you determine what your shift point should be? I know a bigger cam raises the engine power band and better heads allow more air to flow at that higher rpm. Is there a typical shift point that the usual combos like ie; ported irons/206 roller, ported irons/212, aluminums/ 212, aluminum/ 218 with a 28" tire?

Typical healthy heads/cam combo should shift around 5800 to 6000. Higher if it's hotter combo, lower if it's not. Dyno data would be the best way to characterize the power band and select shift points to maximize area under the curve and identify the power ratio associated with before and after a given shift.

 

[Ttype6]

Why would someone choose a Non-LU coverter over a Vigilante LU? It seems to me that a LU would be much better on the topend since you can lock it up.

I did read things about the stall not being as high with a Vigilante LU. How much stall can Precision get out of one of these units?

KS

Which one do you currently have?

 

[KEVINS]

Which one do you currently have?

A few months ago I bought a new 2800 LU.
For what I do with the car I prefer a LU....at least for now. Given the info above I just wish a multidisc LU didn't slip so much...or make so much noise when ideling which apparently is another "feature" they have.

ks

 

[Quik Six]

The vigilante single disc in my wife's 87T slips 22% at the top of 3rd.

PTC 9.5 NL slips 4.5% turning 5750 RPM on 132 MPH run. Might have been better if the ring gear had a full set of teeth.

 

[Ttype6]

A few months ago I bought a new 2800 LU.
For what I do with the car I prefer a LU....at least for now. Given the info above I just wish a multidisc LU didn't slip so much...or make so much noise when ideling which apparently is another "feature" they have.

ks

It's the multi disks that rattle. Precision uses a number system to designate how slippery they are. I have a zero pump that I believe is advertised as a 3,000 to 3,200 stall speed which I think is silly because it will go much higher than that as the boost and power climb. I can easily see 4,500 rpm before I release the trans break.

The problem that I see when people talk about this verses that is that the goals/use of their car isn't clearly defied. Because of this you have one person in the conversation who has the goal of setting a new world record on his mind. He hasn't been told,nor has he asked,about the goals of the person who asked the question so they might not be on the same page.

You and I and many others will not go the NL way because we like to drive our cars on the street most of the time. For us,the only choice is single disk or multi disk. I don't know if I would go LU if my car was race only. Many don't. Red Armstrong runs high 8s at 150 mph and still uses a Vig Multi.

I've compared Powerlogger files of cars similar to mine and noted that their rpm was much lower than mine at any given mph once they were past first gear. First gear was very similar. I also noted that they never got past 5,200 rpm with motors that made max power at 5,800 rpm. Again,my motor would be revving much higher at any given mph,but my motor spent more time in the max power area and gained mph faster.

Yes, it slips a lot as the power goes up when it's unlocked. Not when it's locked. They both have pros and cons. They accomplish things in different ways. It's not a right or wrong thing. It's a choice. It's too bad that you got a single disk.

 

[BEATAV8]

PTC 9.5 NL slips 4.5% turning 5700 RPM on 132 MPH run. Might have been better if the ring gear had a full set of teeth.

My PTC slips close to 8% at 132mph. Love it love it love it. Need one for the wifey.

 

[Ttype6]

A few months ago I bought a new 2800 LU.
For what I do with the car I prefer a LU....at least for now. Given the info above I just wish a multidisc LU didn't slip so much...or make so much noise when ideling which apparently is another "feature" they have.

ks

I don't know how,but I though I read that you have a single disk. If you have a 5 disk,great! Again, the amount of slip is a function of the power produced and the stator used. The slip isn't necessarily bad as it allows the motor to rev into its power band. That's a good thing to a point. Eventually it would become a problem during a run if you didn't have the ability to lock it. If you have a 5 disk,you have the ability to lock it. The Vig is very heavy which should hamper the motors ability to rev fast. Again there are pros and cons to both yet both accomplish great things.