Question for A4 performance gear heads...
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 7,155
Likes: 154
From: The Arid Sunny Desert
Question for A4 performance gear heads...
If you guys had the choice of swapping gears or torque converters, but not both, which would it be and why. I am trying to understand the driveability issues between these two choices. For example how would a small stall/big rear differ from a high stall/low rear & visa versa. It seems that I will stay with my PT 2400 converter & 3.90 rear for now because the car should act more like stock from launch. 
Any help would be appreciated.
Any help would be appreciated.
Le Mans Master
Joined: Nov 2000
Posts: 7,294
Likes: 1
From: Coral Springs Florida
Since you already have the 3.90 rear then I would go with the T/C..maybe a YANK SS3800 or even a YANK Pro Thruster 4000
I'm running a 3.73 / PT4000....Nasty at the track and OK around town. I'll assume you have already invested in a Trango shift kit
...If not...What are you waiting for...DO IT!!
Her's a video of one of my last runs at the track with the combo..
http://www.mydocsonline.com/pub/vstella/1090moroso.mpg
I'm running a 3.73 / PT4000....Nasty at the track and OK around town. I'll assume you have already invested in a Trango shift kit
...If not...What are you waiting for...DO IT!!Her's a video of one of my last runs at the track with the combo..
http://www.mydocsonline.com/pub/vstella/1090moroso.mpg
Drifting
Joined: Jan 2004
Posts: 1,661
Likes: 13
From: Knoxville TN
Question for A4 performance gear heads
Since you have the 3.90s, either the SS3800 or the PT4000 are great convertors, it just depends on your taste. With a higher stall speed, your car will rev higher while you are changing gears. With the 2400 stall you are probably reving to about 2000 between gear changes while driving around town. With one of the above mentioned convertors this would be about 2800 rpms. On the highway it should be the same as what you have now. On the track it will DRASTICALLY help your times.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 7,155
Likes: 154
From: The Arid Sunny Desert
Originally Posted by DBN
Since you have the 3.90s, either the SS3800 or the PT4000 are great convertors, it just depends on your taste. With a higher stall speed, your car will rev higher while you are changing gears. With the 2400 stall you are probably reving to about 2000 between gear changes while driving around town. With one of the above mentioned convertors this would be about 2800 rpms. On the highway it should be the same as what you have now. On the track it will DRASTICALLY help your times.
Team Owner
Joined: Apr 2001
Posts: 26,794
Likes: 614
From: Elmhurst, IL (West Suburb of Chicago) & Home of MEGA Horsepower
St. Jude Donor '06
I've driven a PT 4000 and 3.73s for a long time in my 427 car and it hits off the line like a sledgehammer but if your not concerned about getting the best 1/4 mile times as possible and want to maintain as much of a stock feel on the roads then i say save your $ and be happy with what you got!! If on the other hand your lookig for your car to go 0 to 100 mph by a few tenths faster than it does now and lookig to squeeze as much out of your car as possible from accleration from a standtstill then go with the PT 4000 or Yank SS 3800. It seems from what your saying however you should stay with what you have although a higher would probably not feel much looser to you on the street, as the bigger numeric 3.90 gear helps offset the loose feeling that a higher stall converter give you!!! Hope this helps!!!
For what its worth on my new daily driver 02 A4 coupe i am going to 3.73 gears and staying with the stock converter as i a not looking for the best drag times possible and am more concerned about reliability and not jeopardizing my extended warranty!!!
If on the other hand your lookig for your car to go 0 to 100 mph by a few tenths faster than it does now and lookig to squeeze as much out of your car as possible from accleration from a standtstill then go with the PT 4000 or Yank SS 3800. It seems from what your saying however you should stay with what you have although a higher would probably not feel much looser to you on the street, as the bigger numeric 3.90 gear helps offset the loose feeling that a higher stall converter give you!!! Hope this helps!!!For what its worth on my new daily driver 02 A4 coupe i am going to 3.73 gears and staying with the stock converter as i a not looking for the best drag times possible and am more concerned about reliability and not jeopardizing my extended warranty!!!
Last edited by Mopar Jimmy; Sep 13, 2004 at 11:59 PM.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 7,155
Likes: 154
From: The Arid Sunny Desert
Originally Posted by Face
Don't forget, a high stall converter will also help you from a roll, and on top end.
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Le Mans Master
Joined: Sep 2001
Posts: 8,840
Likes: 43
From: State of Confusion.
Originally Posted by Pewtavert
Then what exactly is the downside to a high stall converter and why would anyone install a low stall converter such as my PT 2400? The way it is being explained to me is that a high stall converter will suffer as you approach top end and is mainly for drag applications from a dead stop.
Converters also make heat, which kills transmissions, so get a cooler too. It shouldn't make that big of a difference with a smaller converter, but with a bigger one, a cooler should be added to the list of necessary items. Take some rides in cars that have converters, and see how they feel to you. I don't track my car, and really like my converter, but we can't tell you what level of driveability is bearable for you. Good Luck!
Melting Slicks
Joined: Dec 2003
Posts: 3,315
Likes: 17
From: Near Jacksonville Fl.
Originally Posted by Pewtavert
Then what exactly is the downside to a high stall converter and why would anyone install a low stall converter such as my PT 2400? The way it is being explained to me is that a high stall converter will suffer as you approach top end and is mainly for drag applications from a dead stop.
Besides the loss of fuel milage they also have another downside, they produce more heat and are a torque mutiplier so the life of your A4 will be shortened considerably.
If your a drag racer or like a lot of street action go for the higher stall.
Frankly IMHO 3.42's and a stock converter are the perfect combo for the street with the stock tires. Since I've added FI and a few other goodies there is no traction anyway off the line.
So I have kept the stock tires for the fuse in the driveline.
Le Mans Master
Joined: Aug 2000
Posts: 5,294
Likes: 2
From: Suffolk, Long Island NY
A high stall converter WILL increase your top end. It keeps your engine in the powerband the whole time, so your motor won't bog down when you upshift, which is especially important with a large cam. Plus most aftermarket converters weigh significantly less than the stock unit.
I took my first *** bike in a top end race the other night, was a great feeling.
I took my first *** bike in a top end race the other night, was a great feeling.
Melting Slicks
Joined: Dec 2003
Posts: 3,315
Likes: 17
From: Near Jacksonville Fl.
Originally Posted by Face
A high stall converter WILL increase your top end. It keeps your engine in the powerband the whole time, so your motor won't bog down when you upshift, which is especially important with a large cam. Plus most aftermarket converters weigh significantly less than the stock unit.
I took my first *** bike in a top end race the other night, was a great feeling.
I took my first *** bike in a top end race the other night, was a great feeling.
Higher stall speed = slip of the fluid coupling (AKA torque converter).
I do agree with you about the importantance of it with a large cam since they typically lack bottom end tq.
Another issue is the apparent lack of understanding of stall speed.
What is a 2400 RPM stall in one car may not be the same in another, it's all related to engine torque and vehicle weight.
A more correct way to look at converters is the "stall torque ratio" this can be applied from one application to another. Apples to apples, not apples to oranges....
Safety Car
Joined: Aug 2000
Posts: 4,154
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From: Murphy TX
Cruise-In II Veteran
People sometimes get confused about the term "locked". "Locked" should mean "the TCC is engaged and slip is at a minimum." (We'll ignore the fact that it's not exactly "no slip" to simplify things.) When this is true, they're all pretty much the same.
That is distinct from when the converter is unlocked but well above stall ratings where there is no further torque multiplication. They are not all the same. One of the things you're interested in here is the efficiency of the converter. Typically, high stall stall converters are not as efficient as low stall converters, and that's not necessarily a bad thing - think about shift extension. Just one more nuance to picking the right converter.
That is distinct from when the converter is unlocked but well above stall ratings where there is no further torque multiplication. They are not all the same. One of the things you're interested in here is the efficiency of the converter. Typically, high stall stall converters are not as efficient as low stall converters, and that's not necessarily a bad thing - think about shift extension. Just one more nuance to picking the right converter.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 7,155
Likes: 154
From: The Arid Sunny Desert
What I'm trying to figure out is if I line up next to a car equipped like mine except for the converter stall what will happen. If I line up next to a car with a 3500 on up stall converter what will happen? If we're both doing 50 and punch it what will happen? Will they jump out on me and then I will catch up? What advantages are there with my smaller stall converter, if there are any except for tranny life? Assume large 3.90 gears for this example.
Le Mans Master
Joined: Aug 2000
Posts: 5,294
Likes: 2
From: Suffolk, Long Island NY
Originally Posted by Pewtavert
If I line up next to a car with a 3500 on up stall converter what will happen? If we're both doing 50 and punch it what will happen? Will they jump out on me and then I will catch up?
