Drivetrain Questions and info regarding transmissions, clutches, etc.

Upgrade 5AT torque converter/stall? Possible?

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Feb 27, 2009 | 07:10 PM
  #1  
Red_G35's Avatar
Thread Starter
|
Registered User
iTrader: (8)
Joined: Apr 2007
Posts: 3,069
Likes: 2
From: Tulsa, OK
Upgrade 5AT torque converter/stall? Possible?

My friend has an ls1 camaro with a 3800 stall, he says it's the best upgrade for any auto. his car hauls ***. I did a quick search and didnt turn up lots of info on this.
Is this something available for our cars? If so, who sells them and what is recommended for a bolt on VQDE? Anyone know what the stock TQ converter is set at?
Thanks for any helpful info.
 
Reply
Old Feb 28, 2009 | 12:33 AM
  #2  
Dsskyline's Avatar
Registered User
iTrader: (15)
Joined: Oct 2003
Posts: 2,729
Likes: 84
From: Owings Mills MD
I think the stock converter is set between 2400-2600 stall (I could be wrong). RCdash is selling his 3600 stall GTM converter.

I had mine modded by edge racing in ca. I think Edge Racing, GTM and Pro Torque are the only ones that mod our converters.

I heard a high stall one takes some getting used to on our car especially if it's your DD.
 
Reply
Old Feb 28, 2009 | 01:22 AM
  #3  
Red_G35's Avatar
Thread Starter
|
Registered User
iTrader: (8)
Joined: Apr 2007
Posts: 3,069
Likes: 2
From: Tulsa, OK
Thanks for the info.
Do you know of some online retailers that sell these parts? Websites?
 
Reply
Old Feb 28, 2009 | 01:40 AM
  #4  
rcdash's Avatar
Registered User
iTrader: (4)
Joined: Oct 2004
Posts: 2,173
Likes: 32
From: NC
As DSSkyline mentioned, Edge Racing (builds for GTM I believe) and ProTorque are the two shops that have lots of experience with our TC.

The stock stall according to the FSM is 2600-2900 but Andre at Edge told me no way, that is only with cavitation. His words - didn't ask for explanation. He said true stall is around 2200. Anyway, I thought my GTM TC was going to be 3200 but what I didn't know is that that depends on the input torque going through it. The more engine torque, the higher the stall. So with 400 ft lbs, I was stalling around 3600-3800. At stock tq levels, it may really be 3200. It is for sale - all internals are upgraded from the lock up clutch to the fins, stator, etc. Will be in Marketplace by Sun. I moved back down to a 3000 stall converter rated at 400 ft lbs torque. All generate lots of heats, so a trans cooler is highly recommended.
 
Reply
Old Feb 28, 2009 | 02:08 AM
  #5  
Red_G35's Avatar
Thread Starter
|
Registered User
iTrader: (8)
Joined: Apr 2007
Posts: 3,069
Likes: 2
From: Tulsa, OK
Very interesting, thanks for the info. Why is this not a popular mod amongst the 5AT crowd? Anyways, thanks for all the input. Did you run a trans cooler?
 
Reply
Old Feb 28, 2009 | 11:31 AM
  #6  
DaveB's Avatar
Registered User
iTrader: (9)
Joined: Aug 2003
Posts: 6,573
Likes: 72
From: Kansas City
Originally Posted by Red_G35
Very interesting, thanks for the info. Why is this not a popular mod amongst the 5AT crowd? Anyways, thanks for all the input. Did you run a trans cooler?
The stock TC has a legit stall of around 2500-2700rpms. GTM is smoking crack if they think the OEM TC only has a stall of around 2200rpms. The reason I say that is can break stall to around 2400rpms and just above that the tires start to let go. On full 2400rpm stall launch, I can see 2600rpms just before the car starts to roll. If the stall was a mere 2200rpms, you would barely be able to brake stall to 2000rpms.

A TC is simply a torque multiplication device. The higher the stall speed, the greater the torque multiplication. It's much like launching a manual tranny at a higher rpm. Instead of a direct connection to the tranny, the auto uses a fluid connection. In simple terms, the TC operates like two fans. Visualize two fans facing each other. One is on and the other off. The one on is connected to the motor. The other is connected to the drivetrain. As you raise the rpm, the on fan starts going faster and faster and the off fan starts to spin. Instead of air being the medium, tranny fluid is. Before long, the off fan is moving as fast as the on fan. That's the stall speed. Aftermarket TCs can typically increase torque multiplication by 2.5 to 3 times. That means launch torque could be well over 800ft/lbs on the initial hit (this isn't sustained though). Having a well matched TC can really give an auto a HUGE advantage on launch. Huge. The other advantage is the auto launch doesn't shock the drivetrain remotely as bad as that of a manual because you can preload the drivetrain by braking stalling. This removes driveline shock.

The downsides to an aftermarket TC include:

1) laggy around town driving because the TC has more slippage before the drivetrain connects.

2) high tranny temps because of more slippage. An additional tranny cooler is needed. Contrary to belief on this forum, the 5AT has a stock tranny cooler, but it's not up to the task of cooling fluid from an aftermarket TC.

The reason aftermarket TCs haven't caught on here is because of expense (product and install) and the fact that to most people, TCs are voodoo.

If you want to take full advantage of an NA 5AT, you need the following:

1) Aftermarket TC (around 3000-3200rpms)
2) Gears 3.7s
3) Cams
4) Rods, valvesprings, oil pump
5) Cosworth intake manifold
6) Longtube headers
7) Tuning

That would be an absolute killer 1st gen sedan and easily a low low 13 second ride. It would reliably rev to 7500rpms while making power to that point.
 
Reply
Old Mar 1, 2009 | 10:27 PM
  #7  
Tollboothwilley's Avatar
Former G35driver Vendor
iTrader: (32)
Joined: Jan 2008
Posts: 3,684
Likes: 28
From: Vegas
that setup would cost a good $8-10K...and I bet you'd be in the high 12's

it would be a great setup
 
Reply
Old Mar 1, 2009 | 10:34 PM
  #8  
urban's Avatar
Registered User
iTrader: (29)
Joined: Jan 2004
Posts: 3,744
Likes: 72
From: California
I have the GTM upgraded tranny which consists of the Edge racing TC and not sure who did the VB but mine is holding 550ft trq for over 50,000 miles so far.

Mine did not cost anywhere near 8-10k
 
Reply
Old Mar 1, 2009 | 10:43 PM
  #9  
Tollboothwilley's Avatar
Former G35driver Vendor
iTrader: (32)
Joined: Jan 2008
Posts: 3,684
Likes: 28
From: Vegas
um, that was in response to the thread above...please read that and see where the 8-10K would come from....
 
Reply
Old Mar 1, 2009 | 10:55 PM
  #10  
rcdash's Avatar
Registered User
iTrader: (4)
Joined: Oct 2004
Posts: 2,173
Likes: 32
From: NC
Originally Posted by Red_G35
Very interesting, thanks for the info. Why is this not a popular mod amongst the 5AT crowd? Anyways, thanks for all the input. Did you run a trans cooler?
I definitely run a trans cooler but with the very high stall converter I had initially, running in the mountains was still a problem (temps would exceed 250 degF; not that I knew what stock temps were but that seems high even for the synthetic ATF we use). I would recommend the more expensive cooler with the fan on it, particularly if you cannot place the trans cooler directly in the path of airflow.

Now regarding the other posts, take everyone's advice on these forums with a grain of salt (including mine of course) . GTM isn't smoking crack as DaveB reports. And it wasn't GTM that said the stock stall is 2200. It was Andre at Edge Racing, a man that has designed torque converters for quite some time by all reports. He also said that the stall may be higher with cavitation, something I did not ask him about because he finds it an undesirable design characteristic and removes it from all of his upgraded converters. Once you start researching into torque converters you realize that there are different ways of measuring stall, hence some of the variability associated with assignment of a single number. Further the actual stall (however you decide you're going to measure it) is a function of the input torque. The higher the engine torque the higher the TC stall, for the same exact converter with the same physical characteristics. So what does this mean in daily driving? A 3600 rpm stall converter at 300 wtq will stall much lower at only part throttle. It's not as though the car doesn't start moving until rpms hit 3600.

It is true that a higher stall converter feels less "direct" than a lower stall converter, but a higher stall converter also has less of that "bog" when you get on it. There are some trade offs. The biggest one is heat and you will want an aftermarket transmission cooler. That said here is the breakdown for upgrading a TC:

Upgrade your TC to a higher stall and strengthen internals to handle higher torque - $400 - $600 (I think you can get a used core for $200 if you don't want to modify yours)
Transmission cooler - $80-$100 ($220 for the one with the fan)
Cooler install - $100 (you can do this on your own if you've got basic tools).
TC install - $500 (requires dropping the transmission - this is a quote from an Infiniti dealer. Forged Performance charges about the same)
ATF Fluid - 10 qts ($80; expensive fluid!).

In terms of performance gains, a torque converter upgrade is one of the best bangs for the buck as it helps the car the most in the launch which is a key component of a good 1/4 mile result.

Gears, VB, TC - are the big 3 I would do while NA. If you think you might go FI, I would skip the gears, but the VB and TC would continue to serve you well.

Good luck.
 

Last edited by rcdash; Mar 1, 2009 at 11:02 PM.
Reply
Old Mar 1, 2009 | 10:58 PM
  #11  
rcdash's Avatar
Registered User
iTrader: (4)
Joined: Oct 2004
Posts: 2,173
Likes: 32
From: NC
Originally Posted by Tollboothwilley
um, that was in response to the thread above...please read that and see where the 8-10K would come from....
The 8-10k is still way off to properly implement a TC, which is the topic of THIS thread.
 
Reply
Old Mar 1, 2009 | 11:04 PM
  #12  
urban's Avatar
Registered User
iTrader: (29)
Joined: Jan 2004
Posts: 3,744
Likes: 72
From: California
My response was to what you can do to the NA 5AT TC and VB so that is what I did, anyone who spends 8-10k on just upgrading a 5AT tranny is out of their mind, especially when people have done and tested this and have shown it can handle XX amount of power.

Just because I am FI does not change what can be done to the tranny.

I also have an oil and tranny cooler to stave off heat.
 
Reply
Old Mar 1, 2009 | 11:10 PM
  #13  
rcdash's Avatar
Registered User
iTrader: (4)
Joined: Oct 2004
Posts: 2,173
Likes: 32
From: NC
Originally Posted by urban
My response was to what you can do to the NA 5AT TC and VB so that is what I did, anyone who spends 8-10k on just upgrading a 5AT tranny is out of their mind, especially when people have done and tested this and have shown it can handle XX amount of power.

Just because I am FI does not change what can be done to the tranny.

I also have an oil and tranny cooler to stave off heat.
Exactly! How did installing cams and long tube headers and all that other crap (rods? LOL) become a part of this TC thread?
 
Reply
Old Mar 1, 2009 | 11:14 PM
  #14  
urban's Avatar
Registered User
iTrader: (29)
Joined: Jan 2004
Posts: 3,744
Likes: 72
From: California
Originally Posted by rcdash
Exactly! How did installing cams and long tube headers and all that other crap (rods? LOL) become a part of this TC thread?
Speaking of cams, that is what's next on my list..lol
 
Reply
Old Mar 1, 2009 | 11:38 PM
  #15  
rcdash's Avatar
Registered User
iTrader: (4)
Joined: Oct 2004
Posts: 2,173
Likes: 32
From: NC
Originally Posted by urban
Speaking of cams, that is what's next on my list..lol
You should go to the CAM thread - I'm sure you'll find it entertaining.
 
Reply


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 08:55 AM.