I'm not really planning on purchasing a torque converter in the near future, but was just more curious as to how it increased performance. does it just make the engine get the power to the wheels quicker, or does it actually incease rwhp by incresing drivetrain efficiency. can someone help me understand!

 

If you have ever driven a manual car then you will know the feeling a TC makes to an auto.
In a manual you can let the clutch out early and then boot it for a slow take off - or give it some revs and then let the clutch out for a fast take off.
Same power in both cases.
Fast take off with high revs.
Slow take off with low revs.
A modded TC is like taking off with an extra 550 revs before letting the clutch out - you take off faster.

Once you are cruising - no difference.
Taking it easy - no difference.
Full throttle take off is the only difference - the engine gets an extra 550 rpm and you take off faster.

Just like giving some revs to a manual car and then letting the clutch out.

There is no need to by an expensive TC sprayed pink. A good trans place will take your trans out, full service, modify your TC with an extra 550 rpm, fit an trans oil cooler and refit the whole lot cheaper than buying a "performance pink" TC.

If you really want the pink colour then perhaps you can ask the Trans shop to spray paint it for you in pink instead of blue before they refit - should only add $5 to the price.

 

Speaking of the price, how much would it cost for the torque converter and the labor required to mod and reinstall it?

 

http://www.users.bigpond.com/pgscott.../autotrans.htm

 

I have read several posts, about this, and I am still a little confused. Should I get a Dragon, or a rebuild TC i.e. I think it is Precision Industries. Other then the fact, that you need to send in the TC for them to rebuild it, I dont see any difference between the two. Is their anyone who has a side by side comparison of the two TC. Please Help

Thanks

Vaki2

 

When I got my PI converter (the one that Swift sells) It was considerably more heavy duty than the factory unit- quite obvious just by looking at it. Even the Lexus tech said that he had never seen such a well built TC (at least it made me feel good). The PI unit was smaller though.

I can not say which is better, but the PI unit was designed from the ground up to be an extreely heavy duty TC for racing or heavy towing applications. The stock converter was not. I doubt that just increasing the stall of the stock converter will give you the same product dependability and reliability; but to each his own. I looked into having my OEM TC modified, but most shops told me the stock unit couldn't compare to a well built performance unit. Upon saying that they were losing money since I was going to pay them to do the work, but they were being honest, . Instead, I bought the PI unit and had the dealer install it. Mental note, never let the dealer install it - its a do it yourself job.

After having it installed, the car is a whole new car now, and I would reccomed that everyone do this mod. I mean Lexus should have the newer models come factory with the higher stall. The enhancement is that noticable.

Reguardless of aftermarket or just modding the original; either way, just get it done.

 

Anyone else here just modify the stall speed on their OEM TC? Results?

 

My car has 150K. Runs fine. I went to a trans shop and ask them how much for them to put the TC in, and the guy start talking about, with that kind a mileage you may want to do a complete tranny service/rebuild, because you may start breaking things in the tranny. Has anyone put in the PI TC in on a high mileage car, and what is the results?

Thanks

 

Guys,

I am trying to understand "stall speed" a bit better. Would that be the RPMs when I come to a stop but the car is still in drive?

If so, my car idles at about only 500 RPM at a stop. When I am seeing discussion of 2500 RPM stall speeds it makes me think that this would be a bit loud at a stop and just while warming the car up in the morning. Is this true? Also, does it have any effect when getting the car smogged (I live in CA)?

Thanks,
Ryan

 

Ryan,

No, the RPM should not change. The "stall speed" means the RPM at which the TQ fully locks up. So from the dead stop when you punch it the car would jump quicker to the useful RPM range, in the cost of additional slippage.

Can somebody correct me if I'm wrong?

 

Stall speed in real world terms is basically how much rpm you can build with the engine while the brakes are applied and not spin the rear tyres. Stall speed is affected by several things, including the torque of the engine, the tyres being used, temp of track/street surface, etc. This is why most converters are given a range, i.e. 2200-2500rpm stall speed, and if a manufacturer or vendor says he can tell you the exact stall speed of his unit without even knowing the output of your engine, I would be suspicious. Flash stall is the rpm the converter will reach before engaging when you're just mashing the gas from a stop, and is better for comparison since it's affected by less variables. There are many things to know when talking converters, and a good understanding of hydraulics and fluid dynamics in general is always helpful, but basically a higher stall or 'looser' converter will allow the engine more chance for torque multiplication before you actually get going. As far as how much stall is considered streetable, that depends on the individual, one of my T-Type Turbo's had a built BOP TH350 with over 4000 stall, it was a hump sometimes, but that's the price you pay to be able to drop people's jaws when you get the left frt wheel off the ground on the street on a DOT. For the SC, you'll want to look for 2600-3000 stall, I wouldn't go past that unlesss you're running a turbo large enough to require a small converter to spool it.

- Jon

 

Jon,

Thanks so much - you kick a$$. Let me see if I really understand.

1) At stop light in drive, foot on brake, no foot on gas - RPM on tach would show "flash stall?"

2) At stop light in drive, foot on brake and foot on gas - the highest RPM I can reach by increasing the gas until the car stalls would be the stall speed?

If the above understanding is correct, then:

1) Is the flash stall changed with a new TC?
2) Do I have to "load up" the transmission with foot on brake and gas to really benefit from the TC or can I just hit the gas and see a big difference?

Thanks,
Ryan

 

No - Thats your idle rpm in gear. Hit the gas ; and the rpm at which the car starts to move is the flash stall.


No, if the car stalls; you need to get it looked at (lol). Foot on brake, and foot on gas - increase gas till the car inches forward or starts to spin the tires. Thats the stall speed.

Yep! Its quite noticable w/ the new TC BTW. Its hard to really understand the flash stall untill you drive a car w/ a higher stall TC.

Just hit the gas and watch the smile spontaniously form on your face. You can load up the transmission (power brake it) if you want, but you really just cook the tires doing that. The better TC will flash as high or higher than the factory stall speed, so you will not need to load the transmission up- it kinda does it for you. Just hit it and go!!!!


No prob - Keith

 

Keith,

Great answers - just what I needed! This TC really sounds like it kicks a$$!

Thanks,
Ryan

 

Thx Keith.