torque converter traffic response

[Nacho-RT74]

as many of you knows, trying to make some performance upgrade in my car with KB240 pistons, suregrip, 3:55, 280/474 cam ( what I hope will give me a nice iddle too because I'll keep my A/C working ), mill down heads and metalic head gaskets. Now about that averybody told me go with a higher stall converter to get the cam really working that I'll do, mostly sure 2400-2500 stall ( 175K Mopar one or similar ): I also have read with torque converter upgrade will get better throttle response and everything, but:

Does a higher stall change the low speed/RPMs response ior initial movement car ? I mean for example being on traffic and riding  from traffic light up next traffic light on a NORMAL speed in the city, just touching gas pedal to start the movement etc... Sorry a CHEBBY guy got me scared about higher stalll converter will make no move on car untill arrive to stated RPM.

Sorry the ignorance.   

[aifilaw]

a converter slips until it hits its stall rpm.
If you are driving at 25 mph in 2nd gear and your gearing is such that your engine is turning at 1500 rpm, and your stall converter stalls at 3,000 RPM... and you jam the gas halfway down... your car will not respond or accelerate (your engine will) anywhere near what it normally will until it hits 3,000 RPM.
Suppose you hit the gas all the way, and the car responds by down shifting, which puts the RPM's at 4,000 instantly and in 1st gear, then you will get an instant response, far more than what you would achieve with a manual transmission in regards to torque applied to the rear differential.

[John_Kunkel]

Converters can be built to be "loose" or "tight" in the normal driving range.

[Nacho-RT74]

so would it be kinda when you are releasing clutch pedal and press gas pedal untill engages tranny and engine for a perfect coupling without engine stall, on a manual tranny setup

I think maybe I must get a lower stall converter then to a better low speed and RPMs response then. I'm worried about that. Maybe the 166K specs one is a better choice if I go with this chart ( If I take the 383 cam values as example what is the closer to 400 )

Editing: and would it be matching the lower RPMs 993 stated response ( 2000 rpm ) with torque converter stall.

[Nacho-RT74]

Converters can be built to be "loose" or "tight" in the normal driving range.

How ?

[firefighter3931]

Converters can be built to be "loose" or "tight" in the normal driving range.

How ?

The Fin angles in the converter to a large extent determine the stall speed and "efficiency" of that particular unit. Converter's are one area you don't want to go cheap on....you get what you pay for. A smaller diameter converter that is tightened up ill be more efficient than a larger converter that is loosened up. What you want is an efficient converter that flashes high when you hammer the throttle. A good converter will behave much like a stock converter during normal driving conditions....you won't know it's there until you drop the hammer.

Buy a quality converter and you will be much happier. PTC, Turbo Action, Dynamic, ATI all make high quality street/strip converters. The MP stuff works ok but they're not that efficient. For the money a PTC 11in converter is tough to beat for a mild combo. 



Ron

[Nacho-RT74]

ok, yes I know about the fin angles what In fact I still debating on modify my actually stock one or get a new one, but right now I'm still debating about stall speed. You told me about 3500 rpms, but thats too long/high for regular traffic use if I will get engine geared at that point.

The Mopar performance chart I'm using is basically for reference. Is a good chart since they are linking cam lift with stall converter and General usage. I know I'm only basing on theory, but I have noticed mostly of you guys are forgetting I will dirve this car in the city.

I wish to give an example.. how much is the stall on a STOCK Hemi converter and how much is the lift/dur on a STOCK Hemi Cam. I know I'm far away of Hemi Compresion but is just a cam-converter relationship and driveability I want to get.

[Nacho-RT74]

BTW, sent an email to PTC ppl

[is_it_EVER_done?]

Does a higher stall change the low speed/RPMs response ior initial movement car ? I mean for example being on traffic and riding  from traffic light up next traffic light on a NORMAL speed in the city, just touching gas pedal to start the movement etc... Sorry a CHEBBY guy got me scared about higher stalll converter will make no move on car untill arrive to stated RPM.

Sorry the ignorance.   

A street performance type converter in the range you want won't have any effect on normal street driving. The more throttle you give it the more you will notice the increased stall (but not by much till you start reaching full throttle). Back in the really old days, we used to use 340, Hemi, and 383 HP converters (in that order of preference). A 340 converter behind a built 440 would stall at a bit over 3,000 RPM, but was not noticeable in normal cruising. The only downside was it was easy to burn them up.

You should probably add a auxiliary transmission cooler to compensate for the increased heat of the higher stall of whichever converter you chose.

[deputycrawford]

Natcho, I have a 9 1/2in 3500 rpm stall converter. It leaves a street light in traffic around 1800 rpms with light throttle. I can drive it all day with no problems. I mash the throttle and it goes to its advertised stall. I have a friend of mine the uses the 175K converter you speak of. He thinks it is hard to get it to use its entire stall speed. He really has to foot brake the car to get it to come up. He likes that. It makes it great for him on the street. An efficient converter will never be a problem on the street. If you want the 175K and it matches the cam, then use it.     

[Nacho-RT74]

So with a higher stall, not that much for a while I keep on street performance use as stated on chart, will allow me to start to move the car NORMALLY  kinda my stock torque converter... will be really a headache if I have to reach 2400-2500 RPMs if I want to START to move the car.

[deputycrawford]

     Yes, a correctly built converter will not show itself until the pedal is mashed. The rest of the time you will not notice it in there. Just make sure it matches your engine build. Over convertering a car will give it the feel you fear. Match it up and you will not have a problem.

[Nacho-RT74]

well, on that chart my 400 is not stated againts cam lift value spec, but if we compare cubic inches with a value between 383 and 440. 474 lift will use a 166K on a 383 and 145K on 440. So probably a most certain choose would it be 166K than 175K.

I'm expecting around 9.2-9.5 compression, so very close to both earliers 383/440 HP engines.

I'm also still expecting for PTC advice

[Nacho-RT74]

  Over convertering a car will give it the feel you fear. Match it up and you will not have a problem.

well on a majority opinion here I already overcamed LOL

[Nacho-RT74]

another way to get the answer I want to get:
With stock converter what I'm not exactly sure about stall speed, somebody told me around 1800, I'm in neutral at iddle, then gear the car to Drive and car start to moves AT IDDLE, no need to press gas pedal, so If I'm on traffic in fact I'll need to press the brakes to keep the car stopped. In fact on street with a light slope, the car is able to keep on place geared in D without brakes pressed.

I'll be able to have that with any performance torque converter ( talking about the examples I posted 166K and 175K ) like with the stock one ?

[Nacho-RT74]

again...with a higher stall converter will I be able to feel the car GEARED and ready to go at iddle like with the stock one ? or do I need to rev up the engine to feel the car geared ?

when I mean geared I don't mean LAUNCHED... I mean geared just to start to move GOOD in street like with the stock one.

Sorry I have been seartching all this time the right question to get the answer and maybe I have been around this stuff without get the RIGHT QUESTION I wanted to mean

[deputycrawford]

Nacho, the car will move in gear with no throttle input, with a higher stall, if it is the right one for the application. Again, you will notice almost no difference if you have the right converter. Let your cam dictate what converter and stop worrying. You are over analyzing this. You will be fine. You will laugh at yourself when you get it done and drive it.

[Nacho-RT74]

You are over analyzing this. You will be fine. You will laugh at yourself when you get it done and drive it.

Maybe you are right LOL maybe I'm being kinda stupid, but ppl down here keeps saying me car will start to move at stall speed so I need to rev up to stall to start movement, and in board opinions are above 2800, even 3500. So without ANYKIND of experience you could tell my doubts and fears.

Chart apparently dictates me 166K ( or similar not MP one ). Trying to get 400 in the middle of the line with 383 and 440 where 440 with 474 lift would use 145K and 383 166K

[firefighter3931]

Those charts should not be taken as gospel. I don't see how you can pick a converter based on valve lift 

A more accurate method would be to use the cam duration@.050 valve lift because that is what determine's the engine's powerband....not "total" valve lift. 



Ron

[Nacho-RT74]

Those charts should not be taken as gospel. I don't see how you can pick a converter based on valve lift 

I thought on that

[deputycrawford]

Natcho, just call a converter company with the cam specs. You will be fine.

[jg68]

I replyed over in the Perf. section on this converter issue.

Nacho, Don't freak out & stop listining to those guys who buy JUNK converters, call PTC, talk to either Kenny or Tim, tell them Joe Gallo sent you, i've used 2 of there coverters & was more then pleased with them, top Q stuff & the Flash stall was DEAD on with both.

PTC
Muscle Shouls, Alabama

256-383-6868 

[Purple440]

You are over analyzing this. You will be fine. You will laugh at yourself when you get it done and drive it.

Maybe you are right LOL maybe I'm being kinda stupid, but ppl down here keeps saying me car will start to move at stall speed so I need to rev up to stall to start movement, and in board opinions are above 2800, even 3500. So without ANYKIND of experience you could tell my doubts and fears.

Chart apparently dictates me 166K ( or similar not MP one ). Trying to get 400 in the middle of the line with 383 and 440 where 440 with 474 lift would use 145K and 383 166K

Nacho I was just messin around when I said 3500rpm stall.  I was saying it would be "fun"    but I wouldn't do it.  Sry to confuse the issue.

[Nacho-RT74]

don't worry, Ron was the first who said about 3500 stall and 3:91 gears...

[Purple440]

Really?  I guess I missed that.  Ron's response in the Performance section was:

PTC 11in 2800 stall....call Kenny at PTC and order it !

I was the one there that said 3500.  But whatever, if I were you I'd listen to Ron as he knows what he's talking about.

g/l