Whats the best stall for me?

[Nick90vetteguy]

Hey guys so Ive been looking into torque converters and not sure what to look for, Im using my stock cam, stock gears(2.95), few bolt ons, now i really dont know how these work but can somebody briefly explain how they work. Im looking something that can help me with a nice hard launch.

thanks

 

[boomdriver]

Hey guys so Ive been looking into torque converters and not sure what to look for, Im using my stock cam, stock gears(2.95), few bolt ons, now i really dont know how these work but can somebody briefly explain how they work. Im looking something that can help me with a nice hard launch.

thanks

BIG points for being honest !

most folks do not understand what "stall speed" means and how it effects a cars performance.

All SP means ...is the approx point in the RPM range where the torque converter grabs 100% onto the engines spinning shaft...holding that to transmit the power thru the gears to the wheels. Its not about shifting.....its about transmitting ALL the power thru the drive train and not letting any slip by.

So........
wheres the power at? 1500 to 5000 approx? torque starts to rise quickly at 1500, peaks at 3500...levels out then starts to fall toward 5000?
That means you want the upshifts to happen so that the next gear falls into a good point in the "power band". Having a torque converter let the engine spin up past peak power before locking is wasting it and wasting usable RPM. If the engine is pulling hard at 2000...you don;t want to loose a single HP thats not being held by the TC. And you want the gears to run out and upshift so the next higher gear drops right into good power,locks but still has somewhere to go.
It does no good to lock at 4000 when there is good power at 2000...all the power from 2000 to 4000 was wasted when it was passed up by the TC because it can;t grab it all until it hits its designed RPM.

A TC that grabs and locks in too soon, causes the engine to struggle and wait for the rpm to reach the power band, so that means a slower longer run out of each gear. When it locks in too late, you are not getting all the available power to the wheels.

I know a doz guys that love to talk about their 3500 stall speed torque converter that they paid a fortune to have installed, and cannot explain why or how it benefits their car. Installing a high stall TC in a car that does not have a handful of mods and a dyno sheet to SHOW where the power really is, is pointless.
The ONLY guy that benefits from that is the guy selling 3500 stall speed torque converters.

Your stock converter locks in just a little way over idle to help keep a positive drive to the wheels for fuel efficiency AND because your motor has tons of low end torque to pull the gears. Unless you cam it to death, and mod that engine to where the power don;t even start until 3500 rpm, leave it alone. Spend the money on something that WILL do some good.
If anything, if you are planning lots of time at the strip, then with the near stock configuration of the motor you would only need a slightly higher stall speed..no more than 2000, because theres all that usable low end torque to run the car thru the gears. If you;re driving on the street alot, or auto-crossing then you want a low stall TC to be able to grab asap so rpm, fuel and time is not wasted. The idea is to grab that power as soon as its available, not to go past that, or too far under it. Thats why a dyno sheet is a must have before even thinking about a new TC.

Let the TCC does its job. Leave the trans in 3rd for a stick shift feel and low rpm lock up and do not upshift to 4th (OD) until you're wayyyyyyyyy up there where the power falls off. When upshifting manually, you want to be locked in and know at what point is best to grab the next gear, since it IS locked in, you get all the power thats there. Hi stall TC are for cars that spend their day going from idle to redline...

My eng for example, has a fairly straight line power band with a good step at 3000... right around 1500 it jumps up pretty quick, then at 3000-3200 it has a BIG surge up and the line goes straight upward from there until drop off after 5000. If I were trying to launch this thing everyday, I might want a TC that allowed the engine to wind up to 3000 before locking in so it grabbed the max pulling power with some room to wind up. If the eng is not locked to the trans thru the TC it can wind up faster and reach that point where the good power begins. Thats where you want gear change and lock up.
BUT.....because I have to drive this thing on the street and never see the strip, so I'd rather have the efficient transmission of the power to the wheels, which means better MPG and a more drivable set up thats not winding up too far wasting my time and gas by passing up half the rpm before it locks in.

Hope this helps. I'm sure someone else can do a better job of describing what stall speed really is/does...or be able to use better examples. Basically its the auto-trans equivelent of letting the clutch slip until the eng reaches that rpm it was designed for.

 

[Hib Halverson]

If your car has a stock or near stock engine and you have 2.59 gears, don't install a high-stall torque converter. There will be no performance advantage and perhaps a performance loss. You also may see a decrease in fuel economy.

 

[Nick90vetteguy]

Thanks for your help guys, so anything around 2,000 ill be ok, right? :ugh

 

[Hib Halverson]

Thanks for your help guys, so anything around 2,000 ill be ok, right? :ugh

I don't know what the stall speed of the OE converter in a 90, is but that's what you want.

 

[boomdriver]

I don't know what the stall speed of the OE converter in a 90, is but that's what you want.

Its not much....I've seen it but cannot remember exactly what it was. Seems like 1400 or somewhere just a little over idle so the TCC could lock in and operate. Later yrs used a 2000. I think the difference was in the rears and over-all final drive ratios.

 

[boomdriver]

Thanks for your help guys, so anything around 2,000 ill be ok, right? :ugh

You missed the point... :ugh



2000 ONLY IF you;re going to be trying to run that car in that configuration at the strip and NOT driving it on the streets as a DD. 2000 is just an example of what might work for a car thats going to spend its very short life at the strip. NOT on the street. A high stall converter on the street is USELESS as a DD.

If it IS a DD, keep the stock converter, whatever it is. STOCK.

 

[Nick90vetteguy]

gotcha thanks boomdriver and Hib!

 

[boomdriver]

gotcha thanks boomdriver and Hib!

I just don;t want to see you waste your money on things that don't help or do anything to help

If I had a $1 for each BS performance aftermarket HP adding shiney POS that I bought for my Corvettes in the last 24 yrs...I'd be extremely well off....

 

[Nick90vetteguy]

Yea I guess ill leave my stock stall, Ive just been thinkin about what i can do to get a nicer launch i guess i should start being thankful what i have :ugh Thinkin about cams agian(more realisticly and costly) looking into ZZ4 cams with 1.6 RR. Instead a LT4 cam, I just feel the need to modify it until i feel satisfied.

 

[boomdriver]

Yea I guess ill leave my stock stall, Ive just been thinkin about what i can do to get a nicer launch i guess i should start being thankful what i have :ugh Thinkin about cams agian(more realisticly and costly) looking into ZZ4 cams with 1.6 RR. Instead a LT4 cam, I just feel the need to modify it until i feel satisfied.

If you want to do some REAL upgrades that are economical and yeild real results...hers a list..its still gonna cost $1000+, but it works.

exhaust/headers $600

K&N filter w/open air box lid $75

New injectors a size up with an adjustable fuel regulator $350 for all.

SLP runners, then port/gasket match the runners to the plenum and base plate. Cut plenum and match T-body to plenum. Open the base plate ports but ONLY if you can CC the runners to keep them consistant. $350 runners, $300-$500 for the porting

1.6:1 roller rockers $250 +-100 depending on mfg/alum or steel
Cam (cost of is cheap BUT theres all the other stuff that has to be done to pull a cam.

custom chip,. lower fan start up, shoot for an op temp of around 190-200. $150-$300 (last thing to order)

SOME ADDITIONAL GOODIES:

HD all aluminum radiator $250
cast impeller water pump $150
52mm throttle body $350
383 stroker kit ??? crank/rods <$1000

If you only do the things underlined you will get a much better throttle response, more power and a faster revving motor thats still reliable and street friendly as a DD. Simply cleaning up the mass produced intake will do wonders.

have fun, its only money !

 

[Nick90vetteguy]

If you want to do some REAL upgrades that are economical and yeild real results...hers a list..its still gonna cost $1000+, but it works.

exhaust/headers $600

K&N filter w/open air box lid $75

New injectors a size up with an adjustable fuel regulator $350 for all.

SLP runners, then port/gasket match the runners to the plenum and base plate. Cut plenum and match T-body to plenum. Open the base plate ports but ONLY if you can CC the runners to keep them consistant. $350 runners, $300-$500 for the porting

1.6:1 roller rockers $250 +-100 depending on mfg/alum or steel
Cam (cost of is cheap BUT theres all the other stuff that has to be done to pull a cam.

custom chip,. lower fan start up, shoot for an op temp of around 190-200. $150-$300 (last thing to order)

SOME ADDITIONAL GOODIES:

HD all aluminum radiator $250
cast impeller water pump $150
52mm throttle body $350
383 stroker kit ??? crank/rods <$1000

If you only do the things underlined you will get a much better throttle response, more power and a faster revving motor thats still reliable and street friendly as a DD. Simply cleaning up the mass produced intake will do wonders.

have fun, its only money !

See what I have now is a 58mm throttle body(meaning to replace it with the stock), heddman long tube headers, mr gasket 160 degree thermostat, Jet Stage II chip, rebuilt 700r4 tranny, K&N intake, 24lb injectors(Trick flow) summit T56 aluminum heads with 58cc chambers, and mufller eliminators with high flow flowmaster cat thats about it

 

[aklim]

Crazy way of doing it is this. Call Precision Industries. They to make a TC for us. So, buy it and use their recommendation. If you don't like it, send it back and they will re-stall it for you once within 2 yrs.

 

[boomdriver]

See what I have now is a 58mm throttle body(meaning to replace it with the stock), heddman long tube headers, mr gasket 160 degree thermostat, Jet Stage II chip, rebuilt 700r4 tranny, K&N intake, 24lb injectors(Trick flow) summit T56 aluminum heads with 58cc chambers, and mufller eliminators with high flow flowmaster cat thats about it

get rid of that 58mm throttle body until you find about another 50 cubic inches, and your car will run like it has more hp....

You don;pt have the mods to support that much air. Maybe a 52....a 58 even has a warning in most ads...."Do Not use unless your engine is heavily modified"

Your engine works entirely on some principles involving vacume and expanding/accellerating air or compressing decellerating air charges. Unless your motor can suck harder than the T-body can flow....you loose HP and especially torque.

Mines bored, ported and a handful of other things and I would'nt use a 58 ..... :ugh

 

[Nick90vetteguy]

Ok thank you agian for the heads up, how about a cam? Like I said I was thinkin about a Z4 will that work with teh stock penelum?

 

[joe paco]

Ok thank you agian for the heads up, how about a cam? Like I said I was thinkin about a Z4 will that work with teh stock penelum?

go for it, Nick! I'd say that for about $2000 or so, you can get that car equal to my stock '91, if you can put up with the stagger and stumble, with an engine that only runs great in a very narrow RPM band.

what boom and others are saying is that IF you are fortunate enough to get yours back to original performance, you are fortunate, indeed. and will have a lot more $$ in your pockets. all things come with compromises, and to every statement there is a contradiction. many ads are outright lies because that is how they sell us things that we want, but don't need. ever heard of caveat emptor? you want a quick launch and a tough sounding cam, and it is obvious you won't be satisfied until you buy them.

so, ignore the advice, and follow that dream.

saludos, joe

 

[boomdriver]

Ok thank you agian for the heads up, how about a cam? Like I said I was thinkin about a Z4 will that work with teh stock penelum?

The problem with that is that the plenum and intake is part of the problem as well as the solution...

that intake is what gets you that tractor like low end power, but it won;t allow you to pull hard at higher rpm. So adding a cam thats mid range to top end, defeats part of the design and basically all you do is chop off part of the power band. Like Joe says, you can do anything you want, just be prepared to pay twice...some cash for the part, and whatever its worth in performance headaches.

The hot ticket is to simply take the existing design and improve on that. Adding a cam from one place, heads from another, then some time down the road a huge throttle body, yeilds nothing. Empty pockets perhaps.
I am not joking when I tell you that I wasted thousands of dollars on bolt-on BS that did nothing more than alter the way the car ran, usually for the worse. I filled a dumpster with aftermarket performance crap when I moved...it was sickening to throw $150....$200....$75....another $200 piece of crap part in the trash.

Now, IF you make a PLAN, do your homework and talk to some people, buy the right stuff that works well with other pieces, and build that motor by using a plan, then you can build a cool engine that you;ll enjoy. You can build a motor with the exact same power band as the stock motor except with about 100 more HP across the rpm range...Then you've got something.

The aftermarket business is there to convince us all that we NEED their junk and to separate us from our money.. We spend piles of money on stuff that screws up the way the car performs but our pride demands that we walk around bragging on how good it runs...we buy junk and live with the consequences in an ongoing state of denial. Truth be told, most of the bits and pieces don;t do enough to write home about when added one part at a time. In fact, a set of SLP runners won;t do crap without porting the baseplate and plenum to match. How can they help anything when there are still restrictions and problems above and below the new trick runners that were advertised to add 25hp and 30 ft/lbs of torque???
The only way to get a real boost in performance is the develope that plan, save the money, and spend it very wisely on something that you really want... and not fall under the spell of the marketing and advertising that tells you "buy this and get 20hp NOW"...why? when you could save it and have 100hp later? I've known guys that actually added up all the BS 5hp and 12hp and 30hp claims on parts they bought and were walking around thinking they had bolted on 80 or 100 hp....yeah right! It ain't that easy.

You've got a decent running car, start saving the coins, buy a block and start figuring out what you want to put in it...383? bigger? or save toward a crate motor perhaps? blower? NO2? The possibilities are endless. ALL Absolutely possible, IF you have a plan.
Its like a jig-saw puzzle....you can't assemble one buy running around and buying random pieces. You have to start with a whole picture and then assemble the pieces that make it whole when placed together.


Did you hit the lottery or something? I know you've been hot to spend money on car stuff....you have my thoughts on engine building...if you're desparate to spend some cash, hows that interior lookin? Lots of cool electronics that can be dash mounted. Lots of things to do inside, lots of things that can be done underneath too.


Short answer to the question...

I doubt it would do alot. Save the $$ to spend on something that you really want..

 

[Curious George]

I would recommend this cam for a TPI / LT1 350. I just rebuilt a 350 with this cam and it is awesome. Granted, I have a 3.23 rear-end, but still. Very similar to an LT-4 hot cam. The ZZ4 cam I would not use... in my opinion it has too much exhaust duration (relative to the intake duration).

Lunati 54779LUN - Lunati Hydraulic Roller Tappet Camshafts - Overview - SummitRacing.com

CG

 

[Nick90vetteguy]

No, haha Im trying to get a plan but the cam and all the hoopla is whats gettin me lost, i dont know what i should use or what i actually need, this is my first corvette and i read about l98s to ls motors and its just numerous opinions n facts n i get lost thats all lol if i hit the lottery ill let u knoww

 

[Curious George]

No, haha Im trying to get a plan but the cam and all the hoopla is whats gettin me lost, i dont know what i should use or what i actually need, this is my first corvette and i read about l98s to ls motors and its just numerous opinions n facts n i get lost thats all lol if i hit the lottery ill let u knoww

Unfortunately, there are so many parts available for a SBC 350, that making a seemingly simple decision is compounded by the fact that there are just as many opinions about what parts to choose, usually, by people who have not used them or built a motor.

On the fortunate side, if you carefully do your homework and sift through all the BS, you can have a motor that performs exactly the way you want... either a new build or modifying what you have.

You know the end result that you want, now form a plan and stick to it. Don't let each opinion sway your course. Stay on track.

It took me about 1 year to rebuild my motor due to research and thinking.

CG