Zap Racing

Just started this yesteday--when I let off the gas, in any gear, it does not slow down the car like normal. It's like it goes into neutral. It still shifts like it always has,--no slipping-- even at WOT, but when U let off, it's as if U pushed in the clutch (if it was a manual).



I called Owen at ARD last night and he said the more I drive it the more I'm going to toast it and cause hard part damage--said it's probably the front pump starting to go (although it could be other things causing it).


F... ME!

Probably going to AAA it over there Friday, and maybe go by the shop Sat to sit down and talk to him about it and possibly upgrading it a little, and about doing the exhaust right, while he's got it there!

Larry Dunlap

That is weird, never heard of that type of failure before. When mine went it started slipping in the 2-3 shift, then finally wouldnt go into 3 at all. Well maybe if it is an early failure it can be rebuilt inexpensively. I guess it happened right after racing right? Maybe its TH350 time eh?

Zap Racing

Nope--completely different clutch pack assembly from the forward drive clutches--the "overun clutch assembly" or "overun clutch sprag" is a seperate unit--sole purpose is for engine braking (from what I have been told--may be wrong)--a manual valve body like mine is much harder on this unit than a normal tranny--will look into beefing this up--the tranny still shifts in all gears and shifts hard justlike it always has--even at WOT.

Wheel Spin

Zap, did you get it AAA'd over there yet?

Zap Racing

Yes--got it over there Sat morning. Owen and I sat down and talked about what to do to it especially as far as upgrading, and we are pretty much upgrading EVERYTHING, except for one item that would not benefit unless I had a bunch more HP. AND AT A VERY REASONABLE PRICE I MIGHT ADD!!! I would use the word cheap, but it would apply only to the price, not the quality of work or parts being used.

Let me tell U guys in Houston something. If U are not using Owen for any projects that U need help with or any repairs or modifications U want done--no matter what it is-- U are just spinning your wheels!!!

The more I spend time with him and talk to him, the more I am convinced he REALLY knows his stuff. Owen is what the thirdgenners in the Houston area have been needing for years! From fabrication to modifications--engine swaps--NOZ-- anything and everything-- Unless U are doing the work yourself, U should be talking to Owen about doing the work.

Barry 85IROC

BUMMER!!!!!!!!!!!!!!

I know the feeling.....

Glad you got hooked up on the repair.

Zap Racing

Oh Yeah--almost forgot--we are going back with a 2800 rpm stall torque convertor! About as much s I would want on a daily driver and Owen has to twist my arm to go that much--but to be honest, I didn't give much resistance to his suggestion.

Zap Racing

Got my car back from Owen at ARD sat afternoon. Besides doing an awesome job on rebuilding the transmission, they raised up the Y-pipe by cutting about an inch and half/two inches out of the passenger pipe before it joins the main pipe and raising it up and welding it back together. They also mounted my A pillar triple gauge pod water temp, tranny temp, and oil temp. Looks really good!

Barry 85IROC

Ready to get beat?

Zap Racing

By who?



U???

U must have me confused with somebody that runs in the low 14's!

Barry 85IROC

You should REALLY be able to back up your smack. Your gonna feel might stupid when you get beat. Ask Mikey.

esc

iTrader: (6)

More stall is ALWAYS better in my book. 2800 is actually pretty mild. The best way to figure out your ideal stall is this...

If you do a big burnout add more traction.
If you don't do a big burn out, add more stall.
Repeat.

rudyt5000

do you mean burnout on purpose...or when taking off at the strip?

plndtx

If any of you guys are bored and want to take the time and explain to me why you would want to go with a low vs. a high stall speed converter I would appreciate it. You can be as elementary as you want. I have watched almost every episode of two guys shadetree hotrod horsepower trucks rides PHR overhaulin garage on tnn spike speed tlc TV and I still don't quiet understand torque converters. Maybe somebody out there can put it in terms I can understand.

I've noticed in the car mags that people put high stall converters in performance cars. So I guess street cars need low stall converters?

TexasLT1

Think of it this way, the stall speed of the converter is equivalent to the speed you would dump the clutch in a manual transmission car. You can brake-stand the car up to that RPM and it won't try to spin the tires. The higher the stall speed, the higher RPM you can rev the car to on the starting line.

esc

iTrader: (6)

TexasLT1 is correct, but there is a little more to it than that.

The Torque Converter (TC) is a hydraulic coupler. It always has some slip. At low RPM's it has a LOT of slip, at higher RPM's it has less. Also, the more torque you apply the more it will slip.

For example:

Say you have a TC rated at 3000rpm (the "Stall Speed"). If you put that behind a stock TPI 350 at full throttle in first gear you might actually see 2800 rpm (off the line)(A blown big block might net 5000 RPM). It would be just like slipping the clutch in a standard at 2800 RPM.

If you give it half throttle off the line you might see 2000 RPM (again imagine slipping your clutch at 2000 RPM when leaving a stop sign)

At 1/4 throttle you might only see 1200~14000 RPM. Still VERY streetable in my openion.

Some transmissions (700R4 and 4l60) have "lock up" TC's. Which is a hard connection from the input to output side of the TC which eliminates ALL slip when engaged. Once that mechanism is engaged, it doesn't matter what your "stall speed" is.

I could go on more, but I'm out of time and I suspect my audience will be running out of patience so that is all for now.

Zap Racing

excellent explanations guys.

Chris-- basically it lets the motor rev to a higher point where U are making more HP, when sitting on the line waiting for the tree to go green.

If it were a strip only car I would have gone with a 4000 +stall--because it would put it at an even higher HP range, but that is not feasible for a daily driver. For a car that is occasionally street driven U could get away with it (and maybe a little higher), but not for a daily driver--IMO

By the way I can still cruise along at 40 mph in 4th and it is only turning about 2000/2200 rpm.

By the way my TC is a non lockup convertor-- rated at 2800 to 3000 rpm when used with my engine tranny combination. Also, the shop that Owen used to rebuild the TC is the same shop that builds the TC for "King Crunch" the 4x4 on the pro monster truck circuit.

When rebuilding the tc part of what they do is to balance it--just like wheels/tires--the shop said it was out of balance before, and I have noticed that the vibration I always had in third gear is gone!

I like it!!

Owen gets for this one!

plndtx

What would your car behave like on the street if you went with the higher stall speed? Could you tell when you started from a dead stop? Or would you just notice that your rpm would be higher for a given speed.

I have noticed that when I am in my truck stopped at a traffic signal and my foot lets pressure off of the brake, the truck tries to creep forward. Is this a characteristic of a low stall converter?

Sorry for the elementary questions. I hope we can have a little more freedom with question on the regional boards as opposed to plopping 'how does a tc work' on the transmission board.

TexasLT1

I was going for the quick and dirty explanantion

basically it just makes the engine rev higher to get off the line at an intersection with a higher stall. When my brother had his '78 T/A running, he had about a 3800 stall and it would usually rev up pretty good just to get rolling. But when he punched it, boy did it get rolling


and great explanation esc, thanks

Zap Racing

Yes higher rpm to get car moving and maintin speed, buy not as much as U might think.

Yes that is a lower stall trait--mine will kinda still creep forward, but not as much as it used to at idle.

esc

iTrader: (6)

Another factor with TC's, that doesn't get as much press, is torque multiplication. There is a part in the middle of the converter, the shape of which, controls how much torque multiplication the TC will provide while slipping. Generally it ranges from 1:1 up to as much as 3.2:1, 2:1 is typical.

So not only do you need to get a stall speed that is well matched to your engines power band, you also need to select a torque miltiplication that matches your available traction. To low a ratio (3.x:1) and you might just spin out...too high (1:1) and your car will be a dog off the line. It works a lot like your rear end gear.

TexasLT1

I definitely did not know about that

rudyt5000

I have noticed that when I am in my truck stopped at a traffic signal and my foot lets pressure off of the brake, the truck tries to creep forward. Is this a characteristic of a low stall converter?

Since your driving a truck that might be the gear ratio in the differential. Gears used for pullin loads and stuff so it makes it easier on the motor. I've seen one of those rock crawlers go up hill just on idle with 4.56 gearing or something round that range. With tires that huge...gears is what gets them rollin

1bad91Z

iTrader: (1)

Where's the middle finger smiley?? lol

I don't feel stupid at all. I raced it broken (which is more than we can say for you, whom won't race at all)!


One day soon when funds permit, we'll line 'em up. And after they tow you off the track, then it's ZAP's turn!


Commence the sh*t talking ........... you knew this was going to happen!

Maybe we can draw in a bigger crowd like the first Spring Fling!

Barry 85IROC

[QUOTE=1bad91Z]

I don't feel stupid at all. I raced it broken (which is more than we can say for you, whom won't race at all)!
Mark Twain once said, "It's better to say nothing and let people think you're stupid, than opening your mouth and removing all doubt." When you raced, could you shift? I think so. Well, I can't. The tranny has NO synchros.I'm not talkin' a glazed flywheel or a cracked TPS(Your idea of racing broken), but NO SYNCHROS!!!!!!! GET IT!!!!!!! Quite honestly, I think the tranny is just worn out 160K on it. TIME TO GO.


One day soon when funds permit, we'll line 'em up. And after they tow you off the track, then it's ZAP's turn!
We've been hearing this for a year now.
You need to show up for the ZAP defeat and see how bad he gets beat, and then then decide whether or not you want to embrace the pain. Any time, anywhere.
No matter how bad Craig gets beat, he'll still beat you.

FbodTrek

Odd...when Mike went around that corner onto the BW8 feeder (heading to who knows where), I saw that car at WOT. No offense Mike...but I don't see ya pulling on Ole' Craig. As for a slipping clutch, glazed flywheel..didn't look like it. Just race it, if it pops, rebuild it better. Can't be affraid to get walked dude, theres alot of poeple out there that are faster

rudyt5000

AMEN

TexasLT1

You might as well turn and talk to the wall beside you. You'll get the same result.