Anyone able to give a Torque Convertor seminar? What is the stock converter "flash" RPM? If I install a "higher" RPM convertor, this will allow my engine to
"wind up" to a higher rpm before the tranny wants to spin the wheels...correct?...possible increasing the torque and HP at launch...?...getting into the power curve of the cam...? How big a job is it to change the convertor?

Lots of techy torque convertor articles out there. It's a matter of pulling the trans and swapping convertors.

Greg.
Here is a helpful place to start. Look down on the bottom left of the page for a list of all the converter info
http://www.tciauto.com/Products/TechInfo/

TCI will also build or spec you what you need based upon your setup and car. Just give them a call of fill out this form:
http://www.tciauto.com/AboutUs/application.asp

Quick answer, going to a higher stall convertor does two things. One, it allows your engine to rev higher. That helps if your torque peak is above what your torque convertor allows the engine to "stall" at right now - which is very likely the case for you. Two, it increases the torque multiplication slightly.

Both these added together can help a little or help a lot depending on how "hot" your cam is. Usually going from a stock convertor (stalls at about 2200 rpm) to one that stalls at 2800-3000 rpm will drop about .4-.5 seconds from your 1/4 mile time. It'll also cut about 1 mpg from your fuel economy. Next question: do you have enough traction?

Thanks for the info.

You can just hold the pedal to the floor....no idea what "stall" mine is but it changes to 3rd gear at 90 if I floor it....

So if I hold the brake to the floor, and push the accelerator, the RPM where the engine starts to bind is the stall speed of the converter?

Just received an e-mail from TCI Automotive(Thanks Joe). They reccommend a 2200-2400 stall converter...? Sounds a bit on the lower side based on everyone's comments.

I'd go with a 10" 3200.

YOW!!! I nwas thinkn' 2600-2800.

What does "flash" mean regarding torque converters? If you give it enough goose, it won't pull until that "flash" RPM?

The way to find the flash stall is cruise along at about 25-30 m.p.h in high gear and just stab it to the floor and watch the tach and see what it goes up to and that is the flash stall, sitting still and applying the brakes and bringing the r.p.m up till the car pushes is the foot stall, the flash stall is the important one. one thing to remember when getting a convertor is that the stall speed is'nt to high when driving around town,because if the convertor does'nt lock up, all it is doing is overheating fluid and cook'n parts. i use the B&M holeshot 2400 and it works great.

Thanks. FYI, I was advised that the stall on a stock converter is 1300 to 1500.

I think more like 1800?
Check out this HP Pontiac article.
WHEW WEE YANK CONVERTOR! LOL
http://www.highperformancepontiac.com/tech/0201hpp_yank_torque_converter_swap/index.html

Has anyone else played with different combo's ?I have a 2600 between my 428 & a 2004r with a 390 rearend.I'm not happy with the low end. It should be quicker out of the hole I'm thinking of going down to a 2000. I have read alot of the Tech articles and can't decide if it's worth the effort.???

Stock convertors for 1970 were rated at 2185 rpm for most of the 400's and 2460 for the RAIV and 455's.The torque multiplication ratio was 2.04 and 2.30 respectively.

I had a switch-pitch torque convertor in my '69 that allowed me to have a stall speed of about 1500 rpm or about 2800 rpm. When driving around "normally" I preferred the feel of the low stall but when I wanted to make tracks, high stall definitely helped!

Under full throttle, the higher the stall the harder the car will leave the line. Under light throttle the engine will rev higher to produce the same acceleration as a low stall convertor and will "feel" sluggish.

If you have a high stall lock-up convertor you're getting the best of both worlds already.

Loren, I have a strong 400 with a 2200 stall with lock up, 2004r and 3.42 gear.
I find that in 1st it feels just right but if moving slow in 2nd and step on it a little it seems to rev up some be for moving.

Some times around town people would think your showing off leaving a stop light especially if still rolling and it doesn't drop back into first.

The answer to ALL these concerns and issues is a good Muncie 4-speed....

Greg is gonna kill me for posting this!

John, no soup for you!

Nash you did mean 5 or 6 speed??

Anything above 3, I suppose.

One thing to remeber also about torque converters is they respond to torque more than they do rpm. Ie a torque converter behind a small displacement low torque motor might be sluggish and unresponsive where as the same converter behind a big torque motor will light the tires and snap your head off.
Daren

Daren nails an important point. A convertor for a Chevy isn't going to act the same on a Pontiac. You need to buy one for the torque a Pontiac puts out.

I'm looking hard at the TCI "Breakaway" converter. 2400-2600 stall. I sent them detailed info about my set-up. This is what they responded with.

Kaufmann Racing also advised to use a 2500 stall converter.

Sounds about right. When you get your new converter one thing to remeber is to make absolutly sure that the converter is seated in the pump. The reason i say this is since the converter is new the tolerances are tighter. It might seem like it is seated and not be, this will chew the pump tags up real quick. Just something that has happen to me once. Also dont forget to pour a few quarts in the converter before you put it in.

OK. New converter is in. Results are great. Drives as normal in "grandma" mode. Was able to lower idle to 900 RPM. MUCH smoother shifting into gear. Launch is MUCH improved when I stomp it. Should be really good once the carb is set up properly. Now, time for traction improvements...then, to the track!

For reference, which did you use? This could become the official source of knowledge about convertors.

I'm going to come out of the closet.
After talking to a few other Pontiac guys, decided to try a Red Neck convertor.
Normal driving feels like a stock convertor.
Havent been to the track yet, but you would'nt know it has 3500 stall till you hit it.
In fact, there is no stall. Power is right now.
Before this one, had a Art Carr 2800. It was so-so.
Car hooked find, and went straight on G60-14's.
Now it pulls off center and kills the tires.
Cant wait to try it with slicks. Probly have to re-just the Cal Trac's.

What took you so long to come out? That's right in line with my well researched advise; "I'd go with a 10" 3200"

Cause all the Pontiac "experts" think you have to spend $500-$1000 for a convertor that works our cars.
Not affraid to try new things. Limited funds doesnt help either.

TCI "Breakaway" converter. 2400-2600 stall, 11",Part No.240900. $240 This converter will stall at 2200-2400 on small block, lower torque motor.

Stall feels closer to 2600 at hard launch. I ONLY TRIED IT TWICE. Was a bit rushed last night. Spun both the 255/60/15's with no hesitation. Its nice to have a traction problem.

I was obviously confused about what converter to use. It was recommended from 2400 up to 3200. Most agreed that 2500 was about the best. Its certainly better than what I had. Could have probably gone with a 2800-3000 but, I wasn't sure then.

Definitely got the most "bang-for-the buck", "seat of the pants" improvement, compared to anything else I've done to the car, all things considered(idle, drivability, launch, feel).

Choose'n the right one can be dicey. Lots of factors involved.
Beginning power(torque) band.
Tranny.
Wieght of car.
Rear gears/tire size.
Power adders.

Glad to hear you are happy with the initial results Greg. Now, what has your research found reference to improving your traction without installing big ugly traction bars?

Traction modification: Drag slicks.

Or, slider-links. They are shown in the Summit and Jegs catalogues. My buddy has them on his '67 Camaro. Just about invisible. They are the modern evolution of the old slapper bars. But, the old slapper bars are period correct!


Ponchoshop: Good point. Hence my initial confusion. I sent my full detailed info to TCI for evaluation. I went with their reccomendation...which was in line with a most others. What is your set-up?

Did the same thing with Redneck.
Originally wanted 2800-3000. Talked me into 3500 cause i'm gon'a try alittle n2o.

Just your basic FB street car.

8pt mild steel cage.
APC seats.
Ultra Lite speedo/tach and gauges.
MSD digital 6-plus ign module/blaster 3 coil/gutted hei.
Shift lite.
Line lock.
NOS cheater plt.
20G fuel cell/110 pump/8n feed/6n return.
2 f/pressure regulators(one for n2o).
455/stock 87cc e-hds/RAIV cam-1.72 rkrs/RPM int-850 demon/Hedman Huslers/3" x-over-pipes-muffs.
Dual remote oil filters.
Home made a/clr sealed to shaker scoop and cowl panel.
Vacuum tank for p/b's.
Rodney Red radiator.
19" flex fan.
Std HD TH400 build.
B&M ratchet shifter in a 2nd gen console.
Big tranny cooler.
3.42 12 bolt/strg axles(still need to weld tubes). Optional 3.73' and 4.11's if needed.
Cal Trac bars and split mono's.
Bar between frame rails with Edelbrock shocks for alittle more tire clearence. May need different ones cause these dont have much travel.
27.5-10x15 Hoosier QPT's.
26-5x15 M/T's up frt...Both on Weld Pro Stars.

Thats all i can think of for now.
How much $ is that?
Still have rust patching, paint job, vinyl roof, weatherstripping, mldgs and rechrome bars to due.

If you need any nitrous pointers....... I used to have my own filling station. Pull up, pump up, race.

...just your basic FB streetcar!? LOL!!

Apoligize for the hijack.
Just hope'n someone tells me it's worth it cause i sure cant afford it.
Been buying, saving, selling, trading cars and parts for years so i could restore my 67FB.
Got this one to drive in the mean time. But had to do alot to make it dependable(right).
Almost 2 years!
It's a 50'r. Now i'm finding the past repairs underneath the p.o.s. paint job.

Forgot the engine mid plate is installed but not attached to frame rails yet.
Have TA fdr vents(not in yet) to match the TA scoop.
Before you cringe, this one already had the hard work done.
Cage, frm cntrs, fuel cell, etc, so it's way past original.

Thanks Fbody69.
Been helping another guy in Pro Edelbrock Extreme Street.
Also played with it years ago, so hopefully i wont hurt the engine.
Will get to use his station and heater. And since he owes me BIG time, shouldnt have pay for n2o.
Just going to hit it with a 175 shot due to Eagle crk/Scat rods/SRP pistons, and RPM intake.
Then try a T2 to see how the engine likes it. Maybe go 200-250 after that.

Highjacking no problem. Your info is relevent in regard to the torque converter question. Your set up obviously requires a much higher stall than most others.

Mike, did you buy a 3500 RPM stall already?
If not, I have a bran new 2900 B&M stall.

Yep.
Definitely dont park behind me now!