The Money Pit

I'm doing my homework as usual before I spend a fortune buying the wrong parts to hop up my Vette,and as some of you know I trashed my $2000. OD transmission and will need to rebuild it in the spring.My desire is to keep the street manners,but increase durability.When looking into converters everyone talks about stall speed and this converter is better than that because of something they do that the other guy doesn't.Bunch of crap most likely,but anyhow I see the trend is under 2500 stall the majority of converters that even mention hp or torque capacity are rated at 350hp or less,and from 3000 up they tend to mention more hp and torque.Now throw in the lockup feature that I'd like to retain for the 700r4 OD transmission and I find my choices are further limited.
Some converter specialists claim that a lockup is nessessary for street use,few disagree.Some claim 3000-3500 is OK for the street,some insist on keeping the stall down under 2500.

Bottom line is I have no intention of racing this car,but somehow managed to build a monster motor that far exceeds stock torque capabilities.The 295 50 15's can not begin to hold back my 406 even with the 2200 stall I currently have,so I don't think I want to go more than 2400-2600,but with 500 lbs of torque I need a converter that will survive the torque,and still keep the stall down.

I'm thinking maybe somebody makes a nitrous converter that's rated at 2400 for my 700r4 with the lockup,but so far I've not been too successful in finding anybody,except the Vigalante which is a custom,slightly expensive unit.I may go that route,but am still looking for suggestions.Again,my priority is driveability,followed by reliability.Anybody?(Strokers and BB guys)

BTW I've already emailed a half a dozen converter/high perf tranny companies and still don't have a warm fuzzy feeling about this.

AKRAY4PLAY

sorry i can't offer any advice. i am running a th400 with my 406. all the research i did lead me to believe that you can't make a serious tranny out of a 700r4 when you apply big power. i know that they can be built to take pretty good numbers, but then your over the price range of a th400 mated to a GearVendor's overdrive unit. i am pretty sure Santa will be bringing me a GV unit this year. if you figure it out, give me a shout. Brian

gkull

What actually died when your tranny went?

The Money Pit

George I have no idea at this point.Most likely a 25 cent gasket that will cost me a grand to find.The tranny never shifted very firm into drive from day one,and after getting used to the new shift patterns and taking it easy for a week,I belted out a series of 6500 rpm shifts.When I hit drive the tach went off the scale and it felt like I was in neutral.After that the trans began slowly degrading in holding power in drive. I can head up a hill and gradually give more throttle and once I hit 65mph or so the tach will continue to climb and the speed does not.I tuned 5500 one day and the speed never went over 65mph.( No the tires were not spinning.)First and second are solid still,but the speedometer has never been right from day one,and according to the order form I did order the correct gear set,though I haven't confirmed.

To tell you the truth I'm disgusted with it and haven't touched it myself. I did have a local shop change the fluid and inspect my installation and he found no schrapnel in the pan,but when working with BTO determined there was some internal issue.BTO will not honor the warranty due to my lack of radiator tranny cooler,so I'm looking for a local builder to salvage what he can.
My dilemma is the engine far exceeds stock output,though well designed for excellent street manners.I want a daily driver with punch and the stock parts won't hold up,but the race parts will force me to compromise true street manners. I don't want a loose converter that will make it easy to do burnouts,but slip so much I need to run two huge coolers to protect my tranny. :banghead:

TedH

Given your cam/engine combo, it needs stall. I'd say no lower than 2500 stall converter (maybe 2200). I run an 1800 stall converter which is right in the sweet spot of my cam/engine combo (cam comes alive at 2000rpm).

VETDRMS

I was facing the same question when I built my 406 over the summer. I ended up talking with Mickey at TorcoConverters and had a billet 9.5" 3300rpm stall built. I provided vehicle weight, gears, tire size, motor specs and he matched it to my combo assuming 500 ft/lbs of torque.
It turned out to be a lot looser, it will brake stall ~3400rpm, flash stall 4000rpm and when your really on it in 2nd and 3rd it will stall around 4700rpm. Some would say that this isn't streetable at all, but that is hardly the truth, I can put around in any gear without issue.

The only concern with a converter this loose is that it generates a LOT of heat. I am using a B&M stack plate racing cooler with RedLine synthetic High Temp ATF. When just driving around on an normal day it will run ~170F, but when you ride the converter or do some WOT blasts it gets hot in a hurry. After 2 WOT blasts from a 3300rpm brake stall to 100+mph and the tranny will be ~210F. It also cools down pretty fast. Overall it is definetly a different feeling, almost feels like a CVT as when you take off it will go straight to 3000 and stay there as the car accelerates to "catch up."
I was thinking of sending it back to get it tightened up, but I am goign to see how it does at the track this spring. So far I've been very happy with the setup, and highly recommend Torco. Their website is http://www.torcoconverters.com. Great price and has performed flawlessly so far.

Also, there has been some debate as to whether or not a locking converter is not as good for the track. But I will assume you mainly plan to drive this on the street? Such a high stall as mine has a big negative impact on MPG, so I would go with a lockup if your going to stick to the 700r4.

Good Luck!

:cheers:

gkull

I'm not a tranny man. I leave that to professionals. But I will ask my tranny doctor what's up with your indications.

I smoked my first couple of 700's with the same kind of indications as yours. One of them was the 3-4 clutch pack and when they beefed that up the first time day I was doing power brake launches at a sticky drag strip with 10 inch slicks the convertor ripped it's guts apart on the fifth or sixth run.


[Modified by gkull, 12:07 PM 12/9/2003]

Wrencher

I ran a 3200 B&M for years on the street behind a Pontiac Ram Air III/THM 400 combo that ran 12.80's thru cast iron manifolds on 7" cheater slicks. Only problem I had was a split trans case from the torque. I had way more trouble with rear ends 'till I went to a '64 Chevelle 12 bolt and Henry's axles.

Hans

427V8

Talk to the people on this forum about 700r4's
http://www.turbobuick.com/forums/for...66a&forumid=12

gkull

The real thing on all tranny's no matter what they are on any 200 thru 480le or what ever they are called is $$$$$$$

It was the same way with TH200 thru TH400's

or the Power Glide

Bucks make them Go


IN my dragster I ran a 6500 stall 2 speed power glide for 3 years. It cost lots of money. 7 inch convertors and transbrakes are hard on parts

IN the late 70's I had a road racing Monza Spider with a full manual th400 because it went through it TH 250 and the a 5 speed then a th350

It's all no free lunch!:)

Did you see tha Jim with his 540 ci got the fastest Vette in the Texas Drags?

Nothing is free! :auto: