Acceld Z,

johnyIROC and I were chilling at my place last night and he mentioned that you have the part number and some info on the C4 vette torque convertors for TH700r4 transmissions. i am looking for a torque convertor with a higher stall speed (higher than the stock 700r4 stall speed on my 84 T/A). i have been doing searching and reading on the boards here and it seems that the C4 vette convertors stall at about 2000 -2200 rpm. is this correct? and i believe the stock stall for my T/A is around 1700 rpm? the reason i ask is that i will be buying a built 355 with roller rockers and a very healthy cam and i know my stock convertor will not be up to the task. i cant afford a good aftermarket convertor so i was hoping that a remanufactored vette torque convertor would be a budget alternative. any info you can provide would be very helpful. johnyIROC also said you might know someone who is selling one for a good price. thanks again, you insight is much appreciated.


ps...anyone else with any info please post...thanks



hahhaha......i am a terrible typer and speller .....i looked at the title of the thread....hahhaha...i suck

 

I have the part number at home its for the C4 vette or the some 90's S10s...This is what Im using (B-code I think?) right now..Tranny shop maxed out the stall..It flashes at around 2800-3300 on my motor..Stall would depend on your engines torque anyway..

Daz

 

Remember to take into account that there are 2 types of torque converters. Regular TC's and TC's with a lockup clutch. So torque flash of a lockup is not necessarily associated with stall speed. Stall speed is what rpm an engine can rev to without having to move the rear tires. So to test this, do a hard launch and note at what rpm the car launches at. This will occur quickly, but you should notice the rpm jump to a certain amount before the actual launch of your car. You can't do this with the brake method technique as our engines even at the weakest is still strong enough to make the rear brakes fail to hold.

The standard stock stall speed is actually b/w 1200-1500 RPM for most Camaros. This is because designers of tc's found that its best to have a tc about 500-750 rpm less than where max torque is made. Another reason is because for street applications, this is benefitial since at the stall rpm, tc efficiency is close to 1:1 and 1200-1500 rpm is normal cruising rpm in city. A corvette odds are still has the same stall of tc, but most corvette's will have a lockup (vette's are still city driven remember), where as early models of camaro will not necessarily have a lockup. TCC is not the only benefit vette 700's got, the servo's were larger along with the boost valves.

Before you get a new tc, check what rpm is your max torque at then get a tc around 500 less than that so when it does get close to 1:1 you are near your peak torque to provide good energy transfer. You'll hurt in mileage if you go higher without a lockup since with the lockup, you can force it on at lower rpm and get 1:1 ratio. Get a stall too high and even at max torque, you are not at 1:1 therefore you are losing a lot of energy, and by the time you reach stall, your torue curve has fallen off so much that its detrimental to performance. Too low and same issue, too far from max torque, longer to accelerate but more efficient energy transfer.

 

If he's got an 84 he's gotta have lock up...If you get the highest stock type stall 12" converter and its too much...You need more power and/or more cam...no need to f- around the "peak torrque" numbers..Vette/S10 converter is the minimum requirement for a performance F-body PERIOD..

Daz

 

Here ya go................

http://www.theherd.com/articles/torque.html

I think Carm still has that 'Vette converter. If you want a budget converter, look into B&M's Tork Master series. They are well priced and will probably offer you more stall speed and features than a re-man GM unit. The one i'd check out is part # 70418.



If you goofs manage to turn this into another flame war I will be impresed. Well, not really :lala:

 

Let me know what it works out to with taxes and shipping etc....

BTW I fixed your post title for ya

 

Before you throw any parts into a car, there are lots of things to consider. If your car is making max torque in the 3500 range, why get a stall rated to only the 2000 range? That's 1500 off the max torque meaning it has a long way to climb up the torque curve at full load.

Get the stall suited to your engine. You can't just toss in parts and say this is the final word in performance. There is no such thing. If that we're true, there'd be only one of everything made for performance. Doing the research, putting in the right combos, buying the right parts is the key to making the best for the money you got.

The only time I would say spend to your heart's content is if you had unlimited cash flow... but if you're on this board, odds are you don't...

darbleinad, at what rpm does your car make peak torque? If its still making it at the stock rpm level ie no major changes like cam and heads, then you'll still make max torque at the same rpm, just a higher torque number in which the money could be better spent on a vette servo, larger tv boost valve, and some strengthened parts planet gears, clutch packs kevlar rings etc...

 

thanks for all the replys guys. Acceld Z...how much do those Tork Master's run?

Daz...how much did it cost to get the tranny shop to rework you r C4 convertor?

Slade1...i am not sure where this 355 makes it peak torque at. however...it has some pretty serious parts on it and i know that stock convertor will not offer maximum performance. i dont have this motor yet...it is sitting in a Ford Ranger drag truck at my mechanics house...awaiting me to save up enough for it. so, for convience sake, a new torque convertor will not go in until i buy the engine and swap it into the T/A. however, my cammed LG4 could benefit from a convertor with a higher stall speed. i will have to do that lauch test you mentioned...i have not payed attention to the rpms at which the car lauches. i know its important to match the convertor to the engine, but that may be hard to do with the new 355 as the convertor and the engine would go in the car at the same time.

thanks for the advice guys...you fellas know alot more about this stuff than i do.

 

Free with the converter...I forgot how much I paid for the converter(I can look it up)..I got it from Lawrence Transmissions in Etobicoke..Had survived more than 150 13 second runs in 2 years..Ive seen them do turbo Buicks,vettes and some serious rods..Hindsight though I wouldve gotten the one I need off the bat but if youre low on cash cause of the rebuild Its a great compromise..


Unless you moved your peak torque 3K higher you shouldnt worry about anything..These cars could use this converter stock..You can use the $$ on the dyno or just slap it on and do a stall change later..

I got a quote from API(QUeensway/Dixie) for a 9.5" lock up converter,any stall I want,torque multiplication similar to a Vigilante for $750..I havent got it yet cause Im not done with my engine mods and no $$ lol

Daz

 

Cam changes almost always changes the max torque rpm. So if you put anything higher than the 350 hot cam, you're pushing peak past 3200 rpm, which the stock 350 cam does its peak at...

Consider this, his car was an 84, meaning the highest it could have seen was a 305 L69 which its best cam was good at 3200 rpm... Unless he got the L69 engine, his 700 r4 hence his tc is designed with 2400 max in mind...

Another thing to note is 87 earlier 700r4's are junk. Weak transmissions. Putting on a higher stall will put you in a spot when the rest of the transmission breaks from the higher power. That's why I recommended some upgrades to it. A transgo kit is a must for the early 700's. even the late 700's still have major weaknesses to it so adding more power to a tranny like that is asking for trouble.

I'm trying to give you all the info I know about to help with your decision, keep pressing and I'll keep writing till you know what you need. I honestly can't tell you what to get since I don't know a lot about your engine cept it has a 350 in an 84 setup with a hotter than normal cam... that alone though is enough to say that you will have issues crop up as you go along and the worst place to find out you had a flaw was at the track some 300 km away and something breaks on you... I hate seeing that happen to drivers.

 

thanks for the help guys.....i dont know too much about the engine myself, and nether does my mechanic, other than that it had a fresh rebuild last year and was only down the track a couple of times. currently as it sits this engine has:

- double hump heads (which i have a feeeling may have been ported), Crane roller rockers (the gold coloured ones, not sure if they are 1.5:1 or 1.6:1), i am not sure of the size of the valves in the heads (from what i know stock double hump heads had either 1.94 and a few had 2.02 intake valves).

- 350 block bored .030 over, Weiand Xcelerator single plain intake, a big fat holley double pumper/mechanical secondary carb, custom built long tube headers to fit the ford ranger frame

- the engine is connected to a TH350 tranny with some kind of shift kit in it for drag racing

Now if i get this engine, i do not get the carb with it. so i will be using my Ouadrajet on it. i also plan to swap on my edelbrock performer intake (dual plain) and i will be using my flowtech tech shorty headers (i know the 1.5" primaries might be too small. but i already have these headers and they fit the car real good). these headers run into my 2.5" true dual exhaust system w/ hooker aerochambers.

so, the dual plain intake and quadrajet will de-tune this thing somewhat, which kinda sucks, who wants to lose power, but a single plain intake and big holley double pumper are not the best combo for a street-driven (sometimes drag raced) automatic tranny car.