New Stall speed question

[76 Sting]

Hey all… I have read many topics here at CAC regarding stall speed, but the questions I have has not come up, I do not think. I am wondering how my car will respond beyond the initial launch, which I hope is going to be good. Meaning, I catch 2nd gear now on my automatic and wondering if this will improve when second gear kicks in with the new converter, whether it is done manually (up shifting) or automatically. I am going to install a B&M Nitro 2400 stall converter with trany cooler. Also, I normally cruise around 2000 rpm (45mph) side roads and 3000 to 3500 ( 65-75 mph) highway.



Does anyone have any strong recommendations that are against my choice of Stall speed?



Here is my current setup.

350 rebuilt bored .030 over, shift kit, no emissions, 2.25 Borla exhaust, shorty ceramic headers no cats, Edelbrock RPM intake, Edelbrock 1405 carb, Accel HEI disty, NOS PowerShot 125 hp , K&N Extreme filter, Stinger hood with direct ram air injection, VBP Street & Slalom vert suspension package, and 3.55 gears.
Thanks in advance for everyone asistance

 

[Glensgages]

Jeez..... it's been so-long since I had a 'street'-type converter in my hot-rod, I can't recall:
my Z28 has an 8"/4500 converter in it, and it just 'slimes' it's way into the next gear, at a fairly quick rate of acceleration!

I'd offer just a few thoughts:

I always let my converter-maker tell me what would work in my car... HE is 'supposed' to be the authority, and so-far both manufacturers I've dealt with (Transmission Specialties of Paoli, Pa., and ATI of Baltimore, Md.) haven't done me wrong.

Your camshaft's profile dictates when and where your power-making RPMs are located, and that effects what kind of torque your 355 makes, and at what RPM it makes it, too.

I've never played-around with N2O, but I believe that nitrous doesn't NEED as-much stall-speed or gearing:
in-fact, I think the more you 'load' the motor (less gear, less timing, less stall-speed) when using nitrous, the more torque the motor makes, which is what ultimately moves the car forward.

Buying an off-the-shelf converter is not for everybody:
it's effeciency can't be maximized (see above), and sometimes the quality is lacking.
A 'custom' converter may cost you more initially, but it's quality should be better, and if made durable-enough, could last into the future, if/when you begin making "serious" amounts of HP and TQ:
some manufacturers will " adjust " the stall-speed one time, for free, after the purchase is complete.

Wish I could've been more help.....


Somebody much more knowledgeable than me will come-along, and help you out soon-enough.....

 

[76 Sting]

Glensgages- thanks for the reply, you don't take that Z on the road do you, or should I say can you? That is a big converter (high stall)!
I do agree with a custom converter, but unfortuately I barely get to use the car as it is. I am lucky if it sees 25 miles a week, and I only plan on going to the strip once to see what I have acomplished sinse this is my first project. My main goal is to have a semi fast car (350-400 HP with Nitro) and also be able to compete in shows for apearance.

 

[Glensgages]

you don't take that Z on the road do you, or should I say can you?

Many years ago, I had a 'budget' 9"/3500-stall converter in the Z28, and took it on a 660-mile, round-trip journey.....

never-again.

I began racing it weekly in 1990, at a track about 15 miles from my house, and drove it to/from with a 10" semi-custom (Transmission Specialties) converter and 4.10 gears:
it ran 13.30s @ 106 deep-staged, with open headers.....

A switch to an TS 8"/4500 converter (along with slicks and 4.56 gears... the slicks were 2" taller, and the 4.56s got the RPMs back) resulted in 12.80s @ 105 ET/MPH.....

After I got my dragster, I 'retired' the Z28 for many years, then decided I'd put it back on the street, with the intention of going racing occasionally (the dragster had been sold), so I still wanted "some" converter:
A buddy had been using ATI converters, and he suggested an 8" unit that was custom-built, intended for every-day street usage AND frequent drag-racing.

It cost $600 (roughly same as the TS), and stays very cool in street driving ( I did about 300 miles per summer), and while not nearly as 'loose' as the TS 8" converter (I like to vary my RT at the track by varying my launch RPM), it also runs 12.80s, but my MPH has increased slighty:
I recorded the Z28's best ever run 2 years ago at 12.774 @ 109+ MPH.

If I were to go strictly racing, I think I'd prefer the TS piece (I have brutalized their stuff for many seasons, with no failures yet), but the ATI converter is one Helluva street/strip unit.

 

[76 Sting]

The $600 cost is double of the B&M Nitro 2400 stall. I do not know if the $$ difference will be worth it because of the amount or shoudl I say lack of hard core driving I will do. If i were at the strip like you putting a beating on the converter I would go the extra mile.

What kind of HP did the Z have? I would love to be in the 13's

 

[Glensgages]

What kind of HP did the Z have? I would love to be in the 13's

I honestly don't 'know' what HP the Z28 makes:
when I began racing with the current engine (in 1990), I just wanted to run NHRA Heavy Eliminator, reserved for cars running 12.00-13.99.

It weighs 3700+ race-ready, and usually runs 106 MPH, which works-out to approx 300 RWHP, but with a 4500-stall converter, THM400 transmission, H-D axles and spool, 28" x 10" slicks with 13 PSI, etc., drive-train losses may be astronomical:
I'd guess close to 400 crank-shaft HP?????
;help

I really don't think running 13s in a C3 wouldn't be too-hard:
if you (or other CAC-members) would like the particulars of my Z28, I'd be glad to share them with you, either here or via PM/E-mail.

Glensgages@aol.com

 

[76 Sting]

I honestly don't 'know' what HP the Z28 makes:
when I began racing with the current engine (in 1990), I just wanted to run NHRA Heavy Eliminator, reserved for cars running 12.00-13.99.

Unfortunately I still have the stock heads installed, but they have been redone approx 5000K miles ago. By reading many of you posts you are obviously very experienced. Where do you think I should spend the $800 total to get the best bang for the buck? This is what I was thinking: converter $320, trany cooler $50, installation for both pieces $275. I was then going to have them put it on the dyno ($174) and run it once then calibrate it and then a final run. They will measure the vacuum the fuel ratio spark and set the Nitrous accordingly. Since I am not that hands on I will need to have someone perform this.

 

[Glensgages]

With 'just' $800 to play with, it'll be hard to run 13s with a standard mid-'70s L-48, so let's look at this as effeciently and as intelligently as we can.....

A higher-stall torque converter will raise the RPM into the power-band quicker than a 'tight' unit, which is great for motors with a high peak RPM:
since you have no compression, no big camshaft, no high-flow heads, etc., I'm not sure how much the converter would help you...
:confused

Assuming your .030"-over SBC is in good-enough condition for N2O (good head-gaskets, rings, etc.), dollar-for-dollar your best-bet would be a decent hydraulic cam in the .440"-.460" lift, 218*-226* @ .050"-lift range, which'll make gobs more TQ than your stock camshaft does, yet not exceed the RPM-potential of your bottom-end (5500-5800), and work well with the N2O.

Do you know what ET/MPH your '76 runs NOW???

 

[76 Sting]

With 'just' $800 to play with, it'll be hard to run 13s with a standard mid-'70s L-48, so let's look at this as effeciently and as intelligently as we can.....

Sorry...13's is a long term goal not this summer but hopefully next.
The engine was just rebuilt before I bought the car and has less than 10k on it.
The Cam is definately over stock... my friend has a 77 he rebuilt 2 years ago and kept it to stock spec's and you could say I leave him in the dust off the line and down the road. Unfortunately I do not start making good power until the 2000-2500 rmp mark.
I do not know what the 76 runs now hence the reason for the dyno, at least then I would have an idea on the HP.