Non Lock Rpms

j l smith · Aug 20, 2017

I have a 1993 mustang gt b303 cam 1.7 roller rockers and a aod with a edge 3500 non lock up and 323 gears what do ya think about 373's with this set up , street car how many rpms would I turn at stay 60

imp · Aug 20, 2017

j l smith said:
I have a 1993 mustang gt b303 cam 1.7 roller rockers and a aod with a edge 3500 non lock up and 323 gears what do ya think about 373's with this set up , street car how many rpms would I turn at stay 60

With a non-locking converter, rpms vary with engine load. IOW, at cruise, constant car speed 60, not uphill or down, look at your tachometer. Note engine speed, and with 3.73 gears it would be a little over 15% higher, assuming same tire size used. IOW, IF you are turning 2500, new rpms would be about 2875, as an example.

@karthief See, all that "crap" I harbor does occasionally prove worthwhile, no? imp

85ragtop · Aug 20, 2017

jrichker · Aug 20, 2017

j l smith said:
I have a 1993 mustang gt b303 cam 1.7 roller rockers and a aod with a edge 3500 non lock up and 323 gears what do ya think about 373's with this set up , street car how many rpms would I turn at stay 60

See https://lmr.com/products/Mustang-Speedometer-Gear-Calculator for more help.
You will need your current or proposed tire size as well before you can accurately use the calculator.

mikestang63 · Aug 20, 2017

That is a lot of stall for such a mild build. You should be more around 2500 as your powerband is no where near needing a 3500 stall.
Second, I hope you have a decent trans cooler with a non lock up cconverter and that high a stall.

In order to determine what rpm your car will turn at you need to provide your tire size
Assuming a 26" high tire... your tach will be at around 2100 with 3.73 gears and 1750rpm with 3.23 gears at 60mph
An AOD is around .70 to 1 in OD

https://www.ringpinion.com/calculators/Calc_RPM.aspx

Oh and......
.

General karthief · Aug 20, 2017

imp said:
With a non-locking converter, rpms vary with engine load. IOW, at cruise, constant car speed 60, not uphill or down, look at your tachometer. Note engine speed, and with 3.73 gears it would be a little over 15% higher, assuming same tire size used. IOW, IF you are turning 2500, new rpms would be about 2875, as an example.

@karthief See, all that "crap" I harbor does occasionally prove worthwhile, no? imp

Yes, ah no, wait, maybe, how da hell do I know, I'm a boob, observe my ct.

j l smith · Aug 20, 2017

I have 275/40/17 tires and I do wish i'd went smaller with the stall speed

imp · Aug 20, 2017

85ragtop said:
No.

@85ragtop

?? No comprende. imp

General karthief · Aug 20, 2017

imp said:
@85ragtop

?? No comprende. imp

Raggedy was answering for me.
He's my friend

imp · Aug 21, 2017

karthief said:
Raggedy was answering for me.
He's my friend

@karthief
You evidently have far more friends than I. Lucky you.

I'll say this: sparring back and forth here is a good tension easer considering the "far-out-ness" of some of my beliefs/opinions. imp

85ragtop · Aug 21, 2017

@imp I just like to mess with you. For some reason I do like you.
And to the op, that is a lot of stall. At 548hp on a stroke 351w I had 3500 stall converter.

j l smith · Aug 21, 2017

i think we got lost because the question was rpm's vs. 3500 non lock up stall and gear

General karthief · Aug 21, 2017

j l smith said:
i think we got lost because the question was rpm's vs. 3500 non lock up stall and gear

This may help you.

http://bgsoflex.com/rpmmph.html

j l smith · Aug 21, 2017

but my o/d is what .70 then how much to add for the 3500 non lock up

General karthief · Aug 21, 2017

I really can't answer that question, beyond my pay grade.
I can tell you thats a pretty high stall for your combo. There are many factors in determining stall speed, I think in your situation a higher numerical gear can get you to your stall speed for cruzing but do you want to be swinging that crank that fast just to cruze down the highway? A smaller numerical gear puts your rpms below stall speed and the slippage will heat up the transmission fluids causing premature wear. If this is a race car with future mods intended then go for the taller gears, if it's a street car you may need to rethink you parts combination.
Just my opinion and not based on any personal experience or facts.
And if I'm wrong the more experienced guys here will hit me with the appropriate tire iron.

General karthief · Aug 21, 2017

I really can't answer that question, beyond my pay grade.
I can tell you thats a pretty high stall for your combo. There are many factors in determining stall speed, I think in your situation a higher numerical gear can get you to your stall speed for cruzing but do you want to be swinging that crank that fast just to cruze down the highway? A smaller numerical gear puts your rpms below stall speed and the slippage will heat up the transmission fluids causing premature wear. If this is a race car with future mods intended then go for the taller gears, if it's a street car you may need to rethink you parts combination.
Just my opinion and not based on any personal experience or facts.
And if I'm wrong the more experienced guys here will hit me with the appropriate tire iron.

imp · Aug 21, 2017

Don't think I understand completely here. Stall speed is the eng. rpm reached with throttle wide-open and drivetrain locked stationary by brakes. Let's say that number is 3500 rpm.

That has little or nothing to do with the fact that during normal driving, 3500 eng. rpms will be seen often, but but not with throttle wide open.

So, @karthief , what is your meaning in connection with stall speed related to cruising? imp

j l smith · Aug 21, 2017

as of right now I'm running a 323 gear and I'm thinking of putting a 373 in and was woundering about how many rpms I will be turning at 60mph

General karthief · Aug 21, 2017

I maybe wrong or not have a clear understanding of converter stall speeds, higher stall rpm is reached by converter slippage, this allows the engine to reach the desired 'sweet spot' when launching off the line, other things in play here but thats my basic understanding, when cruzing below the stall speed, say 2200 rpms on a 3500 stall converter, I would have to think the converter is slipping at that point causing the fluid temp to rise and premature parts wear, if he had a 2500 rpm stall converter or maybe a lockup there would be less to no slippage, less heat, less wear or a lockup that has no slippage.
Now these are thoughts of someone that reads about stuff but has no actual experience with this stuff, are my ramblings correct, close to correct or wayyy out in left field?
I want this member to get good advice cosidering what we know about his setup.

General karthief · Aug 21, 2017

j l smith said:
as of right now I'm running a 323 gear and I'm thinking of putting a 373 in and was woundering about how many rpms I will be turning at 60mph

How tall are your rear tires.
I linked a calculator to figuare it.

Non Lock Rpms

Member

Mustang Master

BTW, I like dudes.

StangNet's favorite TOOL

wonder how much it would cost to ship you a pair

Member

Mustang Master

wonder how much it would cost to ship you a pair

Mustang Master

BTW, I like dudes.

Member

wonder how much it would cost to ship you a pair

Member

wonder how much it would cost to ship you a pair

wonder how much it would cost to ship you a pair

Mustang Master

Member

wonder how much it would cost to ship you a pair

wonder how much it would cost to ship you a pair

Similar threads

Privacy & Transparency

Privacy & Transparency