engine and drivetrain Math and calculators help wanted

[Britonbees]

Hi so I have been able to some but still missing some info , here goes the info I currently have 

 

10.5:1 Pistons + 20

standard stroke 80

differential ratio 3.91

gearing ratios :

1- 2.56

2- 1.57

3- 1

HP 150 

14" rims  , overal tire diameter 22"

292 cans

Dual 45 Webers

1.75" exhaust 

 

so I am trying to calculate my Torque , unfortunately I am missing the math or info how to calculate at what RPM will I hit max HP . 

 

What you all think it ?

What max RPM could you run at for a few hours continuous ?

 

cheers

Edited June 8, 2016 by Britonbees
Additions

[williamggruff]

I would like to know how many beers you had before you wrote, "What at you all think it know ?"  I suppose I could calculate it, but it would be easier to just ask. 

 

What exactly are you trying to calculate, and why?

[xferboy]

 

7 minutes ago, Britonbees said:

so I am trying to calculate my Torque

hp = torque * rpm / 5252

 

You need the hp curve, which usually come with the torque curve, since the HP curve was derived the torque curve.... kind of a horse and cart thing, imho anyway. 

 

You could have 700 ft lbs at 1000 rpm, but that would be only 133 hp.   Need to see the whole picture.

[Britonbees]

12 minutes ago, xferboy said:

 

hp = torque * rpm / 5252

 

You need the hp curve, which usually come with the torque curve, since the HP curve was derived the torque curve.... kind of a horse and cart thing, imho anyway. 

 

You could have 700 ft lbs at 1000 rpm, but that would be only 133 hp.   Need to see the whole picture.

I calculated HP in 2 ways , none related to the torque , so more of a guesstimate or range , I am trying to reverse the formula above to get torque , perhaps I am over thinking it , yes I am trying to figure out my curves . Thanks for the imput

[Britonbees]

28 minutes ago, williamggruff said:

I would like to know how many beers you had before you wrote, "What at you all think it know ?"  I suppose I could calculate it, but it would be easier to just ask. 

 

What exactly are you trying to calculate, and why?

Haha no beers just stupid auto correct , no I would prefer to do it all myself but also not afraid to ask for more info . It all comes down to understanding marks in tuning , goals and references and to be able to tune or at the very least understand what the potential vs real world numbers and to try to make improvements where I can but I must understand a base line of what I have beyond just driving and having fun or slapping on parts . A beer does sound good now that you bring it up. Also forgive my punctuation or spelling English is my second language even Though I have been in the US 20 years

Edited June 8, 2016 by Britonbees
Additions

[williamggruff]

Is the car currently running?   If so, and assuming you can weigh the car, you can measure acceleration between various rpm ranges and in various gears and derive your hp and torque. 

[Britonbees]

2 minutes ago, williamggruff said:

Is the car currently running?   If so, and assuming you can weigh the car, you can measure acceleration between various rpm ranges and in various gears and derive your hp and torque. 

Touché , you are exactly correct , the car is not running , I blew the engine so it is an opportunity to rebuild , now that being said it is never just a matter of simply buying or slapping on parts . I build normally vintage pre 1963 British single cylinder race bikes and run at Bonneville with good friends and we share our knowledge , failures and success together . Just for personal improvements and support in the end 

[steve k.]

if you are estimating your HP to be 150, do you know at what RPM that would be?  Based on that, you can get the torque at that rpm.

I think 292 cam peaks at about 6000 RPM, so at your peak HP you will get about 131 ft lb.

[TobyB]

Quote

differential ratio 3.91

 

You know, on an autobox, that's going to be pretty darned low.  As in, you may run out of

revs before you run out of speed.  You're losing more than a few hundred rpm into

your torque converter when your foot's on the floor...

...if you're going for top speed, that is.

As an around- town ratio, it'd be perfect- it'll launch like crazy.

 

No calculations here,

t

 

 

 

[Preyupy]

150 HP with a 292 cam is going to be tough.  You will be hard pressed to make 130 lb/ft of torque at 6000 rpm with that little camshaft.  A 2 liter engine (121 cubic inches) , normally aspirated, 2 valves/cylinder, 1 spark plug is a full race engine if it makes 1.30 Lb/ft of torque at the peak per 1 cubic inch of displacement.  A stock euro Tii makes 131 lb/ft of torque@4000 rpm (this is 1.08 lb/ft per Cubic inch)   a 292 cam might move the torque peak up 200-300 rpm and might bump the peak number to 135-140 (about a 6% increase)  at best with your higher compression ratio and some port work,  then it is going to start falling off quickly.  135-140 Hp @ 6000 rpm is a much more realistic number. 

 

It also depends on the dyno you are using, is it calibrated in Clydesdales or Shetland ponies?   

[TobyB]

Arabians...

 

t

 

[Britonbees]

6 hours ago, TobyB said:

 

You know, on an autobox, that's going to be pretty darned low.  As in, you may run out of

revs before you run out of speed.  You're losing more than a few hundred rpm into

your torque converter when your foot's on the floor...

...if you're going for top speed, that is.

As an around- town ratio, it'd be perfect- it'll launch like crazy.

 

No calculations here,

t

 

 

 

Mostly all around town , and some small trips in the mountains , you think she would fair ok on the freeway for commuting ? Think I can do the Ton " 100mph" on occasions ? Thanks for the feedback !

[Britonbees]

4 hours ago, Preyupy said:

150 HP with a 292 cam is going to be tough.  You will be hard pressed to make 130 lb/ft of torque at 6000 rpm with that little camshaft.  A 2 liter engine (121 cubic inches) , normally aspirated, 2 valves/cylinder, 1 spark plug is a full race engine if it makes 1.30 Lb/ft of torque at the peak per 1 cubic inch of displacement.  A stock euro Tii makes 131 lb/ft of torque@4000 rpm (this is 1.08 lb/ft per Cubic inch)   a 292 cam might move the torque peak up 200-300 rpm and might bump the peak number to 135-140 (about a 6% increase)  at best with your higher compression ratio and some port work,  then it is going to start falling off quickly.  135-140 Hp @ 6000 rpm is a much more realistic number. 

 

It also depends on the dyno you are using, is it calibrated in Clydesdales or Shetland ponies?   

Sweet , haha ponies ! All around town , some mountain driving in the blue ridge , commutes and short distance drives maybe 6hours or so , you think it will do the Ton " 100mpb on occasions ?

[TobyB]

Mostly around town, I think you'll be a happy camper.

 

100mph top speed you will probably hit.

 

On a long road.

 

t