Accuracy of Engine Calculators

[Zebedeehall]

How accurate are engine calculators? In particular, the Wallace Racing- Mach Index calculator. Thanks,

[twl]

I have used them, and they seemed to be pretty close in my case.
The better your input data is, the better they will be.

[Zebedeehall]

I have used them, and they seemed to be pretty close in my case.
The better your input data is, the better they will be.

Thanks

[wil8115]

Yep The calcs are only as good as the data you enter. Make it as accurate as you can.
but they are also handy for quick ballpark figures with close enough numbers.

[Caprimaniac]

Hi.

Related question....

Made my best pass ever this weekend. My first 10'er... And my first weekend on ET street wrinkle walls. I think I can og low 10's, With some more time behind the Wheel. I didn't hook very well until the last run- when I discovered the RPM's were too low and stalled....

Anyway. I estimate Power on engine at around 500 Hp.

Went through some Hp estimates on John Wallace's site last night and "best" estimate I could figure, based on weight, 1/4 ET, speed, was 405 flywheel Hp. Using 60' times I end up at 267 Hp.

Thing is, I'm running a syncro H- gear 5- speed (Astro T-5) and had some troubles getting into both 2. and 4. gear. In one of the good runs I find gearchange time 0,78 Seconds from 3. to 4. (The log show driver "looking" for 4. after 0.6 Seconds by a blip on the throttle and a quick rpm change, and then engaging 0.15 thereafter...)

Long introduction,but... The ET/speed/ weight vs Hp calcluators- will they provide good estimates on a stick- shift car as well as a auto? (Assuming average gearshift times- whatever they are- and correct stall speed, convertor, auto- setup.)

Thanks.

[randy331]

Anyway. I estimate Power on engine at around 500 Hp.

The Moroso slide rule calculator shows 500 Hp will pull a 3700 lb car into the 10s and about 120 mph in the 1/4 mile.

I had one engine that made about 520 on the dyno and ran a 1.35 60'/ 6.37 @ 106 mph 1/8 mile and 10.11 @ 130 MPH in the 1/4 mile at a bit under 3000 lbs 600' air.
Powerglide 8 inch converter, deep geared car.

I think the Wallace calculator is a bit generous on HP vs et.

Randy

[vortecpro]

Anyway. I estimate Power on engine at around 500 Hp.

The Moroso slide rule calculator shows 500 Hp will pull a 3700 lb car into the 10s and about 120 mph in the 1/4 mile.

I had one engine that made about 520 on the dyno and ran a 1.35 60'/ 6.37 @ 106 mph 1/8 mile and 10.11 @ 130 MPH in the 1/4 mile at a bit under 3000 lbs 600' air.
Powerglide 8 inch converter, deep geared car.

I think the Wallace calculator is a bit generous on HP vs et.

Randy

We agree, the Moroso is accurate.

[Lizardracing]

That's a mathematical formula of work vrs load. There's a few assumptions of tire/drive line slippage. I'm too lazy to type it out though.

[Caprimaniac]

That's a mathematical formula of work vrs load. There's a few assumptions of tire/drive line slippage. I'm too lazy to type it out though.

Sometimes lazy is OK.

I'm 100% my 60' will be tons better when I manage to hook properly. And ET will move closer to the calculated 10.00.

[Orr89rocz]

Where do you find the moroso slide calc?

[PackardV8]

Maybe it's just my experience, but I find the MPH figures to be a pretty accurate indicator of horsepower. However, ET is so dependent on tires, gears, chassis setup, it seems to be less so.

Some low horsepower but well-sorted bracket cars ET fantastically well and beat cars of the same weight I know to have more horsepower, but their owners don't want to optimize for the 1/8 or 1/4. The higher horsepower cars often are pulling away in the traps.

[randy331]

Maybe it's just my experience, but I find the MPH figures to be a pretty accurate indicator of horsepower. However, ET is so dependent on tires, gears, chassis setup, it seems to be less so.

Some low horsepower but well-sorted bracket cars ET fantastically well and beat cars of the same weight I know to have more horsepower, but their owners don't want to optimize for the 1/8 or 1/4. The higher horsepower cars often are pulling away in the traps.

I agree with this. From what I've seen a well sorted combo can beat the Moroso calculator on ET, but it's hard to out MPH it at the power it shows.
I think that's partially because for lowest ET, you will end up geared to be well past peak HP at the finish line, so MPH suffers. If you just chased MPH only, maybe one could out MPH it?

Randy

[maxracesoftware]

Anyway. I estimate Power on engine at around 500 Hp.

The Moroso slide rule calculator shows 500 Hp will pull a 3700 lb car into the 10s and about 120 mph in the 1/4 mile.

I had one engine that made about 520 on the dyno and ran a 1.35 60'/ 6.37 @ 106 mph 1/8 mile and 10.11 @ 130 MPH in the 1/4 mile at a bit under 3000 lbs 600' air.
Powerglide 8 inch converter, deep geared car.

I think the Wallace calculator is a bit generous on HP vs et.

Randy

[Nikolas Ojala]

Where do you find the moroso slide calc?

My best guess: Amazon.

[GOSFAST]

Where do you find the moroso slide calc?

My best guess: Amazon.

The Moroso calculators have always been extremely accurate.

Thanks, Gary in N.Y.

P.S. It is still available directly from Moroso, part #89650, runs about $12.00 or so.