440 Engine tuning suggestions
Ok, I took a couple of screen shots showing the inputs on the Wallace racing calculator and another showing the results using numbers from my engine.
You can see that the piston is over 3/4 inch up the bore when IVC occurs.
That means my effective stroke length is 2.543 inches.
If we used the exact same numbers we used to calculate my SCR but we only changed the stroke length to 2.543 inches you would get my ECR and that’s what the engines “sees” when it comes to octane rating verses compression ratio (ECR).
In the first picture you see all the inputs.
In the second picture you see the results.
The second picture shows an ECR of 9.74 and an effective stroke length of 2.543 by doing the math.
That all means that under running conditions the engine “sees” a stroke length of 2.543 inches. And if we use all the same numbers we used to calculate the SCR except we change the stroke from 3.313 and enter 2.543 we get a compression ratio of 9.74, which is what the engine “sees”.
I don’t think too many people would say you can’t run pump gas on 9.74:1, assuming a proper spark plug heat range, correct coolant temperature and a timing curve that matches the torque and power curves.
Thats why IVC, effective stroke length and effective compression ratio are critical to calculate so you know what you have and then make an educated decision on the fuel octane rating you need for ECR.
There is nothing “dynamic” about ESL and ECR. They don’t change, just like SCR doesn’t change.
Each one is a distinct and different calculation and they don’t change with rpm, load or anything else.
That’s why I never say dynamic compression ratio because it’s totally different than ECR and it’s based off VE and a bunch of stuff that is over my head.
If you calculate you SCR and then do the math to get ESL and ECR you have won the war.
Ok, I took a couple of screen shots showing the inputs on the Wallace racing calculator and another showing the results using numbers from my engine.
You can see that the piston is over 3/4 inch up the bore when IVC occurs.
That means my effective stroke length is 2.543 inches.
If we used the exact same numbers we used to calculate my SCR but we only changed the stroke length to 2.543 inches you would get my ECR and that’s what the engines “sees” when it comes to octane rating verses compression ratio (ECR).
In the first picture you see all the inputs.
In the second picture you see the results.
The second picture shows an ECR of 9.74 and an effective stroke length of 2.543 by doing the math.
That all means that under running conditions the engine “sees” a stroke length of 2.543 inches. And if we use all the same numbers we used to calculate the SCR except we change the stroke from 3.313 and enter 2.543 we get a compression ratio of 9.74, which is what the engine “sees”.
I don’t think too many people would say you can’t run pump gas on 9.74:1, assuming a proper spark plug heat range, correct coolant temperature and a timing curve that matches the torque and power curves.
Thats why IVC, effective stroke length and effective compression ratio are critical to calculate so you know what you have and then make an educated decision on the fuel octane rating you need for ECR.
There is nothing “dynamic” about ESL and ECR. They don’t change, just like SCR doesn’t change.
Each one is a distinct and different calculation and they don’t change with rpm, load or anything else.
That’s why I never say dynamic compression ratio because it’s totally different than ECR and it’s based off VE and a bunch of stuff that is over my head.
If you calculate you SCR and then do the math to get ESL and ECR you have won the war.