Time to buy a new semitruck, but not sure what brand

So how many psi to make 400 hp?

 

You’d have to bump your rpms up. I’ve gotten on it a few times to get out of a situation and at 1450 rpm it will put out 41psi of boost. That’s pretty close to max. Another 100 rpm higher and I’d be putting out the full 410 it’s got. As rpm goes up so does the HP per pound of boost. When I’ve done that I didn’t have my ScanGauge in here. I only used it for a 2.5 weeks just to make sure I knew what boost equaled 200hp. The ScanGauge can tell you engine load as well. I don’t have the KR version and I don’t think his features are worth the extra cost. I ordered a regular ScanGauge D from the ScanGauge website.

 

And how much torque are you making when your Rpms are 1000 and your boost is 25 and HP is 200? You realize there is usually a inverse relationship between HP and T right?

 

At 975 rpm and 200 HP I’d be making 1077 ftlb. I use this calculator. You can select to solve for torque or solve for HP.

Horsepower & Torque Calculator | Spicer Parts

 

My rating is 410hp 1450/1650 torque. The A26 has ratings up to 475hp 1750 torque.

 

What is max torque for that engine? At 1000 rpm you must be close to max torque. I don’t know anything about your engine but I would expect a 13 L to be around 1300 peak T. Anyway you cut it you are putting a lot of stress on things by twisting things to the max. It’s up to you

 

So without knowing your program and without looking at the HP/T chart, you’re pulling that hill at close to 1600 ft lbs if you have the cruise on. That’s more strain that I would put on my drive line for the sake of a couple tenths of fuel mileage.

 

Or even a lot of tenths, at some point he'll find the weak link and need a tow truck.

 

Hey.....if your a company man chasing fuel bonus what the heck. As for me.....I have well over a million miles on a 20 yr old 10.9 L truck and goodness knows how many miles on a 33 yr old B model Cat. I gotta fix the stuff I break and I’ll continue to downshift at 1500

 

Again, I’m not using full torque, I’m using only 25-27 psi, that about 10 psi less than what I could generate at my usual low rpm shift points when climbing. Peak torque is 1000 rpm in my motor. That’s why I included that calculator earlier. If I’m using only 200 hp at 975 rpm, that equals 1077 ftlb. I never use cruise, only my foot. Cruise control won’t use only 200hp like I do.