Two cam vendors, two (big?) different ideas for my 5.3
05-26-2017, 08:10 AM
#21
You spec the valve events IVC... EVO the same. But you still have to account for overlap differences and IVO and EVC in how the cam performs in a smaller 5.3L.
I can't remember who did it, but they did an overlay of the same cam in an LS1 and 5.3L and the graphs were identical... just the LS1 was up around 20HP and 20ft-lbs of torque everywhere.
Pretty much the same thing you see with an LS2. It's good for about 20/20 over an LS1 cammed the same. The added bore and cubes make more power but the valve events react to the piston speed and intake harmonics the same way. Of course, the added cubes means the bigger engine drives better with the same cam. So you then have to make some adjustments in the IVO/EVC if you want to keep the IVC/EVO the same to bring that overlap number down so the smaller engine behaves as well but produces a similar power curve.
I can't remember who did it, but they did an overlay of the same cam in an LS1 and 5.3L and the graphs were identical... just the LS1 was up around 20HP and 20ft-lbs of torque everywhere.
Pretty much the same thing you see with an LS2. It's good for about 20/20 over an LS1 cammed the same. The added bore and cubes make more power but the valve events react to the piston speed and intake harmonics the same way. Of course, the added cubes means the bigger engine drives better with the same cam. So you then have to make some adjustments in the IVO/EVC if you want to keep the IVC/EVO the same to bring that overlap number down so the smaller engine behaves as well but produces a similar power curve.
05-30-2017, 06:01 PM
#22
Teching In
Thread Starter
Hello (OP here).
I called Cam Motion today to talk about ordering a cam. I discussed the truck's setup and intended use, and was recommended a custom grind. If I wrote this down properly, it's 224/234 on 111.5 with lift in the .600 realm.
After staring at dyno charts, specs online, different vendor's thoughts on usable RPM range, reading the sticky posts here, and this discussion, it was clear to me that I don't know enough about cam design to just pick one off of a website. Making the phone call really helped, and I've got a cam and spring kit ordered.
I also realized that regardless of what I do, this 5.3 will probably make more power just idling than the stock1982 2.8V6 made at its peak (all 112 horsepower of it!)
I called Cam Motion today to talk about ordering a cam. I discussed the truck's setup and intended use, and was recommended a custom grind. If I wrote this down properly, it's 224/234 on 111.5 with lift in the .600 realm.
After staring at dyno charts, specs online, different vendor's thoughts on usable RPM range, reading the sticky posts here, and this discussion, it was clear to me that I don't know enough about cam design to just pick one off of a website. Making the phone call really helped, and I've got a cam and spring kit ordered.
I also realized that regardless of what I do, this 5.3 will probably make more power just idling than the stock1982 2.8V6 made at its peak (all 112 horsepower of it!)