shftn7

In my case looking at a blower cam for my lil ecs1500. Why run 116 and then add +4 or +3? Will that help in getting more power under the curve? In N/A builds I have always down tight LSA's like 110 or most 112.

Proxses

NA and blower cams are very different. You normally want the wider LSA with a blower. And the +3 or +4 indicates a different intake centerline. Advancing the cam 3 or 4 degrees.

shftn7

From what I understand advancing the cam can help with low end power. Is that right? So can you run more duration and not sacrifice as much low end by advancing the cam?

Higgs Boson

these cars have variable valve timing so they can be programmed to advance down low and retard up high.

just call a reputable company and let them spec it for you.

shftn7

Higgs that's what I will do bit I still want to discuss it. How does this sound:

228/234 .617/.617 with a 116+4? This appears viable based on what I have researched so far.

Late Model Racecraft

Lobe Separation angle is just a result of correct valve events. A cam should be picked by valve events and the LSA and advance that is needed to get the valve events you want are just by products.

Say you have a 243/247 112+2 cam as your NA cam here are the valve events
IVO is 11.5 ° BTDC ( - indicates ATDC)
IVC is 51.5 ° ABDC
EVO is 57.5 ° ATDC ( - indicates BTDC)
EVC is 9.5 ° BBDC
Overlap is 21 °

But say for a blower car (Hypothetically speaking, This is just for example to show how changing stuff effects valve events) you wanted a 243/247 116+3

IVO is 8.5 ° BTDC ( - indicates ATDC)
IVC is 54.5 ° ABDC
EVO is 62.5 ° ATDC ( - indicates BTDC)
EVC is 4.5 ° BBDC
Overlap is 13 °


Now look at what has changed just by widening the LSA and adding another degree of advance.

There is lots of posts on topics like this online if you want to read more into it. Alot more goes into picking a cam than just picking numbers.

-Reid

**disclaimer**
I am not saying either of these cams are ideal for what i listed them as. These cams were just examples.

RussM05

It is my understanding with VVT, you have to almost completely wipe your memory clean of what worked with various mods on the LS motors.

Late Model Racecraft

That isnt necessarily true. The VVT has a very limited amount of movement. The idea is to get as close as possible with the camshaft, then do the fine tuning with VVT.

shftn7

Good stuff! ! So then your goals determine the valve events you desire?

Late Model Racecraft

Yes application is everything!

RGT

LMR. Great explanation.