Am I doing something wrong?

Here's what I am putting into the calc.
235 Intake duration
239 Exhaust duration
113 Lobe searation
109 Intake centerline

4.03 bore
4.00 stroke
64cc combustion chamber
.04 head gasket
4.03 HG bore
-.01 piston-to-deck clearance
28cc piston dish

4.00 stroke
6.125 rod length
46.5 adv intake closing angle

RESULTS
3.5509 dynamic stroke length
0.4490 distance of piston from BDC
.03 quench distance
9.508 SCR
8.553 DCR

 

I am assuming those are your @ .050 lift durations. The 46.5 IVC is also a @ .050 #. The DCR # is usually calculated from the "advertised" durations @ .006. Your #s are probably in the mid 280's to 290 degrees. The spreadsheet in the Advanced Performance Tech section on LS1Tech is a easy to use Excel sheet, just plug in your numbers. It gives 9.508 SCR and 7.276 DCR plugging in 284 and 288 as .006 figures and the .006 IVC is 71. Do you Know what the .006 durations are?

 

My cam card says duration @ seat, not at .006

Intake 292, exhaust 298

 

Ok if I put those numbers in I get 7.02 DCR. Wow that's low.

 

but its good for turbo. that means you can run more boost. i would think anyway lol.

 

so the added timing did nothing?

 

The spreadsheet is setup to use .006 numbers. If yours are at the seat it would give low #s, thats why I plugged in my figures. Will the cam grinder give you the .006 #s? If so, you would know exactly where you are. Your cam would need 11 to 1 compression or more to work well n/a. That's why a lot of popular cams designed for cars don't work well in our low compression trucks. They have a low DCR and make them a dog down low. Now with that spreadsheet anyone can change around a lot of things and come up with a cam that will work the best for their application. I would guess you could run around 28' timing with that low compression without KR.

 

I haven't messed with it yet, the track was closed on Friday night and I didn't get a chance the rest of the weekend. Looks like we found the source of the problem. I didn't realize that the DCR was that low on the motor. Looks like it's gonna take a turbo to wake this thing up. Thanks for the help everyone.

I'll keep you guys posted on the effects of the timing changes.

 

I still think its got alot left in it with tuning form my experience with my setup. Good luck. Im sure a turbo would wake it up nicely.

 

HAHAH sorry 1slow.....

But do you think tuning can make up for over 1 full point of DCR? Im asking now doubting!! Yes everyone can tune their vehicle better. None are truely perfect. But iddnt his DCR come out to 7.0? Most N/A on tech are aiming for 8.5?

Solve the problem. Just hurry up and throw on the turbo! lol