408 with stack injection cam selection help
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From: NWI
408 with stack injection cam selection help Been gathering parts for a few years and now it is time to pull the trigger on last few parts to put the engine together. I need some guidance on cam selection or event timing to try and spec one that might be able to take advantage of the individual throttle bodies. Looking to have a weekend warrior at the track, but still be able to take car on long cruise (Power Tour,etc.) and not hate myself do to its lack of drive-ability.
Iron block bored out 4.030" roughly 11.2:1 compression (might be a little bit higher since heads were decked to clean up surface)
stack injection, 8" long runners, 2-1/4" ID at top of throttle body
ls3 heads ported by Frankenstein
1-7/8" headers
4l80e transmission 3200 stall converter
9" rear with 3.40 ratio
Iron block bored out 4.030" roughly 11.2:1 compression (might be a little bit higher since heads were decked to clean up surface)
stack injection, 8" long runners, 2-1/4" ID at top of throttle body
ls3 heads ported by Frankenstein
1-7/8" headers
4l80e transmission 3200 stall converter
9" rear with 3.40 ratio
Last edited by snakeeyes; Apr 8, 2019 at 09:14 PM.
ITB's tend to tame cam idle pretty well by design so if it's a quality ITB then a good tune should make it a good driver.
What ECU are you going to run?
I can't really help you on the cam selection, ITB's are in a class of their own. I would call around and see what some of the major players suggest.
What ECU are you going to run?
I can't really help you on the cam selection, ITB's are in a class of their own. I would call around and see what some of the major players suggest.
IR needs very little overlap. Shoot for an LSA of 114-115*. Keep the duration a little short. Too much overlap and you'll create the famous "fuel cloud" that the Webers were famous for. After Comp Cams bought Inglese, they listed a selection of cams specifically for the 8 stack system. But now I can't find them.
Be careful about the size of your heads and valves. The IR systems are very sensitive to flow velocity. If the heads and valves are too big for your runners, you'll lose all your intake velocity and all your low end power.
The MS3x is an excellent choice for the 8 stack systems. There are a number of tuning strategies available for you to choose from, depending on what you're comfortable with and what your set up is. The self tuning features in MegaLog Viewer are really useful. But it will only get you about 90% of the way there. For that final tune, you'll need a good tuner on a road type dyno.
Avoid the "tea strainer" filter tops. They are very restrictive and will cost you a lot of power. My engine lost 100hp on the dyno by adding the filters. Some of that could have been gained back by some tuning, but it wasn't worth it.
Be careful about the size of your heads and valves. The IR systems are very sensitive to flow velocity. If the heads and valves are too big for your runners, you'll lose all your intake velocity and all your low end power.
The MS3x is an excellent choice for the 8 stack systems. There are a number of tuning strategies available for you to choose from, depending on what you're comfortable with and what your set up is. The self tuning features in MegaLog Viewer are really useful. But it will only get you about 90% of the way there. For that final tune, you'll need a good tuner on a road type dyno.
Avoid the "tea strainer" filter tops. They are very restrictive and will cost you a lot of power. My engine lost 100hp on the dyno by adding the filters. Some of that could have been gained back by some tuning, but it wasn't worth it.
