Big Cam not liking 6th

[n3wbi3]

Hey guys...
Just finished my car and its not liking 6th gear @ 100km.
Getting a stutter/jerky effect and not smooth if the revs dip under 2000rpm in 6th. Put it in 5th and shes fine and smooth.

Spoke to my diff builder and he said move upto 4.11s and it will smooth it out heaps in 6th. Due to the large cam its not liking 6th.
4.11s in a 6 speed auto? Not sure about it.

Some help feed back and info would be great.

Current set up:
Cam 234/244 111
3800 stall
3.7 diff
VF ls3 AUTO

 

[Hq King]

Hey guys...
Just finished my car and its not liking 6th gear @ 100km.
Getting a stutter/jerky effect and not smooth if the revs dip under 2000rpm in 6th. Put it in 5th and shes fine and smooth.

Spoke to my diff builder and he said move upto 4.11s and it will smooth it out heaps in 6th. Due to the large cam its not liking 6th.
4.11s in a 6 speed auto? Not sure about it.

Some help feed back and info would be great.

Current set up:
Cam 234/244 111
3800 stall
3.7 diff
VF ls3 AUTO

39 or 411s probably better suited to your cam and stall but talk to your tuner first i would have thought a good engine and trans tune should be able to smooth things out

 

[07GTS]

tune it down low it needs more attention down there as the airflow/torque model is all out of balance from the overlap/reversion

 

[greenacc]

Keep it in 5th until you get to 110.

 

[Immortality]

Sounds like 3 good options or a combination of all 3. Get the tune looked at and see if the can be solved that way, have the tuner modify the shift tables to stay in 5th longer and a diff gear upgrade isn't the worst option should the first 2 not be satisfactory.

 

[Forg]

Regarding the tune thing ... tuners like to tune for power, because they can do that in a half-dozen dyno runs (OK - I exaggerate - but not much).
The thing that often gets overlooked is the REST of the tune over the rest of the load vs revs range, ie. where your engine spends most of it's time. Stuff like idle, response off idle, low loads at highway speeds, etc. Because that can take day's worth of effort.
I reckon get the tune looked at as a first step ... most likely the low-load highway-speed 6th-gear scenario hasn't been properly addressed.

 

[panhead]

When I've had middling cams of the size the OP is talking about the car usually goes back a couple of times to have little aspects of the tune corrected as characteristics from vehicle to vehicle will often have little differences.


n3wbi3 - what's the lift specs on the cam?





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