pdd

iTrader: (3)

i'll be in a parkin lot lugin along in second at 1300rpm's and the car is surgin/buckin like a bitch. will tuning cure this. im going for a dyno tune thursday.

HumpinSS

iTrader: (1)

mULTIPLY THE VE TABLES AT 400,800 AND 1200 BY 3%

MyLS1Hauls

iTrader: (2)

Yeah, tuning will help...also you should be in first. Bigger cams dont like to cruise unloaded at low engine speed. As long as the motor is loaded, it wont buck, but load it and unload it...I have to keep letting out the clutch, move, then push it back in sometimes.

Slowhawk

iTrader: (12)

Actually tuning will not help much since the H/C setup and aluminum flywheel don't mix very well for low gear/low rpm situations

MyLS1Hauls

iTrader: (2)

Didnt notice the aluminum flywheel...but changing the VE tables and adding a little timing down low helped mine some, but I have a stock weight clutch setup.

SS SLP2

iTrader: (8)

which table in EDIT is used to add timing ?
thanks Johnny

Another_User

I think that the problem lay somewhere in the VE tables, and maybe partially in timing. I have been pondering this very same problem for quite awhile. I wish either I, or somebody else, would just figure it out so we can all fix it!

Slowhawk

iTrader: (12)

There is a point that the car will buck at lower rpms while increasing the Cam size.We are spoiled enough to have fuel injection and can cure most of it.A way to fix it is add some timing and add fuel to bog out that area which is something I won't do.The Corvettes are also lighter,which with a lighter Flywheel and the tallish first/second gear can cause some aggrivating bucking at low rpm which the Cam was not intended to even be driven at.The basic rule is the bigger the Cam,the worse low rpm driving will become

Another_User

A hotcam ain't that big. I just need to figure out where to tune...

Another_User

Aha...darn I love HPTuners. They have a VE item to monitor while you drive. Sweet. Now I need to make a run and see what it does...

Slowhawk

iTrader: (12)

A Hotcam is not hard to tune in Takes practise but you'll get it by spending hours reading this site.

Hard is tuning in a 248/250 .620/.610 on 109 centerline in a 346ci motor for a daily driver in traffic

Another_User

I have been sitting here staring at charts, diagrams, and Autotap logs for hours trying to figure out what is going wrong. I am beginning the think my EGR may be the root of evil in this situation. I am going to disable my EGR and remove all of the timing advance that it dials in just in case, and give it a run tomorrow. I would imagine that the EGR may be part of the problem because of multiple reasons:
1) The EGR spark advance lines up with where the stock program has an unusual spot in volumetric efficiency.
2) Since I can't tune the amount of EGR gas, and the computer probably doesn't know any better, then it is possibly putting in too much exhaust during part-throttle cruising because of the cam.
3) The changes that are made in volumetric efficiency for the cam probably multiplies the EGR problem (lowering the volumetric efficiency at low-rpms).

Just some thoughts I thought I would throw out there.

pdd

iTrader: (3)

Another_User

Well the problem isn't EGR. I have the Knock Retard to prove it...back to the drawing board.

gojo

iTrader: (12)

Have you tried raising RAF's?

ataylors

iTrader: (2)

All I had to do to mine, was raise the timing a few of degrees to 800 and a couple at 1200. Also raised the idle speed to 850. This is with a 224/224 114 +2