Stall & Big Cam
12-08-2004, 06:24 AM
#1
Stall & Big Cam How are you guys getting your High stalled A4 cars to idle and run smooth? I am working on a buddies car, 4400 MW 2.7str, PP heads, and a FM14. I have tried lowering the VE table, Running airflow, timing, ect. It doesn't seem that any of it is really working. I can get the car to either start great or idle great, but neither both. It always has surging.
Thanks
Thanks
12-08-2004, 06:41 AM
#2
Originally Posted by Black02SS
How are you guys getting your High stalled A4 cars to idle and run smooth? I am working on a buddies car, 4400 MW 2.7str, PP heads, and a FM14. I have tried lowering the VE table, Running airflow, timing, ect. It doesn't seem that any of it is really working. I can get the car to either start great or idle great, but neither both. It always has surging.
Thanks
Thanks
Whats the specs of that cam?
I just tuned a 99 Z28 with a 3200 stall and a TSP 231 237 112lsa and it does have some issues but it runs "ok".
12-08-2004, 08:35 AM
#4
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The high stall is not the tuning problem other than
the lighter mass making the idle loop easier to
destabilize. It's the cam I expect. It sounds like
you are tuning blind and trying stuff. I think you
want to force open loop and tune the idle mixture
by the O2s when hot, by the VE table. But many
headers cars also have O2 heat problems making
this a bit iffy (as well as messing with the closed
loop idle, and there are other things about the
trimming that want straightening out on Fbodies).
Might raise the idle up for a start and get it stable,
wherever, and then work on bringing it down as you
get mixture closer to right.
the lighter mass making the idle loop easier to
destabilize. It's the cam I expect. It sounds like
you are tuning blind and trying stuff. I think you
want to force open loop and tune the idle mixture
by the O2s when hot, by the VE table. But many
headers cars also have O2 heat problems making
this a bit iffy (as well as messing with the closed
loop idle, and there are other things about the
trimming that want straightening out on Fbodies).
Might raise the idle up for a start and get it stable,
wherever, and then work on bringing it down as you
get mixture closer to right.
12-08-2004, 02:08 PM
#5
In reagards to tuning blind, that isn't the case at all. I have a wideband setup in his car and put the car in open loop. It appears that no matter what I try, the car won't respond.
Also, I tuned my buddies TSP 231 in his A4 with no problems. This isn't my first rodeo.
Also, I tuned my buddies TSP 231 in his A4 with no problems. This isn't my first rodeo.
