Aleviate bucking not with spark but with fuel...
11-23-2005, 07:05 PM
#21
since I have the same bucking issue and SVo 30's, I've loaded up changes to proportional fuel, but not as agressive as the two of you to start. I'll see how it drives and go from there.
I also went less agressive in the integrator delay (50% increase except for mode 0). Seems like overshooting would would be just as problematic as we are trying to measure the correct time to sample a given AFR change the computer made. Any idea how much further downstream the O2s are in headers than stock? 50% more distance, 100%? And how does the gas speed change with headers??
I haven't sorted it out in my mind, but with 1 7/8" headers, I may go to 2X compared to stock in modes below 10 as my low rpm scavenging sucks.
I haven't had a chance to drive the car yet, but I wonder if some of my trims will turn positive. I cut the VE pretty hard in some low MAP areas and I'll bet it was do in part to proportional fuel issues.
One question though, have you changed the idle proportional fueling? I've cut it from 128 in all cells to 100, but given my idle issues I may try lower.
I also went less agressive in the integrator delay (50% increase except for mode 0). Seems like overshooting would would be just as problematic as we are trying to measure the correct time to sample a given AFR change the computer made. Any idea how much further downstream the O2s are in headers than stock? 50% more distance, 100%? And how does the gas speed change with headers??
I haven't sorted it out in my mind, but with 1 7/8" headers, I may go to 2X compared to stock in modes below 10 as my low rpm scavenging sucks. I haven't had a chance to drive the car yet, but I wonder if some of my trims will turn positive. I cut the VE pretty hard in some low MAP areas and I'll bet it was do in part to proportional fuel issues.
One question though, have you changed the idle proportional fueling? I've cut it from 128 in all cells to 100, but given my idle issues I may try lower.
11-23-2005, 09:54 PM
#22
turn idle proportional off, its worthless IMO. but if you want to keep then just make changes and log, see what helps the o2s oscillate better.
i have been thinking about messing with the delays and what not so the car cannot respond to changes as fast, however i have not found a great "scientific" way to go about this so i havent messed with it yet. i think that could end up making it worse beucase if a lean condition is noticed and then the car goes richer all of a sudden for a throttle chagne, the car will respond slow and could make it buck more. only table i can really comment on is proportional fueling since i know a way to check it out and make sure its right. i would like to see the other changes made and use a WB to confirm chagnes helped.
i have been thinking about messing with the delays and what not so the car cannot respond to changes as fast, however i have not found a great "scientific" way to go about this so i havent messed with it yet. i think that could end up making it worse beucase if a lean condition is noticed and then the car goes richer all of a sudden for a throttle chagne, the car will respond slow and could make it buck more. only table i can really comment on is proportional fueling since i know a way to check it out and make sure its right. i would like to see the other changes made and use a WB to confirm chagnes helped.
11-26-2005, 11:31 AM
#27
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In my A4, I had completely gotten rid of all bucking, even with my 4000 stall TC. But since I have been running in SD, I now have a little bit of it around 1500 to 1800 rpms. To me that sounds more like fuel related than anything.
In our M6 with the large cam, it had very little bucking until he changed the clutch and adjustable Master Cylinder to the HD Ram race clutch.
In our M6 with the large cam, it had very little bucking until he changed the clutch and adjustable Master Cylinder to the HD Ram race clutch.
Last edited by Lady Redhawk; 11-26-2005 at 11:36 AM.
11-26-2005, 12:13 PM
#28
Originally Posted by Lady Redhawk
In my A4, I had completely gotten rid of all bucking, even with my 4000 stall TC. But since I have been running in SD, I now have a little bit of it around 1500 to 1800 rpms. To me that sounds more like fuel related than anything.
In our M6 with the large cam, it had very little bucking until he changed the clutch and adjustable Master Cylinder to the HD Ram race clutch.
In our M6 with the large cam, it had very little bucking until he changed the clutch and adjustable Master Cylinder to the HD Ram race clutch.
Bill
11-26-2005, 12:36 PM
#29
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Originally Posted by Bill Bowling
I am also running SD Mode in my A4 and still have some bucking around the same RPM.
Bill
Bill
11-26-2005, 12:49 PM
#30
Originally Posted by Lady Redhawk
Have you adjusted the TCC Apply/Release tables?
Thanks.
Bill
11-26-2005, 12:55 PM
#31
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Originally Posted by Bill Bowling
No I have not messed with those tables. I did increase the trans pressure long time ago. Are you using FlashScan? If your are can you send me your tune so I can take a look at the tables and compare them with mine?
Thanks.
Bill
Thanks.
Bill
11-26-2005, 01:05 PM
#32
Originally Posted by Lady Redhawk
I don't have my current tunes on this computer. But, I can send you a FlashScan tune from last March. It isn't the SD tune I am running now, but all the tranny tables should be the same. What addy do you want me to send it to?
Thanks,
Bill
12-09-2005, 09:42 AM
#37
Well, I finally said fuckit and went open loop a few days ago. I still get the bucking. Prop fueling should not be playing a role in this anymore since im in open loop and the o2 sensors dont make any difference. Whats more, i used HPTuners realtime AFR control and tried from 12.5:1 to 16.5:1 with little or no reduction in bucking. This leads me to believe that there are other factors at play besides fueling. Ive also done my share of toying with the spark tables and thats not helping much either. I dont know how those guys claim they can cure the bucking out of a t-rex cam, when we cant (well, I cant) even clean up a little f-13 
Im beginning to think it may just be the nature of the beast.
Im beginning to think it may just be the nature of the beast.
12-09-2005, 10:51 AM
#39
Originally Posted by WS6FirebirdTA00
im have troubles with mine at 1600 rpm with my f13, what size injectors you have? my car goes rich on me, i think mine are a little too large