Ive been fine tuning my current tune on my C7, and notice im getting bucking under very light thottle at low RPMs. From the log it looks like torque manament is pulling timing about 12 degrees causing this bucking sensation. But why? can someone please take a look at this log/tune and guide me in the right direction. Im a noob so please be detailed and dont use big words....hahaha. =D
14 c7 lt1 car btr 225 cam FBOs
Last edited by C7vette2014; 2 Weeks Ago at 02:08 PM.
Without digging too deep, torque model and DD are the big two players. If you have a high stall converter there are a couple of background tables that can cause this in lower gears. I know your VE is wrong - look at it in 3d format - big spike in the lighter throttle lower load that needs to be fixed. I know the torque model is wrong - nose diving pretty good for idle without any corrections off idle - doesn't coincide with your air models. DD looks stock below high loads. All of those will play into what you're seeing and feeling. Then sometimes it's dang near impossible to get rid of all of it....
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
7-11 seconds in that log it actually looks like there may be a problem on bank 2. Need a longer data log that 16 seconds to determine.
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I guess i forgot to mention the mods on the car, but i edited the post. FBO btr 225 ccam, stock converter A6. The VTT was lowered in the idle areas for stalling at stops and seems to help. I lowered VTT in the idle areas -- 0 and 550-750-950 rpms and also at 800 in the same rpms then interpolate vert, then took about 3 rows from the whole 0-800 and interpolated horiz to get what i have now. about 35%. just not sure what to change at this point to stop the tq man adv.
Yeah this tune is a combination of my previous tuner and my own stuff. alot i put back to stock, but for some reason, the previous tuner changed the whole tables of map b and C, and only the wot areas for A.Originally Posted by GHuggins
This is a 17 vette I'm tuning right now with the 225 cam, long tubes and a manual tranny.
VE table
225 cam.jpg
Airmass Torque Model
225 Airmass.jpg
MAP Torque Model
225 Map.jpg
Log with light throttle. I should note where you see it dropping slightly to the left, he's actually closing throttle down to 3% at those points, so timing is stable. Fueling and final torque is also still getting corrected and will continue getting tweaked until fueling is right.
Timing 225.jpg
His idle timing and throttle. Again, fueling and torque are still getting tweaked.
225 idle.jpg
So again, fix all of these and it should get you pretty close. Everything changes torque. Don't care if it's a cai. If it requires remapping the air models, torque is changing. It's just some things are more intrusive to it.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Is the bucking worse at 1500-2200?
There is a huge hump in your VVE table in that spot.
Capture.JPG
Tuner at PCMofnc.com
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My idle timing seems okay, however i do have some tq man adv at idle, i thought that was normal? it goes away when i start to accelerate but comes back at the low throttle inputs where the bucking occurs.
I see how smooth your airmass VTT looks, ill try to replicate. Im still working on VVE table everyday. my idles areas are good, around 5% give or take. just gotta do some more WoTs and cruise.
no its just around 1200-1400 ish. and my VVE table doesnt have that ramp in your pic.
I just double checked.. and it absolutely does have that ramp
see image.. you can see your file name in it.
Capture.PNG
Tuner at PCMofnc.com
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Looks the same to me.
C7 VVE.jpg
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VVE.PNG
this is what mine looks like.....granted i dont have it in dual window mode but looks the same either way....wth???? LOL
Last edited by C7vette2014; 2 Weeks Ago at 04:25 PM.
That huge spike is what I was talking about in my first post
What are the numbers in the table?
thats weird tho, why dont i see it on my file??? Trying to smooth out my VTT atm...getting real close
wait ...after looking at your screen shot, your rpm axis is different than mine.
VVE.PNG idk dont know if that makes a difference.....it shows like 2500 ish in those columns on your guys screenshots, i dont see that in the rpm ranges on my file....so weird.
Last edited by C7vette2014; 2 Weeks Ago at 04:53 PM.
The problem is your other axis. It only goes down to 0.3 instead of 0.1. The problem is between 0.1 and 0.3, and you don't show those lines. Change your pressure ratio axis.
The rpm isn't the real problem, it's the map axis and the fact that yours doesn't read below 0.30 that is the real problem.
Double check to see if your zone definitions have been changed under the dynamic tab then it should be the regular 1 bar map config once the ve table is opened.
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