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Rev holding between shifts


GEE-OTTO

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Not new to tuning (used OS to tweak and "correct" stock tune my 09 LGT) but new to the 2.5i specifically a 08 Legacy 2.5i 5MT ECU ID EZ1D302C. Going through trying to figure where to start to eliminate the revs holding between shifts? For me it more annoying than helpful having learned to drive manual on a C50 hay truck :lol: I looked at the DBW and Misc tables but they dont appear to be what/where I need to make the changes. Upshifts only as I rev match downshifts always (may not matter)

 

Thinking through what occurs while changing gears you let off the throttle, press in the clutch, change the gear, let out the clutch, and back on the throttle. Is there some logic to the effect of : while RPMs are rising or above a certain value and clutch switch circuit is closed/open hold RPM? Ive tested thru the situations on the street in any gear between shifts the RPM hold at the shift point until you fall below a certain speed then they will drop off.

 

A better way to describe it is if you accelerate and attempt a shift but do not shift and have the clutch pressed it holds the revs until you coast below a certain speed. Speed varies per gear it seem.

 

With all that said I started looking at the DBW, Idle Speed and Misc tables.

 

Any pointers would be great, also I wasnt sure what to log to further help figure out what to change .

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So it seems there is a table for overrun request that isnt defined for my ECU image yet that may be the cluprit. Ill ask the guru's on RR to define if possible if not do the LGT.com gurus have any idea :)

 

I know it may seem trivial but Ive never driven a manual that hangs the revs up so high btwn shifts or at all really. I rev match downshifts always my LGT doesnt do this btwn shifts

 

 

Also years ago the dealer had a TB to address sporatic idle (when the clutch was pressed in the RPMs would shoot way up then drop then spike again) it was super annoying. If i had a stock image without the update I could compare my updated one and go from there.

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Are you sure it's actually a tune-related issue? Sounds to me that the flywheel might just be heavier on your 2.5i. I can't imagine there's anything in the tune that intentionally keeps the throttle opened when the clutch is pressed in.... perhaps you could look into the idle-mode tables and the switch thresholds, but I honestly don't think the answer you're looking for resides in the tune.
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Are you sure it's actually a tune-related issue? Sounds to me that the flywheel might just be heavier on your 2.5i. I can't imagine there's anything in the tune that intentionally keeps the throttle opened when the clutch is pressed in.... perhaps you could look into the idle-mode tables and the switch thresholds, but I honestly don't think the answer you're looking for resides in the tune.

 

 

Good points! I run the same FW in my 08 as I did in the 09LGT. From day 1 with 7 miles on the clock it hung the revs so at least it didnt develop which is why i started down the path of altering some parameters in the tune.

 

I will seek out a virgin 08 2.5i 5MT map then run a compare in addition to getting those overrun table defined.

 

If only they still produced the COBB AP for our model I would take it to Mach V (my local COBB tuner) and have them button this up in no time.

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Target throttle and accelerator position would be on my list... if the target throttle lags behind your accelerator position, then it's likely something in the tune as you suspect.

 

Found that damned table it is called Target Throttle Angle Idle Airflow Minimum table phewwww and here is what it looks like:

08_25i_Base.thumb.PNG.f9ae0174c27249e69f94c37985d0dde4.PNG

 

I think I know where to start (reducing some of those 100's across the RPM range) but am not sure.

 

I will log those parameters then see where its hanging and the Throttle position to get a starting point. I dont think i will need to deal with AVCS tables but thinking about if i decease the amount the throttle is open (to zero) when it was open previously there may need to be some rework else where.

 

Maybe I should log cam advance and retard?

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Found that damned table it is called Target Throttle Angle Idle Airflow Minimum table phewwww and here is what it looks like:

[ATTACH]236930[/ATTACH]

 

I think I know where to start (reducing some of those 100's across the RPM range) but am not sure.

 

I will log those parameters then see where its hanging and the Throttle position to get a starting point. I dont think i will need to deal with AVCS tables but thinking about if i decease the amount the throttle is open (to zero) when it was open previously there may need to be some rework else where.

 

Maybe I should log cam advance and retard?

 

I don't see how that table would affect your issue. It's my understanding that's a base minimum throttle opening table that maps requested torque (drive-by-wire maps will map your accelerator position to a req. torque) to a target throttle angle. Also, that table only effects idle mode, I believe.

 

I would look at some logs, first. If you're able to monitor it real-time (either through an AP or with BtSsm), watch your real-time gauges as you're driving and trying to upshift.

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