Possible tuning tip for Miniram/LT1/LT4 tip-in stumble - Third Generation F-Body Message Boards

ULTM8Z · 07-29-2007, 05:24 PM

I think I may have <ahem> "stumbled" (

) across something that may help people with the dreaded throttle tip-in stumble on these types of manifolds. Forgive me if this is already common knowledge....

I started taking notice of the fact that very small changes in TPS produced large MAP deltas (at low throttle positions). This is particularly apparent around idle speeds (when the tip-in stumble is generally the worst). So I went to the AE table entitled "Accel Enrich Delta MAP Factor Multiplier vs TPS". For small TPS values, 0% & 12.5% in the table, I richened up the multiplier by 15% at 0%TPS and 10% at 12.5%TPS. My thinking was that at idle, the absolute throttle position is zero and at just barely off idle (where the stumble generally occurs) the it's somewhere between zero and 12%. So I figured could target just the off idle transition by increasing the overall AE vs delta MAP for just these two throttle positions. Now, unless I'm mistaken, the TPS% in this table is NOT a delta TPS, but rather it's the absolute TPS. For example, 0% is closed throttle and 12.5% is 12.5% throttle (NOT a 12.5% change in throttle position).

Any rate, test driving it produced a noticeable results in that the throttle feels particularly more crisp coming off idle. It was pretty damn good before using the $DA3 AE tables, but this little mod almost makes it perfect. I'm still going to play around with it a little more to see if there's any more improvement to be had, but I like the results I'm seeing so far. My '06 Pontiac Vibe commuter car has a VERY crisp off idle transition so I'm kind of using that as my goal. I'm almost there... Though I'm not sure if I'll get there until I completely solve my rough idle issue (I just hope I don't have to start from scratch on the tuning when and if I do).

Grim Reaper · 07-31-2007, 11:01 PM

Great stuff.

Please keep any future "Miniram/LT1" intake tuning tips you develop within this single post and later I'll try collecting this (and other Miniram/LT1) tuning tips together and add it to the "Tuning Guide" in the sticky section.

I believe it is posts like this that people are often looking for, but have difficulty finding.

junkcltr · 08-01-2007, 12:47 AM

If you are talking about the $8D code then this is true. I played around with it quite a bit last year getting the transition from N/A to boost right. It also plays a big role at low throttle settings. One thing to keep in mind is that MAP AE is sync and TPS AE is async. I tried removing as much async as possible. LT1 intake here.

ULTM8Z · 08-01-2007, 09:54 PM

Quote:

Originally Posted by Grim Reaper

Great stuff.

Please keep any future "Miniram/LT1" intake tuning tips you develop within this single post and later I'll try collecting this (and other Miniram/LT1) tuning tips together and add it to the "Tuning Guide" in the sticky section.

I believe it is posts like this that people are often looking for, but have difficulty finding.

I'll try to remember that.
----------

Quote:

Originally Posted by junkcltr

If you are talking about the $8D code then this is true. I played around with it quite a bit last year getting the transition from N/A to boost right. It also plays a big role at low throttle settings. One thing to keep in mind is that MAP AE is sync and TPS AE is async. I tried removing as much async as possible. LT1 intake here.

You know, I still don't get the sync vs async thing...

And yes... $8D.

ULTM8Z · 08-19-2007, 09:43 PM

Well, I tried some different values (higher and lower) for this particular AE table "Accel Enrich Delta MAP Factor Multiplier vs TPS" and didn't see anymore improvement. It would appear I discovered the optimum setting on the first try- richened up the multiplier by 15% at 0%TPS and 10% at 12.5%TPS!

Not that I'm complaining...