Guys with tweecers and low rpm bucking, read this!

CManT1914

New Member
Feb 5, 2004
3,172
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0
Killeen, Texas
Okay, so as anybody in here who has a cammed out stang knows, with the cam comes along some low load and low rpm bucking, mainly below 2000 rpms for the average cam, but more severely sub-1500. Here's a trick to help out with that.

In the tables, find the "Spark Table - Base". Take note of the spark values for sub-2000 rpms and sub-40% load. They are as high as 40* advance! By reducing the timing advance, you are increasing engine load. Higher load equals less bucking. For a full explanation of this, visit this link, otherwise just keep reading.

http://tweecer.oplnk.net/viewtopic.php?t=5434&sid=8c12ae010c34d6b0f7fff54d136edeb6

What I did, was reduce everything 40% and 2000 rpms and under by half. So instead of having 40* advance at 1500 rpms and 20% load, I have 20 now. The better way of doing this is recording a datalog, and pointing out specific areas where the bucking is worst, and target those. I didn't have a recent datalog to do this though, so I just did everything below 2000 rpms.

When I went for a drive, the low rpm low load bucking was 95% GONE! I was cruising along in 5th gear, 40mph at 1200 rpm and it felt like stock!

The only disadvantage to doing this that I can possibly see, is you might lose a little fuel efficiency since spark is added in to increase efficiency. I can confirm or disprove this later, I haven't driven it enough to see if it effect the gas mileage. But it's worth it to me to get rid of that neck snapping, u-joint breaking sensation. :(

Hope this helps out some of you cammed guys with twEECers! :banana:
 
zenboy99 said:
Awesome, thanks for posting that.

I have a Tweecer R/T, just waiting on a laptop and my new 2006 Milan to arrive so I can tune the car and not have to worry about driving to work.

That's why I'm just getting around to doing any tuning. I have the bike I can ride if something goes wrong, lol.
 
CManT1914 said:
Okay, so as anybody in here who has a cammed out stang knows, with the cam comes along some low load and low rpm bucking, mainly below 2000 rpms for the average cam, but more severely sub-1500. Here's a trick to help out with that.

In the tables, find the "Spark Table - Base". Take note of the spark values for sub-2000 rpms and sub-40% load. They are as high as 40* advance! By reducing the timing advance, you are increasing engine load. Higher load equals less bucking. For a full explanation of this, visit this link, otherwise just keep reading.

http://tweecer.oplnk.net/viewtopic.php?t=5434&sid=8c12ae010c34d6b0f7fff54d136edeb6

What I did, was reduce everything 40% and 2000 rpms and under by half. So instead of having 40* advance at 1500 rpms and 20% load, I have 20 now. The better way of doing this is recording a datalog, and pointing out specific areas where the bucking is worst, and target those. I didn't have a recent datalog to do this though, so I just did everything below 2000 rpms.

When I went for a drive, the low rpm low load bucking was 95% GONE! I was cruising along in 5th gear, 40mph at 1200 rpm and it felt like stock!

The only disadvantage to doing this that I can possibly see, is you might lose a little fuel efficiency since spark is added in to increase efficiency. I can confirm or disprove this later, I haven't driven it enough to see if it effect the gas mileage. But it's worth it to me to get rid of that neck snapping, u-joint breaking sensation. :(

Hope this helps out some of you cammed guys with twEECers! :banana:

Well Now! ...... Lookie Here! :shock:

Who Would'a Thunk It :shrug:

A few short weeks ago you were all like .................

Man, I just don't get it :(

All this pcm & Tweecer stuff is just kickin my azz :bang:

I ain't never gonna learn all this stuff :fuss:

Seems to me ... someone ... on this site told you to keep at it :D

They said, " Don't worry Chris, things will start to make sense after a while if you give yourself time to learn a bit" :nice:

Makes one say hummmmmmmmmmmmmmmmmmm! :shrug:

Now ...... here you are ...... giving self tuning advice :rlaugh:

A short while ago ...... you couldn't even spell P C M :nono:

Now you're a friggin .......... :banana: TUNIN GURU :banana:

HA HA HA































I TOLD
YOU SO

Grady
 
BlueOvalStangGT said:
Thanks, I do have a recent datalog though, what do I need to look for?

Just keep an eye out for what rpms you're bucking worse at, and in the datalog, look to see what your load percentage is. Then adjust for those load percentages and rpms.

final5-0 said:
Well Now! ...... Lookie Here! :shock:

Who Would'a Thunk It :shrug:

A few short weeks ago you were all like .................

Man, I just don't get it :(

All this pcm & Tweecer stuff is just kickin my azz :bang:

I ain't never gonna learn all this stuff :fuss:

Seems to me ... someone ... on this site told you to keep at it :D

They said, " Don't worry Chris, things will start to make sense after a while if you give yourself time to learn a bit" :nice:

Makes one say hummmmmmmmmmmmmmmmmmm! :shrug:

Now ...... here you are ...... giving self tuning advice :rlaugh:

A short while ago ...... you couldn't even spell P C M :nono:

Now you're a friggin .......... :banana: TUNIN GURU :banana:

HA HA HA































I TOLD
YOU SO

Grady


LMAO, you were right Grady, it just takes patience. Thanks for the encouragement along the way! I'm still confused to what the PCM is though, where is it? What does it do? How do I get a good idle? Can you help me with my maf transfer? What injector slopes to enter?








:jester: j/k!

BlackVert said:
good info, thanks for sharing it!

No problem! :nice: