Low RPM bucking... can it be cured?...

WA2FAST · Post by **WA2FAST** » Thu Oct 27, 2005 9:51 am

I just finished tuning a friends car on his TwEECer, he has a 90LX, 347, 10.5:1 compression, all of the goodies, stout motor. He likes driving his car in his neighborhood at very low RPM's for noise reasons and I can't talk him out of it. I have drivability nailed on it perfectly, but when he gets down around 1500rpm, it starts to buck really bad. I attribute 95% of this to the cam... it's bassicaly a .600 lift B303 cam (I can't remember the exact specs right off of the top of my head). Is there ANYTHING I can do to try to remedy this at all? I don't think there is, but I could be wrong. Please let me know if you have any ideas, thanx!

Paul · Post by **Paul** » Thu Oct 27, 2005 10:28 am

Mine 347 has perfect drivability and will lug @ 1000RPM in 5th all day long. My cam isn't that big (E cam with 1.72RR) but it used to buck like crazy until got the load and the maf correct. I nailed the MAF with my LC-1's and then nailed LOAD with some 3rd gear WOT runs.

SHaFT7 · Post by **SHaFT7** » Thu Oct 27, 2005 10:30 am

i'd like to see your tune paul...specifically your sealevel load table :D

WA2FAST · Post by **WA2FAST** » Thu Oct 27, 2005 10:45 am

That's just it though... the KAMRF's on his car are damn near perfect... that's why I say it's probibly the cam, maybe something with timing, I don't know... Mine with the B303 cam is perfect down low as well, but I can get another 300-400 out of it... that could just be the difference in cams though. I don't ever drive my car down that low so I don't care... but he does.

Paul · Post by **Paul** » Thu Oct 27, 2005 10:48 am

WA2FAST wrote:That's just it though... the KAMRF's on his car are damn near perfect... that's why I say it's probibly the cam, maybe something with timing, I don't know... Mine with the B303 cam is perfect down low as well, but I can get another 300-400 out of it... that could just be the difference in cams though. I don't ever drive my car down that low so I don't care... but he does.

My KAMRF's where perfect as well but commanded was in the 16 - 17 range. It took my wideband to get it right. Now the KAMRF's = commanded = wideband and all is right in the world

Paul · Post by **Paul** » Thu Oct 27, 2005 10:49 am

SHaFT7 wrote:i'd like to see your tune paul...specifically your sealevel load table :D

I'll post the LOAD table after work.

Jack Hidley · Post by **Jack Hidley** » Thu Oct 27, 2005 6:17 pm

A friend of mine, Nate, solved this problem a while ago. Here is the link to the problem and solution he posted.

viewtopic.php?t=5434&highlight=

It has always shocked me that Ford wasn't able/willing to solve this problem on the several hundred thousand EEC-IV/V Mustangs that they sold over the years.

WA2FAST · Post by **WA2FAST** » Thu Oct 27, 2005 8:28 pm

Looks good, thank you very much for the info, I'll give that a shot the next time I work on the car.

Low RPM bucking... can it be cured?...

Who is online