So I just did a whole bunch of mods:

Billet K16
injectors & boost hoses
coils & new plugs
larger intake piping
intercoolers
997 throttle body
IPD plenum
AMS 1 bar wastegates
fuel filter
Sachs 2.5 clutch
MAFLESS tune

The issue I am having is some very noticeable distinct surging up and down while at constant speed. On the highway, my foot is not moving at all but the car is clearly surging up and down significantly. It's like the throttle plate is constantly opening and closing even though my foot is not moving on the pedal. Especially bad between 2k & 3k rpm's. It seems to get a little worse when the load increases such as when going up slight inclines on the highway. It also surges up and down really bad on initial cold start up. There also is a significant cut off/hesitation every time I re apply throttle after letting off.

I did a thorough boost leak test and found no leaks. I did some data logs and sent them to the tuner. He is still working on it but his initial findings are that it is not the map but something mechanically wrong with the car.

Of note is that the car did not do this before.

 

what a well considered mod list and terrific improvements. can't offer anything on your issues, but once you sort them, that thing'll be a blast. good luck.

it's possible you've discovered a weak fuel pump issue with the added demands the bump in power is making upon it.

 

Maybe...the issue is only at very light constant throttle. At WOT there is no issue at all.

 

i feel foolish for even mentioning it, but is it even possible you're experiencing our "variocam" stutter, so peculiar to our cars? ( others could explain this more knowledgeably than i'm able ) and i ask only because i avoid the range btw 2800-3100rpm as deliberately as i can. for just that reason. it goes into 'hi-lift/low-lift alternation btw the two at will, and it bothers me a lot.

makes me wonder if your new parts are accentuating this phenomenon. either way, it's a range i think most will agree is a rev range to be in, and thru, and as quickly as is possible and not one to stay in for long.

just a thought.

 

With what you had done it could be many things but my guess its in the software connected with mafless.

 

you changed t/b. did you calibrate the new t/b to the dme?

 

Not familiar with that one...how is that done?

 

https://www.6speedonline.com/forums/...ody-reset.html Second post.

 

Turn the ignition on without starting the car, leave it on for 1 minute or until you hear the throttle body open and close.
Your symptoms sound like a boost leak, maybe your diverter valves are acting up.

 

WOW!!!! that made it a lot better....bad news it came back after a few full throttle runs. Good news, did another reset on the side of the road...fixed it again. I think somehow there is some kind of back pressure getting back to the throttle body and setting it off some how. I purposely did a bunch off abrupt on off's with the pedal...that when the issues came back.

What resetting didn't fix is the cut off / hesitation when I subtly re-apply throttle after letting off subtly. Hard pedal inputs are fine.

I would suggest everyone does a reset on a regular basis.

Thanks guys