My car has done it off and on not to badly I just did the TB mod and it does it a little worse. if I go into boost below 3500 RPM's at about 3PSI it studders till the secondarys kick on at 3500 RPMs. it feels kinda like I dont got the fuel for the air going into the engine witch is BAD I do it every once and a while when im not paying attention and I get on the gas a little to much, but now that I did the TB mod its as soon as it sees boost. any ideas of how to make it stop or what exactly it is???
thanks

 

Holy crap! I noticed my car doing that yesterday when I was on the freeway...

I'm not supposed to be seeing boost yet (400mi. on rebuild), but I "accidentally" wanted to see what would happen at low (2-3psi) boost in 5th gear. The exact same thing that Josh is describing happened to me too.

Like, let's say I'm watching my boost gauge, so that I'm in the little "BOX" that connotates '0-1psi', if I stay in there, the car runs rich on my A/F gauge. As soon as I give it more throttle (and begin boosting between 2-3psi) the car will run lean and stutter... Weird.

 

I dont knowwhat it is???

 

no one knows???

 

No one knows...

(lol)

We're screwed man.

 

i had the same problem.....but i doubt my solutions is the same as yours....... i accidently put 460cc injectors in my car instead of the 550's.......so everytime it would hit around 3500rpm...it would hesitate really bad, then start boosting'........ i tried everything.....then i replaced the injectors thinking they were bad, and noticed the part #....... put the 550's back in..hesitation is gone!....

all i can say, is maybe the injectors are bad? just a possiblity

 

its the secondary staging with the Rtek ECU, the fuel mixture needs more fine tuning since you have 550 primaries and 720 secondaries, it will be tough to get seamless staging with any form of stock ECU.

if you are using an SAFC or equivalent to tune fuel it should be slightly rich to lean at that point in the RPM/throttle range since it is dumping more fuel with the larger secondaries it will require leaning out some after that point but i only suggest doing it with a wideband or by a professional tuner, if you do not have a MAF tricking device you will need one to even consider trying to clean up the hesitation.

 

hmm interesting, my AFR even though I know its not accurate at all never goes down when im getting that hesitation. its running way rich the whole time. it wasnt doing this befor last week and when I put the TB mod on it got real bad. My throttle response has greatly improved but also I noticed on today(havnt drove the car all weekend) and notice that the boost is also droping boosts hard to 10 PSI then falls off to 5 right away. could all of this be a boost leak from my FMIC couplers??? I know both my reducer couplers both look pretty rough im in the process of getting new ones and Tbolts.