annoying "binary" throttle feeling, please, any ideas.

[thomasK(austin)]

ok my rb25 240sx has this really annoying problem. what is does is this:ill be accelerating throu, say, 3rd gear up to about 4k rpms with about 75-90%throttle, i let off the throttle and it feels as if my car hits a wall, a very binary feeling. my acceleration is either OFF or ON. what usually causes this?

i currently have a recently tuned powerfc and a blitz bov vented to atmosphere, but it cant be that because my friend ran this exact bov on his car before he gave it to me and his car didnt have the binary throttle feeling.any ideas?

heres a pic of the motor for a referencethnaksthomas

[Wulfgang]

Actually, the symptom you describe sounds EXACTLY like a vented BOV.

[SeVa-S13]

Sounds like it to me too; different engines act differently.

[Shocker]

you might have the bov set to loose, and it just stays open and leaks out air longer than it should.. also it does look like you have an unsealed vac nipple by your throttle body, fix that as well, it will mess up your idle, its basically a boost leak. check your fpr and see what psi its at too.

[Nismo_Freak]

Your RB ready to have a train ran on it with SR power?

[Kansei240sx]

Your RB ready to have a train ran on it with SR power?

[Nismo_Freak]

External wastegate on what looks to be an HKS log manifold, and other parts = should try his luck against a few SR's here in Austin, one of which puts down over 600whp.

[Imissmyturbo]

Does your FPC have the O2 sensor feeback on or off? It's under the menu for the boost controller and warning functions. Mine is switched off. My does the same thing but it's more at highway speeds when I try and feather the throttle. It really sucks. I am using the stock Recircualtion vavle.If I keep the o2 feedback switched on the car will surge while cruising.

[Vkoslak]

Ha! someone else in Austin with an RB!

My car does the on/off throttle when cold. Once it warms up it goes away.

I think something may be wrong with my stock BOV as my motor tends to backfire at about 3-4k rpm once I let off the throttle (like when changing gears)