RB25 boggs right after shifting....

[Imissmyturbo]

For the longest time I thought I was loosing boost between gears but I was watching my boost gauge this morning and I was seeing full boost but the car will lag for a split second. I then came to the conclusion that it was running rich between gears and it must be related to Airflow throught the MAF/Recirce valve. I have the stock valve on the car so it is running closed loop. I am guessing that the valve isn't able to flow enough or isn't setup right. I don't get any flutter or compressor noise. I guess I could look into some electronics to solve the problem. Kinda sucks since I have a PFC but there isn't anything on them to deal with MAF voltage between shifts. I hate MAF setups!

[Slo_240sx]

How is your idle? When you free rev does it drop down a lil then come back up? I'd check your timing.-Alex

[Imissmyturbo]

Idles pretty good. Free reving it won't make it stall but if I drop to idle under load it some times will stall. I am used to it but when others drive my car they stall it out. I also have a problem with going down the road and I am accelerating slowly with light throttle it's will open the BOV and the car will jerk. I feel this is another one of the crappy things about having a MAF car.

[goofynick6]

Make sure you have no boost leaks (pressure test system).

I find that when you let off to shift and nail the throttle again, the rb20 ecu likes to make the car go very rich for a second due to the tps adding throttle enrichment...there's a way to adjust it in the eprom, but I haven't found it yet.

Nick

[Slo_240sx]

Have you tried a diff BOV? It sounds like your diaphram inside the bov its weak. Alot of DSM guys like to do a penny trick. They take a penny and dent the top of the bov and it holds the diaphram tighter. If not then I have one laying around I can sell to you.

[Valley]

so.. figured out what was up?

is the rb a cbv or bov stock? if its supposed to be a cbv and you're venting to atmosphere then it will cause EXACTLY what you're describing. try recirculating the vented air behind the MAF if it is was a cbv. (from the pics i just looked up, it DOES look like a cbv after the MAF stock, please correct me if i'm wrong though)

dsm guys crush the 1g cbv such that it will hold more boost than the spring will allow, they crush it a bit... when i had my gsx it was crushed with a bench vise. no penny involved.

[Slo_240sx]

Same difference. They crush it down to hold more boost so it won't creep open. His might be coming open early of the diaphram is damaged.

[Valley]

true true.... if it isn't caused by preassure loss elsewhere in the system, or through something in the ecu like goofynick6 suggested.

whooops... missread his first post... heh... i feel like an ***,