A Couple Of Niggling Rb26 Questions,very Laggy...

[groper]

ok, just a couple quickies in relation to a modded r33 gtr... its running pfc, stock turbos with steel wheels @19psi, stock bovs and a bigger apexi intercooler... car was already modded when purchased recently so i dont know exactly how its all been done. also, im not sure if the setup is working as best as it could be... the car makes good power when turbos are spooled but lags more than i believe it should after a gear change at WOT. i have a suspision that the tubos stall (or surge?) when the throttle shuts when shifting, as i hear a `ptrrrrrrr' (slowing down) then spool up all over again, then feel the accel again...shouldnt they already be spooled and whine almost immediately?

1. how is boost controlled (by what mechanism ie. bleed valve etc) on a stock rb26? could there be room for better response with the $22 boost controller...

2. what does compressor surge sound like? Is it like a 'ptrrrrrrr' sound im getting?...(not just the ptshhhhhh of the bov) and how can i fix? BOV issues maybe?

id love to eliminate some of this lag, any suggestions?

[T04GTR]

you get that..

[GeeTR]

Groper,

What RPM are these laggy WOT gear changes occurring at ?

[groper]

Groper,

What RPM are these laggy WOT gear changes occurring at ?

flat bikkies mate, it does it even at 7000prm+... only time i can keep them spooled is if i dont shut the throttle completely, like when accel full boost, back off a LITTLE for a sec (small bov sneeze) then foot back down again in same gear. i get what id call `normal lag` to recompress all the intake plumbing but at least i can hear the whine almost immeditately telling me they didnt spool down...

if i back off COMPLETElY in same gear fully boosted for a sec, (take right foot OFF) same prrrrrrr sound, and the turbos slow right down, when put foot down again, i can hear them spool all the way up again and i get my very laggy problem...

is this normal?

[groper]

anyone?

[WilYawn]

Can you hear your bov's releasing pressure at gearchanges?

[groper]

yep, but perhaps they open too late maybe, or not capable to release/flow enough volume perhaps?

i thought it might be the bov`s, but read on here some people reckon they get less lag without bov`s at all. or block them off???

failing that, i think it might be the boost controller not closing the wastegate quickly enough after a gear shift? how is the wastegete(s) controlled on a 33GTR? new car, im learning still...

what you think???

Edited February 26, 2007 by groper

[SiR_RB]

I'm getting the same problem with my car lately on Hi boost @18ish psi,

Running -7 turbos, and greedy profec b spec 2 boost controller. Never had a problem with lag/flat spot between high rpm gear changes but lately it's started

Even tried turning my gain and set gain down still no luck, car doesn't even chirp 2nds anymore cos of this delay,

Anyone know what may be the problem?

Ps. It doesn't do it on low boost @14psi

[Rolls]

Maybe the Bov isn't closing properly.

[SiR_RB]

How can you check the stock bovs are opening and closing properly?

[Room42]

If the throttle is closed at revs this is what happens... open bov means the turbo will gently slow down. Closed bov means the turbo will rapidly slow down... there is more to it but this is the basic scenario