turbo transition

[pigeon]

Hey guys.
Im sure this has probably been brought up a hundred times before so here it is for the 101 time.
My primary to secondary turbo transition, is not what I would consider smooth! Up to 4500rpm, boost control (10 psi) engine smoothness and power delivery it superb. Then, when the second turbo should spool, I get a hesitation for a few seconds and a hear a kind of (pssstt…..pssstt…….pssstt……) noise before the second turbo kicks me up the arse and boost spikes to 12.8 psi.
Any one experienced this before or got any ideas?
Mods are:
trust airinx dual air intake system
hks 3 inch downpipe, mid pipe and exhaust. (Currently running with a 3” cat converter)
nippondenso fuel pump
NGK ht leads
cooling mist water/methanol inj kit
sheepdog blow-off valve
hks twin power ignition system
bonez street clutch
knightsports ecu
apexi avcr
after market AST
stainless intercooler pipes


cheers adam.

[pigeon]

anyone?

[ianelvar]

Hi there

Best place to start is here: http://www.autosportracetech.com/RX-7/TurboTroubleshooting.htm

At a guess, you\'re looking at a problem with either the vacuum or pressure tanks holding pressure. Use this: http://www.turborx7.com/images/Technical/vacuum_hose_diagram2.jpg to find all the one way valves, take them out and test them all by blowing through them.
They have an arrow pointing in the direction that air should flow, and should stop you blowing through the other way. Pretty sure that\'ll be at least part of your problem. Also look for hoses that look like they\'ve split, but they can be really hard to see.

Post up the results of your investigation and hopefully we can get to the bottom of it.

HTH

[pigeon]

Hi there
 
Best place to start is here: http://www.autosportracetech.com/RX-7/TurboTroubleshooting.htm
 
At a guess, you\'re looking at a problem with either the vacuum or pressure tanks holding pressure. Use this: http://www.turborx7.com/images/Technical/vacuum_hose_diagram2.jpg to find all the one way valves, take them out and test them all by blowing through them.
They have an arrow pointing in the direction that air should flow, and should stop you blowing through the other way. Pretty sure that\'ll be at least part of your problem. Also look for hoses that look like they\'ve split, but they can be really hard to see.

 
 
cheers mate.
i had chance to have a quick look under the bonnet today, in between the rain, and found that the hose going to the vaccuum/boost port on the charge relief valve has a kink in it. not enough to completely stop flow but enough to reduce it. im hoping that this is whats causing it. if not, well never mind will have to keep looking.
thanks for the help.

[ianelvar]

No worries, that\'s what we\'re here for
I sometimes tee my boost gauge into one of the lines for either the vacuum or pressure tanks to check them if I\'m having problems. Might help if you still have issues.