Boost Drop

[bugz]

Hi, I was hoping someone could help with trying to maintain boost in between gear changes. It hits 16psi then drops right down to around 3psi. It takes a second or two and then gets back up there. Just not sure if this is normal for my setup which is as follows.

R33 GTS-t RB25DET

GT3540R .86

Turbosmart 48mm ext wastegate

Tomei poncams

Blitz SBC id3 boost controller

Apexi N1 exhaust/ hi flow cat

Fmic

all required supporting mods... makes 434 RWHP

Any suggestions would be greatly appreciated

[DECIM8]

Got a atmo bov?

Ever doubt clutch?

Either of the two will help obvious double clutching will keep the revs up during changes but the atmo bov kills boost as vents air instead of recirculating.

[R34GTFOUR]

Either of the two will help obvious double clutching will keep the revs up during changes but the atmo bov kills boost as vents air instead of recirculating.

there wont be a difference in how boost is held between an atmo and recirculating bov, they both do the exact same thing bar the obvious part where on recirculates back into the intake

its normal for a turbo that size to take a second to respool inbetween gear changes. If you dont have a bov at all, that can cause the turbo to "lag" inbetween gears due to compressor surge, so get a nice sized bov thats going to breathe well and that should help.

Other than that, theres no real streetable solution, unless you like flat changing, antilag etc etc, its just the joys of having a large turbo on a smallish displacement engine

[DECIM8]

Yeah Im obviously on crack today, try again..

I was refering to a incorrectly setup bov i.e fluttering.

Edited June 3, 2008 by DECIM8

[R34GTFOUR]

Well you'd think that but how many people do you notice running insanely low psi gate opening or insane high gate psis? heaps..

So if it opens to early leaks, opens/doesnt open well/dose etc means boost is going to drop off because air is not correctly exiting the system.

Dont forget youve got that gate on there.. spring??

sorry i couldnt make out any of that lol

[DECIM8]

to much sugar my bad.. but yeah gt4 is right

[R34GTFOUR]

drugs are bad mmmkay

[bugz]

Thanks for the reply.....yeah should have said. It has an atmo BOV with a soft and hard setting. I think it may be on too soft. I will adjust it and see what happens. It was on the car when i bought it...is the adjustment option just a rice thing?

[dmr]

lol DECIM8

[joeyjoejoejuniorshabadoo]

flatshift...

[dmr]

Thanks for the reply.....yeah should have said. It has an atmo BOV with a soft and hard setting. I think it may be on too soft. I will adjust it and see what happens. It was on the car when i bought it...is the adjustment option just a rice thing?

adjustment option will be for your bov spring to suit your vac/boost. if it's too tight it will comp surge, which is why they can be adjusted.

[DECIM8]

Its prob to tight mate, losen it ..

I Had a pink donut.. 3 cheese burgers and a coffee milk shake... give me a break, maybe also a weight watches number :|

[joeyjoejoejuniorshabadoo]

clicky

[GeeTR]

In regards to turbo size....

What RPM do you make full boost?

When your changing gears and feeling this "lag" what RPM are the revs falling back to? Id thought the A:'s right there.

[nizmonut]

flatshift...

yeah what he said.

[TTT]

AntiLag

then change plates to WRC R33

[scathing]

AntiLag

then change plates to WRC R33

Or WOT-CAT

[R31Nismoid]

So is it this order?

16psi

gear change

3psi -->16psi

gear change

3psi -->16psi

???

If so, thats normal if your not shifting to kill the box

[bugz]

Hey Nismoid, thats pretty much exactly how it behaves on gearchange. Now that i know this is normal for this setup i wont go spending a ton of cash trying to fix it!

Thanks everyone for the input

[R33Turbo]

lol thought u were worried about boost drop in between gear shifts due to putting the clutch in lol