Greddy Profec B Spec Ii Problem!

[R33Turbo]

Hi,

The EBC is installed and tuned by Unique Auto Sports, it boosts up to around 11psi however it drops further near the redline to around 9 psi. This issue i already gave up on, but another issue that popped up is that on "peak boost" it shows my boost went up to like 12psi, but when i accelerate and look at the gauge it never even goes past 11psi, then the "last boost" shows as 11.4. So i dunno how this happens maybe it spikes as soon as i lift off the throttle? And the peak boost shows like at 12 psi which i was real shocked about, but i never saw this happen on the gauge (EBC gauge as i don't have a proper boost gauge)

I don't know if i explained myself properly so if u didn't understand ill explain it again

[Yo-Yo]

list of mods and specs like turbo etc. would help shed some light for the guys on here

[SL1D1N]

its probly just spiking and does it that quick it doesnt regisiter on the screen

if that helps, correct me if im wrong

Edited February 5, 2008 by SL1D1N

[NYTSKY]

its probly just spiking and does it that quick it doesnt regisiter on the screen

if that helps, correct me if im wrong

BINGO

[R33Turbo]

its probly just spiking and does it that quick it doesnt regisiter on the screen

if that helps, correct me if im wrong

Well thats correct!!! But then i thought the EBC "peak boost" mode was faulty cuz ive never seen it go over 12 psi, and if it did it shoulda alarmed as 12psi is set as "WARNING". ANywayz it spiked so fast i guess, and it spikes this fast everytime i accelerate cuz the "LAST BOOST" shows its also more than what the boost actually reached every gear i accelerate.

Mods are simple:

Cat back exhaust, EBC, pod filter

Do i lower the the "SET GAIN" or something? wat do i do? cuz it is spiking right?

Edited February 5, 2008 by R33Turbo

[R33Turbo]

reason why i didn't want to drop the "SET GAIN" is cuz it is said that it should be increased if it cannot hold the desired boost till redline, and it drops 3 psi so obviously it doesn't. Or can increasing it too high can cause the boost to tail off as well?

[R33Turbo]

any help is appreciated !!! really ?

im pretty sure im not the only one with greddy profec b spec II

[gtstee]

any different at night time? i found my peak boost hit better and more often at night time

[R33Turbo]

yer i mean peak boost does hit better at night cuz its colder, but theres no reason why it shouldn't show on the "EBC gauge" and only shows on the "peak boost" mode. which means it spiked real fast.

what settings do u have?

[Wacky Dee]

'peak boost' is the maximum boost the ebc has EVER recorded ... eg. when it wasn't tuned properly, you may have reached 12psi. It's the 'last boost' you should turn on and watch out for. Best to do it on a dyno though.

The greddy profec b is a PITA to tune ... imo.

[bubba]

If it's spiking when it comes on boost then it's likely your SET GAIN is too high, the gate is being held closed till too close to your target boost setting. Try lowering it slightly.

I managed to get rid of a hesitation my car had when it came on boost by lowering the SET GAIN by 0.2psi, now it comes on just as strong but is smooth as.

If boost is tapering off you need to play with your GAIN setting, do this slowly, a couple of % at a time.

[Wacky Dee]

the worst thing about the greddy ebc is that you don't know what the boost is being set to as it's set in a stupid percentage value ... eg. 50%

50% of what ??? It just makes no sense and without spending a couple of hours on a dyno and trying to tweak the settings, it's impossible to get it right imo. But even on dyno it's shit because you can't really create load on the engine on the dyno like you can on the road (up a hill for example).

[bubba]

It's a percentage of your base boost. Not hard dude, not hard at all.

i.e. to get 12psi with my RB20 actuator I use a SET value of 22%

You just have to remember that your GAIN slightly affects the max boost aswell so if you find you are needing a high GAIN value to stop creep or taper, you will probably have to lower your SET value to compensate.

[Wacky Dee]

what do you mean by 'percentage of your base boost' ? You mean stock boost ? From what I understand stock boost on an R34 GTT is 7psi. So if you set the 'SET' value to 50% does that mean it adds another 50% of 7psi on top of 7psi ie. 10.5psi all up ??

[bubba]

"base boost" meaning "actuator boost"

So yes, if your actuator is good for 7psi then a SET value of 50% would be a 50% increase on 7psi (so roughly 10psi).