I've read about this in STi's, I'm wondering if any TT'd Z's have experienced this? From what I understand it is an unexpected increase in boost for example you're set at 8 psi, then as the rpms go up you're slowly hitting 9psi, 10..11 and so on. How is this addressed and prevented?

I know boost spike is somewhat similar as well.

 

Some members have said it does happen on their Greddy kits. A lot is dependent upon the type of solenoid used and the responsiveness of the type of controller used. I have not heard of any boost creep issues with the APS. Maybe Peter can answer how they avoid this with their kit.

 

No boost creep I've heard of with the APS integrsated WGs ; however, for those needing more than 11psi boost (ie low CR LB), the defualt WG springs need to be upgraded. Peter could you confrim this? I wanna do it before my LB goes in next month , since getting access to the WG once installed is a PITA.

 

The greddy kit doesnt creep, but it does spike. There is a little difference. Creep is much worse then a spike tho.

Creep is when the wastegates simply cannot keep up anymore and boost will progressivly rise up... and in lots of situations it will happen very very quickly.

Spike is just a breif moment where its almost as if there is a lag in the wastegates response. I think the Greddy kit only does this because of the steep reentry angle of the wastegates... there is no reason twin 38mm gates shouldnt be able to keep up. If someone made custom downpipes and vented the wastegates open atmosphere, I doubt it would ever spike like that... this is something I may do eventually.

 

This generally occurs when there's not sufficient wastegate exhaust flow, if you have boost creep then you will need to install larger wastegates in order to gain control of the boost pressure.

Peter

 

The APS/Garrett turbos have larger than stock Garrett bypass orifices (32 mm from memory) to ensure well controlled boost pressure in high rpm/high boost conditions.

Peter

 

Depends on how much boost pressure you intend running G3po, there are a good number of higher pressure actuators than can be utilised depending upon your boost strategy.

I normally like to use a combination of a pressure actuator and electronic solenoid to control/map the boost pressure though some guys just prefer to let the high poundage actuator control the boost pressure.

Thanks

Peter

 

Peter,
Do you have to change the springs to run 12lbs on the APS kit or is programming the Unichip sufficient?

 

I may go as high as 20psi. So what mod to the provided WGs would you recommend up there?

 

I talked with MRC about this , And they found that with low CR and APS TT they were maxing out at about 11psi without modification to the default actuator. Peter can you confrim this info?

 

Peter I may go as high as 20psi Unichip controllable down to ~10. So what mod to the provided WGs would you recommend up there?

I intend to try something with two maps , one for pump 91 and another for track 100.

 

Both my old Greddy kit and my PE kit "spike" at high RPMs, especially in 2nd and 3rd. Pisses me off somewhat. Colder weather makes it worse.

 

yah..my greddy kit spikes from 16psi to 18psi...a/f still looks fine..did this on the dyno as well in 5th gear pulls...still at low 11's:1...but i'd like to keep a consistant 16psi...unable to set the stupid-a$$ auto mode...WTF...any suggestions besides what everyone else has already said in the past- as to how to set the auto mode???
and, while on the subject..anyone else have a profec e-01 that registers lower boost than a mechanical gauge??? my defi shows 16psi..the e-01 shows 10psi..maybe altitude affects this??? any ideas..same thing on going deep's car (same altitude-5500ft)
any suggestions??? thx!
TODD

 

Bump for info from Peter on this.

 

Only a matter of mapping the computer to run 12/13 psi boost, over this pressure a higher poundage actuator will be required to increase boost pressure.

Peter

 

Thanx any recommendation as to who sells a compatible higher poundage actuator?

 

I suspect we would need to fit 14/15 psi actuators and then map the computer to control the boost betwwen the actuator pressure and the actual pressure required.

I prefer not to rely on the actuator only for the boost curve, I prefer to map the boost via the electronic solenoid and therefore have far greater control of boost across the entire rpm range.

Peter

 

Well I'm not surprised at that pressure as they disconnected the electronic solenoid so all of the turbo pressure was only being controlled via the actuators, not clever imho.

Peter

 

Makes sense now. Thanx