Q: Settings on Profec B Spec II -Stock Turbos

I recently reconditioned my engine, replaced the stock turbos (manual turobs, car is a manual) and installed a Greddy Profec B Spec II (I removed the original boost solenoids and plumbed it in as per the manual). Only mods are Pod filter, Upgraded Side Mount Intercoolers and Cat Back Exhaust. All I am hoping for is a about 10-11psi.

I have been struggling to tune the thing to find the right balance of all the settings. I followed the guide on TT.net but it doesn't provide much insight as to what the correct settings should be.

I have it currently on
Duty Cycle- 65%
Gain - 11%
Set Gain 0%
Limiter 0

I have a feeling that 65% is too high for that kind of psi, based on searching previous posts.

Boost spikes at 10.5psi and maintains about 0.5bar ~7-8psi, 8.5 in 1st, 8 in second and 7 in 3rd.

In lower gears I get a higher sustained boost pressure, but on the highway say at 90-100, WOT, 3rd gear, i seem to max out at 0.5bar ~7psi

At WOT in any gear - should I not be able to sustain full boost pressure? I realise the manual says that "boost pressure may not stabilise depending on engine characteristics", but i would think it should be more stable than what i am experiencing. With the OEM solenoids, I did not take much note of what boost pressure i was hitting/sustaining, as its ages since the engine was working with them. I have a feeling it could hit and sustain 9psi in almost any gear - is this correct?

I haven't yet touched the set gain because I am still not happy with the boost characteristics.

What do you think, and what are your settings for stock MT turbos?

 

This post on tt.net might help.

 

Thanks IB.

I have been through that. It doesn't say what is an appropriate value though. Any other ideas?

 

Its easier to read on psi.

Set gain is a psi/bar value depening on what u set it to. I put mine on 10psi to boost to 12.5psi. Set gain holds the wastegate closed until u reach the specified psi then is uses the other valuse. I would reccomend 7psi or 0.5 bar

set limiter to 12.5psi or whater bar

duty cycly would be around 50-60% (6psi stock acculator + 50% = 10psi give or take) (gain seems to effect this value).

then adjust gain to suit boost drop off and peak charastics.

The best way to learn is play with it.

 

What gain value are u using Zedzy? (do you have stock turbos?)

Cheers

 

i use 65 % for about 12-13 psi. dont remember my gain but its no higher than 9

 

Re-check your plumbing to the solenoid, if you've got them plugged into the wrong ports you will get similar results to yours.

 

beat me to it, that AND have you dc'd the wastegaste solonoids?

 

Will do that lol. It does work fairly reliable, although it does boost a bit slow.

 

The last couple of post were directed at fuzz, your install should be OK.

Your SET value should be about 1 psi less than your required boost to get fast boost.

 

I was overboosting when i set to about 1psi less, i think a few psi is slightly more consistent. Although i do have auto turbos.

 

I completely removed the original plumbing when i reinstalled the engine, I did take my time and double check everything, but there is a chance is stuffed something up.

boost solenoids were completely removed, and all 6 and 4mm hoses replaced.

I will do a boost leak test and check plumbing and see if that changes anything.

Cheers

 

Make sure hose going to actuators is connected to COM and hose from boost pipe connected to NO. If other way around, then you can't raise the boost.