Jump to content
SAU Community

Help Setting Boost Controlla

Mareko

By Mareko,
in Queensland

 Share

Recommended Posts

robbo_rb180 Grand Master

robbo_rb180

Posted
Posted

adjust the duty cycle in 5% increses til you get boost u want. if it starts to creep or spike turn down the gain.

there is no exact setting to achieve acurate boost levels, its all trial & error.

Bunta Grand Master

Bunta

Posted
Posted

How To Tune Your Greddy Profec B spec II

Before you begin, you should have an idea of what you're aiming for. Due to my Turbo having steel wheels I will be aiming for 19psi , that leaves me some headroom for the occasional spike, I will henceforth refer to what you're aiming for as "desired boost pressure".

Definitions and things you need to know before you start:

SET:

This is how you set the boost pressure. Rather than setting it in psi or kPa, the Greddy unit allows you to adjust it as a percentage value, from 0% (greddy unit essentially turned off) to 100% (greddy unit will set the boost as high as it can). This setup demands a certain amount of trial-and-error to properly configure it since you have to make adjustments, then drive under WOT (Wide Open Throttle) and see what the maximum boost pressure achieved was throughout the entire RPM range.

SET SHOULD BE SET TO A CONSERVATIVE VALUE WHEN BEGINNING TO TUNE YOUR GREDDY UNIT. 30% SEEMS TO BE A CONSERVATIVE SETTING BASED ON MY TESTING AND BASED ON OTHER REPORTED NUMBERS, AND TAKING INTO CONSIDERATION THE LINK BETWEEN SET AND GAIN (see GAIN below).

GAIN:

Is defined in the manual as the value to adjust the "boost consistency". You should set GAIN to 0 when beginning, and you will then test the car under WOT while paying attention to the boost pressure. If the boost goes up and then falls off at higher RPM, you will want to increase the GAIN by a conservative amount (5% should be relatively conservative to begin with, then when you want to fine-tune it, you can go down to intervals of 1%). When you increase the GAIN value, the corresponding boost that you will go up to will be higher even if you leave the SET value alone. GAIN SHOULD BE SET TO 0 WHEN BEGINNING TO TUNE YOUR GREDDY UNIT.

START BOOST:

(also known as SET GAIN because that is what is displayed on the unit when adjusting this setting) is the lowest boost that the Greddy unit will begin increasing the boost from under WOT. You want this to be as close to the SET value as possible, since you want to keep as close to your desired boost as possible. However, setting it too close to the SET value will cause the boost to spike. You should set this to a conservative setting when beginning to tune your Greddy unit. Then you can fine-tune it later to get it as close to the SET value as possible without causing the boost to spike. Fortunately, you can set this in psi or kPa, thankfully Greddy didn't decide to let this be adjustable in % like the SET value.

START BOOST SHOULD BE SET TO YOUR DESIRED BOOST PRESSURE MINUS 4 PSI (about 28 kPa).

WARNING:

This is the maximum boost that you do not want to exceed.

Fortunately, you can also set this in psi or kPa like the START BOOST value. When the boost exceeds the WARNING level, it will kick in the LIMITER, which decreases the boost a certain amount that you can set.

WARNING SHOULD BE SET TO YOUR DESIRED BOOST PRESSURE PLUS 1 PSI FOR THIS TUNING STAGE .

LIMITER is the boost percentage that the Greddy unit will lower by when the WARNING boost pressure is hit. LIMITER SHOULD BE SET TO 4%.

PEAK is the peak boost value that the unit has seen since the last time it was cleared. To clear it, go to the peak boost display, and hold down the set knob until the unit beeps and "---" is displayed. CLEAR THIS BEFORE YOU BEGIN JUST IN CASE YOUR UNIT HAS A HIGH BOOST ALREADY RECORDED.

LAST BOOST shows you the last boost that was recorded every time the accelerator is released for 3 seconds. TURN LAST BOOST ON BECAUSE IT IS A GOOD DIAGNOSTIC TOOL WHEN TUNING YOUR UNIT.

Keep in mind that when displaying in kPa, it does not show it technically in kPa, but rather misleadingly in bars, which Greddy inconveniently tries to justify by sticking x100 kPa next to the display. Therefore, 100 kPa will be displayed as 1.00 x100 kPa. Psi will also unfortunately be displayed in psi x10 so that 19 psi will show as 190, adding to the confusion.

Another very important thing to keep in mind is that when you first power on your car or the Greddy unit, WARNING will be set to 14.5 psi (100kPa, or 1 bar) until you interact with the Greddy unit by pressing any button. This "feature" is not documented in the manual.

The following steps should be taken in exactly this order, taking into consideration all of the previous information:

1. Change boost pressure units to psi if so desired (see manual).

2. Set WARNING to your desired boost pressure plus 1 psi (about 7 kPa) (see above).

3. Set START BOOST (SET GAIN) to your desired boost pressure minus 4 psi (about 28 kPa)(see above).

4. Clear PEAK boost value (see above).

5. Set LAST BOOST to ON (see above).

6. Set GAIN to 0 (see above).

7. Set SET to 30% (see above).

8. Set LIMITER to SET minus 4% (26% if you followed #7).

9. Test for boost falloff at high rpm. You should probably do this in a wide open area with no other cars nearby and preferably no cops. It is also good to have somebody in the car with you that can watch the gauge while you concentrate on not wrecking your car. If there is no boost falloff, then go to #10. If there is boost falloff, then increase the GAIN by 5% and test again. Keep in mind that when you increase the GAIN value, the corresponding boost that you will go up to will be higher even if you leave the SET value alone. Repeat until the boost pressure does not decrease, or until you feel surging. If you feel surging and the boost pressure still decreases (not sure if this is possible) then decrease to the last level that you did not feel surging at.

10. Increase SET by 2% and adjust LIMITER accordingly, then test again. Keep increasing by 2% until desired boost level is obtained.

11. Increase START BOOST (SET GAIN) by 1 increment and test until surging is felt or the WARNING level is hit and the display turns red, then decrease to the previous setting.

Once you have followed these steps, you will have roughly tuned your unit. To fine-tune it, repeat steps 9 and 10 except this time only increase or decrease by 1 increment.

This is a bit of a bitch to do on the road, I would suggest doing it on a dyno if at all possible.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • 677_GTR
      R33 GTR running -9 with no tune

      By 677_GTR · Posted

      Thanks for all the replies fellas. Gonna finish putting it back together and see how it handles the set up. If it starts pinging it’ll be parked.
    • suko
      J50 clock date suddenly reset to January 1

      By suko · Posted

      Well, I can recommend the partial AV system translation CD I ordered from Car Audio Workshop in NZ. Whilst it didn't address the date issue, it has conveniently translated on-screen menu items into English, and now allows the GPS-received time to be offset in hours rather than minutes, so I can display Eastern Australian time accurately ( and bump it by another hour when daylight savings starts ).
    • GTSBoy
      Baron's R34 GT-R build thread - car in Japan for 5 years -_-

      By GTSBoy · Posted

      Yuh, if it's 45°C outside, my car is driving in it.
    • soviet_merlin
      Baron's R34 GT-R build thread - car in Japan for 5 years -_-

      By soviet_merlin · Posted

      I'd be curious to hear more. Otherwise, have you driven a modern x-trail? I wonder how it compares. Here in Australia they are/were popular for rentals and fleet vehicles. I have been in some and my impression was they are bad. But, this may have been very different in the 2000s at a good trim level. Twenty years is plenty of time to make the model worse. I do very much agree with the 2 silver cars in the garage approach. But, not driving because it's too hot would not leave a lot of time in the year for many Australians. I don't think you need to worry too much unless the car has actual issues with overheating. 
    • BaronOBeefdip
      Baron's R34 GT-R build thread - car in Japan for 5 years -_-

      By BaronOBeefdip · Posted

      Back again. I returned to Japan in Jul/Aug to spend time with the car on my birthday and remind myself what all the sacrifice and compromise is for. It happened to line up with the monthly morning meet in Okutama, which I have been wanting to go to for a long time. It's a unique event at a unique spot with really rare, interesting, and quirky cars. It's where all the oldheads and OGs gather. The nighttime scene at DKF certainly has its place and should be experienced if you're into cars, but there's too much bad attention and negativity around it now. IMO the better time is Sunday morning at DKF or Okutama; it's more chill and relaxed. I'm glad I was finally able to go, but not sure it's worth the drive from all the way from Nagoya immediately the day before, unless I was already staying in Tokyo for the days right before the meet, because you have to wake up quite early to make it in time. Funnily enough though I didn't drive the car all that much this trip because it was just too damn hot. While there were zero issues and running temps were nominal and the A/C was strong, RBs already run crazy hot as it is. Sure, it took it all like a champ but something about driving these cars in the ridiculous heat/humidity bothers me and makes me feel like I'm asking too much of it. I'm just me being weird and treating the car like a living thing with feelings; I'm mechanically sympathetic to a fault. Instead I was mainly driving something else around - a KX4(silver) 2001 X-Trail GT, that I acquired in May. There's a few different flavors to choose from with Xs, but visually it's the Nissan version of the Honda CR-V. Mechanically it's a whole different story as this, being the top-trim GT, has an SR20VET mated to a four-speed auto and full-time AWD! It was a very affordable buy in exceptional condition inside and out, with very low mileage...only 48k kms. Most likely it was owned by an older person who kept it garaged and well-maintained, so I'm really happy with how it all worked out. It literally needs zero attention at the moment, albeit except for some minor visual touch-ups. I wanted something quirky, interesting, and practical and for sure it handily delivers on all three of those aspects. I was immediately able to utilize the cargo and passenger capacity to its full extent. It's a lot of fun to drive and is quite punchy through 1st and 2nd. It's very unassuming -in the twisty bits it's a lot more composed than one would think at a glance- and it'll be even better once I get better tires on it(yes, it's an SUV but still a little boat-y for my liking). So...now I have two golden-era Nissans in silver. One sports car and one that does everything else; the perfect two-car solution I think👍 The rest of the trip...I was able to turn my stressed brain off and enjoy it, although I didn't quite get to do as much as I thought. I did some interesting things, met some interesting people, and happened into some interesting situations however, that's all for another post though only if people really want to know. Project-wise, I went back to Mine's again to discuss more plans and am hoping to wrap that up real soon; keep watching this space if that interests you. Additionally, while working in the tormenting sweatbox that is the warehouse, I was able to organize most of the myriad of parts that my friend is storing for me along with the cars, and the 34 has a nice little spot carved out for it: And since it can get so stupid hot in there, that made it all the more easy -after I was standing there looking at the car and said 'f**k it'- to finally remove all the damn gauges that have mostly been an eyesore all this time. Huzzah. The heat basically makes the adhesive backing on the gauge mounts more pliable to work with, so it was far less stressful getting this done. I didn't fully clean it up or chase the wiring though; that will happen once I have the car in closer possession. Another major reason to remove all that stuff is to give people less reasons to get in my car and steal s**t while it's being exported/imported when/if the time comes, which leads us to my next point... ...and that is even though it's time in Japan is technically almost up since it's a November car and the X would be coming in March, I'm still not entirely sure where my life and career is headed; I don't really know what the future looks like and where I'm going to end up. I feel there's a great deal of uncertainty with me and as a result of that, it feels like I'm at a crossroads moreso now than any point in my life thus far and there are some choices I need to make. Yes, I've had some years to consider things and prepare myself, however too much has happened in that time to maintain confidence and everything feels so up in the air; tenuous one might say. Simply put, there's just too much nonsense going on right now from multiple vectors. Admittedly, I'm struggling to stay in the game and keep my eyes on the prize. So much so in fact, that very recently I came the closest I ever have before to calling it quits outright; selling everything and moving on and not looking back. The astute among you will pick up on key subtext within this paragraph. In the meantime I've still managed to slowly acquire some final bits for the car, but it feels nice knowing there's not much left to get and I'm almost across that finish line; I have almost everything I'll ever want for my interpretation and expression on what it is I think an R34 should be. 'til later.
×
×
  • Create New...