bayside_supra Posted March 14, 2015 Share Posted March 14, 2015 Hi people Not being particularly knowledgable about these things I am hoping someone can give me some advice. Car is a TT 6 bpu, with a Greddy profec b spec 2 boost controller. A more knowledgable mechanic then me tried to help me set it up along with the fuel cut defender. The car spools up great now and is properly quick! Last night at midnight when it was very cold out I think I may be overworking the turbos abit though. At first the set boost was at 23% and while testing in the daytime on Thursday it was boosting to about 1.15 bar. Last night though I think it might have gone abit far? As fun as this was I don't think it will do the turbos any good will it? Or is it an ok level? I turned the set boost down and down, it's now at 13% and last night it was still peaking at over 1.2 bar, then I ran out of road and time to test it anymore. It's also odd because on Thursday it would hit fuel cut at around 1.25 bar but last night it didn't? These are all the current settings. Any advice on what to change if I do need to change anything would be great. The car is rapid now but I just don't want to over work it. Quote Link to comment Share on other sites More sharing options...
Ric Posted March 14, 2015 Share Posted March 14, 2015 A boost controller can't lower boost, only raise it. The jspec without a restrictor ring will boost upto 1.6bar on it's own due to the inadequate wastegate. You need a restrictor ring in the exhaust to limit boost to 1.0 bar (with the boost controller turned off) Then you can raise it to 1.2 bar reliably. Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted March 14, 2015 Author Share Posted March 14, 2015 Right ok that sounds simple enough. These symptoms will definitely point to my car not having a restrictor ring? One of these will do the job? Quote Link to comment Share on other sites More sharing options...
Nic Posted March 14, 2015 Share Posted March 14, 2015 (edited) If it's only boosting to a maximum of 1.15bar and 1.28bar with the boost controller on, it must already have a restrictor ring fitted, if it didn't it would be a lot higher than that. What boost pressure does the car make with the boost controller turned off? Have you gone through the set up process in the manual? http://www.greddy.com/upload/file/PRofec_Bspec2.pdf Edited March 14, 2015 by Nic (see edit history) Quote Link to comment Share on other sites More sharing options...
Scott Posted March 14, 2015 Share Posted March 14, 2015 That's your peak boost. I wouldn't worry in the slightest about 1.28 to be honest, I happily set mine like that to get the boost coming on hard and strong. It'll only peak at that for a fraction of a second and then settle at whatever you have it set at. Do you have a boost gauge? If so, turn off the boost controller and see what the boost settles at on a hard pull. You may need a second pair of eyes to do this. If you don't have a boost gauge, set the boost controller as low as it'll go on the gain and boost settings and see what it reads on a hard pull as above. When you have that reading, you want to be around 1.0-1.1 bar. If it's less then you need to open out the restrictor ring as it's causing too much of a restriction on the exhaust flow. If it's more than 1.2 then you'll overboost no matter what you do and you need a better restrictor ring. Once you are happy that all the above is in order, set the boost setting at what you want then start incrementing the gain setting. Start at around 10% and increase until the "hard pull" test settles happily on 1.2. Keep increasing the gain until it won't hold 1.2 on the hard pull then step back a bit. Do another couple of pulls and see what the max peak is, you don't want to have that any higher than 1.3(ish)bar to be on the safe side. The odd flash peak of 1.35 didn't even bother me, as long as it settled down to 1.2 during the pull. Remember, your turbo's aren't working hard when they come on song, they only start really working hard at the top end of the rev range where they have to keep up with the consumption of the engine. A peak of 1.3 coming on boost is nothing compared to 1.2bar at the top end Quote Link to comment Share on other sites More sharing options...
Nic Posted March 14, 2015 Share Posted March 14, 2015 Just to add, peak boost pressure will also vary depending what gear you are in, the higher the gear the higher the peak boost will be, so you will need to set up the boost controller to reach the desired level in a higher gear. Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted March 14, 2015 Author Share Posted March 14, 2015 From memory it will peak at about 1.15-1.18 with the controller off. I do have a defi boost gauge though so I can test that again tomorrow. It definitely did not hit fuel cut even with the FCD set lower then it is now with the controller switched off. So can't be any higher really. If this is the case I have a restrictor ring already? It seems the adjustment is all in the gain setting then? What about the set boost that I was adjusting last night? What does that change? It's interesting that it didn't make a huge difference from 23% down to 13%... Thanks for the advice so far. Quote Link to comment Share on other sites More sharing options...
Scott Posted March 14, 2015 Share Posted March 14, 2015 From memory it will peak at about 1.15-1.18 with the controller off. I do have a defi boost gauge though so I can test that again tomorrow. It definitely did not hit fuel cut even with the FCD set lower then it is now with the controller switched off. So can't be any higher really. If this is the case I have a restrictor ring already? It seems the adjustment is all in the gain setting then? What about the set boost that I was adjusting last night? What does that change? It's interesting that it didn't make a huge difference from 23% down to 13%... Thanks for the advice so far. Definitely sounds like you have a restrictor ring in. If you are peaking less than 1.2bar just now then you should be ok. Make sure that this is in 4th or 5th gear at least though, as Nic says. It's a little over the ideal but I wouldn't get too worked up about it. You have 2 different settings in these boost controllers. Boost and gain. The boost you want to set at the level you are after, in this case 1.2bar. The gain is how hard the controller comes in to hold the pressure, the reason for gain control is that every car/setup is different and it's good to get it running at its optimum. You want the gain as high as you can get it while the controller still maintains boost levels. Following my instructions above will get you there. If you want to be cautious then keep your peak at 1.2, I was happy with 1.3 but that's up to yourself Just to clarify, my boost level was 1.2. My car would run at 1.2 and I would only ever see 1.2. The peak of 1.3 that I was happy with was a split second overboost when the turbo's both came online. The gain was set in such a way that it took the boost controller a split second to get the boost under control. This does 2 things, 1 it gives you 1.3bar for a split second and 2 it comes on so savage that you can't help but laugh out loud when you put the foot down. The gain function is what really sets aside electronic boost controllers and manual boost controllers. Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted March 26, 2015 Author Share Posted March 26, 2015 Coming back to this I have just had a slightly smaller restrictor ring fitted then the one I had before. I am now peaking at around 1.0 bar with the boost controller off. This used to be close to 1.2 bar so it's amazing the difference a couple of mm makes. I now need to set the controller up again and I am a bit of a novice so I have some questions. So the screen that says 'set gain' should be turned up to 1.2 bar? What about the 'set %' that you set by just turning the dial and not pressing any buttons? I understand about the gain but what should the set boost % be? I know this will differ from car to car but from you're instructions above I get everything apart from the set %. Quote Link to comment Share on other sites More sharing options...
Scott Posted March 26, 2015 Share Posted March 26, 2015 Gain shouldn't be the boost setting.... is it? What are the options for setting it? Does it scroll 0.1-x.xbar? If so, then yes... set it to 1.2. With regards to the %age start off at 10 and record your peak boost. Increase the %age until the peak boost goes too high (1.3 imo but if you want to be safe you can make it 1.2). Once you have done that, you're finished Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted March 26, 2015 Author Share Posted March 26, 2015 There are 3 settings which is what I am struggling to get my head round, set boost which is a %age, gain which is a %age and set gain which is a bar setting. If anyone can advise on how to tweak the 3 settings that would be great.... I have been on a run and my HKS FCD has decided to get involved. I was attempting to follow the instructions above and was gradually building boost up, but I kept hitting fuel cut when really moving (on a private road) coming up to 6,000 rpm in 4th and bit lower in 5th I hit the wall! My fuel cut defender is set to 12, which is the highest setting, the peak boost when it cut out was only 1.15/1.16... Is it time for a new one? Quote Link to comment Share on other sites More sharing options...
Mk4Gaz Posted March 26, 2015 Share Posted March 26, 2015 (edited) From memory, the hks fcd should be on setting 9 With the profec, they can be a real sod to set up properly, but they are quite a good unit when working properly. The 'set' option, also known as 'duty' on some other boost controllers, is the target boost level you want to achieve, and is set as a percentage. Zero everything, and start again like this: Set the 'set' at 20 and go for a wot run in 4th. Note the max boost level you achieve, and raise or lower this setting, until you reach the boost level you want Then adjust the gain. This is how fast the boost level builds, and keeps the level consistent to avoid it tailing off at high rpms, so , start at say 10, and keep raising it until the boost starts to spike above your desired level. Then set it to 10% lower. You should also ALWAYS keep the gain setting lower than the duty (set) setting. Set gain is the lowest boost setting, that the unit will try to adjust boost under wot. This is set as either psi or bar, and should be as close to your desired boost level as possible, but to avoid spikes, you should set it circa 0.3bar (4-5psi) less than the max boost you intend to run. Then you can set the warning feature, to alert you if you get a boost spike. This should be slightly above your desired boost level Its been a while since I've used one of these, but hopefully that helps explain it a bit Edited March 26, 2015 by Mk4Gaz (see edit history) Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted March 26, 2015 Author Share Posted March 26, 2015 Thanks mate that does give me a good idea of what to do. I will change the hks to 9 and do that this weekend. I guess if I keep getting boost cut again I will have to look at a new FCD. Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted April 17, 2015 Author Share Posted April 17, 2015 Coming back to this. After a new smaller restrictor ring and a new FCD I have got the car boosting properly and it's lovely. I have the set at 47% and the gain at 44%. It holds boost at 1.2 bar nicely, I think I could set the gain slightly higher but you said it must be lower then the set:/duty setting. Out of curiosity why is this? I have the Quote Link to comment Share on other sites More sharing options...
costas1 Posted April 18, 2015 Share Posted April 18, 2015 First of all do not worry about these boost spikes..i have the same setup and i have.been hitting these boost for.years now...second get used to the fact that j spec turbos.tend to overboost a bit...now.you.got.your ring keep.in mind that that 1 bar is.the lowest.you.can.hit..(bcc turned off)..as the settings go mk4gaz explained it very nice..one thing he.forgot.and important make sure you set at 10-15% the limitation ...it is after the high boost setting and this for the controller to lower the boost 10% when you pass the desired limit..(maybe cold night or.different gas )..other than that you will be fine... i made 425 on the wheels at 1.25 on a dynojet with exact same setup... Quote Link to comment Share on other sites More sharing options...
bayside_supra Posted April 19, 2015 Author Share Posted April 19, 2015 I will set the limit function next time I drive the car as well. Why does the gain have to be lower then the duty setting? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.