Evan Purple240zt Posted April 9, 2008 Share Posted April 9, 2008 Alright, as some know from DNI my boost controller was going nuts. I had suspected it was because it was running rich but I am almost 100% sure thats not the problem now. A/Fs look good. If I drop the hammer around 2500rpms, the car will boost 20psi (where its set to). If I drop the hammer at 4k (right in the boost threshold) it generally only makes 7psi of boost (spring pressure).... Is my boost controller flaking out on me or do I have it setup wrong? I have an RB25DET with an external wastegate. I have played with dip switches and the knobs on the front panel in an attempt to make it consistent. Thanks guys. Evan Quote Link to comment Share on other sites More sharing options...
dhartig Posted April 13, 2008 Share Posted April 13, 2008 I was hoping someone with more knowledge might have jumped on this thread since up to now I have only been looking at EBC's. Sports Car Magazine ran an article recently that compared various EBC's including the Greddy PRofec A. Here's one of their points... "The final feature offered in the PRofec is an overboost warning alarm and protection function. If the boost exceeds a specified amount for more than one second, the system will drop the control pressure to the base boost level until the manifold pressure drops below the alarm point. This occurs in addition to visual and audible alert." Their article discusses the PRofec A needing to be setup using its alternate learning procedure. http://www.sportcompactcarweb.com/tech/0207scc_blitz_sbc_i_d_boost_controller/index.html Not sure if this helps but good luck. Quote Link to comment Share on other sites More sharing options...
madmatt48 Posted April 13, 2008 Share Posted April 13, 2008 Alright, as some know from DNI my boost controller was going nuts. I had suspected it was because it was running rich but I am almost 100% sure thats not the problem now. A/Fs look good. If I drop the hammer around 2500rpms, the car will boost 20psi (where its set to). If I drop the hammer at 4k (right in the boost threshold) it generally only makes 7psi of boost (spring pressure).... Is my boost controller flaking out on me or do I have it setup wrong? I have an RB25DET with an external wastegate. I have played with dip switches and the knobs on the front panel in an attempt to make it consistent. Thanks guys. Evan I have not used the profec-a boost controller however, I have had great experiences with the Greddy profec-b series boost controller in two R-32 Skyline GT-R's with both stock twin turbos with internal wastegates, a T-88-34D and T51-kai single turbines both with external wastegates. Both above applications I used the same profec-b boost controller (after adjusting dip switches and boost lines) with outstanding boost consistency, no spikes with boost backing down to stock or below. It is also a very easy boost controller to set up and use. Its simple on/off switch, low/high boost selection switch and a knob for each to precisely set until you find the boost that fits your range of engine modifications and fuel flow is great. I had the problem you are describing above where the boost starts off hard(spikes up)where you have set your boost and then suddenly just backs off to stock or less than stock boost(very frustrating especially in a 0-400 meter race) I had that problem, just with a different brand/style of electronic boost controller, the HKS EVC. In no way am I knocking a specific brand of boost controller, it just happened to be that brand I had the problem with. That boost controller, during the time I was running the RB26DETT with the stock twin turbines(internal wategates). I tried several things, changing out the EVC control unit, the vacuum control unit(used parts), checking/adjusting all my boost and vacuum lines many times, same results. Basically after I bought a new (never installed) Greddy profec-b, from Bee Racing(in Japan) that was the last time I had that problem and it was the last boost controller I ever bought new for the two GT-R's I tuned (1989 and 1992 R-32). I used the same profec-b when I converted both to single turbines with external wastegates (T51 kai on the 1992, T-88-34D on the 1989) with the same consistent results. With all of the above being said, perhaps if I had bought the HKS EVC brand new in the box instead of getting it used, I most likely would not have had the above described problems and it would have worked as advertised. In my experience I have found that purchasing used electronic boost controllers is a hit and miss thing. Some controllers have a long service life and others work for just a few years. My recommendation is purchasing electronic boost controllers new. After all, they come with all the instructions(where to set the dip switches on the back of the for either external or internal wategates), settings and hardware. Here is a link you can check out see if it helps: http://www.fd3s.net/profec_install.html I know the link says its for FD rx-7s but it has a universal profec-a or b boost controller settings page that is descriptive in setting up controllers. Hope this helps you with your current or future boost controller. Good luck and please do post what ends up fixing your boost problem for all of us to benefit and learn from. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted April 16, 2008 Author Share Posted April 16, 2008 Thanks for the information guys, unfortunately it seems as if my boost controller finally died today. I can't get boost over spring pressure at all now. I bought it 10 years ago, used.... I think I got my money out of it. I think I am going to go profec B this time. Evan Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted August 11, 2009 Author Share Posted August 11, 2009 I know this post is very old, but thought I would update. The cause of the issue was...... Wrong W/G spring pressure! Thats right folks! I am an idiot. I was attempting to run 20+ psi on a 7 pound spring. Quote Link to comment Share on other sites More sharing options...
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