pleiades Posted December 3, 2003 Share Posted December 3, 2003 More info to come, but the short of the story: Installed a MBC (manual boost controller) tonight. The homemade type of course... The car was peaking ~17psi. Yes I KNOW this is to high. lol.... But I didn't say I held it there. I re-adjusted and it's around 11psi-12psi now. That's a little more manageable. lol.... But the intersting thing is, even the couple of times that I let it get up very high, the car did not show any sign of fuel cut, nor was there any audible detonation! My rx is a '88 with an '89 motor, so it should definatly have the electronic cut according to everything I've read. Who knows! More updates when it's dialed in a little more tomorrow. Quote Link to comment Share on other sites More sharing options...
Skip Posted December 3, 2003 Share Posted December 3, 2003 The fuel cut protection is on a timer circuit. Try holding it at 12 or so for more than four seconds. How does Emril say it "BAM" MAF voltage following clamping circuit under design, need +5Vdc ref voltage. Watch the engine temps. I have never seen a lean condition running those pressures but ..... Do your engine a favor get an EGT gauge good luck Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 3, 2003 Author Share Posted December 3, 2003 Originally posted by Skip The fuel cut protection is on a timer circuit. Try holding it at 12 or so for more than four seconds. How does Emril say it "BAM" MAF voltage following clamping circuit under design, need +5Vdc ref voltage. Watch the engine temps. I have never seen a lean condition running those pressures but ..... Do your engine a favor get an EGT gauge good luck Thanks for the reply! I re-adjusted this morning, and it's running right around 12psi. The car is strong! OMG! lol... I think it did hit the cut though. Somewhere about 12psi & 6krpm. It was right as I was just before I let off the gas to slow down, so I'm not sure that's what it was. I'll have to investigate later. hehe... EGT and A/F are in the near future for sure. It's nice now, as it's cold outside. Quote Link to comment Share on other sites More sharing options...
XSNRG Posted December 3, 2003 Share Posted December 3, 2003 What's EGT? Exhaust gas temp? Tell me how it works please:-) Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 3, 2003 Author Share Posted December 3, 2003 Originally posted by XSNRG What's EGT? Exhaust gas temp? Tell me how it works please:-) Yes EGT=Exhaust Gas Temp A/F= Air/fuel mixture of course. The egt has a probe that goes in the ehxuast and measure the exhaust temp. Pretty simple eh. lol.... Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 3, 2003 Author Share Posted December 3, 2003 Ok, so the boost is dialed in at 12psi now, and I still don't seem to be hitting the fuel cut. Any ideas? The car just stepped sideways when I launched to get across traffic! What a beast! Quote Link to comment Share on other sites More sharing options...
MilesFox Posted December 3, 2003 Share Posted December 3, 2003 so what did you use for a manual boost controller? tell us quickly, so we can make one for the RX before it snows!!!!! Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 3, 2003 Author Share Posted December 3, 2003 I went from this page: http://www.geocities.com/chmwatson/FAQs/mbc.html but I bought slightly different parts. I spent a total of $9.00 and an ink pen. lol..... If you want to get all the parts in one location (ie home depot, lowes), you can get a female air hose quick disconnect for the ball bearing. That's what did it for me. I kept thinking, now where in the hell am I going to come up with one little ball bearing. lol..... Plus you'll have 3 more bearings for making more controllers. hehe.... Sort of like $9 in parts for the first, and about $6.50 in parts for the next 3! lol.... Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 3, 2003 Author Share Posted December 3, 2003 oh, and I used a spare subaru bolt that I had for the adjustment screw. So it's fully SOA approved! (THAT IS A JOKE OF COURSE! SOA please do not come repo my nice RX. lol...) Quote Link to comment Share on other sites More sharing options...
Skip Posted December 3, 2003 Share Posted December 3, 2003 pleiades You have not said you have held it on 10 psi or above for over five seconds ? Find a long hill and in an upper gear get it over ten psi and hold it there for atleast five seconds. Please report your findings. Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 4, 2003 Author Share Posted December 4, 2003 Originally posted by Skip pleiades You have not said you have held it on 10 psi or above for over five seconds ? Find a long hill and in an upper gear get it over ten psi and hold it there for atleast five seconds. Please report your findings. I have not noticed it doing the fuel cut when holding it in for 5 or more seconds, however, the turbo does seem to fall off about 6k by the time you hit 3rd gear. WJM is here, we'll go test it some more. hehe... Quote Link to comment Share on other sites More sharing options...
submonkey Posted December 4, 2003 Share Posted December 4, 2003 you can get the ball bearing in home depot or lowes to, look in the section with all the little bins they usually have many sizes. just my .02 Quote Link to comment Share on other sites More sharing options...
Subarutex Posted December 4, 2003 Share Posted December 4, 2003 5th gear accelerate on freeway for 20 seconds. Gauranteed to hit fuel cut. Skip... are we sure we need a 5vref? Can't we just use the ref signal that is already going to that, even if it is less voltage? :: I know nothing about electronics :: PS, mines almost done... hows about yours? Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 4, 2003 Author Share Posted December 4, 2003 well we went back out a bit ago. The car seems to loose power, but it doesn't seem to be the fuel cut. If I am correct, the fuel cut is a hard rev limit type power loss. I'm just getting to a point where it's like hitting a wall. Just no more power. Quote Link to comment Share on other sites More sharing options...
Skip Posted December 4, 2003 Share Posted December 4, 2003 The over boost control feels like the ignition switch was turned off for only 1/2 second. The driveline shock is severe. The engine will then pull like it was until the timer times out again. Your MBC may be to blame as it may be allowing waste gate creep i.e. leaking some of the pressure through and causing the waste gate to open slightly. My wagon pulls like crazy right up to 7 k RPM. Ask Trogdor he has seen it do this. I recco you put your boost gage on a tee fitting in your waste gate control line, see if you get any pressure before you get to the "dialed in" pressure. I experimented with many home made MBCs the spring is the second most critical component right after the ball / seat. Good luck. Tex, my parts have not arrived yet??!! Am calling Jameco today. Yes we need the 5Vdc ref to calibrate the op amps for the proper control (clamping) voltage, I also ordered an 5volt VR IC (voltage regulator), BTW, no foolin' I honestly don't kow much about 'trisy either. Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 4, 2003 Author Share Posted December 4, 2003 Thanks for the input Skip! I definatly know that I need to polish the setup a little. I will move the boost gauge location and see what I find there. By your description of the fuel cut, the car is most definatly not hitting the fuel cut. Quote Link to comment Share on other sites More sharing options...
Warp3 Posted December 4, 2003 Share Posted December 4, 2003 Originally posted by pleiades I went from this page: http://www.geocities.com/chmwatson/FAQs/mbc.html Oooo...thanks for the link...sound like time for a trip to Lowe's and/or Home Depot for me! Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 4, 2003 Author Share Posted December 4, 2003 No problem. hehe.... If you need a bearing, I've got three more. Quote Link to comment Share on other sites More sharing options...
Warp3 Posted December 4, 2003 Share Posted December 4, 2003 Originally posted by pleiades No problem. hehe.... If you need a bearing, I've got three more. Actually, Lowe's didn't seem to have any ball bearings, so I took your suggestion and picked up a female air hose coupler. Now how do I get the freaking bearings out of it? :cornfuzz: I picked up everything I needed PLUS I had to buy a tap set and teflon tape (as I had neither) and STILL came out for under $40 after tax! (The tap set was $26 by itself!) Also what's the deal with drilling the 1/32" hole in those instructions. First of all, I don't understand what the hole does. Secondly, I couldn't even find any 1/32" drill bits, so I assume he actually meant 1/16" (the smallest I could find in the store and I already have bits that size). Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 4, 2003 Author Share Posted December 4, 2003 Originally posted by Warp3 Actually, Lowe's didn't seem to have any ball bearings, so I took your suggestion and picked up a female air hose coupler. Now how do I get the freaking bearings out of it? :cornfuzz: I picked up everything I needed PLUS I had to buy a tap set and teflon tape (as I had neither) and STILL came out for under $40 after tax! (The tap set was $26 by itself!) Also what's the deal with drilling the 1/32" hole in those instructions. First of all, I don't understand what the hole does. Secondly, I couldn't even find any 1/32" drill bits, so I assume he actually meant 1/16" (the smallest I could find in the store and I already have bits that size). Man, you're making it too complex! lol.... Do you want me to make you one? I can do it for about $7. I used the dremel to cut the 'sleeve' off of the female air adapter, then the bearings just fall right out. I also didn't go with exactly the same parts as the diagram. I guess I'll build another one this weekend and do a writeup with pictures. The parts I went with seemed a little more plentiful. lol... Shane, What did you do for a spring? I think that's the only department where mine needs a bit of improvement. Quote Link to comment Share on other sites More sharing options...
Warp3 Posted December 4, 2003 Share Posted December 4, 2003 Too complex!? With all new parts (except for the spring where I'll probably go the "pen" route for the time being unless I can find a better substitute) and ignoring the tap set and teflon tape roll (which are more tools/supplies than parts), I only paid $9.17 before tax and some of those prices are for multiple items (i.e. 4 bearings, 4 nuts and 2 bolts). So I'd say I'm getting by quite cheaply here... I used the dremel to cut the 'sleeve' off of the female air adapter, then the bearings just fall right out. Ahhh...that makes sense. Dremel time! Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 4, 2003 Author Share Posted December 4, 2003 lol.... Ok. Quote Link to comment Share on other sites More sharing options...
Meeky Moose Posted December 4, 2003 Share Posted December 4, 2003 heh would ya mind makin me one of them contraptions and ship it to me? I don't have a tap and die set, so it'd cost me more than i'd wanna spend to do it... i've seen those on ebay for about $15 shipped, but would rather get one from someone on the board so i know who put it together.. versus, ed in the bayou in the usa somewhere know what i mean.. lol Quote Link to comment Share on other sites More sharing options...
pleiades Posted December 4, 2003 Author Share Posted December 4, 2003 Originally posted by Meeky Moose heh would ya mind makin me one of them contraptions and ship it to me? I don't have a tap and die set, so it'd cost me more than i'd wanna spend to do it... i've seen those on ebay for about $15 shipped, but would rather get one from someone on the board so i know who put it together.. versus, ed in the bayou in the usa somewhere know what i mean.. lol Ok, you can have the one I build for instructional purposes. PM me your mailing info. I'll probably build in on Saturday. If I send it via us postal, the total should be ~$9 for the parts and postage. Quote Link to comment Share on other sites More sharing options...
Meeky Moose Posted December 4, 2003 Share Posted December 4, 2003 works for me, PM comin your way.. if i get the 87 1/2 turbo xt on ebay i might have ya make me another lol... although the wife won't need 12psi of boost... Quote Link to comment Share on other sites More sharing options...
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