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Old 07-27-2004, 04:01 PM   #1
ride5000
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Thumbs up new hybrid mbc/ebc method of boost control

ok, here's my latest boost control setup:



essentially a cockpit-adjustable ball and spring mbc (hallman evo rx) in parallel with a GM "3 port" solenoid (in interruption-based boost control) which is controlled by a UTEC.

the UTEC boost map ends on 500 in the 100% tps column, and ramps down to 150 in the 60% column.

this setup allows for a couple of key points:

a) cockpit adjustability of max boost via a knob.
this is one aspect that i can't stress enough. it is by far the best way to account for atmospheric changes in boost levels as well as driving style changes (highway vs. city, wife driving, valet, etc). two seconds in the morning and it's set for the rest of the day.

b) throttle dependant boost levels.
obviously, this is key to avoiding stoichiometric boost, and also allows a ramping up of manifold pressure so that boost is controlled at partial throttle, instead of coming on when it wants to (ie pure mbc). this improves drivability and prevents engine damage due to PTFB scenarios.

c) rpm dependant boost levels.
haven't tuned this in yet, but the capability is certainly there. i have a strong hunch that tuning in a bit of boost taper at the top end of the rpm range while using the oem turbo is a "good thing," since it will cause the wastegate to open, reducing EGBP without decreasing manifold pressure, since that's pretty much capped by the compressor anyway. less EGBP for no hit in MAP is without a doubt desirable from an efficiency standpoint.

d) rock solid boost response.
when i say rock solid, i mean ROCK SOLID. those who have never used a GOOD MBC will not really know what i'm talking about. what i am talking about is a boost level which will NEVER be exceeded, even for the briefest of spikes. there are simply no spikes whatsoever to speak of.

e) very quick boost increase.
when the throttle is floored, the UTEC's boost map is set to 500, essentially max boost. the GM solenoid closes, which prevents any pressure signal from going through it to reach the wastegate acutator. the ball and spring mbc is a very good MBC in that it provides a very tight seal, and essentially no air gets through that until the spring tension is exceeded by the pressure signal. bottom line: boost response just as fast as a good ball/spring MBC, which is as fast as it gets.

i'm going on day two with the setup and i could not be happier... pretty much every thing i could ask for is addressed. since the picture was taken (during the testing phase) i have shortened all boost/vac lines as much as possible, and secured the junctions with zip-ties. having short, non-obstructed lines is also critical to having rock-solid boost control.

any questions, ask away...

ken

ps a tip of the hat to TMS for finding the very economical GM solenoid, which enables us to use a direct interruption based boost control method. i had tried the method i just described once before, using the oem bleed based solenoid (along with its attendant restrictor), and it didn't work at all, so this was key to the success.

Last edited by ride5000; 07-27-2004 at 04:14 PM. Reason: added link to TMS' thread
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Old 07-28-2004, 04:25 PM   #2
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Very impressive arrangement!

I would be very interested in running a setup like that, but partial throttle boost isn't a problem with 20G and FMIC.
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Old 08-04-2004, 02:55 PM   #3
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Ken, that looks pretty good. I'm just not sure it's going to meet my needs unless I change the way it's working for you. I don't want more boost down low. I do get some spike, though, and if this helps rid me of that, all the better.

-Sean
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Old 08-04-2004, 03:43 PM   #4
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This is interesting to me because I have been considering using a GM solenoid for some time now. The AEM ems uses gm solenoids because their one of the best. I was going to just replace the stock solenoid with a gm one and hook it into the Utec and use it that way. I am not understanding why the manual controller is needed? Is it solely for boost spike atmospheric changes? I now have a profec b spec2 and cant tell you how it works yet. Im braking in a new clutch and cant boost the car. I have been told over and over not to use the utec to controll boost on my 18G because the factory solenoid wont respond fast enough to regulate boost spike. So my first thought was to change to a gm solenoid. Like I said before is the manual unit necessary or just for spike situations? Im tossing this one around again now. Anyone want a Profec thats a week old????

C-Lo
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Old 08-05-2004, 09:59 AM   #5
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Quote:
Originally Posted by CeeLowe
I am not understanding why the manual controller is needed? Is it solely for boost spike atmospheric changes? I now have a profec b spec2 and cant tell you how it works yet. Im braking in a new clutch and cant boost the car. I have been told over and over not to use the utec to controll boost on my 18G because the factory solenoid wont respond fast enough to regulate boost spike. So my first thought was to change to a gm solenoid. Like I said before is the manual unit necessary or just for spike situations?
frankly i don't think many people would argue with the fact that nothing beats the stability and response of a mechanical boost controller. electronics are nice, but by virtue of their flexibility they give up a bit of that rock solid response. so to that end, i think the utec's EBC algorhythm isn't that bad, plus, it's "free" with the purchase of a utec, so that goes a long way.

to answer your question, yes, the MBC is there for two reasons:
a) provide adjustability of max boost without a laptop and without stopping the car and getting out and popping the hood.
b) provide a boost level which simply will not be exceeded.

a) is really about convenience and laziness! b) is important to me because it seems that with any EBC (not just the utec's) you are always trading off response/spool time against freedom from spikes. either you've got a quick boost control, or a stable one. maybe it's because i've used an MBC since my first month of owning the car, but having to make that choice is just not acceptable to me!

generally those boost spikes come on during highly transient conditions, when boost pressure shoots up fast. for example, you're past the boost threshold of the turbo, driving at part throttle, then you mash the gas. the boost responds so quickly that the EBC cannot react in time to prevent a nasty spike. (honestly i think this is where a lot of problems arise when only dyno-tuning is used... on the street, things are a lot less smooth and predictable and i'll bet quite a bit of money that boost spikes are what's causing knock when there was none on the dyno. it's just a theory of mine though.)

i also noticed a stability problem when using launch control for flat-foot shifting... when the clutch goes down and the rev-limiter kicks on, my manifold pressure drops to around 14-15psi. the TPS is still at 100%, which means the utec is still using that column for the EBC algorhythm. i complete the shift, pop the clutch and the sudden increase in load gives me a surge of exhaust energy, which causes a nasty boost spike. with the utec solely in control of boost i got a spike of around 3 psi above my "normal" 17psi. that put me up around 20psi, which was WAY too much, and i'd generally get a shift knock when using LC for FFS. if i shifted normally, the boost was better controlled, but c'mon--FFS is VERY COOL...

now, using the MBC "clamp," i get a spike of <1 psi. this is acceptable to me (and my engine) so we are both happy. (i know i could get it lower, but i'd have to do some relocating of parts in order to shorten hoses, and they would be placed closer to the very hot turbocharger, reducing their lifespan.)

as TMS pointed out in another thread, essentially i am using an MBC with the UTEC to control part throttle boost levels via the GM solenoid. i think this is a great way to look at it. you can't use the oem solenoid to do this since it is a bleeder based system, and you need an interrupter.

i'm going on my second week with this rig and it's the best boost control system i've used yet (first was totally stock, then 3/16" mod, then joe p MBC, then throttle switched wastegate/MBC using the grainger solenoid and an electronic TPS switch, then i added a cockpit bleeder to the MBC, then i went back to the FBC system with the UTEC in control, then i went back to a straight MBC [this time with the much higher quality hallman unit] with UTEC's open loop fueling to mitigate PTFB, then finally the system you see here, [which not only prevents damage from PTFB, it completely prevents it from occuring]). it has been a journey of mine to find a much better boost control system for my car, and i am zeroing in on it.

hth
ken

[OT] eventually i would like to impliment my own outboard PWM controller that takes its signal from TPS and outputs a PWM signal whose duty cycle is proportionally adjustable. low TPS = low DC, high TPS = high DC. because i would still have the MBC clamping the boost limit, it would not have to be very accurate or repeatable--it would strictly be in order to prevent the PTFB as well as provide a smoother throttle response. as a result, the circuit would be pretty simple.

the reason i'd like to do this is so that i can free up the UTEC's boost controller driver to drive a high speed solenoid for water injection. i've heard that some customization of the UTEC's software can be done (with assistance from txs, of course) to change the TPS-based column reference of the boost map into a MAP-based column reference. this would make it MUCH easier to develop your h2o injection map, and having a mappable injection setup is obviously much better than a static one. i'll get there eventually![/OT]
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Old 08-08-2004, 07:59 PM   #6
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quick question on the way you have things routed. Where do you have the 3rd port on the GM solenoid routed to, or is it capped off?
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Old 08-08-2004, 09:09 PM   #7
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veck: it is capped off, since there is no need to route it anywhere. i also plugged the old air inlet (where the bleeder used to bleed to) which is on the intake pipe.

hth
ken

ps. recently remapped my boost map with ECU values in all but the 100% column. this way the ecu's part throttle tapering of boost is in effect. so far, so good:the fbc algorhythm seems to be handling the GM solenoid well.

in other words, you could use the above topology, along with a tps switch (as seen on my website) and DPDT relay, the stock ECU and an MBC (to "clamp" the max value) to the same effect. the DPDT relay would be energized at some value of throttle position sensor voltage, and it would:

1) disconnect the the GM solenoid from the ECU
2) switch IN a suitable "dummy" resistor (so as to avoid the CEL for a BCS failure)
3) put a steady 12vdc across the GM solenoid.

voila--MBC boost levels and response with full part throttle taper. i'll get around to trying this out sooner or later, in order to free up the UTEC boost solenoid driver circuit.

Last edited by ride5000; 08-08-2004 at 09:19 PM.
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Old 12-22-2004, 01:53 PM   #8
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Default Clarification on GM solenoid hookup

Quote:
Originally Posted by ride5000
veck: it is capped off, since there is no need to route it anywhere. i also plugged the old air inlet (where the bleeder used to bleed to) which is on the intake pipe.
Hi, could you clarify this for me? Do you mean that you leave the little foam filter on the solenoid, or do you mean that you SEAL UP the port? I really like your setup; I was just about to try something almost identical, but as far as I understand three port solenoids, you need to alternate the turbo outlet pressure and atmospheric pressure to the common (wastegate) port for it to work properly. I was assuming that I would pull off the little filter and route that port back into the stock fitting on the intake for the atmospheric source, as it is filtered and past the MAF. If that port is sealed, I would think that there is no way for the pressure in the wastegate actuator to fall, except through a bleed hole on the MBC

Thanks for your help,

Mark
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Old 08-09-2004, 05:10 PM   #9
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Ken,

Why the fear of PTFB when you have OLF software installed? The risk of PTFB is just that it causes lean conditions, but with OLF software in place, that won't happen. I understand the desire for rock-solid boost. I understand the desire to be able to taper boost at the upper rev ranges at WOT. But I LIKE PTFB on my car - working around it sounds terrible.

-Sean
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Old 08-09-2004, 06:52 PM   #10
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Quote:
Originally Posted by big_adventure
Ken,

Why the fear of PTFB when you have OLF software installed? The risk of PTFB is just that it causes lean conditions, but with OLF software in place, that won't happen. I understand the desire for rock-solid boost. I understand the desire to be able to taper boost at the upper rev ranges at WOT. But I LIKE PTFB on my car - working around it sounds terrible.

-Sean
sean, perhaps it's the stock turbo, but i found it actually made driving around town difficult. i'd start from a stop light, for example, with a normal take off. probably light throttle to 2k or so, clutch slip into first, then giving it a bit more gas, perhaps 20 percent or so.

with the MBC only, suddenly i'd get a huge torque bump as the turbo spooled up, which was around 4k. throttle hadn't changed at all, but suddenly i was accelerating much more rapidly, and it made driving slowly (ie, past a peace officer) much more difficult.

it wasn't dangerous, since i did have OLF turned on. in fact, it was the reason i went to the OLF fuel map! but it was annoying. perhaps i could have trained myself to drive around it, but it was strange to have the turbo come on when IT wanted to, rather than when *I* wanted it to.

i guess my big complaint was in power modulation, which i found much more difficult with just the MBC. i would think that with a big honkin turbo that didn't spool up until much more air was pumping through it, the problem would rear its head much less often, and would therefore be much less of an issue when putting around town.

ken
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Old 08-10-2004, 09:24 AM   #11
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After I wrote that, I guessed that was the reason. I've been on the BIG turbo diet for so long, where you will do ANYTHING to get some real boost at low revs when putting that I didn't really think of life sans lag. In fact, when I was vf34 bound, I did the same thing, even on OLF - I started scaling boost from 10psi at 30% TPS to 20psi at 80-100%.

On this beast of a turbo, boost comes on FAST...

...once you're over 4.5K revs.

-Sean

Quote:
Originally Posted by ride5000
sean, perhaps it's the stock turbo, but i found it actually made driving around town difficult. i'd start from a stop light, for example, with a normal take off. probably light throttle to 2k or so, clutch slip into first, then giving it a bit more gas, perhaps 20 percent or so.

with the MBC only, suddenly i'd get a huge torque bump as the turbo spooled up, which was around 4k. throttle hadn't changed at all, but suddenly i was accelerating much more rapidly, and it made driving slowly (ie, past a peace officer) much more difficult.

it wasn't dangerous, since i did have OLF turned on. in fact, it was the reason i went to the OLF fuel map! but it was annoying. perhaps i could have trained myself to drive around it, but it was strange to have the turbo come on when IT wanted to, rather than when *I* wanted it to.

i guess my big complaint was in power modulation, which i found much more difficult with just the MBC. i would think that with a big honkin turbo that didn't spool up until much more air was pumping through it, the problem would rear its head much less often, and would therefore be much less of an issue when putting around town.

ken
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Old 08-09-2004, 11:20 PM   #12
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I have been looking at that MBC for some time now. From the looks of it it has just like a cable and turning the knob changes boost. Can I ask where you mounted the knob? Good write up.
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Old 08-10-2004, 10:38 AM   #13
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Quote:
Originally Posted by subiekid
I have been looking at that MBC for some time now. From the looks of it it has just like a cable and turning the knob changes boost. Can I ask where you mounted the knob? Good write up.
subiekid,

the system has essentially an integrated "twist cable" (for lack of a better term, it's just like a speedometer sense cable, only a bit more robust) that adjusts the MBC spring preload bolt.

i found that the cable itself is pretty flexible, but the plastic housing that is provided is fairly stiff. this is probably done purposely, since it prevents you from running too tight a radius bend and kinking the cable. obviously the friction is reduced to a minimum when you keep the bending to a minimum too.

because the twist cable is made up of a good number of solid strands it is difficult to cut. hallman recommends using a plasma cutter, which i do not have! i'm sure a dremel or other cutoff wheel would work too, but it was too much for me to take on at the time. you'd have to grind the tip down so that it does not fray. so i left the cable as long as it came from hallman, which is pretty long.

you can see where the MBC is situated underhood. the adjust cable then routes below the IC and makes a gentle arc right into the firewall hole to the outboard side of the clutch actuator.

from there, it makes a turn to the outside of the car, up under the dash, then down back towards the front of the car, then finally to the knob which i located on the driver's plastic kick pannel next to the dead pedal. it isn't the MOST convenient place to locate it, but since i didn't want to cut the twist cable i kind of had to put it where it wanted to go, to avoid tight bends and such. still, where it's located, it's out of the way, in such a place that most people would NEVER see it, and there's no way anybody but the driver could adjust it.

i find that it actually does not require much adjustment, despite weather changes, and when it does it's a quarter turn in either direction. that's enough for about a pound of manifold pressure difference. i have gotten good at reaching down while left-foot brake loading and quickly dialing in the boost i want to run. it takes literally 5 seconds.

i originally balked at the thought of spending 180 bucks on an MBC, but i have to say that this MBC is very nice and has features that you're just not going to find in any other unit. i actually went out and bought a speedo cable to see if i could make my own in this style, but the speedo cable was only really good at transmitting torque in one direction of rotation. attempting to source a cable similar to the hallman was fruitless. the ceramic ball makes a VERY good seal in the valve body and is a decent diameter (around 1/4") and the adjustment resolution, even with the "stiff" spring, is very fine.

i'll take some more pics of the install and get them up soon.

ken
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Old 09-01-2004, 07:15 PM   #14
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Got those pics? Im really starting to worrie about my sock ECU map with my MBC and PTFB. I prob need to just get a knock link and know for sure whats going on.
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Old 09-15-2004, 02:21 PM   #15
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ride, sent you email
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Old 10-15-2004, 04:51 PM   #16
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i've got a pic of the route the hallman twistline takes under the ic and through the firewall:

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Old 12-19-2004, 06:48 PM   #17
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today, i removed a tiny bleed hole from my hallman evo rs. it was "built in" to the "outlet" hose barb, so i replaced it with a brass 1/8" npt 3/16" hose barb fitting i had handy.

this resulted in overall lower boost levels, as expected, but it also resulted in more stable boost. in theory, a ball/spring mbc should not work without a bleed hole, but this works not only well, but better than with one.

i ended up giving it another whole turn to put boost back to 19psi. i had to go back through my utec open loop boost map and give it a kick in the rear... almost 100 duty to get it up that high. the map now looks like this:
Code:
78	85	92	98	100
in the 60-100 columns. only when the 100 column is hit does the boost get limited by the hallman... at 60% it is approximately 10psi, at 90% it's 17 or so.

hth
ken
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Old 12-22-2004, 05:25 PM   #18
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mark, i once thought exactly the way you did. in fact, when i started futzing around this past weekend, i fully expected the boost to be uncontrollable. imagine my surprise (and joy) at finding out it was not.

when the solenoid is not energized, the pneumatic circuit is "shorted" -- the line from the nipple goes through the solenoid and right to the WGA. the common port of the solenoid goes to the nipple, the NC port is capped, and the NO port leads to the WGA.

when the solenoid is energized, the pneumatic circuit is "opened" -- ie, the line from the comp nipple to the solneoid goes NOWHERE, and the line from the solenoid to the WGA goes NOWHERE. the only "control" of boost comes from the ball+spring MBC.

i would say that there was reverse flow back through the ball+spring mbc, but when i first got it i tried to blow back through it, since i have found that the best ball+spring MBCs do NOT allow backflow. i was happy to find that it made a very admirable seal to reverse flow, so i cannot say that appreciable pressure is being lost via that route.

the last possibility is that the WGA itself has a small bleed built into it. i haven't tried the very scientific "put mouth on hose and blow" method of testing for that yet, though, so i can't tell you anything more. all i can say is that boost is more solid than ever with NO discreet/discernable bleed hole on my setup, and it doesn't "latch up" in the "limit boost" condition.

hth
ken
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Old 12-22-2004, 09:32 PM   #19
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Who'd a thunk!!! I can't argue with real-world results. I'll have to try this myself cuz it sounds so good. Thanks!

Mark
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Old 09-07-2005, 08:03 AM   #20
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great thread. will any ball-spring MBC work? of course it won't be cockpit adjustable but that's ok. are the E-bay $20 MBCs a complete waste of money?

is it necessary to use a 1watt 10-ohm resistor in line with the GM BCS?

if i were to use a cheap E-bay MBC, is there a chance of getting boost spikes? the protection against boost spikes is a result of a high-quality MBC or is it b/c of the inherent design of this system?

what's better to use. open loop boost control or closed loop? i have an 04 and remember reading somewhere that open loop boost control was the way to go. any comments on that?


thanks for your response.

Last edited by MRF582; 09-07-2005 at 08:12 AM.
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Old 09-07-2005, 08:53 AM   #21
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Quote:
Originally Posted by MRF582
great thread. will any ball-spring MBC work? of course it won't be cockpit adjustable but that's ok. are the E-bay $20 MBCs a complete waste of money?
well, for <20 bucks you could go to home depot and cobble one together yourself. what is important is the seat of the ball which can be ascertained by attempting to blow through the mbc backwards, while closed. obviously a good seal will allow only a tiny (preferably zero) amount of reverse flow.

if you can't be bothered to DIY you can go for the ebay specials, but i have no experience with them so i can't help you much there.

Quote:
is it necessary to use a 1watt 10-ohm resistor in line with the GM BCS?
no i have not had any issues leaving the resistor out.

Quote:
if i were to use a cheap E-bay MBC, is there a chance of getting boost spikes? the protection against boost spikes is a result of a high-quality MBC or is it b/c of the inherent design of this system?
ball and spring mbcs are second only to bleeder types WRT spiking. if you use tubing/fittings that are too small in diameter, or too long in length, spiking is more of an issue, but generally only the most expensive EBC systems out there (avcr, oem ecu) will have a more stable/predictable response.

Quote:
what's better to use. open loop boost control or closed loop? i have an 04 and remember reading somewhere that open loop boost control was the way to go. any comments on that?
honestly closed loop boost control via the utec would PROBABLY be a little bit better as it attempts to more closely control the boost via feedback from the MAP sensor. thing is, it takes more time to set up and for the rough "ramp" curve that i have set up the open loop boost control was sufficient. it does vary more WRT ambient temperature than closed loop does, but the high level clamp provided by the MBC is surprisingly absolute. i dicked around with CLB for a while but i grew impatient.

as far as one being preferable to the other on the 04s, are you sure you're not confusing open and closed loop boost control with open or closed loop fuel control? the post bugeyes should DEFINITELY use open loop fueling to combat the crossover delay programmed in those later ecus

lmk if you have any more questions.

hth
ken
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Old 09-09-2005, 04:50 AM   #22
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thanks for the quick response. and you're right. i was confusing open loop fuel with open loop boost control. i may try tuning with closed loop boost since you said it's reacts to different ambient temperatures better. when you use closed loop boost do you have to calibrate the map sensor?

i mean, how does the UTEC know which boost values to reach and then start leaking pressure once such a boost value is reached? i don't recall there being a place to enter in such a value. basically i want to learn exactly how the closed loop boost control system works in a UTEC so i can understand it and tune it. thanks for your help. i will be trying the GM BCS soon with a cheapo MBC. i'll post up my results when i do.
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Old 09-09-2005, 08:32 AM   #23
ride5000
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the utec's closed loop boost is a strange duck. it works PRETTY well, but not nearly as accurately as a more advanced system, such as an apexi avcr, or the oem ecu. basically it DOES use feedback to alter the duty cycle of the wastegate solenoid in order to actually target a particular MAP. unfortunately the numbers are mostly unitless.. you don't just type in 14psi and have it hit it.

if you haven't done so already, download mick the ginge's guide to utec tuning which will help you out a bit.
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Old 09-10-2005, 02:52 PM   #24
2phless
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I like Ride's MBC better than mine, but here is how I did it to get some control to my fingertips.

I used the TurboXS dual stage MBC. It is not a ball and spring BC but a bleed-off style BC similar to the ABC that comes with the UTEC. Difference is this one always has a little bleedoff, and the nipple for it's inlet port is restricted to about the same size as the stock 'pill'. That could be replaced with an open port but I just pulled out the stock restrictor and replaced it with this setup, stage 1 closed all the way.








Like this it acts like the ABC to give the solenoid settings a little more headroom. And by swapping the pill for this part closed I gained about 1 psi across the map. So it won't take a lot of change to the map to get it set back the way you want it.

I have stage 2 turned out 2 turns and is activated by the UTEC's built-in AND activated output solenoid. It's designed to come on over XX rpm at XX tps etc... and I use it to fightof the taper. Which is not so bad anymore now that I installed a larger helper spring.

I have a manual activate button (momentary so I have to hold it to get the 2nd stage to open on the TXS BC.) And in solid full boost situations that'll bump the boost up from about 20 to about 25? (where I rease the button in a hurry so it might go higher... I'm not that curious.) But above 5.5-6k areas it just helps the taper and keeps me well above 15 psi like I used to see.

Although it's a little outdated, I'm on the front page of this site with a list of most of my mods.

www.subarusti.org
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Old 09-11-2005, 11:33 AM   #25
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I have been looking for a way to get that instant spool of a MBC without PTFB.
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