Date: Thu, 25 Aug 2005 17:44:00 GMT
From: "Dexter J" <lamealameadingdongnospamlamelame.org>
Subject: Re: Massive Loss of Oil... Did I kill her? (loooong)


On 25 Aug 2005 15:42:34 GMT, Dave Hinz <DaveHinznospamcop.net> wrote: > On Thu, 25 Aug 2005 09:32:05 +0100, Grunff <grunffnospam.com> wrote: >> Chris Campbell wrote: >> >>> A few days ago I installed an MBC+A in my beloved '94 Saab 9000CSET (An >>> MBC is a manual boost controller, for those of you who aren't >>> performance savvy... I bought it to replace a bad BPC so I'd get stock >>> boost levels again). >> >> I'd like to take this opportunity to ask a question (and I'm not having >> a go Chris, honest). Why do people install MBCs on APC equipped Saabs? >> What exactly is the point? > > Because they think they can modulate boost faster than a few hundred > times a second, I suppose... Grunff, Dave - long time no read. Actually - the MBC and particularly the MBC+A have definite benefits (and challenges) as regards uprating your APC cut outs. Have a poke around saabnet.com in the performance BB over there. Very rum stuff. First - they are both *much* less expensive than the replacement OEM BPC valve and frankly, set up carefully, either device will last the remaining life of the automobile once installed. This sadly cannot be said of the OEM BPC, however I happen to have an ongoing project I can't seem to get time to get back to regarding rebuilding/bullet proofing the stock BPC. Have a poke around saabnet.com 9000 BB on my nick. The primary 'performance' benefit of the MBC or MBC+A is that it bypasses the APC logic regarding locking down boost in 1st and 2nd gear (some care must be taken when engine is cold in the morning or hot in traffic) as well as squeezing several extra pounds of boost into the system in all gears. In top gears - stock SAAB APC BPC logic sees the waste gate cut out about 8-10 pounds short of theoretical max automatic timing adjustment to allow for longevity and to provide some buffer in operational and fuelling parameters. This max point is different depending on model - so - higher on Aero, lower on CS(E), lower still on LPT. The MBC and particularly the MBC+A lets you reclaim some or all of that extra boost - which is particularly exciting in first and second gears .. :) .. Even with MBC or MBC+A - the APC still controls timing independently and the system still has a built in fuel cut-off points depending on chipset version (CS/LPT/AERO). However - unless you are really careful about using premium fuel *at all times* and making seasonal adjustments for ambient air temp - you must adjust the MBC max pressure waste gate open point somewhat lower than maximum possible limits (but still above stock settings). MBC+A allows slightly higher/safer adjustments as it defeats 'overshoots' on the turbo. In either case however, failing to back off the pressure a little from max at set-up will result in regular 'adaptation' CEL's as well unchecked detonation during high RPM spools as you start to run momentarily lean before fuel cut. Interestingly, the same sort of thing happens in reverse when you run hard with a shorted BPC - only in reverse. The injection logic sometimes cannot adjust quickly enough and you start dumping raw fuel into the exhaust system. You start to get erroneous 'O2 sensor' and 'adaptation' CEL's if you are boosting on and off in the 3,500-4,5000 rpm range. In all cases with an MBC, you know you are getting into the 'danger' range regarding fuel octane and boost settings when your engine starts to run a hotter during normal driving. It's not yet detonating, but it is in the neighbourhood - and fatal piston damage can occur in about 10 seconds in the right conditions. Say, you start to show off your new MBC on a hot and humid day at an on ramp after a rough day at work and bumper to bumper traffic from the office to the highway. Anyway - I bet what has happened to the OP is that the oil pan or timing chain cover has been cracked, bent and/or he has knocked off a gasket and it might be a little early to really be condemning the whole system until you can get a competent wrench to have a poke around. It may be that the oil pick-up is now pressed flat on the pan or kinked. Don't drive it at all until you get to fixed (hello towing service), but SAAB engines are remarkably tough when push comes to shove and while the OP may well have shortened the total life of the engine/turbo - it may be fine for several tens of thousands of miles yet to come with short oil changes and not-so-hard driving. Find a good indie shop in your town, explain you have hit something and let them have a close look over it. Back off the boost pressure and stay off the gas peddle for a while if you do go ahead and fix it. It will probably be more noisy from here on in though. Your MBC+A likely didn't cause any extra damage other than the driver was no doubt watching the gauges (in amazement) rather than the road (in stark terror). -- Radio Free Dexterdyne Top Tune o'be-do-da-day Nelson Charles - Seven Spanish Angels http://www.dexterdyne.org/888/179.RAM all tunes - no cookies no subscription no weather no ads no news no phone in no sign up required - all the Time

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