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Date: Mon, 13 Dec 2004 23:41:51 +0100
From: Frode <>
Subject: Re: 99 Turbo update - vroom vroom

Dave Hinz wrote: > On Mon, 13 Dec 2004 20:31:00 +0100, Frode <> wrote: >> Dave Hinz wrote: >> >>> It's a _very_ abrupt cutoff; maybe I'm just hitting the rev limiter. >>> Need to try again tonight and see what RPM it's happening at; I was >>> watching the boost gage rather than the tach. > >> The 99 fuel cutoff is really just the fuel-pump being switced off. I >> don't know how that feels since I don't have that feature, but I would >> think not quite as abrupt as total ignition misfire. > > Probably not that, then. > >> The rev limiter is supposed to >> cut in at 6000 rpm and as far as I can tell from design, it will stay out >> until the rpms have dropped substatially. 6000 rpm is way beyond where I >> shift up and I have never experienced that. It is a simple spring-loaded >> centrifugal device in the distributor, quite easy to disable just for the >> sake of ruling out that possibility. > > This is the inductive sensor distributor, yes? Thats the one. In my car (taken from a 1980 or 1981 900 I think), the purely mechanical RPM limiter is built into the high voltage (secondary) circuit only and does not involve the low voltage parts at all. > I'm not actually sure if > this is the right dizzy for the car, it was just the only 99/900 dizzy I > could find with the right gear cog on it (course teeth rather than fine, > to mesh > with the older-style countershaft in the engine). I should look at > numbers, and/or try another dizzy I think. > >> It could be that the spring is getting >> old. Your original post indicates that it is boost related, not RPM. > > I thought it was just as it crossed over into the red boost, but it may > have been also when I hit 6K RPM. I'll check tonight rather than second > and third-guess my second-guessing. As you may have noticed, the 99T has a quite unusual boost control system that actually senses and controls the exhaust manifold pressure via a rubber diaphragm regulator. At high RPM's, (max BHP is at 5000 remember), I would expect that the added back pressure from the exhaust system will keep the needle away from the red area. If the rubber diaphragm is in good order and the wastegate valve isn't stuck, that is;-) I dont have a tachometer and only a self made digital boost pressure gauge, but my impression is that the torque while quite impressive at around 3000 rpm it rolls off quickly to just above adequate when I feel like it is time to shift up. This is quite good for the limited cooling capacity of the 99 and quite contrary to the 2.3i I must drive when I need AC;-) >>> Which adjustment screw, please? This is a CIS fuel injected system, >>> does that change what you're saying? > >> It is the green one here displayed at this page: >> > >> An allen screw, buried deep inside the unit betwen the airflow meter and >> the fuel regulator. It is accessible from the top. You'd really need a >> tool like this: >> > > Excellent. I've got pretty much that exact tool from my days as a > biomedical electronics technician. > >> I'm sure the web is full of info on CIS / K-jetronic, it was/is used in >> every kind of vehicles from the Golf to the 911 turbo and Lamborghini >> Countach, Ferrari Mondial And that V- thing too... > > It's a delightfully elegantly simple solution. I'd love to refit one to > a V4 Saab. > >>> Sounds like I need a Haynes for the 99T then. My 900 manuals are good >>> for almost everything, but they're too new for some stuff, and my 99 >>> manual is >>> too old for the turbo stuff. Ah well. > >> No big deal, I can take some photos of selected pages, and cite some key >> figures if needed. > > I am likely to take you up on that at some point. Right now things seem > good aside from the above. I got a new cap for the expansion tank today, > because the other one was very scary looking, so hopefully I can bring the > system up to normal temperature and pressure to check for leaks. The oil > system seems intact, and the turbo sounds good. Still haven't heard the > bypass valve noise I remember, so I'm not sure what that's all about yet. >>> >>> I put BCP6s in there, which I think is as hot as I should go, yes? > >> In the long run, yes! Good luck with a fun engine! > > It's been a dozen years since I drove (a/this) 99 Turbo, until yesterday. > The steering is a bit heavy, but it's a _very_ fast/responsive rack. > Handles good, even on not so good tires. I plan to put on more than 3 > miles tonight, but since it hasn't moved on it's own power in more than > a decade, I'm going gently and cautiously. And double-checking that the wastegate is operational before you go all the way could be a good idea. I am on my second tranny and third head! A bicycle-pump will help you in revealing any leaks and perhaps you can hear the shaft moving as well. -- Frode

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