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Discussion Starter · #1 ·
This topic was started on 3rdgen.org. I own a saab 9000 and an 87' Monte Carlo. This is a quote from someone who claimed "they worked with saabs" and their turbos are out of date.

"You are correct in that Saabs use turbos on most everything they sell. However, for this very reason, Saabs do not sell very many cars.

Their turbo theory is quite out of date, and when people have problems with "turbo-lag" it is normally associated with Saabs.

Saab continues to design it's turbocharged engines in a way that most companies abandoned 20 years ago, putting a very large turbo on a motor that takes a good amount of time to spool up, making a motor that feels very, very peaky.

Modern turbo engines use much smaller turbos, which spool up faster and create a much smoother power curve with more availible power at lower rpms, as well as greater tourque and power across the whole band. The beauty of this system is that a smaller turbo can also provide similar power gains up high, however the turbo is spinning a good deal faster.

The difference between a Saab and a "modern" turbo design is immediately apparent. You floor the Saab, and nothing happens for several seconds, then the turbo finally spools up and the car suddenly lurches forward. A "modern" turbo gives you a smooth rush of power, starting at around 1500 rpm, and building as the revs increase.

Saab even goes further to compound the inherent problems with their design. Saabs use a computer controlled wastegate, that bleeds off boost under computer command.

Many turbo setups use a wastegate, but most are set up simply to limit boost to a level that will not damage the engine.

Saab takes this a step forward, and basically makes it IMPOSSIBLE to drive the car in a performance aspect.

Saabs bleed off boost under anything other than full throttle. Also, the wastegate opens fully whenever the clutch is depressed.

So lets break down what happens when you accellerate in a saab.

You floor it. The car goes nowhere, as the turbo has not spooled and the 4 cylinder is quite anemic without boost.

After about three seconds, the turbo comes up to speed, and the car shoots forward. In many cases, Saabs will actually lay rubber starting at 10 mph when the turbo hits. This IS a large turbo and it does produce power.

Then redline hits, and you push the clutch in to shift. The wastegate opens, and all the boost bleeds away in an instant. You shift to second, and floor it.

The car once again does not accellerate. For an interminable about of time, you putt in place. Then once again, the turbo hits, and puts you back, but just for a few seconds, as you now must shift to 3rd.

See the problem? This wastegate actuation makes what could be a 14 second car a 17 second one, and the turbo is unspooled more often or not.

Also, this makes the car a pain in the ass to drive daily for somebody not wanting to drive fast.

To the normal person, they accellerate off the light. The car does not accellerate well, so they give it more throttle input. Then the turbo suddenly spools, shooting the car unexpectedly forward, sometimes accompanied by squeling tires.

While working at a Saab dealership, I saw plenty of Saabs with front end damage from hitting somebody. THIS IS THAT EXTREME OF A PROBLEM, that people actually rearend people when the turbo hits.

So you get the best of both worlds. A car that goes slow when you want it to go fast, and a car that goes fast when you want it to go slow."

Opinions please. Though some good points are made I don't think that the lag is THAT noticalbe and will take off when drivin hard.
 

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What a load of rubbish. Saab started using smaller and lighter turbochargers, and experimenting with other ways to reduce lag, many moons ago.

Has the author of this misguided opinion ever driven a 9-5 Aero?

James
 

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By the tone of the article it sounds circa 1984 and the criticism could possibly be levelled at early turbocharged cars e.g 99, 90, early 900s etc.

Saab's apc turbo charging concept is well developed and you will see that historically turbochargers have got smaller (as turbocharging technology has developed). LPT cars normally don't use the apc system and so addresses the author's criticism.

I have driven a '89 9000 Carlsson for the last 3 years which was a beautiful car - no lag, power always available.

My current 9000 is a '92 CSE auto which is having the apc fixed so I have that carefully managed and controlled extra power back.

The SAAB apc turbocharging system is carefully designed and engineered to get the maximum, tractable performance with reliability and longetivity, from the available fuel (i.e avoiding knocking). A properly maintained turbo charged car, with oil changes at the right intervals, will give you no problems from the turbocharger.

I had a C reg MG Metro turbo from new and drove it for 112,000 miles no problems with the turbo (and no lag as the system had been designed by lotus, and on inspection bears agreat resemblance to a SAAB system). Later MG Turbo's had a larger turbocharger and were a bit of a dog to drive as a result.

If you wan't raw power I have been driven in a lpg (112 octance fuel) Griffin (full turbo) with the MAP sensor disconnected (so that the turbo can run at full speed ). Fantasic power, but uncontrollable for everyday use and ultimately will affect the reliability of the car.

Bottom line. Ignore this waffle go and drive your car carefully and it will reward you. If you look at a scrapyard you will see lots of front-ended performance cars because the drivers' get used to the performance and speed and fail to appreciate that all the other traffic doesn't accelerate or stop as fast as you. I have noticed this over the years whilst driving MGB GT (race-tuned), Rover SDi V8 and turbo charged SAABs.

I have driven a 9-5 2.0 eco estate and had to remind myself that it was turbocharged. It just isn't an issue. The average driver wouldn't notice, nor needs to know that they are turbocharged. Hence there is no reference to turbocharging in the model names.

Hope that this puts things into perspective for you.

Above all drive safely.

Gavin
 

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What a load of non-sense. I own a 94 9000 cse ecopower. Which has been chipped by Hirsch performance. producing 215 bhp as apposed to the standard 150. I do not get turbo lag now or previously the only thing is my car have better pick up, higher top end, and torque. And yes under full throttle the wheels spin like crazy but then so do most front wheel drive cars if you floor them. As you accelerate the engine physically pulls back and up on the car. hence lightening the load on the front wheels producing spin. If my lead footed girlfirend can do it in her 1.0l Nissan Micra what hope is there for more powerful cars.

Put it this way I once read that Erik Carlsson was asked about his name sake car in the respect that it is too powerful, and a danger to drive and should have traction control. His answer was simple, the car is not dangerous it is the driver, you must learn how to drive a car like that properly, and respect it.
 

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Discussion Starter · #5 ·
James, my point exactly. My dad has the 95 Aero and if you put it on sport there is virtually no lag, if none at all. I agree that he was probably talking about turbos from 1984 or around there, I don't think Saab would actually still be using that system today. My Saab however is a 95' 9000 CSE with 180,000 miles on it so its showing its age. Its still fast and I can notice the lag when I [expletive deleted] floor it, when I get on it HARD there is basicly no lag, just like the 00' Aero.
 

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What a load of ............! The author of that article doesnt have a clue what he is talking about. He mentions the APC, and says it limits power.... WRONG it allows more power, only limiting it when neccesary to prevent pinking, wheras cars without apc have to be set up so they are on the lower power all the time. He says that pressing the clutch causes the wastegate to fully open.... since when has there been any link between the clutch and the wastegate, I assume he is refering to the dump valve, which dumps the boost when you release the throttle as you would when pressing the clutch, but this allows the turbo to keep spinning, so actually reducing lag, not increasing it as he states. Saabs bleed off boost under anything other than full throttle... WRONG the APC is more lilely to reduce boost at full throttle than at part throttle. Do you think when he says he 'worked with saabs' he actually meant 'I worked with saabs but was sacked 'cause i aint got i clue what i am talking about, so now ive got a grudge'? :)
 
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