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My 1995 900s (2.3na) starts to lug and vibrate a lot if I use 5th gear any lower than 45 mph, and even at 45-50, it has to be mostly level or downhill to feel really smooth. I drove a 1996 with the same engine and it seemed to do a bit better. I remember that that car had the shift-up indicator and I thought that SAAB was probably just advocating straining the motor for those precious fuel mileage estimates, because the alleged shift points on that car were even a little optimistic. Does anyone's car drive comfortably in 5th from say 35-45?
 

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in my v6 its realy chuggy, it takes untill at least 50 untill its smooth, but it has been brought to my attention that the v6 is geared differantly, so my experiances may be different
 

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The turbo runs fine and does not lug down to about 1500-1600 rpm, in 5the gear, that is about 38-40 miles per hour. The car can be driven by the shift indicator, in "grandma" mode, as the guys on the performance board would put it. The three models have different manual gear boxes and ratios, so it can be hard to compare drivability between the turbo and other engines.

5th gear ratio, and speed at 1500 rpm:

B204I, FM51, 3.13, 34 mph
B234I, FM54, 2.85, 37 mph ("S")
B204L, FM55, 2.69, 39 mph ("SE turbo)
 

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Are the engine/transmission mounts in good condition ?

I'd think that any efficient engine would lug some when in 5Th gear at less than roughly 2 grand, even on the level with very light throttle pressure ....but, then, I do drive an automatic and pay for it at the pump....
 

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My '97 2.3NA will do a small hill in 5th at 45mph without complaining, but I wouldn't want to step too heavy on the gas in that situation. I don't usually worry about downshifting until I hit about 40.

I would be interested in hearing some opinions on this matter though. I remember reading that one way to extend the life of a timing chain is to avoid lugging the engine. What exactly is considered Lugging? Driving under a particular RPM? Or is it one of those things you just get a feel for?
 

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Well, if you shift when the shift light tells you to in my 900, then then 5th is practically ALWAYS going to buzz. It usually tells me around 37mph.
 

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see to me that seems realy slow for 5th
i figure 10 mph per ger like 1st up to 10 2nd to 20 and so on
 

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t_buck09 said:
see to me that seems realy slow for 5th
Can't really compare the 4-cyl and the V6 that way, even though the gear ratio in 5th is about the same as the 2.3l engine.
 

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Frogdude said:
What exactly is considered Lugging? Driving under a particular RPM? Or is it one of those things you just get a feel for?
Lugging was a term used to describe damage to old car engines as a result of running an engine at high load and low rpm (giving the engine too much gas at low rpm).

The expansion of the hot gasses is working against too high a resistance (load on the crankshaft), and does not allow the piston to move as quickly as it should for an even load on the connecting rods and other parts. Combustion becomes uneven, to the point of piston slap (piston hits cylinder walls). Cylinders become marked up. Other bad things happen.

I don't think classic lugging happens on cars with Trionic ECU's, and I would be surprised if it happened with the Motronic.

However, if you overload the engine habitually to the point of hearing engine knock at low rpm, it won't do it much good. If you like to cruise at low rpm to save gas, you basically have to get used to anticipating downshifts before jumping on the throttle, not after.

The comment about the chain likely refers to the balance chain and balance shaft system, which probably could not do its job if the combustion in the individual cylinders did not follow the predicted timing and load - another reason to get rid of the pesky things, IMO... :cheesy:
 
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