[California Saab Tuner]

Does anyone know what the Connecting rod ratio is for a 2.3L Saab turbo? Or any other 16V Saab motors. I'm interested in knowing how well they could be made to rev reasonably high. I know it's not traditionally how Saabs are tuned. But the hillclimb Viggen had a revlimit well over 8K RPMS ... so the 2.0 at least must have some potential in that catagory. I'm just curious about the 2.3 and older Saab turbos and looking for a specific rod ratio for each (the ratio of the length of the connecting rod from center to center divided by the diameter of the crankshaft).

 

[Eric van Spelde]

The B23x con rod is 147.5 mm IIRC. The slant block 2.0l (B201/B202) is 134.5 or so. In both cases it makes for a quite favourable ratio...

 

[California Saab Tuner]

YES!!! That means the old slant 4 Saabs have a 1.724 Con rod ratio. That means they're most efficient (well from a purely connecting rod standpoint) at easily upwards of 7500 rpm. Most of the little Vtec Honda boys that rev to 9K rpm and up, use the B16 here in the states, and that has a 1.7 con rod ratio. This could be good news indeed. The B23X engines are still 1.64 which would be still easily acceptable to very high RPM though not as efficient. Looks like Saabs were made to rev high after all *insert evil laugh here* Now I seriously hafta find a way to supercharge an old slant 4 Saab. That would be über cool. At least some of you out there need to try making those motors rev past the stock 6000 or so rpm. These engines are 16V! I guess though, if you're going to change the redline, you'd need shorter gear ratios, and since most of the tuning companies don't want to touch the gearbox they just up the boost and leave the redline alone. But I think in the near future we should be hearing about Saabs realizing their high revving capabilities. Just seems such a waste to not utilize a 1.72 ratio and 16 valves, especially in the short stroke large bore motors of the 2.0 and 2.1!

 

[Eric van Spelde]

I am at the case for the sake of FWD handling/driveability and the relative fragility of the c900 drivetrain - mine is turbocharged though, and will max out at around 7,000. Much higher would require solid valve lifters, and I'm not sure whether I would be able to live with those on a 16 valver...

According to Johann Heuschmidt, a well known German Saab tuner of the '80s who claims to have done some development work with/for Saab, there is some kind of resonance in the block structure above 6,500 which urged him not to rev it above 7K for a long lasting street engine. Could be a red herring, though.

 

[California Saab Tuner]

Oooh. Ouch. That could be dangerous. And as far as the solid lifters. I agree, on a daily driver it's insane. You could possibly be forced to readjust the valve lash on a daily basis with shims! (though more likely a semiannual task) Not a fun thing to do to say the least. But I would assume the inline 2.0 of the later generation turbo probably has the same ratio. Which would be why the hillclimb Viggen can rev to 9K rpm with no apparent power issues. Anyone selling their B204R?