Has anyone super charged a Volvo 940? I've been looking around to see what that would be like.

 

not much different than turbocharging, except there would be a belt driven blower instead of an exhaust driven turbine. you'd get less low end torque than the turbocharged systems get, since the turbocharger volvo uses developers full boost at a quite low RPM and any excess boost at higher RPMs is bypassed via the waste gate. it would be easier on a 92+ rather than a 91 because they did away with the mechanical fan in 92, instead using a larger 2-speed electric fan, so that makes for more room in front of the motor for the extra drive belt. you'd probably still want to relocate the air filter to the rigth side like on the turbo cars.... the air path goes air filter -> MAF -> charger -> intercooler -> throttle body -> intake manifold.

you'd probabl ywant to start with a turbo, as it has lowered compression ratio to better handle the boost pressure, larger fuel injectors, bigger radiator, and the intercooler.

simple mods to a turbo 940 can easily get you up and over 250HP with a lot less work. above 250 HP, you'd best start thinking beefier transmission, beefier rear differential, beefier brakes(!).

 

Ah, I had that idea too, was thinking of a SC14 supercharger with clutch so the supercharger can be disengaged when not needed. Too bad I don't have the time, money or space to do that.

 

There we're down sides to Volvo's use of turbos in the 940's. The rear ends had very low gearing(3:73 to 1) so the turbo could keep spinning and stay in it's power range. The result is some of the worse gas mileage for any 4 cylinder car ever built. Also, the transmission didn't have a lock up torque converter because that acts as an overdrive and would also delay turbo spin up. Besides the poor gas mileage the engine buzzed at 3,000 rpm at 70 mph, which made it a very twitchy highway cruiser. Mercedes on the other hand decided to supercharge their 4 cylinder cars from that era. The engines we're the same displacement - 2.3 liters but performed very differently. By design the supercharger developed torque at a much lower rpm so more power was available sooner. With more torque coming on sooner the final drive gearing was higher which gave them way better gas mileage yet they also accelerated much faster than the 940's. And the transmissions had a lock up converter which lowered cruising rpm's. The final numbers seem misleading - Volvo's put out 168 hp and the Mercedes' put out 190 hp. You would think less hp better mpg. But this reflects the difference between a turbo and supercharger. Plus superchargers don't need to be lubricated or water cooled or idle down after a hot run. Too bad Volvo didn't copy Mercedes instead of Saab.

 

my 6 cylinder similar-vintage mercedes, non-turbo, and no lockup, are spinning 3000 rpm at about 62-65 MPH..... and they are quiet and smooth as silk.

pretty sure the gearing on our non-turbo 87 240 was about the same as my 92 740T, around 3000 rpm at 65 or so. ditto my 4 cylinder 1989 jetta gli with a 5-speed stick, it turned about 3000 rpm at about 62mph.

 

An inline 6 will always be a lot smoother than an inline 4(especially without a balance shaft), and have a lot more torque which wont make it as "twitchy" at cruising speeds. More torque, less gas pedal, better mileage. What did your Mercedes get? The non turbos did have a few different rear end ratios including the 3:73 to 1 that the turbos had. The problem there was not enough power(no boost) so they had to gear for that. They did have a lockup torque converter which lowered the cruising rpms slightly. The result was slightly better gas mileage than a turbo but slow as molasses on a cold day. Where Volvo missed the boat on their turbos was the engine management system. They should have copied Saab completely. Saabs from that era had more boost(power), better performance and better gas mileage.