Engine Performance Upgrades for "Red Block" Volvos
The upgrades discussed here are for what Volvo calls the “Red” engines. Primarily the 4 cylinder pushrod and overhead cam models used from 1962 to 1995.
Something to keep in mind if you are new to Volvos is that Volvo has pretty much always provided well designed and efficient power trains. The ignition systems are strong, the fuel systems have some extra capacity built in, and the intake and exhaust systems are generous. It is unrealistic to expect dramatic performance gains from any single upgrade.
For example, some cars made by other manufacturers may be equipped with a marginal air intake or exhaust system and it is possible to gain 5-10 and up to 20 HP on some larger displacement motors by upgrading to a performance intake system or exhaust. This doesn’t mean that you can’t improve the performance or tailor the power delivery of your Volvo to your tastes however. It’s just a bit more involved than on some other cars. As with any endeavor to improve vehicle performance, make sure you are starting on a sound running engine in proper tune by performing an intensive inspection and tune up. Nothing is more frustrating than installing an upgrade and ending up with poorer performance due to an ailing subsystem such as the ignition system or fuel delivery system that is unable to keep up with the upgrade.
Replacing the camshaft with a profile that is more closely matched to your driving style is probably the best single improvement you can make and a good foundation for building on with other upgrades. Study the cam description and if available HP and torque graphs. Ask for feedback from other users on one of the popular Volvo owners bulletin boards like swedespeed.com, brickboard.com, or turbobricks.org.
Adding an adjustable cam timing gear to the overhead cam models allows you to tailor the power delivery to better suit your application. We find that most owners will advance cam timing to help punch up the low end torque a bit and help overcome the Volvo mass. For non-turbo models, there really is no need to alter the air intake system as it flows very well and provides good cold air intake outside of the engine compartment. This is generally the case for turbocharged models as well until you begin to exceed the 200+ HP range, then you might want to consider making improvements here.
Now that you’ve got all that extra air crammed into your motor, how do you get it out unrestricted? With a larger exhaust! Again, Volvo has always done a pretty good job here so upgrading the exhuast is usually not needed unless you have made intake improvements such as a cam, increased boost etc. On non-turbo models, be aware that if you increase the pipe diameter too much, you lose the required back pressure for low rpm throttle response, so don’t get carried away in this area.
Generally speaking a 2” to 2-1/4” system will be plenty on a non-turbo model and 2-1/2” to 3” on turbo models. Exhaust system design is a science, so you are usually better off purchasing a manufactured system vs. building one on your own as it is not uncommon to end up with a raspy or droning exhaust from a home built system. If you’ve got a vintage pushrod powered Volvo, we do offer a 4 into one exhaust header that provides a good increase in mid range and top end without sacrificing bottom end performance. Also a good replacement for cracked original cast iron manifolds that are hard to replace nowadays.