Maintaining Supercharged Engines

Aside from the obvious of having to use premium fuel and changing the supercharger oil every so often, what, if any, are the other bumps of owning and maintaining a supercharged engine?

I’m assuming you’re talking about an Eaton supercharger commonly used on Fords, Buicks, Pontiacs, etc. Check the oil level now and then just like on an engine and the SC should last a long, long time. About the only problem that may crop up would be if a rattle develops in the SC and that’s not a major fix. It’s usually caused by a failing coupler; about 15-20 bucks and a little time.

In normal driving you would see little if any boost anyway due to the design of the intake tract. Getting into the boost usually means the foot has to be firmly down.

Treat like any other engine.

It’s surprising how many people don’t know that the supercharger has oil that has to be maintained just like the engine.


I got a good offer on a 98 Regal GS with only 44k miles. Not sure I want to be pumping premium though, as it would be my daily driver for a bit.

It’s possible that the car could run fine on 87 or 89 octane as it can vary case by case. No pinging on a fully warmed up engine with the pedal nailed to the floor means it should be fine on 87.

I’d like to see an image of that vehicle.

Yep! Any engine that’s turbo/super charged requires high octane gas.


Yeah, I’ve read that if you are being a “frugal” driver and just doing daily drives then 87 is good to go. I’ve also read that people have had a lot of issues doing this. The manual says “91 or greater ONLY.”

How much do you drive? Do the math. Say the difference in price is .25/gallon. Say you drive 200 miles a week at 18mpg. That’s 11 gallons, say 12. That’s $3.00 a week difference between regular and premium. Is that a noticeable amount in your monthly budget?

As for the car, I’d want to know as much about the driver as the car. If it’s Ricky Racer selling it chances are that engine has spent some time with the pedal on the floor.

I knew a guy that tried to run a supercharged Regal GS on 87 octane. I told him he needed to use premium, but he didn’t listen. It started out with a blinking CEL every time he tried to accelerate. Then, after time, it degraded to running like crap. Hard to start, and would stall at idle. I had changed out the plugs twice on it for him, each time getting a bit better performance, but stopped working on it after realizing he kept using 87 octane. The old excuse, ‘It costs to much!’

I make it a point to avoid buying any turbocharged or supercharged vehicle. There are many reasons why I choose to do this.

Missileman, I too prefer a naturally aspirated engine for daily use, but we may have no choice in the very near future. All the manufacturers are turning to boost to get decent performance with better all around mileage.

Just because it’s 17 years old doesn’t mean it is any less expensive to maintain than it was in 1998. If you want the car, use the high octane gasoline.

I see that day coming the same mountainbike but there always be vehicles available that don’t need them…for as long as I’m alive anyway. I’m currently looking for a '57 Bel Air that’s going to get the updated engine/transmission, brakes and AC routine if I can find one. I’m not a stickler for “original” restores so that will work for me. My brother-in-law has a '62 Impala SS convertible that needs a new home so that would work as well. I would already have it in my driveway but I’m not a big fan of convertibles and my wife wants the '57 like we had when we were newlyweds.

Ohhhh yeahh … sweet rides.
Personally, I love convertibles. Always have. I love concourse restorations, but I also love sympathetic restorations and even old cars brought up to modern standards. Never could afford such a toy, however.

NH law is funny on old cars, however. I was talking at a show to a guy who had a restored '72 Vega with a V8 conversion with NH plates, we got to talking about the advantages and disadvantages of using a modern motor vs. a rebuilt old motor, and he told me that if he’d put a new motor in he would have had to meet emissions requirements based upon the year of the motor. Yet we also have really junky rat rods running around with plates. He also had some Thrush Sidewinders on it, but he couldn’t hook 'em up because NH law requires that the exhaust exit aft of the rear axle. Yet some states allow all-out pro-stock cars on their streets. NH law is sort of pathetic on hot rods.

I had a Chevy Cruze rental with a turbo…it was nice and fun, but I’m not sure I’d want to pay a note on it and have it for the next five years. Turbo lag…but I could burn the front tires at 35mph and still get 38mpg.

@Tester some of the newer DI turbo engines will run fine on 87 octane.


But are we talking about a newer direct injection turbo engine?


No we are are not, but you did make sort of a blanket statement with the

“Yep! Any engine that’s turbo/super charged requires high octane gas.” comment

For a 98 a Supercharger/Turbo adds a bit of complexity. I would steer clear of them as an older used vehicle.

“The L67 is the supercharged version of the 3800 Series II L36 and appeared in 1996, one year after the normally aspirated version. It uses the Eaton Generation III M90 supercharger with a 3.8” pulley, a larger throttle body, fuel injectors, cylinder heads, and lower intake manifold than the L36 uses. Both engines share the same engine blocks, but compression is reduced from 9.4:1 in the L36 to 8.5:1 for the L67. GM listed the engine output as 240 hp (180 kW) and 280 lb·ft (380 N·m) of torque, although broad torque span and perhaps conservative rating by GM due to the engine’s temperature sensitivities, have established a belief in higher actual output."

This '98 model has the bugs worked out and they were very reliable…The larger M90 Eaton blower used a larger drive pulley which reduced blower speed considerably over earlier versions…Tuners have been known to drop the pulley size from 3.8" to 3.00" or even less and generate some SERIOUS power. Of course, reliability suffers when the pressure increases…