Is my supercharger working?

[OpenClose]

I'm running my '99 Buick Regal with frest ATF and SC fluid thanks to the help from you guys at this site!

I just have something I have been curious about. I can't tell whether or not my supercharger is performing its function.

-I have never really seen my boost level change on my dash (the display on my dash also no longer works due to bad resistors). It just stays at 0.0psi, even when I have nearly floored it. (In performance shift, it usually shifts 1-2 right at 5000RPM if that is of significance)

-I seem to get a fair bit of horsepower, but it isn't quite leaps and bounds better than my brother's 3.4L, which would make sense if it was the 3.8L running stock.

-My car apparently requires 91+ octane to prevent knock ("use only premium"). Therefore I should notice either knocking or a reduction in power due to knock retard. I have experienced neither. I can tell no difference between octane selections. So I have been running regular ever since.

-My dad and I checked the vacuum line/valve and it seemed to function properly.



Also, why is both the LS and supercharged GS models rated at 240HP? And why does it feel so much more powerful than my mom's Ford Escape, which is apparently 240HP as well from a 3.0L?

 

[OneEyeJack]

Hook up a temporary gauge, or hook it up and leave it instead of repairing the stock gauge.

Maybe your mom is sandbagging to protect your ego.

 

[OpenClose]

"Hook up a temporary gauge"
I'll have to give that a try. Hopefully not too pricey.

"Maybe your mom is sandbagging to protect your ego."

I've driven her car. it's a 2009 Escape. It has a wicked first gear, but drops off rapidly after that.

 

[CT8]

Is my supercharger working? If you can't tell there must be a problem.

 

[linksep]

Torque. Your Buick has 280 lb*ft of torque, your mom's Escape has 233 lb*ft of torque, (a first generation Honda S2000 made 240 HP with 150 ft*lbs of torque, an early Powerstroke diesel made 250 HP with 505 ft*lbs of torque). Torque does the heavy lifting, like moving your heavy car from 0-60, or passing on the highway without down-shifting 3 gears.

Is your supercharger working? Yeah, because if it wasn't you'd get smoked in a race between your car and a little old lady with a walker (on foot). GM used a small supercharger for that size engine, and they didn't use an intercooler, hence they kept the boost level pretty mild.

 

[double vanos]

Disconnect the belt to the super charger and go for a ride. You'll know within 500 feet if it's not working.

 

[ironman_gq]

Plug in a scantool and watch the MAP output during acceleration. Anything other than vacuum means the SC is working.

 

[440Magnum]

Originally Posted By: double vanos
Disconnect the belt to the super charger and go for a ride. You'll know within 500 feet if it's not working.


Isn't that a Roots-type blower? If it is, it won't MOVE 500 feet without the SC working... ;-)

 

[901Memphis]

I've heard of quite an few people removing the belt from the supercharger on 3.8 and driving it save gas.

 

[440Magnum]

Originally Posted By: 901Memphis
I've heard of quite an few people removing the belt from the supercharger on 3.8 and driving it save gas.


Maybe its not a roots, or has bypass valves so that it doesn't become a potato in the intake with the belt disconnected or broken- been a long time since I've even seen a 3.8 blower, and I never was all that familiar with it. I'm not really sure pulling the belt would save any gas since all the PCM programming expects boost to be there, though. Seems like it would be highly UN-optimized...

 

[901Memphis]

I've also seen some listed on Craigslist that say they were elderly owned and usually the son is listing it saying he disconnected the belt so it wouldn't be too fast for the elderly driver, because it can sometimes give you more torque than you're expecting.

Not 100% sure about the fuel economy, since I've never had one myself

 

[sciphi]

If you're running regular and comparing it to the N/A 3.4, that's the reason.

What else have you done to this engine? Recent tune-up with non-platinum plugs and good wires? PCV valve? Hooked up a scan tool to tell how much it's boosting?

Lastly, these engines are meant to run on premium all the time. The low-octane maps in those cars were meant for limping home, not daily driving.

 

[Clevy]

Originally Posted By: sciphi
If you're running regular and comparing it to the N/A 3.4, that's the reason.

What else have you done to this engine? Recent tune-up with non-platinum plugs and good wires? PCV valve? Hooked up a scan tool to tell how much it's boosting?

Lastly, these engines are meant to run on premium all the time. The low-octane maps in those cars were meant for limping home, not daily driving.



Too add to this
If it's been babied it's possible that there's carbon built up in the combustion chambers which increases compression and can cause pre-ignition so the knock sensors retard timing which also lowers power output.
And just running one tank of premium isn't going to fix it. The ecu learns,gradually adjusting the running parameters and storing new values as the inputs change.
You could unhook the battery and totally discharge the system the ecu would return to original stock so it might improve zip a bit if you start using premium again.
I loved the boosted gtp,Bonneville,regal etc with the 3.8. You could pulley them to increase impeller speed for more boost so modding them was fun.

 

[Shannow]

Originally Posted By: Clevy
I loved the boosted gtp,Bonneville,regal etc with the 3.8. You could pulley them to increase impeller speed for more boost so modding them was fun.


10lb pulley on my Caprice was noticeable.

 

[artificialist]

Sometimes the supercharger bypass valve could stick open. It opens at idle and low rpm to reduce power loss at the supercharger, then closes so the supercharger can build boost.

I rarely ever encountered a 3800 S/C engine, so I am limited in what advice I can give you. In fact, a 3800 S/C might not even have a bypass valve, I don't know for sure.

 

[emg]

Originally Posted By: 440Magnum
Isn't that a Roots-type blower? If it is, it won't MOVE 500 feet without the SC working... ;-)


I drove my supercharged Lancia about ten miles home with the supercharger belt disconnected after it blew all the oil out the exhaust when the seals failed. I never understood how it managed to drive that way with such a tiny gap between the rotors for the air to get through, but I presume there must have been a bypass valve somewhere.

 

[R2d2]

Originally Posted By: OpenClose
I'm running my '99 Buick Regal with frest ATF and SC fluid thanks to the help from you guys at this site!

I just have something I have been curious about. I can't tell whether or not my supercharger is performing its function.

-I have never really seen my boost level change on my dash (the display on my dash also no longer works due to bad resistors). It just stays at 0.0psi, even when I have nearly floored it. (In performance shift, it usually shifts 1-2 right at 5000RPM if that is of significance)

-I seem to get a fair bit of horsepower, but it isn't quite leaps and bounds better than my brother's 3.4L, which would make sense if it was the 3.8L running stock.

-My car apparently requires 91+ octane to prevent knock ("use only premium"). Therefore I should notice either knocking or a reduction in power due to knock retard. I have experienced neither. I can tell no difference between octane selections. So I have been running regular ever since.

-My dad and I checked the vacuum line/valve and it seemed to function properly.



Also, why is both the LS and supercharged GS models rated at 240HP? And why does it feel so much more powerful than my mom's Ford Escape, which is apparently 240HP as well from a 3.0L?


FYI those dash units are easy enough to repair, I've done two (bad resistors) and I have no electronics repair experience. Just watched a video on youtube and about $ 25 in supplies from amazon.

 

[ls1mike]

The 3800 will run without the supercharger spinning, belt disconnected etc etc.

They have a bypass valve. It is vacuum actuated. Located on the blower it is a black cylinder with a rod coming out of it.Make sure that isn't stuck.

Are you sure the coupling inside the blower nose isn't broke? I have had that happen. The belt and the pulley continues to turn but the blower does not.
coupler is the green thing.

The LS is 200 HP the GS is 240. There was also a GSE and GSX.

Do not run regular, With a scanner you will see the computer pull timing way back! That is killing you and the car. Get the right fuel in and go from there.
You might not feel it or even here it but you are getting detonation and spark knock. I am on my 4th 3800. 3rd supercharged one. My 01 GTP ran 12's, my 98 GS ran low 13's and the Grand Prix runs mid 13's. I know a little bit about them. Get that cheap gas out of it.

Removing the belt saves no gas. You want to save gas and money? Keep your foot out if until you need to embarrass someone.

 

[HangFire]

Agree on the don't-run-regular comments.

Originally Posted By: emg
I drove my supercharged Lancia about ten miles home with the supercharger belt disconnected after it blew all the oil out the exhaust when the seals failed. I never understood how it managed to drive that way with such a tiny gap between the rotors for the air to get through, but I presume there must have been a bypass valve somewhere.


My guess is that supercharger was free-wheeling.