Supercharger/Bus/Trains

68/70Vette

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Jun 19, 2008
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1,051
Location
Torrance, Ca.USA
Ok I'll try again. Yesterday's post should be deleted by the administrators.

I drove my C6 2008 A6 to A&A Corvettes in Oxnard, Ca for a supercharger installation. It's about 90+ miles from where I live. When I dropped it off, about 2 1/2 weeks ago, I had to ride public transport to get home; Amtrak train to LA and city bus to Torrance, Ca about a mile away from my home. I walked the mile. This morning I did the whole thing in reverse. Walked to the bus stop at about 5:40 AM and caught a city bus. Surprisingly it was pretty full. Normally I see buses that are virtually empty. Caught the Amtrak train at Los Angeles Union station. Going into the station is like going back to the 1930's. From the Amtrac train you see California that you don't see on the Freeways. California is a pretty dry place, driving the freeways you wouldn't know it because everything is irrigated. I enjoyed my train ride. I hadn't been on a train since 1991 when I rode the trains in Europe. They travel, of course much faster, I think Amtrak was doing max at about 70+ mph.

My stone stock 08 automatic, with Andy Green's centrifugal supercharger (Vortec) pumped out 580 wheel horsepower at 6500 rpms. He spent quite a bit of time on dyno runs to get everything correct. His supercharger installation from it's appearance and attention to details looks like it came from the factory. The intercooler now completely dominates the airflow into the front grill work of the car. The supercharger intercooler installation has shrouds that forces all air into the intercooler. I think Andy advertises that he has sold 2000 of these kits and he has installed about 500 at his Oxnard garage. He is really devoted to supercharging and he also installs Edelbrock E force superchargers. He bought a supercharged Cadillac CTS-V with a supercharger that I assume is pretty much the ZR-1 Corvette supercharger, and replaced it with an Edelbrock. I didn't ask why!!

Anyhow, another trip on city buses and Amtrak and I picked up my car today to drive home. I had a discussion with Andy to learn about taking care of the supercharger, etc. I was a little wary about driving the car. Andy verified for me that some of his customers cars, leaving the facility, ended up in body shops before they ever made it home. The power from the supercharger will overwhelm the traction control feature, so you can get wheel spin and possible spin out with the extra power even with traction control active.

So...for now I just wanted to get home. I drove the car home very gently. At 70 mph, the engine is turning 1700 rpm and the centrifugal blower is just dead at that rpm. Also, at 1700 rpm, I have a lot of engine vacuum, and the blower bypass valve is open so what little pressure it generates is blown off. With my automatic I did apply a little gas pedal to accelerate and the car seemed to accelerate a little faster than stock. For just street and highway cruising, the engine response is that you have no idea that you have a supercharger. However, I never used enough accelerator to get the tranny to downshift. Downshifting awakes the supercharger. The centrifugal blower starts life at about 2500 rpm and the supercharger bypass valve closes to pressurize the intake manifold. I do plan on taking the car to a drag strip. My fastest drag strip time so far is 13.5 seconds at about 115 mph in my 69 Corvette (1975!!). This was with a L88 clone engine and old fashioned street tires. I wonder if I can get into the 11 seconds??

Because, the centrifugal blower doesn't interact much with the engine, say below 2500 rpm, the cars drivability and gas milage are not affected.

Google A&A Corvettes. Andy ships his supercharger kits world wide. Its a big 104 pound box. The precision brackets and professional intercooler and plumbing make this system work. Once again, 580 rear wheel horsepower at 6500 rpm on the dyno. Andy had a customer that wanted 1000 hp on the dyno, but the guy accepted 990 hp. For these extra HP outputs with a LS2 or LS3 you have to make major lower engine upgrades$$$$$.
 
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Easyasone2three has his first kit. He asked me if I'd help install it, and I declined. (Andy also changed the cam).He then asked Andy, and Andy gave him a good deal since it was his first kit.
I have driven the car with that set up. DON'T punch it going 70. It WILL break loose and scare the crap out of you.
 
You'll have lots if fun with it. At cruise your mileage will be worse, spinning the blower isn't free, even with the surge calve open

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Easyasone2three has his first kit. He asked me if I'd help install it, and I declined. (Andy also changed the cam).He then asked Andy, and Andy gave him a good deal since it was his first kit.
I have driven the car with that set up. DON'T punch it going 70. It WILL break loose and scare the crap out of you.

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big2bird....thanks for publishing the photos. I have an iPad class at the Apple store tomorrow, so hopefully I'll soon get into the photo attachment business.

The picture you see looks exactly like my installation. Notice the stainless steel hose connection into the top of the blower. This is for high pressure engine oil. There's a similar drain hose that returns oil to the engine pan. Some of the Vortec units have self contained oiling. My Vortec blower is a V2 with the Si Trim. The Vortec website discusses their various blower configurations. (Google Vortech)

Twin_Turbo. Yes, I'd expect to get some reduction in miles/gallon since the centrifugal fan is always taking energy to turn. I think the fan (actually the word turbine is probably better) spins at about 7.5 times crank speed. So at a lazy engine speed of 2000 rpm, the fan is turning 15,000 rpm. At 6000 rpm engine speed, the fan is turning 45,000 rpm. With regards to fuel consumption, Andy claims that his centrifugal blower doesn't affect fuel consumption very much for street and highway cruising. The main reason is (my words) is at these low engine rpm's the fan is just not creating that much pressure, notwithstanding that the by-pass valve is open. But the Roots blower (aka Edelbrock E-Force) is producing positive pressure at any engine rpm. It too will have it's bypass valve open at cruising speeds, but I was told that anytime you bobble the accelerator, you will get positive pressure and an accompanying fuel mixture enrichment. Hence, the story goes that the Roots blower will more adversely effect fuel consumption. I've never driven a car with a Roots blower, but from what I've read, the Roots blowers provide classic Big Block Chevy power; lots of power at low rpms. With the centrifugal fan you have to get rpms up (downshift).

Driving home, as soon as I got on the freeway, I did check out the mileage figures. I noticed that my long term average mileage was 9.8 miles per gallon. Since the car had been on several dyno runs and two that went to 6500 rpm, this was not alarming. However, when I checked the instantaneous mileage figures, I couldn't believe them. Running on a straight and smooth freeway at about 65 mph, I was getting instantaneous numbers in the high 30's and low 40 mile per gallon range!!!!! I wonder if something in the supercharger installation has caused a mile per gallon calculation error in the car's computer. Before, I never saw instantaneous mpg figures above the low 30 miles per gallon range. (30? Yes that's right. My C6 08 A6 window sticker lists 27 mpg highway. On the highway at 65 mph, etc, I typically see instantaneous mpg numbers bouncing around the high 20's and 31, 32 mpg.) Andy's supercharger installation replaces the stock 50 pounds per hour fuel injectors with 60 pounds per hour injectors. Maybe this is throwing off the mpg calculation.

Some other somewhat unrelated comments. The A&A supercharger installation fits entirely under the stock hood. From inside the car, with normal street/highway driving, you cannot hear the supercharger. With the hood open, you will hear a whirring sound. The stock fuel pump cannot supply enough fuel. A Kinne Bell fuel pump controller is installed to boost the stock fuel pump flow at high rpms. Loingenfelter uses this booster in their installations, interestingly Edelbrock advises to not use it but instead install a Z06 fuel pump. Andy thinks the K Bell booster is not a problem. (The orthodox procedure for replacing the stock base engine fuel pump with a Z06 fuel pump, requires dropping the fuel tanks, which requires removing the rear suspension!!). How much did it cost? I don't want to quote the exact price...since I did have some extra repair work not associated with the blower install. The dyno tune was $650. The labor charge for the supercharger install was a little less than $2000. The main driver for installation charge, for both Andy's and Edelbrock's E-Force. is pinning the crank pulley to the crank. From the factory, the pulley is force fit to the crank. With a supercharger, the pulley will slip. A tool is required (supplied with both kits) that allows you to drill a 1/4 inch hole between the pulley and crank and then hammer in a 1/4 inch round key to prevent slippage. Unfortunately to get access to drill this simple little hole, you have to remove a lot of front suspension and front body fascia!!!! Removing the front body fascia (i.e. the bumper) panels also aids installing Andy's intercooler. When you look into the front grill work of a C6, all you see is wall to wall intercooler and shrouding top, bottom, and sides. Any air going into the car radiator has to go throughout the intercooler first. The Edelbrock E-Force installation will cost about $3000 more than Andy's supercharger, with the Edelbrock you're starting to push a little less than $10,000 Andy's Edelbrock installation price does include extensive dyno tuning. The stock Edelbrock flash is pretty conservative, so a custom dyno tuning gets more hp out of the install. And regardless of which supercharger you buy, you get a nice hp/torque versus rpm!

My dyno tune was with 91 octane fuel (arghhhh!). When I take the car to the drag strip, I'll put in a glugg of racing fuel, 110 octane, unleaded. I ask Andy about the octane boosters for sale in auto stores. He said that the only brand he tried, that worked was Torco. He said that on one of his installs, working at the 700 rwhp range, he got a 70 hp boost with Torco. I looked at Torco's website, and although they weren't straightforward with what was in their additive, it appears that it's just pure heptane and octane. I was expecting toluene.

The A&A supercharger installation is approved by the California Air Resources Board (CARB), it has a CARB registration number stamped into the head of the blower housing, and it will pass the smog test.
I'm tempted to recommend this for anyone with a C5 or C6, but I should reserve comments until I've driven the car more....especially trying some brief WOT blasts on the freeway.
 
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