Supercharger for the TR6

Just purchased this supercharger for use with the MPI system on my 75 TR6. It will be summer 2004 at the earliest before it is grafted on (guess that that should have said Summer of 2005). The plan is to mount this Eaton M90 blower from a GM 3.8 to the left of the engine. It’s output will go to an intercooler mounted ahead of the radiator. This will be fun so I’ll be sure to post progress reports.

March 2005

It’s now Spring 2005 according to the calender in Maine. The local drive in reastaurant has opened, the ice breakers are heading up river, and the snow starting to melt. Time to get serious about all those TR6 projects including the supercharger. This is a photo of the the alternator’s new home on the other side of the engine. It is from a late model GM something rated at 104 amps. You may have noticed that it uses a six groove serpentine belt as does the new harmonic balancer in the background. That balancer is from a Caddy V8 and although it weighs the same is seven inches in diameter. The larger diameter will spin the supercharger faster therefore more boost. I expect to be post more pictures here in the next few days.

This is the mock up used to get everything aligned. In fact it is a spare engine that will soon be rebuilt and installed with the supercharger. Inside the gray colored loop will be the output pipe from the supercharger. Next up is to convert the water pump.

Converting to a serpentine belt to run the supercharger clutch means that all pulleys need to run the same 6 rib belt. And converting the water pump over is a bit more involved than at first glance. With the serpentine belt being wider it needs to run very close to the water pump housing leaving little space for the pump mounting studs and nuts. A removalbe pulley allows access to the bolts and by adding shims it can be precisely aligned. The original TR6 pulley easily pressed off the shaft so I thought it would be quick and easy to make a press on hub to mount the new pulley. It would have been if I had paid attention. On the second try the hub came out perfect and pressed on with notable resistance so it won’t fall off. Next up is to make the pulley.

April 2005

This is the new waterpump pulley sitting atop the hub in the above picture. It still needs to be trimmed down at the nose end once the alignment is set. Got to admit I’m very pleased with the way this pulley came out and it’s fit espececialy since it is my first serpentine pulley.

Here is the belt routing that I hope will work best. The idler pulley is just laying there for the photo. The hope is that the idler will have the easiest time taking up slack there because that side of the balancer is the “return” side for the belt. As you can see there isn’t much room at all for the idler but I think it can be squeezed in. Worst case it will take an idler with a longer arm. The output from the supercharger will just squeak out inside the corner of the gray loop. Next up is the mounting the tensioner.

The belt routing in the above photo just wouldn’t allow enough clearance for the tensioner to function. This set up is still tight but there is room for the tensioner to swing. The mounts have all been welded and the hope is that it will fit in the car. The car is still away in storage so it will be another week or so to see exactly if there is enough room. I’m wondering about the steering shaft.

Yet to be done is lightening the water pump pulley, making a hub to retain the harmonic balancer that will hold the timing wheel, fabricating a magnetic sensor bracket, and adding a timing mark indicator. Not to mention plumbing it all up.

May 2004

Test fitting the supercharger into my car. This is the first time that the car has been available since last Fall. The fit is very good and there is enough room for the blower, as a amatter of fact it could have been moved up half an inch and outward the same. That may not sound like much of a move but the installation is very close. Beneath the blower a tan pipe heads forward and it is destined to become the ouput tube that will meet up with the intercooler. The tan color is masking tape to keep the polished aluminum tubing from getting too badly scratched.

Here is the blower mounted to the spare engine with it’s outlet tube in place. Making the tube took nearly a day but it is a great fit and shouldn’t impede the blower’s performance in the least. Once again it has also been test fitted to my multiport car. The tolerance is close but it will fit.

A pretty good look at the blower and it’s new aluminum outlet tube. The tube is 2.75″ and if I had to do it over it would be 2.5″ tubing. Next up is to make a retainer for the harmonic balancer with provisions to mount the toothed timing wheel. Finally getting close to sending this engine to the machine shop! Anybody have a spare late model low compression cyinder head at a reasonable price?

This is the Cadillac V8 balancer. The retainer is cut from 6061 aluminum and is keyed with a 3/16″ dowel pin to the keyway of the balancer. The pin is required to maintain alignment of the toothed timing wheel that will soon be mounted in front. Two small socket head screws will hold the timing wheel to the retainer.

Original cast flywheel lightened to 22.5 lbs. Still quite heavy but it started out just over 28 lbs. All the material was removed from the backside. I’ve seen some pictures of TR6 flywheels using much smaller clutches that would allow a substantial amount of weight be cut from the outer perimeter of the clutch plate side. Tomorrow, May 20th, this engine goes to the machine shop! Anybody have a spare late model low compression cylinder head at a reasonable price?

June 2004

The intake piping to the supercharger is finally done. It was one of those projects that can be put off time and again. The big hang up was to come up with a neat effecient way to attach the oversize 2.75″ aluminum tubing to the small slotted opening on the back of the blower. The tubing heads forward to mate with a cold air intake that will be mounted ahead of the radiator on the left side.

Front view of the supercharger with the intake piping. Not shown is a similar sized output pipe that comes out below the supercharger. Both pipes head forward out past the radiator, one to an air cleaner and the other to an intercooler. Intake flange | Next up is to mount the intercooler and get it plumbed to the throttle body. The replacement engine is now at the machine shop.

July 2004

The supercharger in place with intake and exhaust piping attached. The alumninum tubing is the intake air and will attach to a K&N filter in front of the radiator. Not seen is a similar sized output pipe that comes out below the supercharger. Both pipes head forward out past the radiator.

Same as above. The coil packs, once located on the inner fender, are temporarily laying on top of the valve cover and eventually will be relocated to the battery location.

Looking across at the supercharger. In the foreground is the fuel rail. Down under the supercharger is the output tubing with a blue coupling.

Overall view of the engine bay. Placed in front of the radiator is a salvaged Audi intercooler. The next project is to mount the intercooler and fabricate new end tanks that align and connect with the aluminum tubing.