We have not started this page to be vindictive or to name and shame anyone. This section of the Aussiespeed Street Supercharging website is to hopefully share some of the things to avoid if you are making your own components to fit a supercharger to your engine or buying a used kit that some one has made up them selves. We want to share some of the nightmares people paid there hard earned money for only to be sold or delivered junk. We are all for people having a go them selves and putting there own kit together. On this page we hope you might get a bit of an idea on how some of the products in the Aussiespeed range might be able to help you complete a quality fit up to your engine.
Someone has gone to alot of trouble to extend this M90 supercharger drive. Remember a supercharger can spin up close to 20,000 rpm. When you are talking in some instances that the drive end can be running at 1.5 or twice engine speed its spinning fast. Besides the balance of the components weight has also got to be considered as well as seal and bearing speeds.
We have seen supercharger snouts extended in this way before, a press fitted bearing is fitted into the existing original housing where the pulley once fitted, we have seen this done where the extension piece between the end of the snout and the pulley spins as a long extension with a steel shaft press fitted to either end of the spacer in between. It is a big load to be spinning of that bearing and as it isnt rigidly mounted it can really become a Weapon of mass destruction.
The end has sheared of, its a thick section of the shaft.
There once was a bearing on the broken end, its a solid steel shaft and was an interference press fit with out a key or taper. Force it on, force it off a few times plus running at even 1/2 engine speed on a baby street engine at 1 to 1 could see 5000 rpm.
Our Aussiespeed supercharger drive has the bearing set in from the end of the shaft with a moderate wall thickness on the outside of the bearing, a 3/16 key is used to hold the pulley hub in place and doesnt need to be forced on or off.
Chevy inline supercharged with an Eaton M112, The customer had let a few people look and quote on doing the fit up. After crunching the numbers on a custom set up all the components used are of the shelf items produced by Aussiespeed.
This bottom supercharger pulley was fitted up relying on the bolt to locate it to the balancer, We would never recommend using bolts to locate any pulley used on a blown engine. These were not even drilled in the centre as you can see the pulley is off set. Another thing is the bolt holes are not even round and a good fit on the bolts.
No location, bolt holes not true, the ribs on the pulley have pulled in in the centre as the belt whipped around. This can only be described as poor workmanship that is also unsafe. Have you ever seen a 3 inch re enforced blower belt fly off ? it can be rather scary.
If you look closely you can see the wear in the centre of the pulley, the way this set up was fitted and aligned can only be described as Crap. The bad part is the customer spent lots of money and in the end gave up and traded the kit on a Aussiespeed 142 Weiand kit.
If you look at the top of the picture you will notice the coating on the rotors is starting to peal, the teflon coating starts to de-laminate from the rotors and in many cases sticks in the corners of the blower housing. As the coating peals and collects it acts as an abrasive and can wear the corners of the rotors or the housing. When inspecting a used supercharger look for pealing coating on the rotors.
Scuffs and rotor wear .
The question has been asked many time about poly rib belts and gilmer toothed belts. There are a few advantages that not every one will agree , belt wrap is easier with a poly rib, if you get a backfire the belt will slip with a poly rib as a toothed belt can cause damage to blower/manifold. A poly rib running moderate boost does not necessarily need a back fire valve. If you are running a toothed belt you need a BURST PANEL / BACK FIRE VALVE and as boost increases the size of the opening needs to as well. We use steel pulleys not aluminum, the poly rib pulleys are cheaper to produce as they do not need hard anodising after machining. belt sizes with poly rib are ready available and our tensioner works well with our current set up.
Cutting, Welding and modifying a Supercharger Housing.
Dont even consider it, companies who design, develop and manufacture supercharger housings and rotors have things to consider when they take on the job. A supercharger can spin at up to 20000 rpm so the front and rear end plates have to be so exact.
Consider Manifold Designs & Dont Get Caught
If you are going to spend the money on supercharging your engine you would be a fool to do so by simply welding or bolting on a plate to a 2 or 4 barrel manifold that is designed for a naturally aspirated engine. When increasing the amount of air on the intake side you need to increase the volume of the manifold. There are people who put together what they sell as supercharger kits that use recycled parts and some times junk who look for the uneducated and push there own barrow and quote un supported horsepower figures and boost figures. Dont be fooled by these” Lets Make Some Pizza & Beer Money ” back yarders. We are not saying that there are not people who are putting together low volume high quality supercharger kits. If you look at any of the purpose built turbo kits you will notice that any of the draw through systems have a larger plenum. Unlike blow through systems the area between the turbo and carburetor increases the area. Things like blocking bypass valves in the rear of a supercharger when it is proven that the twisted style rotor and bypass valve run a cooler charge. If you are relying on 4 x 5/16 carburetor hold down bolts to correctly align, seal and support your supercharger you are asking for trouble. This is information we hope will help you to understand that when fitting or building your own kit that you need to investigate what is available and there is a lot more involved than just wacking on a blower.