Well recieved my water pump pulley yesterday so decided to get it fitted.
Now you might think this is just a bit of bling but this has a fundemental change to the belt system on an rx7
due to the nature of a rotary engine, they require a lot of fuel to pretty much do anything, which means when idleing they put out a lot of crap.
very strict emmisions around the world has caused problems for the rotary engine so what the designers did was fit a belt driven pump onto the engine that pumps pure air into the exhaust system to fool the MOT places into thinking the casr pumps out very little fumes.
It also has the effect of helping to cool the cat, an average piston engine when pushed very hard will get up to 1300-1400f exhaust gas temperatures, a rotary will put that sort of temps out cruising, and can get up to 1800f flat out, as you can imagine its very easy to cook a cat in that situation, infact its a very common thing on rotarys that they can cause the cat to infact collapse from this.
Now on my engine i have removed the cat, so pump is purely a parasitic loss that is just pumping air to an open ended pipe under the car, plus it will be in the way when i fit my big turbo
If you look at where water filler cap is, you can just see the pump the left hand side of it with a pipe coming off the top which feeds the pump its fresh air.
This is then removed and looks like this, weights 5kg aswell so another little weight saving cant hurt.
Leaves this gap here, you can now see the front turbo and another black bracket that helped hold the pump, this is then removed.
we then remove the original water pulley, the reason this is removed is because the pulley runs off the outside of the belt, while normally this is fine as 60% is in contact so theres no slippage, with the pump removed this becomes an issue.
so we replace the waterpump pulley with one that has rougher outer edge as you can see from the picture to gain back some of that friction
installation is pretty easy, just use the 4 new bolts provided and bolt back up
next up is replacing the alternator pulley, this is partially to make it look better than the stock one and also because the pulley is larger it makes choosing a new belt much easier as you can use a standard 78cm belt.
This was a bit of a pain in the arse to get off, ended up using a mates impact gun as i bent a screwdriver trying to hold the alternator internals in place while unscrewing the bolt.
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once bolted up i put my new belt on
one issue ive had with my new radiator is that because the inlet pipe doesnt stick out enough, my air filters have been pushing on the waterpipe which meant the rad fan was catching the pipe....as you can imagine thats gonna end in disaster so now i have all this extra space with the airpump gone i decided to move my airfilters back into the engine back to relieve the pressure on the water pipe.
started it up and all sorted, i know its only a small update, but slowly getting there
