Quote:
|
Originally Posted by DevoutWankelist
I want to get a rear differential with lsd in my 91 n/a, so I am going to go to a junkyard and hopefully find one out of a 86-88 GXL, 87-91 T2, 88 GTU, or a 89-90 GTUs, luckily J-Rat was nice enough to list those in previous threads, but I was wondering if I needed to know anything else about the process of switching my rear diff at all other than bolt off, bolt on?? before I buy it. I'm kinda learning about mechanic type stuff currently on my own and if I've learned anything so far, its ask first if you have a question at all.
|
If I remember correctly, the drive shaft (called the propeller shaft, in Mazda speak), will need to be modified. Should not be a big deal, nor should it be to expensive.
NOW, on to the octane... Here is a little something I posted on another forum a while back:
The fuel property the octane ratings measure is the ability of the unburnt end gases to spontaneously ignite under the specified test conditions. Within the chemical structure of the fuel is the ability to withstand
pre-flame conditions without decomposing into species that will autoignite before the flame-front arrives. Different reaction mechanisms, occurring at various stages of the pre-flame compression stroke, are responsible for the undesirable, easily-autoignitable, end gases.
and:
If you are already using the proper octane fuel, you will not obtain more power from higher octane fuels. The engine will be already operating at
optimum settings, and a higher octane should have no effect on the management system. Your driveability and fuel economy will remain the same. The higher
octane fuel costs more, so you are just throwing money away. If you are already using a fuel with an octane rating slightly below the optimum, then using a higher octane fuel will cause the engine management system to move to the optimum settings, possibly resulting in both increased power and improved fuel economy. You may be able to change octanes between seasons ( reduce octane in winter ) to obtain the most cost-effective fuel without loss of
driveability.
and:
Once the octane and run-on requirements of the engine are satisfied, increased octane will have
no beneficial effect on the engine. Run-on is the tendency of an engine to continue running after the ignition has been switched off, and is discussed
in more detail in Section 8.2. The quality of gasoline, and the additive package used, would be more likely to affect the rate of engine wear, rather than the octane rating.
And:
If you use a fuel with an octane rating higher than what the engine can use, you are just wasting
money by paying for octane that you can not utilise. The additive packages are matched to the engines using the fuel, for example intake valve deposit
control additive concentrations may be increased in the premium octane grade. If your vehicle does not have a knock sensor, then using a fuel with an
octane rating significantly below the octane requirement of the engine means that the little men with hammers will gleefully pummel your engine to pieces.
Jarrett