Originally posted by Blah12543
I heard sometimes you need the racing exhaust installed to get the engine sound,
Yes and no. Although this is absolutely true for when you are installing a race car's engine into something, if the engine you are using has other exhaust options available it doesn't matter what exhaust you use.
Originally posted by MFX150
The new engine has to be the same aspiration type as the stock engine of your car.
Not in my experience, it doesn't.
So long as you don't try adding a turbo or supercharger to the wrong engine type there isn't usually a problem. For example, I've put together a Motorsports Elise with a Ford GT engine. The MS Elise only has a turbo'd engine in stock form, whereas the Ford GT is supercharged. Adding the stage 3 turbo removed the sound completely, and as soon as I removed it the Ford's sound returned.
Also, if the car has no turbo or supercharger options, both seem to be an option through hex that actually work. My Fiat 500 Lounge edition has a Ferrari 458 italia engine, the Ferrari engine has no turbo tuning options on the standard car, yet doesn't lose it's sound when you add them.
In the case of your Blitz, it has a turbo code which is not the default 091D which the 350z would have on, which is why your sound didn't appear MFX. Change that on the 350z to 121F and the Blitz engine should make some noise.
The same is true of the GT86 and Supra RZ, the default (or stock) turbo codes are different, so you need to adjust accordingly. The stock turbo code for the Supra engine is 0934, so you need to check the GT86, as it's likely to have 091D in there at the moment.