April 1st was last week.
Yes, but I am really wondering this. From your response, I gather that these questions are either ridiculous or obvious.April 1st was last week.
Someone probably has, there are all kinds of crazy people out there. Only reason (other than "for fun") that I can think of is if your 7A engine blew up, and the only replacement engine was an AAN and you didn't mind losing power.Has anyone done a NA build of an AAN?
Basically, yes. The engine blocks are very similar, essentially identical. Different pistons and bore. The AAN went to a distributorless ignition system, so the cam timing sensor is in a different location (at the cam sprocket), but still just a single window hall sensor. Oil pan is different because they went into different chassis cars. AAN has a serpentine belt setup for its accessories, which are mounted in slightly different arrangement. Intake is different. Different camshafts with the 7A having higher lift and durations.Is an NA aan functionally the same as a 7a?
Not from the factory. But plenty of folks have welded the center diff and simply not connected the front driveshafts in order to convert to RWD.Was a rwd trans made for any of those 3 engines?
No. Same crankshaft, which is forged. Bore is slightly smaller in the AAN to yield 2.2l displacement vs 2.3. Pistons are different on AAN to provide lower compression which was necessary for forced induction of this era. Rods are same dimensions. If not the same, then at least interchangeable. For high power turbo builds the rods become the weak spot before pistons or crank.Does the AAN have stronger internals than the 7a?
I think redline is like 7200rpm. Can be made faster but probably requires internal modifications to be reliable.Do 5 cylinders rev decently fast?
There isn't much support for any classic Audi I5 anymore. There isn't any dedicated support to convert the AAN to NA that I know of, but any parts that work with the 7A should work on the AAN. 034motorsports still has some stuff.Do AANs have much NA support?
In the sense that it has higher compression and cams with higher lift, yes.Are 7As more optimized towards NA functionality?
Lofty goals. Factory crank HP from the 7A was 164hp. Without touching the internals, you are left at modifying the intake and the exhaust. The throttle body and intake on the 7A already flow very well for what the head can handle, so your restrictions are theoretically in the MAF/filter/ducting. Minimal gains by removing all restriction there, at least in the normal RPM range. The factory exhaust can be improved. The factory 7A came with two different exhaust setups, one using a cast manifold, and another using a header (search "bag-of-snakes"). The header is more sought after but not sure if it improves flow all that much. With a custom install like this you would probably use just a straight pipe after the header, which would remove some of the factory restriction. OEM was a 2.25 pipe, going to 2.5 is all you need for NA. That leaves RPM as your main factor in pumping air and fuel. The crank, rods, and pistons are probably up for the task of a modest increase (maybe). You will probably reach the limit of the valve lifters and valve springs first. If these are allowed to be modified you might be able to bump the RPMs somewhat. Getting to 250 rwhp would be very impressive and into territory few have achieved even with massive internal modifications that seem prohibited by your rules.I probably should have stated this, but my HP goal is 250-300 rwhp, though I do not know if that is going to be through a stock RX7 5 speed or something else.
Thank you for the clear response, Ive seen people on old S4 forums (IIRC) say they're the same but no one gives specifics on how.Basically, yes. The engine blocks are very similar, essentially identical. Different pistons and bore. The AAN went to a distributorless ignition system, so the cam timing sensor is in a different location (at the cam sprocket), but still just a single window hall sensor. Oil pan is different because they went into different chassis cars. AAN has a serpentine belt setup for its accessories, which are mounted in slightly different arrangement. Intake is different. Different camshafts with the 7A having higher lift and durations.