S8 Motor vs. A8 motor
 

Like many of you, I am looking toward my next car. I recently drove and M5 - that was a mistake. My car felt so bogged down and slow after that test drive.

Why can't we chip our engines or change parts to get more out of them?

I realize that the S8 transmission is not geared as tall as the A8, but what is different about the engine? Is there any hope of squeezing 60 more hp out of a 32V or 40V engine?

It must not be easy or we would all be making our A8 engines in to S8 engines.

Educate me!

The 4.2L has been used in exotic vehicles with 420 naturally aspirated HP
 

This leads me to believe it's all a matter of camshafts and induction. Regarding some of your questions: chipping our engine is worth 5 to 10 HP. Aftermarket exhausts and induction pickups are available. That's about all.

If you are looking to "work" the engine, it would have to be all custom, from a good Speed Shop.

That said; please be honest with yourself. You are comparing an extreme sport coupe to a luxury saloon.

At least compare it to a recent S8, and not an 8 year old A8 with worn suspension components, a worthlessly small factory anti-roll bar and no shock tower cross-member bracing.. :)

OMG are u suggesting our babies are actually Grand Daddies in car years???

Well said . .
 

You are right, I don't expect the A8 to be an M5 - they are completely different cars with different purposes.

What you are saying is what I have always understood - there is precious little power we can squeeze out of these V8's.

It just seems like it shouldn't be all that hard to change parts to get at least the S8 360HP out of it.

Likely it is possible, but so expensive that buying and S8 is just better.

If you drive a S8, you could beat almost any car on the road
 

But not a M5. I drove one....both the old and new version....very fast.....but in the end, as a daily driver, I would rather have an A8 (actually an S8, but I made my A8 into a S8 without the power and gearing.

improvements in performance for the A8 seem to be recode for transmission-
 

upgrade in sway bar-lowering /upgrade of suspension-exhaust changes and brake improvements to counter the above.
For what they are these cars are amazing given the weight and comfort add ons.
there is very little in the same age bracket that would compare with power/comfort and reliability.
remember these were cutting edge technology at the time of manufacture and from my own experiance the only poor performing components are the OEM POS jack and the front end components in that order.
That said I drive a 4 speed.And run 98 octane fuel

So, do you know what is different?
 

What would you have to change on your 32V motor to make it more like an S8 motor (besides the fact that it is not 40V)?

This is the mysterious part to me. What makes the motors so different. I realize it is probably not practical to change - I just wonder what makes the two machines produce such different power.

here is a partial list
 

cylinder heads
pistons
camshafts
valve springs
rocker arms
camshaft adjuster unit
intake manifold
fuel injectors
maf
exhaust including manifold cats and pipe
ecu

and other bits including:
vibration damper
timing belt cover
intake manifold cover
etc.

One Thing ...
 

... I was actually saying that there IS a mountain of HP to be found, but you are correct in inferring this would mean a mountain of cash, so to buy an S8 is your best bet.

As I mentioned, our engine HAS been tuned to 420HP, without turbos or superchargers.

Ahhh, that is what I was looking for, thanks.