Anyone ever think of doing Custom Headers, Downpipes, catback, custom software, custom cam and a custom cold air intake on the RS4? Im sure the headers and cam would cost a pretty penny but if there are gains to be had without going forced induction then why not. 60 or 70WHP is going to put this car into another league. With some weight reduction wheels, seats etc... this car can definently see high 11's in the quarter mile. My son just did a turbo kit on his tip b7 a4 and i think its faster than my RS4 with milltek catback:)

Remember that in trying to build the engine to get more power, you'll likely be the first, so there's a ton of R&D costs that you'll have to absorb. AFAIK, there's no real off the shelf parts for the 4.2 to the extent you're talking about

but you'd have to drop an LS7 in there

if you can dodge a wrench, you can dodge a ball?

LS7 is 24 inches long. (Yes, I just happen to have one sitting loose in my garage). The LS7 is shockingly compact for a 7 L motor, and very light. But the Audi V8 is deliberately short because they knew it would be completely in front of the axles with AWD.

While we are comparing, the 5.2 L V10 in the Audi R8 is 569 pounds. My 7 L LS7 completely dressed with AC is 400 pounds even. Same hp, significantly more torque (near to 500 ft/lbs) with the LS7).

Not a chance bro.

More importantly, whatcha putting it in? :-x<ul><li><a href="http://www.google.com/search?hl=en&amp;safe=off&amp;q=ls7+458+lbs">Click</a></li></ul>

It's destined for a GT40 replica.

When you start looking at weight and packaging, pushrod engines start looking pretty good. I wonder what a really top engine builder like Audi could do with one.

The headers are already optimized. You cam profile would really hurt low speed drivability. You would definitely need to lose all the emission controls. You would likely need 9000rpms at least with injectors that could provide sufficient fuel at that engine speed. The list goes on. Basically, you could not do this on a streetable RS4, if at all. If you could, I promise you it would be a $40,000 engine build.

You son's A4, gives the illusion of speed due to the torque swell produced by a high boost turbocharged car, thereby giving you a brief yet hard peak acceleration. I promise you that if you look at times, the RS4 is faster, by a good margin.

The stock 4-2-1 headers are very efficient. I haven't done a data log recently, but if I recall, the fuel injectors already operate close to 90% duty cycle at full load already. Any change in cam profile would necessitate modified pistons due to valve clearance so you might as well add a little more compression and use race gas while you're at it. Going cat-less on the exhaust would help. I suppose you could dump mega bucks into the engine to do this and get close to 500 hp at the crank, but it certainly wouldn't be a happy street car.

What about port and polish the intake manifold and intake manifold spacers?

<center><img src="http://i299.photobucket.com/albums/mm303/silverRS4/allports.jpg"></center><p>It certainly doesn't hurt. The casting is pretty good from the factory, but there are a few bumps and lips that can be removed. The airflow capacity of the engine was improved over the entire powerband. Was it worth my time? I'd say so. The casting is surprisingly hard for aluminum, so a Dremel (and a six-pack) won't get you very far. The proper tools aren't at your local hardware store.

Spacers? You mean between the intake and the head, to reduce heat transfer from the heads to the intake? The engine compartment is pretty much an oven anyway. That and the fact there are the manifold flaps at that interface make spacers unfeasible.

The 13B is much smaller than the 4.2 audi FSI and trust me there is a lot less space in the engine bay of an RX7.

If it fits in an RX7, it can fit in an RS4

put in a 2.7tt

What "stuff" do you think it's gonna have?

I've heard twin turbo 4.0

I've heard turbo diesel

I've heard high rev version of the current RS4 4.2FSI

What have you heard?

And you're right, the 4.2 is 18", but not fully dressed.

And the schematic you have is not of an LS7.

I may be a wankeldude, but that doesn't make pistons a foreign thing to me :-)

Higher octane will most certainly help - a little. To stick with natural aspiration on a car as highly tuned as the RS4, we're going to have to nickel and dime our way up the horsepower ladder.

Most convincing thing I have seen. A thread started by an Audi dealer employee who saw the test mule up close when it came to the US for testing last year.<ul><li><a href="http://www.audizine.com/forum/showthread.php?t=230228">AZ thread</a></li></ul>

I think he thought N/A was "neutered or altered" RS4. :-)

Still snowing out there in the east?

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