Question for the RS6ers

[killintime]

The 4.2L V8 in your cars...besides the turbos, is it the same as the 4.2L V8 in the other AUDI's that use it? For example, the S4 4.2Lv8...

Can any one comment?

[kingofnyc]

i read an article before , cant recall where but its a different engine.
you cant take s4 and use rs6 manifold and turbos to make rs6 engine.
it would be easier to get rs6 engine.

[Daft]

I think his question is more of a "Can I add turbos to N/A 4.2L V8?". The answer is no. There is alot more at play that just a pair of snails and supporting plumbing.

The BCY motor from the RS6 had a lower compression ratio for example. The 4.2 in the B6/B7 S4 runs 11.0:1 -vs- the BCY Biturbo's 9.8:1 ratio.

Things that are resistant to the higher combustion temps like the sodium filled exhaust valves were used too.

There is no easy way to put a turbo setup on that motor without doing some internal work to cover your self from failure.

The only thing on the horizon that I'd watch for is the S/C setup that places like APR and GIAC are working on. Those would bring the N/A 4.2 up to RS6 HP levels and run a very low amount of boost.

[killintime]

I think his question is more of a "Can I add turbos to N/A 4.2L V8?". The answer is no. There is alot more at play that just a pair of snails and supporting plumbing.

The BCY motor from the RS6 had a lower compression ratio for example. The 4.2 in the B6/B7 S4 runs 11.0:1 -vs- the BCY Biturbo's 9.8:1 ratio.

Things that are resistant to the higher combustion temps like the sodium filled exhaust valves were used too.

There is no easy way to put a turbo setup on that motor without doing some internal work to cover your self from failure.

The only thing on the horizon that I'd watch for is the S/C setup that places like APR and GIAC are working on. Those would bring the N/A 4.2 up to RS6 HP levels and run a very low amount of boost.


Close, but no...I'm not planning on making it a forced induction motor. What I was trying to ascertain was the motors durability. Meaning if it can handled an extra 110hp via twin turbos...can it handle a 50hp Nitrous Oxide shot occassionally shot into the motor.

[Daft]

Close, but no...I'm not planning on making it a forced induction motor. What I was trying to ascertain was the motors durability. Meaning if it can handled an extra 110hp via twin turbos...can it handle a 50hp Nitrous Oxide shot occassionally shot into the motor.

Well are you asking if the N/A motor can handle or if the turbo motor can?

On the N/A motor I say, no. High compression coupled with a really high redline is a dangerous place to spray. The redline wouldn't matter as much if the compression was lower. A 50 shot wouldn't be extremely harmfull in rare use but, lets be honest, "once you pop, you can't stop".[;)]

The turbo motor would take it no problem. The chip upgrades on the RS6 yield an extra 75HP/100ftlbs. A 50shot on a stock RS6 would be feasable but, who'd want to bother? This isn't Ronin, RS6's are expensive.[wrench]

[oc-drop]

here's a thread that was not too far below with some info...

http://audizine.com/forum/showthread.php?t=160670

[killintime]

Thanks fellas for the feedback. As I read your responses, I was doing research on the side.

Nitrous Oxide is a relatively "safe" mod to do to your car/motor. It's only the misuse of it that can render things broken. In fact once you're off the button the additional stress on the motor is relieved, where as with a permanent modification - that stress continues.

Let's face it, if adding Nitrous Oxide to your car/motor was all that bad like a lot of people think...well then all of these companies that create and sell kits would be going out of business.

As far as the make up of the N-A 4.2Lv8, I found out that it's plenty tough and can handle a 50-75hp shot quite easily.

Anyway, thanks again.

[Wicked6]

..Wow - first post !! ..2002 S6 Avant is purchased & headed home next weekend.. (yeah, Audi noob.. but I do have an '03 VW TDi!!) I am geeked.. Except about the lack of speed parts for the 4.2.. Which brings me to the point.....

Daft - I think you've seen too many idiot Mustang / Chevy drivers spraying the snot out of their 250-300 HP boat anchors with a 250 HP shot.. They race to 6k, blow their wad & forget to get their foot out of it before the engine spins to 7000.. crank coming apart in the process...

A 50 HP N2O shot is more akin to driving your car at -35 deg. F.. The latent heat of vaporization (vaporisation for you UK types) of nitrous in the intake is what gets you the "extra" 50 HP.. the temperature _drop_ ... that extra oxygen molecule is kinda lonely, and *may* affect the A/F ratio, but not by much.. my guess is that the Audi folks have the 4.2 running a bit rich anyway at WFO - probably in the neighborhood of 11.5 - 12.0 to 1.. "fat" fuel curves by the OEM preserves engines, and leaning them out / advancing the timing is where the chip tuners make their $$..... somebody please correct me if I am wrong.. like I said - Audi noob here.....

killintime - ...at 75-100 HP, you gotta start adding fuel to the mix to balance the oxidizer & your BMEP will jump substantially when you hit that throttle limit switch - testing your rev limiter and shocking your tires / tranny / CV joints as they shriek "WTF was THAT?!?!" in unison...

..and putting Daft closer to saying.. "told ya so.."

FWIW, I plan to dabble in the 25-50 HP spray region with my S6... if it blows, you guys will hear about it..... [wrench]