How much power could a 2008 Audi S4 4.2 V8 hold?

[MiguelExclusive]

Soo just getting this car at 80k miles with a stock 350awhp was quick at first but I'm wanting to make more power but not sure how much it could hold, not trying to go overboard.

[VinnysS4]

Soo just getting this car at 80k miles with a stock 350awhp was quick at first but I'm wanting to make more power but not sure how much it could hold, not trying to go overboard.

The B7 S4 came with 344hp to the crank, not the tires. With full bolt ons(minus cams as no one has tested them yet to my knowledge), NA, you will get to about 300AWHP. With forced induction, the rods are the weak link and are safe to about 450aehp.


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[Jdsb6s4]

Soo just getting this car at 80k miles with a stock 350awhp was quick at first but I'm wanting to make more power but not sure how much it could hold, not trying to go overboard.

Mannn. I wish it was 350 awhp but I think that is closer to RS4 numbers.

[ven0m]

RS4 b7 is 320-330hp at the wheels. Drivetrain loss on a quattro is ~25%

[q_dubz]

stock is around 250whp and the RS4 is around 320whp
Modded is around 290~300whp

Max is around 500whp but wont last long.

[Mr.Wrong]

What he said^

I’d stick around 450awhp if you want long term reliability. Anything above that, you’d need forged internals... possibly sleeved bottom end depending how far you wanna take it and how deep your pockets. It adds up fast, real fast.

[Jdsb6s4]

stock is around 250whp and the RS4 is around 320whp
Modded is around 290~300whp

Max is around 500whp but wont last long.

Yep! My BHF is modded I my dynos were between 290-302 awhp

[q_dubz]

What he said^

I’d stick around 450awhp if you want long term reliability. Anything above that, you’d need forged internals... possibly sleeved bottom end depending how far you wanna take it and how deep your pockets. It adds up fast, real fast.

I wouldn't touch sleeves unless going north of 800awhp

[Mr.Wrong]

I wouldn't touch sleeves unless going north of 800awhp

I have yet to see any BHF anywhere even close to that number. I’d love to believe that, but let’s be honest, there’s a lot of testing to be done to claim that. And if it is indeed so, then just upgrade what, forged pistons & rods, crank up the boost on Stage 1 sc and there you go, but nobody has done it yet....
Excited for you to finish your build and see what it’ll put down though

[Jdsb6s4]

I wouldn't touch sleeves unless going north of 800awhp

X2. If you are trying to go crazy with this application you are better off saving yourself time and insanity and just purchase a ttrs or rs3

[QIKRNU]

How do you sleeve a bottom end?

[Jdsb6s4]

How do you sleeve a bottom end?

LOTS OF MONEY!!

[q_dubz]

How do you sleeve a bottom end?

Basically you cut the bores a tiny bit bigger so you can drop a iron sleeve in that brings it back to the appropriate size.

[VinnysS4]

Basically you cut the bores a tiny bit bigger so you can drop a iron sleeve in that brings it back to the appropriate size.

I want to see somebody put sleeves in the engine and destroke it to a 4L. :D

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[q_dubz]

I want to see somebody put sleeves in the engine and destroke it to a 4L. :D

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You should

[QIKRNU]

Basically you cut the bores a tiny bit bigger so you can drop a iron sleeve in that brings it back to the appropriate size.

I always thought the bottom end was the rotating mass, not the reciprocating mass.

[q_dubz]

I always thought the bottom end was the rotating mass, not the reciprocating mass.

Why you talking about the physics at work when I'm talking about how sleeves are installed lol?

[QIKRNU]

Mr Wrong's post had to do with sleeving the "bottom end". I'm still wondering how one does that?

[Velox]

Mr Wrong's post had to do with sleeving the "bottom end". I'm still wondering how one does that?

The cylinder block is part of the bottom end, I think that's why you're confused

[q_dubz]

Mr Wrong's post had to do with sleeving the "bottom end". I'm still wondering how one does that?

Oh I see the confusion.

The bottom end refers to the block itself and everything contained in it.

[QIKRNU]

Oh I see the confusion.

The bottom end refers to the block itself and everything contained in it.

I always thought that was called a "short block"?

[q_dubz]

I always thought that was called a "short block"?

That's another term for it but it's usually used when discussing sales. John doe purchased a short block instead of a long block.

[QIKRNU]

Only discussing sales???

Long block includes the heads but not manifolds or other parts.

Maybe Mr. Wrong could chime in and enlighten us?

[QIKRNU]

Why you talking about the physics at work when I'm talking about how sleeves are installed lol?

I wasn't talking about physics, I was speaking of physical parts.

[VinnysS4]

When you say built bottom end, that usually refers to the rotating assembly. A sleeved bottom end means that the engine block has been bored to accept sleeves. Not many people sleeve a block and run stock rotating assembly. The only real need to sleeve, would be to hold the power you are going to throw at it. A short block is the engine block from below the heads and down and a long block is the entire engine minus accessories. If you buy or build the bottom end, you are doing work to the engine block and its contents. If you are sleeving the bottom end, you are usually doing it to accept upgraded rotating assembly.

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[QIKRNU]

"A sleeved bottom end means that the engine block has been bored to accept sleeves."

Thank you. I have had sleeved engines, among the 20 or so I have built, but I never heard that terminology.

And they say you can't teach an old dog new tricks...

[Mr.Wrong]

Only discussing sales???

Long block includes the heads but not manifolds or other parts.

Maybe Mr. Wrong could chime in and enlighten us?

Just different terminology, that’s all. Short block, bottom end, block, motor, engine, potayto, potahto you get the idea

[Mr.Wrong]

OP if you’re not trying to go overboard(missed that part), I think you’ll be happy with just Tune, DPs, Catback, IM, lwcp and some lightweight mods. Basically match stock RS4 output. It really transforms S4. Throw in some suspension mods and it’ll be night and day, I think many on here could attest to that.

[q_dubz]

Yes, when you go to summit or jegs catalogs or a junkyard, typically you're offered a long block or a short block to purchase. It's terminology used in the sale of engines to indicate what you're getting as Vinny explained in-depth above.