Milltek News: V8 S4 Exhaust Re-development happening in November

[Greg@Griffin]

Gentlemen,

I've been taking what you've been saying into consideration and have asked Milltek to get a car and do some re-development on the exhaust. They'll be moving the cats downstream and testing some robust, yet less expensive substrates so we can have a more affordable offering.

In addition, I've asked them to evaluate the 2.5" catback option with X pipe. I've given them input on making the system more linear and perhaps adding flanges. We'll see where the price comes in.

That's all, just some news. I'll keep updating once some progress has been made. Any feedback you'd like me to share with them is welcome.

-Greg

[91gl]

Greg, two thumbs up for you! It's nice to see someone finally take into consideration what a few of us have been preaching for some time now. Hopefully this goes through and gives everyone another option. Very exciting news and looking forward to hearing more

[Whatset]

Sweet - downstream cats, 2.5, x pipe!

What more could a B7S owner want? Go big! Make an extra buck and sell the catless section too. The one pictured below never materialized, at least not in the US.

[dparm]

Glad to hear this. I always loved the Milltek sound but could never bring myself to buying it because of the tubing size. Please make sure they don't neck it down anywhere, especially since a lot of guys go for downpipes and such. If a 2.75" system could be investigated that would be amazing.

As long as they can keep it simple and tasteful in terms of sound and appearance (muffler tip), I'll follow this closely.

[patastinky]

Sweet! This is great news.

[beemercer]

ooooh this will be the best sounding catback out there, I loved my 2.5" xpipe milltek when I had it. Just make sure they open the mufflers to 2.5".

[boravr6]

Great news indeed! Cant wait to see what they come up with!

[Docwyte]

Need a testing car? I'd be happy to offer up mine and trade in my current Milltek system..

[Lefthook]

Glad to hear this. I always loved the Milltek sound but could never bring myself to buying it because of the tubing size. Please make sure they don't neck it down anywhere, especially since a lot of guys go for downpipes and such. If a 2.75" system could be investigated that would be amazing.

As long as they can keep it simple and tasteful in terms of sound and appearance (muffler tip), I'll follow this closely.

The 2.75" exhaust would be a big moneymaker IMO.. sell it to the guys making big power, and the guys hoping to someday make big power....

[B6JoeS4]

Guys 2.75 is not needed in ANY application on an S4.

Good to see this happening Greg, now I don't have to shit on Miltek every chance I get!

[CHECKERED]

this is news...how? I love how vendors find any excuse to post something, anything…all you did is ask them to look into it….talk is cheap

when they actually start doing something then its "news" anything before that is hearsay

[Greg@Griffin]

this is news...how? I love how vendors find any excuse to post something, anything…all you did is ask them to look into it….talk is cheap

when they actually start doing something then its "news" anything before that is hearsay

The car is booked for 5 days in the development shop in the beginning of November so I'll be sure to keep you posted.

[dparm]

this is news...how? I love how vendors find any excuse to post something, anything…all you did is ask them to look into it….talk is cheap

when they actually start doing something then its "news" anything before that is hearsay

Why so cynical? Has Milltek or Griffin screwed you before or something? Let's give them the benefit of the doubt here and see where it goes. Not like they took your money and vanished...

[Greg@Griffin]

Checkered has got a point, lots of us vendors have been known to make useless posts.

We'll make it happen though. Its equally important to Milltek and Griffin that this gets done. Cheers guys.

[Mr. Corey]

Always great to have another alternative.

[SquiddyB6S4]

I'm honestly hoping for a somewhat larger cat than that. I've been thinking that my super downpipe solution is going to be stock main cats with inlet and outlet opened up to 2.5" combined with 2.5" mandrel-bent piping and such. It would be nice to have something that flows as well in the aftermarket, especially if it doesn't cost an arm and a leg.

As for 2.75" . . . let's see what happens with the S/C. I'm going to go out on a limb and say that if you nearly double the power output of the existing S/C cars (i.e. the eventual Stage 3 and 600-800whp), a 2.75" exhaust would be very nice to have. But probably wouldn't sell as well as a 2.5" system, so the development money wouldn't really pay for itself IMO. I'm sure you wouldn't lose power with a more normal car going from 2.5" to 2.75", but you probably won't gain a much unless you're making big power. I've seen 3" full-backs on little N/A Hondas actually make pretty good low end and midrange power (and still make gains in the top end), so I strongly doubt that 2.75" duals is too big for a 300whp motor (S4 with some bolt-ons).

[dparm]

Is that a 300-cell spun body? Who is supplying them, Challenger?

[x X CLoud X x]

dont forget to make a B7 Quad Tip version

[beemercer]

any car going built motor could benefit from something larger than a 2.5" dual... if you have the money for the build though you can probably afford to eat the cost of swapping to a 2.75" catback (JHM RS4 catback for instance).

[boravr6]

I'm honestly hoping for a somewhat larger cat than that. I've been thinking that my super downpipe solution is going to be stock main cats with inlet and outlet opened up to 2.5" combined with 2.5" mandrel-bent piping and such. It would be nice to have something that flows as well in the aftermarket, especially if it doesn't cost an arm and a leg.

As for 2.75" . . . let's see what happens with the S/C. I'm going to go out on a limb and say that if you nearly double the power output of the existing S/C cars (i.e. the eventual Stage 3 and 600-800whp), a 2.75" exhaust would be very nice to have. But probably wouldn't sell as well as a 2.5" system, so the development money wouldn't really pay for itself IMO. I'm sure you wouldn't lose power with a more normal car going from 2.5" to 2.75", but you probably won't gain a much unless you're making big power. I've seen 3" full-backs on little N/A Hondas actually make pretty good low end and midrange power (and still make gains in the top end), so I strongly doubt that 2.75" duals is too big for a 300whp motor (S4 with some bolt-ons).

Is the redline a factor in the exhaust design? a JHM bolton car has the same or more power then a stock RS4. Yet the RS4 benifits from a 2.75" exhaust where the bolton car still runs at optimum levels with a 2.5"

One of the factors that differentiate the 2 cars is where the RPS's hit the redline. Could it be those higher RPM's making a 2.75" optimal on the RS and not the power output per say?

[noznab]

Is the redline a factor in the exhaust design? a JHM bolton car has the same or more power then a stock RS4. Yet the RS4 benifits from a 2.75" exhaust where the bolton car still runs at optimum levels with a 2.5"

One of the factors that differentiate the 2 cars is where the RPS's hit the redline. Could it be those higher RPM's making a 2.75" optimal on the RS and not the power output per say?

Basically, yes. The 2.75" piping allows the RS4 to keep flowing at high RPM where it would otherwise be choking if it were 2.5". I don't think we'll need anything bigger than 2.5" until we start seeing stage 2/3 setups or people start building their heads to rev higher.

[SquiddyB6S4]

It's all about flow. Power very nearly equals flow (it has to, if the motor is running properly). So if you have an RS4 making 320whp and an S4 making 320whp, the only difference will be how the two respond to the exhaust at low and mid engine speeds. Since they're making the same power, their top end flow will be nearly the same, even though they're not at the same engine speed. Hence, a turbo four or turbo six also making 320whp will also have similar flow requirements at peak power (though a turbo car will respond much more differently in transient response due to their sensitivity to backpressure).

[jmpaul320]

Great news

[dparm]

It's also about flow quality, that's why the tubing has to remain a constant size but be appropriately sized for the powerband "width" and "location". Turbulent flow from a tube that's too big hurts power, as does the opposite.

[patastinky]

isnt' the RS4 Milltek 2.50?

[SquiddyB6S4]

It's also about flow quality, that's why the tubing has to remain a constant size but be appropriately sized for the powerband "width" and "location". Turbulent flow from a tube that's too big hurts power, as does the opposite.

Sure, but the question is "how big is too big?" I've seen at least a couple tests showing "too big" is a little bigger than what a lot of people say it is. Maybe it is, maybe it isn't. There are so few tests out there that directly compare exhaust piping size while eliminating other variables (properly).

[dparm]

The only way to truly test would be to install different sized exhausts on the same car on the same day and do some dyno pulls.

Dave Stadulis at SMSP once told me "60HP (at the crank) per square inch of (cross-sectional) flow area." There's fudge room in there depending on the header design and the use of X/H-pipes or none at all.

[B6JoeS4]

Read Justin's post here: http://www.audizine.com/forum/showth...101.-VERY-LONG

[drew]

A full Milltek system sounds incredible. I am looking forward to hearing the revised system.

[Lefthook]

Read Justin's post here: http://www.audizine.com/forum/showth...101.-VERY-LONG

I did, it's a great resource, and that's exactly what the statement I made is based upon... by "big power" I don't mean the guys who have bolt on's and a tune - we're talking about the SC guys getting upwards of 400whp. At that point the flow will have exceeded the 576CFM that the 2.5" exhaust will support, and you start entering RS4 territory where the 2.75" becomes a return on investment.

[SquiddyB6S4]

The only way to truly test would be to install different sized exhausts on the same car on the same day and do some dyno pulls.

Dave Stadulis at SMSP once told me "60HP (at the crank) per square inch of (cross-sectional) flow area." There's fudge room in there depending on the header design and the use of X/H-pipes or none at all.

That's what I mean. It would be an interesting test, but expensive, hence it's so incredibly rare to actually see such data. I'm sure there's a sweet spot, and maybe that's it (60bhp/in^2), but there's a whole bunch of gray around that, so it would be interesting to see how different sizes of piping affect the power curve.

[beemercer]

some of the blower cars have a jhm rs4 catback in prep for the stg2 blower. Honestly I think stock tune 2.25" is fine, stock motor 2.5" is fine, beyond that 2.75" and up. Its easy enough to remember.

[SquiddyB6S4]

some of the blower cars have a jhm rs4 catback in prep for the stg2 blower. Honestly I think stock tune 2.25" is fine, stock motor 2.5" is fine, beyond that 2.75" and up. Its easy enough to remember.

pretty much

[Greg@Griffin]

The car arrived at development on Monday as scheduled. I'll see if I can get some updates shortly...

[vdubjetta02]

too bad I just ordered my FI exhaust last week...... Still, I can not wait to see what you guys come up with!

[Levinoss08]

Mmmmm, quad exhaust, x-pipe,and 2.5 and I'm sold.

[Docwyte]

You guys going to do a trade in program for the old 2.25" versions?

[B6JoeS4]

^that would be an excellent idea, however, what are they going to do with all those used catbacks?

[cheewy16]

oh boy oh boy oh boy!!!!!! I really hope Milltek comes up with something solid.

[Docwyte]

Beats me. Would just be good marketing for them.