Intake Manifold flap lock in long position thread

A6 All/ S6 All
#41

Good morning Justincredible,

Thank you for the time you dedicated to your response !
Just a couple clarifications :

Yes, absolutely. I did not express myself correctly, I see that now.

  • You mean epoxied the runners locked in so to always be in the long runner mod, right ?
  • 40TQ, N.m or ft.lb ? (sorry, I have not ran into the dyno results just yet)

For now, the car that I have views on seems to have a working intake… Or at least, runner pieces have not fallen near the admission valves :smiley:

For what it’s worth, and it is not my view on the subject but a former ferrari’s motorist take on the matter : he’d rather have the intake locked on the short runner path, for better high end hp and getting in the upper rev range faster. Now, since this type of car is not very common here in France, he can’t give me numbers or percentages.
Now, of course, the guy spends half his time actual performance and/or track cars. Both S6 and S8 V10 are not the average cars, they have torque and power, but I myself do not consider them performance cars. In the end, what I mean is that even if it is out of my knowledge sphere, I do not share his take on the subject. I would, just like most of you, have better MPG (even if it’s only by 10%), smoother car down the rev range, which is where 95% of my driving will occur.

Thank you (and you all) once again for the share of knowledge !

#42

I would just add that I got the intake flaps in pieces from another member (mine were tossed years ago before we even spoke of epoxied flaps). They were without the mounting hardware, and the edges were so far gone that some flaps wouldn’t even cover the short position holes completely. That’s why I ended up cutting sheet metal to close the short runners instead.

#43

Yep, that’s what I had understood from reading the thread :+1:

#44

Hi revving cars have different camshafts and power curves so something like an 8500rpm ferrari is going to want the short runner as all of the power is in the back half.

Since the S6 and S8 shift at about 6500rpm. You’d be silly to not take advantage of the low end since there is only 2000 RPM after the flaps switch.

The void of any flaps causes turbulence. This causes many offset issues including but not limited to poor performance… idle and low end power.

There have been several dyno tests and the average seems to be 40wtq and 35whp. some more some a little less but that is the average. The unique fact that the V10 motors in the S6 and S8 make so much Tq it’s a case where they still make more tq than standard cars even with no flaps.

If your looking at a S6 or S8. I would use the intake… carbon clean and injectors as part of your leverage on price.

#45

I will probably travel to look at the car by the end of january. For what I know (and I have talked with the owner via text and on the phone), the car is well taken care of. No long life maintenance but every year : carbon cleaning then oil change with filters. The gearbox has also seen its oil changed (which is very rare here in Europe). Some O2 sensors have been changed (one was changed last month - 900€ bill), the two front air suspension bags, AC compressor which is an engine out job if memory serves, AC radiator, etc…
The inside of the car looks fabulous.
The only thing not working is the sunroof and the guy told me right away. He never used it so he did not bother having it fixed.

EDIT : But I shall not discuss a future S8 here, no point for me to pollute this interesting thread. Thank you again for the insight.

#46

Always feel free to make a free standing thread on the car itself.

#47

Hello everybody.

Long time no see. I haven’t had the chance to update here but I did end up buying an S8 and I’m working around the intake atm because it’s started making noises about a month ago (haven’t driven the car since, sad life).
So 3 of the 10 change-over flaps are spinning free but still there. I remembered what we talked about and therefore thinking about the epoxy solution. What epoxy did you guys choose ? My guess is that it kinda needs some epoxy that can resist some quite high temperetures, right ?

I’ll be testing that but will eventually replace the manifold after successful testing (I hope).

Thanks in advance,
Max

#48

Max. Look for the high strength hi temp. Epoxy. It takes a little longer to harden but it’s what you want.

#49

Sorry to bring the thread from the dead but I have a quick question. Locking them in the long position does give you more torque in the low revs but if you lock them in the short position it will give you top end. So how do you lock em in the short position ? Do you just remove em ?

#50

One of the things about this website is that we encourage old posts to be bumped to keep conversations going.

So locking the runners in the short position will give the car more power over 4500rpms but cost you about 35/35 Tq and hp down low in the rpms you drive most.

If you wish you can just remove the flaps for the same results for the most part as locking them in the short runner. You just tend to get more turbulence and loose some power totally removing the flaps.

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#51

The manifold had some of the plastic flaps fallen , some stuck in front of the valves but none have fallen in the engine. The manifold design is good but this plastic flaps crap is a joke. I cannot believe Audi came with this or approved of it. My manifold has been changed TWICED for an insane price because of the magnesium it is made of and it keeps failing after 50k miles. I will try to make the flaps out of metal , lasercut them or whatever is needed because after 2 manifolds and so much money spend on them they almost destroyed my engine. Keeping a manifold with the plastic flaps in is like playing with fire , its a ticking time bomb. Its not a question if its going to break , its a question of will your engine granade when the plastic flaps holder falls inside the engine.

#52

Hello, everyone!

Two comments above it was said that it’s ok to revive old threads, so I hope it’s ok if I do just that.

I don’t have an S6, but considering getting one. I already did my research about the potential issues, and it seems that the IM might be the biggest pothole.

The thing I don’t really understand is, is it really not possible to get it new anymore?

I see that JHM have some, but it’s very expensive and to add salt to the wound I’m located in the EU so after shipping and import fees it’d cost more than $5k. So ok, I understand that these were high-end luxury/performance cars when new and that maintenance is never going to be cheap, but it’s just not realistic spending that kind of money when it’s 30-50% of the whole car’s worth.

Is there no way to buy a new IM in Europe? Everywhere I looked it’s out of stock…

As for locking the runners in the long position…I understand that is the way to keep low end torque, but how much power does it exactly take off the top end? Did anyone here who’s got the IM modded like that measure a 0-60 or 1/4?

Cheers

#53

There have been all kinds of tests done over the years. A few dynos but more or less it’s been dynos on how much power you loose if you end up locking them in the short runner or gutted.

If you’re considering getting an S6. Most people have realized that you can gut your intake manifold and then get the full JHM ECU / TCU and intake spacers for a fraction of the cost of the new intake manifold and the JHM tune will give you a handsom amount of power well over what you’d loose with the non fully functional intake.

#54

I see, thanks.

Last night I’ve also found this. Could this be a solution? Am I right in understanding that it’s the flaps themselves that break on these, not the motors that control them or the electronics? In that case, this could be a remedy for less than $200 (+ labor of course)?

#55

To be honest it’s almost best to remove the flaps Vs putting in 3D printed. On average the material used for 3D printing is not likely to hold up to the huge amount of heat and stress you’re going to have in the intake. Consider there is already so much stress on the OEM unit that they broke.

Taking a risk on something that is going to be subject to less ability to resist melting and heat along with structurally weaker. The issue you worry about is the parts breaking off and then ending up in the motor. Now what starts as a possible cheap fix ends up being a requirement for a new motor.

#56

The flap debate is one that is going to be dependent on each user.

With so many people having broken or fully gutted intake manifolds I’d say while there is a difference in power. As mentioned the cost of the JHM ECU and TCU tune will not only offset the power lost in gutting the intake. It’s hard to argue performance under WOT conditions are hampered by the incredible low 12 second 1/4 mile times from the JHM tuned cars.

While it will result in a bit of lost power. It’s hard to argue with the simplistic and safe version of just gutting the intake.

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#57

Thanks guys. I agree, it would probably not be worth experimenting with a 3D printed part when the risk is actually blowing the whole engine :slight_smile:

Anyway, not exactly intake related but I hope it’s still ok if I ask this one question here. So I’ve been looking for S6s and until now, haven’t really found any desirable examples where I live. I did see some better S8s tough. At first I discarded them completely thinking it’s a large car, it’s probably slower, but I have just realized it has an alu-body and essentially weighs the same or even a bit less than an S6 Avant? Is that actually correct? I understand the drivetrain is the same…looking around, a bit hard to find a good exhaust system for the S8 but Supersprint has one and it’s always a possibility to have one custom-made anyway.

So do the JHM ECU and TCU tunes apply to the S8 aswell? Can it also be made (with the right supporting mods) to run the 0-60 sub 5 and the 1/4 in the 12s? Thx!

#58

I have an S8 and the great part about the JHM package is that it works between both.

The S8 exhaust is better than the S6. So are many supporting hardware parts.

I would rather have an S8 than an S6. The record so far on NA is held by a S6 as 12.2 but I’m not far behind at 12.4. And to be honest I can probably run faster if I put forth the effort. But I’m very happy with how the car is so I don’t do much to push and test.

So basically the S8 is very much able to do the work of the S6 performance wise but with a IMO a much better trim.

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#59

12.4 sounds very decent from what is - at least dimensions wise - such a large car. Like I said I initially thought it’s similar to an S vs E class situation, where the S is also regarded to be a better place to sit in, but is always heavier and slower with the same drivetrain. Anyway, cheers for the feedback!

#60

If you’re planning on going fast in corners, then the S6 may be the better option. If not, then S8 all the way. I cross-shopped an S6 vs S8 back to back before I got my S6. The main thing that sold me on the S6 was driving it fast around a couple corners on the test drive compared to doing the same in the S8. S8 was way more relaxing, but at the time, I was looking for maximum distraction (death of a loved one) and to start doing track days/HPDE, so the S6 won.

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