Hoppy

I've got an S4, 55 plate V8 tiptronic paddle-shift.

Manual says peak power is 340bhp at 7,000rpm. Red line is at 7,000rpm, but it will not rev past 6,800 under any circumstances, let alone hit the rev limiter, even in manual mode. Furthermore, the handbook has various illustrations of the rev counter, and in there the red line is clearly marked at 6,500, or 6,700 depending on which page you're on.

Nowhere is a 7,000 red line shown, like my car, although the sales brochure produced when the car was new also shows a 7,000rpm red line in a tiptronic car. I have also noticed references to a 7,200 rev limiter in road tests of manual gearbox cars.

The handbook offers no explanation, and neither can Audi UK, or any of the three dealerships it was suggested I speak to. They all say, bring it in and we'll take a look. The car is running perfectly by the way.

Am I to believe that while my car may well produce 340bhp at 7,000rpm, will not actually hit those revs? It might as well say it will deliver 400bhp at 8,000rpm, but since it can never get there...

Any ideas? Thanks

Richard.

RS Grant

Have you tried to get hold of an owner of a manual version to check that its the same as yours??

Would be interesting to see if they have adjusted the rev limit between the two.


Cheers,
Grant

HankScorpio

No ideas but would have liked to have been in the vicinity as you repeatedly took the V8 to 6800 RPM

pippyrips

If your every in south wales give me a shout, mine regularly sings at 8200

what would scooby do

The rover K series 1.8 VVC developed over 300BHP at 9000+rpm IIRC - milliseconds before it went bang in testing

richs2891

Why not ask on here Audi-Sport.net
Answer might be there /

Pippyrips whats your real world mpg like ? Thinking of trading in my S3 for RS4

Richard

pippyrips

without stating the obvious, it depends on driving style. With mostly round town i get between around 20. Long journeys as high as 29, country blasts 16.

Sorry for the hijack

ScoobyDoo555

Also try AudiSRS.com & rs46.com

Hoppy

LOL Hank I would have liked to have seen it go by at an indicated 160 when the speed limiter eases in. It will do this in both 5th and 6th. So a friend told me.

I will do some more research, especially re manual box cars, but I've posted on a few other car forums lately and none are anywhere near as knowledgeable and helpful as this place.

So, would you guys be happy with a car that produces 340bhp at 7,000rpm but has the rev limiter set to cut in at 6,700-6,800? That is effectively what I've got with the auto box. This is just not right. I should be able to red line it at least in manual mode, and even go to the rev limiter if I was daft enough. There's a power graph in the sales brochure which clearly shows the engine revving to 7,200 before the graphic is chopped.

The only thing that makes sense to me is that the S4 was maybe launched with an engine that gave 340bhp at 7,000rpm, but for whatever reason (reliability?) this never actually made it into my car. The way it behaves is entirely charcteristic of a car that produces peak power at around 6,500 and changes up in sport/manual mode at 6,800rpm to maximise power either side of the peak. 7,000rpm is the rev ceiling at which point I would expect the rev limited to call a stop. This makes sense. If this is the case, then (all things being equal) the motor is perhaps delivering only 316bhp at 6,500 - 24bhp down. That's a lot.

Not happy and feeling miffed Not that I thrash it all the time, but if the power is there I want to be able to get at it now and then. I still have three weeks to take it back, but if there's another 24bhp and a few more revs to be had just by tweaking the gearbox shift point?!? It'll f00kin shift with that

Richard.

RyanSTI

iTrader: (1)

saftey for the engine? most cars have cut off points. take it on a dyno and see if your loosing any bhp.

Hoppy

LOL, this makes my point exactly. Let me put it like this.

RS4 produces 414 bhp at 7,800rpm. Red line on the clock is 8,000, yet it sings quite happily to 8,200 if you bounce it off the limiter (that's what it's there for ). This is standard behaviour I think.

Using very crude numbers, and assuming you're sensible and don't exceed the red line, you will have something like 400bhp average to play with over 1k revs from 7,000-8,000.

But how would you feel if you were forced to change up every time at 7,600 (not 8k) when you're getting more like 380bhp average over 1k from 6,600-7,600? That is effectively what my car is doing.

Assuming it's the auto box doing this, it's hardly the end of the world but I do feel a bit cheated. If I was tracking the car, I'd kill for that extra 20bhp

Richard.

PS I've established that every S4 like mine, autos and manual, is red-lined at 7,000rpm (should be 7,200 though?). I just need to find someone with a manual box to go and nail it

pippyrips

I would be annoyed!

A remap would cure the problem (though the arguement of why should you is still there..)

I know a lot of tuners who raise the RS4 limit to 8500

Jacey Boy

Is there a rev limiter that you can adjust?

Hoppy

Quite

I've posted on Audi forums and guess what, silence so far. They just don't get the traffic like here.

Been out in wife's TT V6 which gives 247bhp at 6,300rpm. My my, that DSG box is so sweet. Anywayz, it red lines at 6,550rpm and changes up bang on 6,500rpm every time. Perfect, whereas my Tiptronic slushbox always shifts at 6,700-6,800rpm - 2-300rpm short of the red line and peak power.

An Audi technician implied that all auto boxes did what mine does, but conceded my point and said they should be able to get the box to do whatever I wanted, in theory, but that they had no normal facility to reprogramme it.

I seem to have got the attention of Audi UK press office who's immediate reaction was to contract Germany for an answer, so we'll see.

Meanwhile, I'd love to hear from other S4 owners

Richard.

HankScorpio

Is it feasible your rev counter is out?
Can you borrow a vag com and check it?

TopBanana

Maybe it's making the revs but the display is a second or two behind

pippyrips

Well i've got the latest version of vag-com if your every near and want to hook it up

Dracoro

Does the engine actually rev to 7000rpm or is it the gearbox "forcing" a change up before 7000?

dpb

Id just get um to take it back - you cant be missing 200rpm

im slightly amazed its possible to feel 30 hp difference at this sort of horsepower , the guy who serviced my sti claimed its pretty difficult for the average person to tell 280 from 250

Hoppy

"Is it feasible your rev counter is out?
Can you borrow a vag com and check it?"

Yes, it's feasible. My first thought was that the rev counter could be out, but even if it is, why is it red lined at only 7,000rpm when every other car or bike I've ever had is red lined higher than peak power, and Audi's own graph shows the engine revving past peak to 7,200rpm? My wife's Audi TT, also automatic, is redlined 250rpm higher than peak, and revs 200rpm higher than peak before shifting.

I'm also suspicious as to why the handbook shows numerous illustrations of the rev counter with both 6,500rpm or 6,700rpm red lines on different pages, yet the car is actually red lined at 7,000rpm. It's as if Audi has been messing about with different rev limits in pre-production


"Maybe it's making the revs but the display is a second or two behind"

I don't think so, because it does it in high gears when the rev counter is moving up quite slowly.


"Well i've got the latest version of vag-com if your every near and want to hook it up"

Cheers, and local dealership has offered to hook it up for me. I'll get over to them soon.


"Does the engine actually rev to 7000rpm or is it the gearbox "forcing" a change up before 7000?"

Assuming the rev counter is accurate, there is no doubt the box is forcing a change consistently 2-300rpm below peak power. It will not rev to 7,000rpm under any circumstances.


"Id just get um to take it back - you cant be missing 200rpm

im slightly amazed its possible to feel 30 hp difference at this sort of horsepower , the guy who serviced my sti claimed its pretty difficult for the average person to tell 280 from 250"

LOL It's a fair cop Yes, this is largely a hypothetical question. The difference is small and there's no way you could ever feel it. It might make a few yards difference on track or illegal drag, no more, but even then you'd have to be very sharp with a stop watch to measure it.

It's a matter of principle. I paid for 340bhp at 7,000rpm, and Audi said they'd deliver it. If what they are doing here is ok, then it's equally ok for a manufacturer to say here's 400bhp at 8,000rpm, but sorry, we've put the rev limiter in at 6,800rpm so you can never actually get it.

Buying fast cars is not a logical thing to do under any circumstances and most of the performance is largely in our heads. It is never realised by most people most of the time. It doesn't stop me wanting a McLaren F1 though.

Thanks for the feedback chaps

Richard.

scoobberdoo

Funny you should mention this. A mate a work has a B5 RS4 and the opposite was the case. He was going well into the red before it cut out and thought there was something wrong with his limiter after it was re-mapped. Turns out the cut-out is spot on, it's the rev counter that's not reading correctly. Don't know why though

NotoriousREV

It's not unusual for the auto version of a car to have a lower rev limit than it's manual counterpart due to the fact that torque converters generally don't like high revs. My guess would be that the box is programmed to change before redline for that very reason.

Dracoro

So it revs to 7000 when in neutral? If it only gets to 6700 in neutral then it's the rev limiter rather than the gearbox. If it does rev to/over 7000 then the gearbox is changin up *early*.

Try posting this in the Audi forum in Pistonheads, I think there's an Audi mechanic or two there, they maybe able to help more....

Hoppy

If that's so, I've never heard it before. I accept that there are transmission losses which dent accelleration and make the mpg (even) worse. This is clear from the specs. But not that the auto can never take the engine's full performance. The differences between auto and manual are clearly stated and it doesn't say that anywhere at all.

Richard.

Hoppy

The limiter cuts in at 7,200rpm exactly in neutral, so it's the gearbox 100%.

Thinking about it some more, and guessing, my conclusion is that Audi has a reliability problem with this engine/transmission configuration at high revs.* But they need the headline figures, which are importantly just 1 PS/bhp higher than rival Beemer M3 (343PS plays 344 ). I bet the press test cars revved their **** off

So after dithering about what to do, they've put the red line at dead on peak power to hit the numbers, then sneaked in a lower shift point which only stoopid people like me will realistically object to.

It is cheaper for them to field complaints from just three picky buyers like me, and re-programme the box if needs be, than to face the potential warranty costs from every other owner.

They are prepared to take the risk with manual cars, as there are not many S4 Audis about anyway and even fewer manuals (only eight cars listed on official Audi site at the mo, a fraction of the number compared to most models, and they're all autos).

Just a guess, but this is the only thing that actually makes sense of all the conflicting info I've collected. If I'm right, Audi will sheepishly say I've got a one-off programming error and they'll fix it pronto with a gearbox remap. Very sorry etc etc.

We'll see

Richard.

* NB Although the high-revving RS4 has a similar engine, it is heavily reworked internally and is much more than just a hot cam shoved in the S4 engine. It is also manual only. And it apparently has its share of engine reliability issues.

SteveV-WRX

Hi Richard,

i've got a late 2000 reg S6 with the same Auto/Trip 4.2 V8 as your S4.

Having read through my books, my engine figures are the same 340bhp @7000rpm, but the same as you, even in manual mode, maximum is 6600 - 6800 rpm before forced upchange.

My dash also shows from 7000rpm upto 7600rpm as red, but never got close to that and never thought to try in neutral though.

I'd be interested to see what kind of outcome you get with things from Audi.

regards

Steve

scoobberdoo

Steve

In the next 10 mins, I'm going for a pint with a guy I know who has the same S6 Avant of 2000 vintage. I'll ask him what his does and report back on Monday.

Hoppy

Steve and S'doo, thanks for your posts. All info greatly appreciated.

Took my car to local dealership today. Technician said what I told him didn't seem right. Then he drove it and, guess what, it did exactly what I said it would do. He said it still didn't seem right to him, VAG diagnostics came up with nothing, so he'll report his findings to the great VAG computer in the sky.

So VAG UK and VAG Germany now has access to all my car's data, which I'm sure proves the car is 100% as they intended. It is just not how it should be, or how I'd like it to be, so I'm still pushing for an answer as to why my car changes up so far below both peak power and the red line for no apparent reason.

I have to say dealing with Audi people has been very good and they seem to be on my side

Richard.