Max Speed in 4th Gear for V8?

[bz888]

Hey, does anyone know what the max speed is at redline in 4th for the 4.2 V8?

Thanks!

[SebringSilver]

That would be 123 mph @ 8,000 rpm.

For added clarity:

1st gear = 41 mph @ 8,250 rpm
2nd gear = 66 mph @ 8,250 rpm
3rd gear = 95 mph @ 8,250 rpm
4th gear = 123 mph @ 8,000 rpm
5th gear = 154 mph @ 8,000 rpm
6th gear = 187 mph* @ 8,000 rpm


* drag limited

[kebabman]

SebringSilver - where did you get those figures? I, erm, tested my completely standard 2009 R8 4.2 V8 today to the rev limiter in 5th gear and it showed 171mph on the digital speedo and 170mph on my escort passport 9500ci.....mine has the 6-spd manual gearbox, are your figures refering to that horrible R-Tronic box? (No offense people with an R-Tronic but a) I prefer a manual gearbox in a sports car (the 458 Italia excepted) and b) why the hell aren't Audi using the double clutched DSG box in the R8 instead of that ancient single clutched POS??)

Disclaimer: none of this was done on public roads, of course.

[mngolfer]

"That horrible R-tronic gear box" is the SAME manual transmission with an electronic shifter. In auto mode it is not smooth. In manual mode it is quicker than you can shift your "manual" transmission even if it is not in sport mode. It automatically matches RPM when you down shift. Does it take some time getting used to it? Yes. I don't know of anyone that has driven it in manual mode for more than one month that does not love it. You may have guessed that I have an R-Tronic and love it.

How many 458's have you driven? How many R8's with R-tronic have you driven for more than a month?

You might also put your location into your profile. It will help getting support if you need it in the future. R8's are equipped differently in different locations around the world.

[exhilR8]

Where's the rev limiter in the 4.2, 8000, 8250, or higher?

[SebringSilver]

SebringSilver - where did you get those figures? I, erm, tested my completely standard 2009 R8 4.2 V8 today to the rev limiter in 5th gear and it showed 171mph on the digital speedo and 170mph on my escort passport 9500ci.....mine has the 6-spd manual gearbox, are your figures refering to that horrible R-Tronic box? (No offense people with an R-Tronic but a) I prefer a manual gearbox in a sports car (the 458 Italia excepted) and b) why the hell aren't Audi using the double clutched DSG box in the R8 instead of that ancient single clutched POS??)

Disclaimer: none of this was done on public roads, of course.

Stats are from Road & Track's test of a 2009 V8 R-Tronic. Full details available for download from my Dropbox account.

http://dl.dropbox.com/u/24023333/RT_...2-FSI_data.pdf

[kebabman]

"That horrible R-tronic gear box" is the SAME manual transmission with an electronic shifter. In auto mode it is not smooth. In manual mode it is quicker than you can shift your "manual" transmission even if it is not in sport mode. It automatically matches RPM when you down shift. Does it take some time getting used to it? Yes. I don't know of anyone that has driven it in manual mode for more than one month that does not love it. You may have guessed that I have an R-Tronic and love it.

How many 458's have you driven? How many R8's with R-tronic have you driven for more than a month?

You might also put your location into your profile. It will help getting support if you need it in the future. R8's are equipped differently in different locations around the world.

My R8 is a US Spec car. I was lucky enough to get to nanny a 458 Italia around a car-park with some cones on a demo day, so one. I drove the R-tronic R8 before buying the one with the Lambo box, I'm pretty sure it's not the same gear box with an electronic shifter, I believe it is an entirely Audi built box not sourced from the Gallardo - to quote Wikipedia "The transmission options are either a Lamborghini sourced six-speed manual gearbox with metal gate for the shift lever, or an Audi-developed R tronic gearbox—which is a semi-automatic, without a traditional clutch pedal with automatic gears shifting mode.A double clutch direct-shift gearbox (DSG), now badged by Audi as S tronic, is not available (as of April 2010)" but I'm willing to be corrected on that.

Anyway, the R-Tronic was just like the SMG III 7-spd single clutch transmission I had in my E60 M5 back in the UK which I had plenty of experience driving, I didnt hate it, it was ok if you're gunning it (which with that V10 you just have to) and I liked the full throttle shifts, but it was so bad in a car park or traffic and very slow changing compared to the dual clutch DSG (now S Tronic) which I had in my previous car, an Audi TT 3.2 DSG (S Tronic). I also like to have a clutch, otherwise I get flappy-left-foot syndrome, plus it's fun to heel and toe, I don't want the car matching the revs for me on down-shifts that's my job. I just think it was very cheap of Audi to fit the single clutch R-Tronic not the dual clutch S-Tronic when they put the S-Tronic in the TT! Go test drive a 2012 R8 with the S-Tronic when it arrives and you'll see what I mean.

Back in the UK I did a lot of track days in various different cars (circuits WITH corners are all so much closer together in the UK for obvious reasons, why do so many people here think a drag strip is a race track?) and I always wished my M5 had a manual transmission. I did love the M-Active seats that push you in the side though, oh and of course the M-button that added 100bhp.

Here's my UK vehicle list which I had over the years, I miss biking a lot, been here since May 2009 and not being able to "cut the lanes" (we call it filter) just does my head in, we actually get taught how to do that in the UK bike test....I don't want to sit in 100F heat traffic in a full set of leathers. Shame as I really want a Ducati 849 in white..

Former UK Vehicles:
2007 Interlagos Blue E60 BMW M5 5.0 V10 - White Interior, 7-spd SMG III transmission, HUD, magneto rheological suspension, M-Active Seats, Harmon Kardon Logic-7 Sound System

2005 Mk1 Audi TT 3.2 Quattro with DSG (S Tronic) gearbox

1995 Ice Grey Violet VW Corrado VR6 (Had European 2.9L Engine not the 2.8 like the SLC over here) Manual

1997 Blaze Yellow Peugeot 306-GTI6 2L 6-Spd Manual

2008 Metallic Grey Triumph Daytona 675 with carbon fibre TOR baffle free exhaust, sounded so good!

2008 Blue/white Yamaha R1, too fast and unruly, scared the **** out of me in 1st-3rd, couldnt keep the front wheel on the floor and it tried to high-side me too many times.

2005 Blue Suzuki SV650S - my friendly learner sports bike. I passed in 2001 and had a CB500 up till this…ahem.

I miss my Daytona, hated selling that.

Where's the rev limiter in the 4.2, 8000, 8250, or higher?

It's 8250RPM.

Stats are from Road & Track's test of a 2009 V8 R-Tronic. Full details available for download from my Dropbox account.

http://dl.dropbox.com/u/24023333/RT_...2-FSI_data.pdf

Interesting, the R-Tronic must have different ratios. I swear gods honest truth I did 170MPH in 5th gear this morning in my 4.2 6-spd manual.

[willyjp]

A couple of comments: US R8 4.2's have EXACTLY the same transmission and final drive ratios in the MT and R-Tronic (in fact, as mngolfer says, it's EXACTLY the SAME transmission, differs only in how it's actuated.

At my local track (PIR), a fairly "short" course, I have had the opportunity to repeatedly test the W.O.T., redline speed in 4th, because on the only real straight, the 4th-5th change is strategically placed in the stock R8 to create a tactical problem in whether or not to shift up to 5th.

If you really exit the last turn well and really get on it, you can JUST get into 5th for a moment before it's time to shut down for the low speed chicane at the end of the straight. But if you're at all held up in traffic, or it's wet and you think you're going to need to shut off a bit earlier, you might be better off holding redline in 4th for just a moment and then starting your deceleration....one less shift with it's momentary loss of pull (I know guys, it'd be quicker with R-Tronic ) and one less downshift to contend with while braking hard to get down to turn speed.

My observation is that the car is still pulling strongly at the redline in 4th, and it SEEMS to me that the rev limiter comes in just a bit ABOVE 8000 rpm...could be 8250 (not looking long and close at the panel at that speed!).

Now, given the speeds in gears cited above (from the R&T test I believe):

8250 in 4th should be 126.8....and that seems pretty right. I had the feeling that I was hitting the rev limiter (and I did hit it a couple of times in this spot) at 127 on the speedo (or close enough for the glance I gave it!).

So, I don't THINK the rev limiter comes in lower in 4th, and I don't know why they used 8000 for the max speed in 4th & 5th. I think it comes in at 8250, from my humble experience. I could be wrong.

Anyway, using the same logic: the rev limiter in 5th gear should come in (if it comes in at 8250) at 158.8 mph.....and 170 mph in 5th would require 8830 rpm....well above the v8 rev limiter, but just under that if the v10 IIRR, which comes in at 8900, right??

Are you sure this isn't a v10?

Also, you said you "erm tested" your car to 170 in 5th. I'm probably the only dolt that doesn't get what "erm" means...but what is THAT? If you're talking about a chassis dyno run, I'm sure you know that it's EASY to hit redline or beyond (if rev limiter allows) on a chassis dyno because no air resistance.
The R8 could be redlined in 6th on a chassis dyno, but I doubt there's a hill in the world long enough to get it there IRL.

I have not been anywhere near 170 in 5th (see my description of my local track), but the acceleration rate in 5th at 130+ (seen, if briefly) is leisurely enough that I wonder how long a distance it took you to get to 170 in 5th (assuming the rev limiter will allow it)?

Always possible that somehow this "US Spec" car doesn't have stock ratios in the tranny, I suppose.

PS: also, unless you were traveling around 170 for a bit of distance, I would discount your gps speed. GPS is notoriously prone to errors in measuring speed over short distances or time spans. Not that it can't be right, but there's a substantial chance of significant error. Over large fractions of a minute or longer, it gets quite reliably accurate in speed measured. The reasons for this should be fairly obvious if you look at how, for brief moments, your Garmin or etc. will show you a few to a few dozen feet out of position, and then get you right back in the lane or etc. that you are in. 170 mph is, roughly, 250 ft/sec, so if you're position is 25' off, you speed over that second is off 10%, and 10% is the difference between R&T's 154 and your 170! (I know, your digital speedo agreed, just giving an example of how unreliable gps is as a speedometer.)

[kebabman]

Lol, yes, I'm sure it's a V8 and I'm pretty sure I'd have noticed if someone changed the transmission on it during a service, the reason I "erm" tested it might be becuase it might not have been on an "erm" track that I did said speed. I make no further comment on this.

I swear, no word of a lie, when I hit the limiter on my 2009 US spec 4.2 R8 it showed 171mph indicated on the digital speedo and 170mph on the Escort Passport 9500ci GPS display....I did a good few miles at this speed....don't make me do it again and take a video, I don't want to get deported. :P

[willyjp]

Lol, yes, I'm sure it's a V8 and I'm pretty sure I'd have noticed if someone changed the transmission on it during a service, the reason I "erm" tested it might be becuase it might not have been on an "erm" track that I did said speed. I make no further comment on this.

I swear, no word of a lie, when I hit the limiter on my 2009 US spec 4.2 R8 it showed 171mph indicated on the digital speedo and 170mph on the Escort Passport 9500ci GPS display....I did a good few miles at this speed....don't make me do it again and take a video, I don't want to get deported. :P

well, if that is so, then your rev limiter is set at 8900 rpm (the v10 redline)
NO OTHER CONCLUSION CAN BE DRAWN WITH THE FACTS AS YOU GIVE THEM