Another stake in the heart carbon naysayers

[JCviggen]

I was talking more about the 30-50k mile cars not being all that affected

Well thats not really established yet...obviously your car and the other one certainly seem to be suffering hardly any performance loss at this mileage but that's not something I would automatically assume for all othe cars. There is some evidence to suggest that not all cars are affected equally, and that driving habits have an influence (having your wife drive it around town slowly not being ideal)

and the fact that cleaning every 10,000 miles a some advise is excessive to this end.

That does certainly seem rather pointless, the car would be having a real issue if that were necessary.

The quarter mile is an acceleration test. We are using it as a measurement of how our cars stack up to clean cars that were tested by periodicals when the platform was launched , or by other rs4 owners. Some use the dyno to measure power...and I am sure Audi didn't design the car for the dyno, but I don't see you giving your opinion that it wasn't designed for the dyno in those threads?

Actually I mentioned an autobahn run would be more ideal to measure performance than something that is fairly heavily driver influenced.
A single gear (say 4th or 5th) pull from 3000 to 8000+ provides better conditions than from a dead stop through the short gears with varying shifting times (heatsoak a possible issue as well)

A road course excursion is a fun time but useless for measuring acceleration. Useless. I don't even know how that comment you posted was relevant?

It was just a side note really, but in any case you already knew your car's performance. I seem to recall from a previous conversation that you have done lots and lots of 1/4 mile passes which seems unnecessary to merely establish the performance of your stock car. You had already done that before and this latest slip offers nothing new.
if you were constantly modding it or something it would make more sense. Not that I want to appear to be judging anyone's hobby, if it's fun then it's fun. But the B7 isn't a straight line monster and its main feature that won it praise was that it handles a lot better than the audis before it.

Both cars are on stock wheels. Avus car has the rs4 ti package wheels 19x9 255.35.19. phantom car has rs4 silver wheels same size, same tire size.

I do actually have poor eyesight, that was no joke

[sakimano]

There is some evidence to suggest that not all cars are affected equally, and that driving habits have an influence (having your wife drive it around town slowly not being ideal)

That was also already addressed above.

Actually I mentioned an autobahn run would be more ideal to measure performance than something that is fairly heavily driver influenced.
A single gear (say 4th or 5th) pull from 3000 to 8000+ provides better conditions than from a dead stop through the short gears with varying shifting times (heatsoak a possible issue as well)

Comparing our times to altitude corrected professional driver times released by periodicals actually works against my thesis...and despite this our cars are right there with them. So there goes the driver dependent concern.

As I already addressed above (again repeating everything for you) the guys who suck at driving and run shitty times, then blame carbon for their inadequacy..that's where driver dependency is a concern. Not here.

It was just a side note really, but in any case you already knew your car's performance. I seem to recall from a previous conversation that you have done lots and lots of 1/4 mile passes which seems unnecessary to merely establish the performance of your stock car. You had already done that before and this latest slip offers nothing new.
if you were constantly modding it or something it would make more sense. Not that I want to appear to be judging anyone's hobby, if it's fun then it's fun. But the B7 isn't a straight line monster and its main feature that won it praise was that it handles a lot better than the audis before it.

Again..already addressed. Someone asked me to go with him, as he had never been before, so I did. It also gave him a benchmark for how close he could get to my car and since I have times run in cold, ideal conditions, that was more valuable info.

My computer science professor had a great tip for people who have lots of questions, and it applies here to you. RTFS!

[JCviggen]

As I already addressed above (again repeating everything for you) the guys who suck at driving and run shitty times, then blame carbon for their inadequacy..that's where driver dependency is a concern. Not here.

Maybe you need to get out the reading glasses as well, your reply is totally disconnected from what I said.

I was talking about the ideal way to measure performance (as a reply to your reply to my initial post in this thread, mind you) and you go off into a tangent.

In any case, are you saying that every "slow" RS4 out there is down to a bad driver? Or are some due to mechanical issues such as carbon buildup? How is one, being a bad driver possibly, supposed to tell the difference then?
Answer: use a performance test that isn't f-ing driver influenced instead.

I guess I was just expecting a bit more based on the thread title. If your only point was to show that there are at least some cars out there with no issues at 60k then I guess we can consider that as established.

RTFS!

Communicating with Americans is always such a pleasure, I wonder why I don't go over there more often.

[sakimano]

Maybe you need to get out the reading glasses as well, your reply is totally disconnected from what I said.
I was talking about the ideal way to measure performance (as a reply to your reply to my initial post in this thread, mind you) and you go off into a tangent.

yes, but you said the quarter mile is so 'driver dependant' to which I said the results we're talking about here (and half a dozen other guys who have done so) show that amateur hacks like us can indeed replicate the 'professional' drivers who pilot the test cars for the periodicals in the quarter mile....even with 30 to 50 thousand miles of carbon on our cars.

In any case, are you saying that every "slow" RS4 out there is down to a bad driver? Or are some due to mechanical issues such as carbon buildup? How is one, being a bad driver possibly, supposed to tell the difference then?
Answer: use a performance test that isn't f-ing driver influenced instead.

lol read the original frigging post already. I said that many people who take their car to the quarter mile don't drive very well, but I also said many others don't know how to get a good quarter mile ET out of their car (they don't know how to stage, they don't know simple things like where to shift gears etc) . They also most often go to the track in the summer on a hot night with shitty density altitude, and on a busy night too...when the lineups are massive and the cars run crap times due to heat soak. Again, all addressed in the OP. Do you EVER ask an interesting question that hasn't already been answered before in a thread?

I'm a good driver jcviggen. I don't need a non-driver dependant test. While I realise a single gear pull is nice, how are we going to standardize that? Are we really getting enough info from someone measuring their own time while driving? Are we really assured they're on a standardized grade road? Are we really sure they're running the car out to 8k RPM? Are we really sure they're not just letting their ego get the better of them and producing a better result post clean to justfy their $1000/600 pounds in expense getting the car cleaned??? None of those sound like good variables to inroduce. I'd much rather have a standardized test on a standardized grade with a standardized set of timing equipment, all certified by a governing body. You might not. That's fine.

Any good driver (not great) will produce a result that is very close to what a 'pro' will produce in the quarter mile in the same car, provided they know what they're doing, and don't run their car in <beep> conditions. It's an AWD Audi and we're not powershifting (nor do periodicals who test cars) so this is not that hard. I realise you drive an automatic (C5 Rs6 not an RS4) and probably find the quarter mile a terrifying prospect in a manual car, but it's not that bad. I think you're one of these guys who has never been to the dragstrip, but talks about it like he knows everything. Am I close?

Communicating with Americans is always such a pleasure, I wonder why I don't go over there more often.

I'm Scottish, living in Canada. RTFS is a universally known acronym it appears. Unfortunately, you still haven't done so, and I am stuck on page 3 spoonfeeding you answers to your questions that were all addressed in the original post.

[P_G]

Get a room you two or this thread will end up like all the others on this subject which is a contributing factor to the subject's derision.

[Stoffle32]

I personally think there is a 3rd category to your original 2, and this is based on reading up on many of forums around the world, as well as some experience.
so here is goes...
The 3rd category: The Rs4 does suffer from carbon build but its not as big an issue as we all think and the cars are down minimal amounts. However some cars do suffer big losses but is down to another parts failure that increases the carbon build up IE. Manifold flaps failing/Vacuum system. (which is why the have huge amounts of Carbon) - My opinion

Im part of the Audi Club in South Africa and have been for many years, a couple of years ago before I had my Rs4 my mate Dynoed his Rs4 and got 301KW on the fly, so just off the quoted audi figure of 309KW... on the same day another Rs4 dynoed at 254Kw, many questions where asked and carbon was blamed almost instantly, he took the car back to Audi and told them to sort it out as he was not happy... They came back to him and the replaced the manifold, as the flaps where sticking.... (No EPC fault was shown on the dash) He went back to the dyno and on the first run got 281KW... Yes he is still not at the 301KW the other Rs4 did, but how long was he driving it with the sticking flaps, and I firmly think that carbon deposits would be more if you had this issue as less air is flowing over the valves etc....

On many of the forums including this one, low numbers on the dyno have been because of other issues and not just the carbon build up.

[JackS4]

In my case the carbon had built up to the point where valves where not seating properly (I do a lot of slow commuting) and this caused a considerable drop in power as combustion wasn't happening properly in 3 of the cylinders so I guess this makes it 4 catagories of stuff that causes a loss of power.

J

[sakimano]

well in reality there are probably 50 groups. I was generalising nicely in my original post about the two main groups.

That 'group 3' mentioned by stouffle is where I sit now, as I mentioned above.

I would really enjoy seeing more performance data from cleaned and dirty cars alike. This wednesday night that car I mentioned that went 13.06 @ 107.6 will be going back to the strip, post carbon cleaning. Will be interesting to see what he can do. 2 weeks removed from his first runs.

When we went last time, here were the conditions at the time of his best run (best run was his second run...as the day wore on it got up to about 28-29 celsius, and the cars just got slower and slower). Best for me was at 11:18 am. Best for him was at 11:26 am.

11:00 AM 69.8 F 64 % 29.98 in - Density Altitude 1615 feet
12:00 PM 69.8 F 64 % 29.97 in - Density Altitude 1627 feet

[sakimano]

UPDATE

so we went to the dragstrip two weeks ago in my 40k mile car never cleaned and Mistro's 55k mile car never cleaned. Both cars stock.

In warm conditions around twenty degrees, with DA of around 1200 feet:
Sakimano 12.92 @ 108.0
Mistro 13.06 @ 107.6

Tonight we went back again. I am still stock and never cleaned, Mistro though got carbon cleaned a few days ago (pics above). Very similar weather fortunately...DA 1200 feet again:
Sakimano 12.89 @ 108.0
Mistro 13.0 @ 107.8

So he didn't gain a lick!

Interestingly he had the jhm intake spacers added. When we arrived after a one hour drive for me and a two hour drive for him including rush hour fighting his way out of Toronto, my intake manifold was almost scalding hot. His though we could lean on with our bare hands with no discomfort. Just warm. I will review his timeslips as the night wore on vs mine to see if the spacers preserved his car's performance better than mine during the two and three at a time runs we would do before parking the cars for forty minutes to cool down.

I'm a bit shocked though regarding his times. He must have made ten passes as he really want ed to break into the twelves.

[adsgreen]

Or it coild show that the JHM intake spacers are adversely changing the intake tract length and reducing performance more than heats soak was. FWIW a very rough rule of thumb relating intake length to power results in a 1cm increase in length dropping peak power by 500 rpm.
Pointless testing two things at once and would also be interesting to swap drivers. By your own admission you are very experienced at drag strips.

[P_G]

Your clutch must love you saki.....

[sakimano]

Or it coild show that the JHM intake spacers are adversely changing the intake tract length and reducing performance more than heats soak was. FWIW a very rough rule of thumb relating intake length to power results in a 1cm increase in length dropping peak power by 500 rpm.
Pointless testing two things at once and would also be interesting to swap drivers. By your own admission you are very experienced at drag strips.

No point in swapping drivers...he is a good driver and was very consistent both times. Why would you want to add another variable anyway? Our cars are pretty much dead equal and our third gear pulls we did earlier this year showed that. I think I'm a good driver and I get everything out of the car without hurting it if that makes any sense. I won't powershift it for example.

As for the theory on the intake spacers...interesting but I wouldn't put much stock in it. Easy thing to point to I guess. Must folks will say they will give you a mild torque bump if anything.

[sakimano]

Your clutch must love you saki.....

I don't get the clutch fear. My b7 s4 clutch lasted the full 60,000 miles I owned the car and was as strong as ever when I sold it. The car must have had 100 dragstrip passes on it and easily double that number of launches on top of that.

check my YouTube...no shortage of launches in that car.

Like anything if your technique is bad you will do more harm than if it is good. I know rs4 owners who have replaced their clutch after zero launches and only twenty thousands miles...and in many cases their gear engagement technique us the cause.

A quick perusal of rs4 videos reveals that many rs4 owners slip the clutch WAY too much, on start and on gear changes. I think that's the biggest challenge for these cars' clutches especially when they do that damaging action thirty times on a drive to work...and do that drive five hundred times a year! That is FAR more damaging than cleanly launching it at 3800 RPMs seven times in four hours, five times a year.

[adsgreen]

As for the theory on the intake spacers...interesting but I wouldn't put much stock in it. Easy thing to point to I guess. Must folks will say they will give you a mild torque bump if anything.

Yes you'll get midrange torque increase from the intake length however it's effecively moving the entire torque curve down by about 500 rpm. Les torque at high rpms though so less ultimate power with the same peak torque at lower revs.

[sakimano]

As for the theory on the intake spacers...interesting but I wouldn't put much stock in it. Easy thing to point to I guess. Must folks will say they will give you a mild torque bump if anything.

Yes you'll get midrange torque increase from the intake length however it's effecively moving the entire torque curve down by about 500 rpm. Les torque at high rpms though so less ultimate power with the same peak torque at lower revs.

Anything to back that up on the RS4?

We've seen plenty guys dyno with them and they don't have any drastic shifts that I've seen. In fact this is the first I've heard of such a dramatic shift.

In any event, His MPH was improved last night, ever so marginally. His best MPH last week was 107.6 MPH and last night he hit 108.2 a couple of times. In fact top end was the least of his problems last night...his times would have been a hair better if he wasn't launching the car with 1.88-1.90 60 foot times. I reckon he had a 12.99 @ 108 in him last night. Would have been fun to drive his car, but again I don't think it would help our test...it would simply identify who shifts better.

I did drive another friend's car last night. His best 13.30 @ 106.9. My one pass in his car was 12.83 @ 109.75