Buying an '08 Q7 - have a few questions

I’m going to be buying a 2008 S-line Q7 tomorrow with the 4.2 FSI V8 and have a few questions for anyone that knows the answers:

  1. It has the 21" S-line wheels on it and they are fucking trashed. It rides pretty harshly for what I would expect from an Audi. I’m guessing most of it is due to big wheels and thin tires, but I’m sure the suspension plays a part also. If I buy new wheels, what it a good middle ground with regards to ride comfort, tire price, and looks? I’m thinking some 18"x8" BBS SR wheels with 255/55-18 touring tires. Any opinions?

  2. I have done a bit of research and haven’t really found anything bad about the Q7 variant of the 4.2 FSI. I’m assuming it has the same carbon problems as the RS4 version, but haven’t seen much info on it. Any other long term problems as these engines age?

  3. Any helpful hints on improving gas mileage? I’m going to be doing the normal stuff like plugs, low resistance tires, etc but was wondering if there is anything off the wall for these things. I’m not expecting it to match my A4, but a solid 20 mpg or better on the highway would be great.

  4. Is there a difference between the suspension with S-line and base suspensions? I do not have the air suspension but the suspension stuff I’m seeing says that it fits Q7s w/o S-line and w/o air suspension.

The Q7 4.2 is a nice car I was looking at some a few years ago.

1 the tires you mentioned are a night mare. Low pro tires have harsh sidewalls and that kills the ride. The bigger side wall tire you listed should be able to offer much more comfort. The syspension on the car stock should be middle of the ground so it would most likely be the tires and that should be an easy fix. Also I noticed if its cold outside it takes a little while for the suspension to flow freely if that makes sense.

2 The Q7 motor is the RS4 motor but with different cams and different low RPM chain parts on the back of the motor. There are a few different parts here and there but the block and core parts are right off the RS4. Its a good motor. The carbon is going to be an issue and given the Q7 market isnt full of hot rod guys Vs soccer moms you will be in for a good amount of carbon work and also consider maintance work

3 After doing maintance work getting better flowing air filters plugs and other usual things like that you can look at removal of the cats. That seems to help on the RS4. I would contact CV on here and see if he can help with a tune. I know he was working on a few Q7 tunes for the 4.2 and taurag last year. That would be helpful

4 not too sure on the suspension stuff. from what I under stand suspension upgrades will fit both set ups.

18s will look comically small. On that car. 19s might even.

Also from Justin’s post I think the pistons and Rods are different to the rs4. Different metallurgy.

It would be easier to sat it’s the same as the S5 4.2 engine (the Q7 is). As we know those engines are excellent. Carbon and fuel efficiency are the only problems you can really guarantee to be part of the package.

As Justin said, the 4.2 Q7 is a nice car. It is a bit small on the interior behind the front seats headroom wise but still very useable. Most of the stuff that failed on the Q7s was optional interior crap that you don’t really need anyways.

They did have a lot of issues with water damage though. Especially if the vehicle is parked under trees so leaves and debris can fall into the cowl area. If you go through my Jimmy’s Garage thread there are multiple times that I remove the cowl drain plugs and you would very wise to do that on that Q7 right away. Then the sunroof drains would fail right where the plastic coupler piece for the actual sunroof cartridge meets the drain line. The official fix is to replace the whole drain line but we would reseal them with PCV pipe sealant. Finally the AC drain that is under the front passenger part of the dashboard would clog up. We would just blow it out with compressed air and then it would be fixed.

Now for the stuff that you asked about.

  1. 18 inch wheels and tires were an option from the factory and they gave the best ride for these big heavy beasts. They do look small over the big Brembo brakes but that is okay. Those 21 inch wheels and tires are not only really hard but they weigh a shit ton too. I would look for the lightest 18 inch wheel that you can run.

  2. The Q7 4.2 FSI V8 came out at the same time as the RS4 4.2 FSI V8. I look at the Q7 version as being the low revving but high torque engine. It works well and holds up to any abuse that you can throw at it. Audi put the Q7 4.2 FSI V8 into a lot of other cars like the C6 A6, facelift D3 A8, and B8 S5 coupe. It gets carbon buildup just like the RS4 and I have done a bunch of carbon cleans on the Q7s. It is sooooooo much easier to do on a Q7 than any other car with that low revving 4.2 FSI V8 because the front of the engine is so accessible when compared to the other cars. With higher than 60K miles I would also replace the PCV valve/oil separator and send out the fuel injectors to be flow matched/rebuilt. You might want to contact JHM about intake manifold spacers because they might fit the Q7 too.

  3. Lightweight 18 inch wheels + low rolling resistance tires (that are properly inflated) + tune up + carbon clean (with replacing the PCV and getting the fuel injectors flow matched/rebuilt) + driving with the windows up and AC on if you need it = the best gas mileage that you are going to get.

  4. I don’t think so. Check the shocks for a valve on the bottom and if it doesn’t have it then you are fine with whatever you want. We had a few Q7s that had standard suspension but with Bilstein shocks and they rode great. Plus Bilstein shocks are cheap as hell.

So I just got a quote for a carbon cleaning from a place relatively local to me. This is what I got back:

I need to get into the carbon cleaning business of people actually pay these prices. Looks like I’ll be doing it myself.

That is fucking nutso, especially considering it’s one of the easier vehicles.

how is it easier? it’s a V8

Easiest of the V8 cars. Almost everything is so much more accessible after you climb up and into the engine compartment.

Much more room and less involved than a car like the RS4

Ok but he/you said easier vehicles. Maybe he/you meant to say easier 4.2 v8 FSI.

Unrelated question : Why don’t we hear r8 guys bitching about carbon?

R8 guys not on forums as much? Not as many R8’s?

I would say both of those and most R8 guys post on R8talk. I hate doing a carbon clean on a R8. It sucks because I have to lay across the back of the car to actually reach the ports.

Perfect thread as we’ll be shopping for one in a near future. Probably going to stick with 2011 as it was a last year for V8 version. Anything in specific you fellas would recommend to look closely at during PPI? Periodic carbon cleaning and other basic maintenance items(spark plugs, PCV valve, injector cleaning, etc.) don’t scare me at all. Seems like this engine is quite sturdy.

Also, any options you guys would recommend to have or a must have?

I have heard that the optional air suspension can be problematic and expensive to repair. My '08 Q7 had pretty much every option except the air suspension and B&O sound system. I promptly took off the stock S-line 21" wheels in favor of more a budget and comfort friendly 20" setup. I really have no complaints with mine, other than the fact that it sounds good at high rpm and that cause my mileage to go down lol.

I only ever had one Q7 with air suspension where the air springs failed. It was the rear air springs I was very surprised with how easy it was to replace them. The parts are expensive as hell though.

Stupid or more like lazy question as I haven’t researched this yet, but do all S-Line Q7s come with air suspension? I’ll be on a hunt for S-Line one and hopefully will find one in a decent condition, would hate to settle for plain Jane one. Would love to get one with W12 TDI appearance package on it, but that only started recently, so S-Line would have to do it.