MEgearhead
Veteran Member
Thought it might be interesting to start a thread on Post Emissions Modification observations.
We have a '15 Q7 TDI Prestige S-Line. It was an upgrade for our '09 they bought back. Had the fix completed in Feb. So far we have noticed the following (short list format, more info below):
All out performance is hardly changed.
More lag in the throttle response under certain conditions.
Mileage has dropped around 1 point so far.
Transmissions shift points are just plain weird.
Far more regenerations.
Overall, I'd say we still like it better than the non TDI's we tried, and it's not bad enough to wish we would have passed on the $9500 and the extended warranty. They gave us a '18 2.0T Q3 loaner while it was being "fixed", and I can't imagine a Q7 with a 2.0T. That would ruin the vehicle in my opinion. We also tried a new domestic SUV between the '09 and '15 which we came to loath enough to unload and buy the '15. If we were to have a regret it would be not keeping the '09 and the $11K for having it fixed, but we're still satisfied with the '15.
The more info:
It seems there might be a small decrease in WOT performance, but rough 0-60 times don't indicate that. My sons love doing 0-60 times and before and after are right around 8 sec's. (I know, I'm teaching them bad habits I will likely regret later since they are not driving age yet.) So, the difference is in the tolerance of a 12 yr old operating the stop watch.
The intermittent lag in throttle response is the most frustrating. It's similar to the VW B5.5's, only worse. Once in a while it decides to hesitate then it launches like it's been prodded. This is especially bad if you get on it right after letting off. (I know, I know, you shouldn't drive it that way, but sometimes in traffic you just have to.)
It will take a few more tanks to really determine mileage impact, but on two fills it seems to be around 1 point lower.
The change in shift points is hard to explain. Before it seemed the transmission always upshifted too soon and downshifted too late, but it was easy to get used to, and overcome with throttle angle. Now it seems to be a little shifty about shift timing. Sometimes it seems better, others it hangs way too long with a harsh shift, and others it jumps the shift. This is both in upshift and downshift. The rapid changes in throttle sometimes required in rush hour city driving seem to confuse it the most. It's not really bad; some may not even notice it. Having rebuilt and upgraded THM's for budget street rodders, I'm a little more perceptive to shift timing and quality.
Before the change we never really noticed a regeneration (in either the '09 or the '15). Now since the change at least five times after getting out it smelled very hot and the fan was running. I have not had a chance to look at the regeneration status with VCDS to know for sure, but it seems to me regens are being interrupted.
I'm very interested in what others have observed.
We have a '15 Q7 TDI Prestige S-Line. It was an upgrade for our '09 they bought back. Had the fix completed in Feb. So far we have noticed the following (short list format, more info below):
All out performance is hardly changed.
More lag in the throttle response under certain conditions.
Mileage has dropped around 1 point so far.
Transmissions shift points are just plain weird.
Far more regenerations.
Overall, I'd say we still like it better than the non TDI's we tried, and it's not bad enough to wish we would have passed on the $9500 and the extended warranty. They gave us a '18 2.0T Q3 loaner while it was being "fixed", and I can't imagine a Q7 with a 2.0T. That would ruin the vehicle in my opinion. We also tried a new domestic SUV between the '09 and '15 which we came to loath enough to unload and buy the '15. If we were to have a regret it would be not keeping the '09 and the $11K for having it fixed, but we're still satisfied with the '15.
The more info:
It seems there might be a small decrease in WOT performance, but rough 0-60 times don't indicate that. My sons love doing 0-60 times and before and after are right around 8 sec's. (I know, I'm teaching them bad habits I will likely regret later since they are not driving age yet.) So, the difference is in the tolerance of a 12 yr old operating the stop watch.
The intermittent lag in throttle response is the most frustrating. It's similar to the VW B5.5's, only worse. Once in a while it decides to hesitate then it launches like it's been prodded. This is especially bad if you get on it right after letting off. (I know, I know, you shouldn't drive it that way, but sometimes in traffic you just have to.)
It will take a few more tanks to really determine mileage impact, but on two fills it seems to be around 1 point lower.
The change in shift points is hard to explain. Before it seemed the transmission always upshifted too soon and downshifted too late, but it was easy to get used to, and overcome with throttle angle. Now it seems to be a little shifty about shift timing. Sometimes it seems better, others it hangs way too long with a harsh shift, and others it jumps the shift. This is both in upshift and downshift. The rapid changes in throttle sometimes required in rush hour city driving seem to confuse it the most. It's not really bad; some may not even notice it. Having rebuilt and upgraded THM's for budget street rodders, I'm a little more perceptive to shift timing and quality.
Before the change we never really noticed a regeneration (in either the '09 or the '15). Now since the change at least five times after getting out it smelled very hot and the fan was running. I have not had a chance to look at the regeneration status with VCDS to know for sure, but it seems to me regens are being interrupted.
I'm very interested in what others have observed.