How low will it go, without lugging?
 

What is the lowest rpm that you are supposed to go (under load) on a 951?

The reason I ask, is that at anything under 2K, I get substantial vibes, like the car is lugging, unless I am VERY light on the pedal. I can run the 924S down to 1500 without experiencing this. Is this normal? Why the difference?

depends if you're uphill/downhill/flat. uphill, i try to not get below 3k.

That is only because you are in to the pedal farther for flat vs down hill, and for uphill vs flat. I am talking about how low the 924S can go on flat vs how low the 951S can go on flat.

when i'm tuning the car for WOT fuel map, i start out at full load at 1200rpm with no vibration problems.

What are your engine mounts looking like?

I'll have to take a close look. What should I be looking for?

they will look smooshed in the rubber part... almost flattened. and of course vibrating is one symptom

Had the same problem. Turns out my engine mounts had completely disintegrated. I'm looking forward to testing the car with the new mounts.

Both of them? Not having checked them yet, it sounds likely that's what it is. I used to have a couple of them lying around. But since I have moved twice since then, I'll have to search to see if I still have them.

What's strange is that my 924S also has vibration issues, but they are of a completely different sort. At idle, you can feel the whole car shaking. But as soon as you touch the gas pedal, the vibes instantly vanish. Anyone ever had THAT symptom?

Yep. Both of them. Shorn clean off and had probably been that way for some time. They were completely dry, no oil left what so ever. Funny thing is I did not really notice it when driving or idling. The shaking was not bad at all. I assumed it was due to the lower compression of the turbo engine and a requirement of higher revs... I can't imagine how smooth it will be with the new mounts.

You know, I was attributing it the lower compression of the turbo engine too. But also the different intake runner geometry. With your response, as well an nize's, I've now put those thoughts to rest.

I don't give it much throttle below 2000 rpm. The bigger problem is that car dis dog slow will that little rpm. I try to never go WOT below 2500 rpm. Seems like a waste.

Now my 8.0L V10 gas tow vehicle tows at 1600 rpm.