garrett376

958 tows just as well as a 957, maybe better thanks to things like Adaptive Cruise Control (only available on the 958) and better gas mileage (on the 958) and the 958's LED tolerance. A 958's interior is too nice to cut up and it has a knee airbag, so I needed a Prodigy RF when I got the 958, but that's not a big deal.

The 958 is fantastic off-road - I actually prefer it to my prior 957. The 958 will go anywhere a similarly equipped 955/957 will go, and there are more 958's with locking rear differentials than there are 957/955's, so it's possible a 958 may be able to go further than 955/957's...

nodoors

So basically you are saying the low range transfer case is an entirely unnecessary feature and all engineers, manufacturers, and offroaders to date have just been confused about that?

deilenberger

Since the 958 starts out in 1st gear (unlike a 955/957) and it's a low first gear - a low range probably would be unnecessary. When the 955/057 was first engineered (think back in 1999/2000 probably) - a 6 speed transmission was as good as it got. Since the 958 got an 8 speed - that allowed Porsche to use a lower 1st gear and eliminate the need for a low range transfer case, which on probably 99.9% of the 955/957 Cayennes sold - was never used.

oldskewel

My 955 (2004 S) starts in 2nd gear. Is something wrong? BTW, it also shifts really early. Driving like a granny (sorry, only as a test), on level ground, it will shift from 5th to 6th before 40 mph. Is that a problem too?

Petza914

That's normal behavior. You can push the Tip "-" button while at a light to make it start in first or if you have Sport mode, that will also make it start in first. When I get in my 957 Turbo S, I put it in Sport mode for the 1st gear start, but that also lowers it, so then I have to lift the air suspension back to Normal - wish there was a way to have it remember some of these parameters and make them the default like there is in the 958 from that aftermarket company

oldskewel

Yes, that's what I thought. I now see that I misread deilenberger's post. Don't know how I did that. I thought he was saying my 955 should start in 1, but clearly I just misread that.

nodoors

That is good to know, but you forgot about the diff gears. Despite the extra transmission gears, the 958 CTT appears to me to actually be taller in 1st gear than the 955 CTT. With the low transfer case gear the crawl ratios between the two still aren't even close... please let me know if my Math or numbers are wrong:

955 CTT
1st gear: 4.15
Final drive ratio: 3.7
Transfer case High: 1
Transfer case Low: 2.7

1st Gear Crawl Ratio High: 15.36:1
1st Gear Crawl Ratio Low: 41.46:1

958 CTT
1st gear: 4.97
Final drive ratio: 2.92

1st Gear Crawl Ratio: 14.51:1

Don't forget that the 955 transfer case allows the use of the other transmission gears as well.

garrett376

No, I am basically saying: The 958 is fantastic off-road - I actually prefer it to my prior 957. The 958 will go anywhere a similarly equipped 955/957 will go, and there are more 958's with locking rear differentials than there are 957/955's, so it's possible a 958 may be able to go further than 955/957's...

deilenberger

Do the same calculation for the 995 starting off in 2nd gear.. which is where most people would be if they weren't shifting it manually.

nodoors

By offroading standards, 50:1 is decent, but many people shoot for twice that. I have an offroad rig with 62:1 and I still want more gear.

nodoors

955 CTT 1st Gear Low Range Crawl Ratio:: 41.46:1
955 CTT 2nd Gear Low Range Crawl Ratio: 23.68:1
955 CTT 3rd Gear Low Range Crawl Ratio: 15.58
955 CTT 1st Gear High Range Crawl Ratio: 15.36:1

955 CTT 2nd Gear High Range Crawl Ratio: 8.77:1
958 CTT 2nd Gear: 8:21:1

What's your point? If one is offroading in a 955 and is using low range, they are going to manually select the gear they wish to use. They have 4 total choices (1,2,3 low and 1st high) that are lower range than 1st gear on a 958, which is 14.51:1. I could be wrong about these calcs, but I pulled them from Porsche's data sheets:
http://press.porsche.com/archive/pro...enne_specs.pdf
http://press.porsche.com/vehicles/20...pecs_w_GTS.pdf

nodoors

Sorry I worded my other response in such a snarky way. I am glad the 958 works for your uses, but you are going to be hard pressed to convince many people who intend to drive offroad especially when loaded down or towing that the numbers I detailed above don't mean anything. The points of this thread was for people considering upgrading and I am just trying to help make sure we have the facts straight, but your experience is also valid.

As far as Don's point about 99.9% of the 955/7 sold have never used low range - GREAT. That means enthusiasts who break things will have plenty of fresh transfer drivetrain parts in the future! Some of the older drivetrain components loved by offroaders are getting harder to come by these days. This is sometimes frustrating for me on other vehicles because it makes me want to limit the fun that I have with them which defeats the whole point!