Derek H

Hi!

I test drove a '92 968 here in Sweden today, and noticed that it really seemed to pick up at about 4,000 rpm. I have driven several over the last few weeks but didn't notice such a step in the torque curve at this point. Is it normal for there to be a marked increase at around 4,000 rpm? Performance below 4,000 was good, no holes in the torque curve. It reminded me of my old Yamaha 250 two stroke that suddenly hit the powerband!

cheers

Derek Holliday
Linköping, Sweden

Damian in NJ

4000 is where the Variocam kicks in.

Tabor

Actually, there is no big torque jump anywhere. Here is the factory dyno chart:

CBass

Yes, this is the 968s greatest advantage over the 944 series motor. It has over 200 lbft of torque through the entire rpm range. This is why it also is a superior motor to the flat 6 when the 3L has been turbocharged.

luckett

[quote]Originally posted by Tabor Kelly:
<strong>Actually, there is no big torque jump anywhere. Here is the factory dyno chart:
</strong><hr></blockquote>

I don't know how large the actual torque increase is, but there is definately a nice little kick at ~4000.

CBass

Now imagine 1.3 bars of boost, at double the hp and torque, with the same powerband.... Tool around town in 5th and 6th anyone?

adrial

From 3500rpm to 4k rpm it looks like there's a nice little peak in the torque curve...

Chris 968

[quote]Originally posted by CBass:
<strong>Yes, this is the 968s greatest advantage over the 944 series motor. It has over 200 lbft of torque through the entire rpm range. This is why it also is a superior motor to the flat 6 when the 3L has been turbocharged.</strong><hr></blockquote>

The chart shows torque in Nm. That would be no less than 147.50 lbft.

CBass

I wasn't working from the chart, I was informed the motor makes more than 200 ftlbs from 2000 rpm on.

I have researched the cost of the turbo conversion, and to build a 450hp motor it would take 5-6k in work.

megatron

[quote]Originally posted by Damian in NJ:
<strong>4000 is where the Variocam kicks in.</strong><hr></blockquote>

Actually, no. ~4000 is around when the intake manifold hits resonant frequency. ~5500 is when the valve timing switches.

CBass

Something I have been meaning to ask a 968 owner sometime, how often should you replace the timing chains? Is there any room to use a heavier guage chain?

Chris 968

[quote]Originally posted by CBass:
<strong>Something I have been meaning to ask a 968 owner sometime, how often should you replace the timing chains? Is there any room to use a heavier guage chain?</strong><hr></blockquote>

The 968 uses a timing belt, also called a cam belt.
Porsche recomends 60K miles, but many owners change it earlier just to be safe. I had mine changed at 45K miles. I have heard people suggest that 2 years also be a time to change it if you don't reach the mileage, because age is also a problem.

Tabor

Chris,

There is also a timing chain that connects the two cam shafts. Most owners change it at 100,000 miles, because Porsche doesn't publish an interval.

Chris 968

[quote]Originally posted by Tabor Kelly:
<strong>Chris,

There is also a timing chain that connects the two cam shafts. Most owners change it at 100,000 miles, because Porsche doesn't publish an interval.</strong><hr></blockquote>

My apoligies, if that is what CBass was refering to.

Tabor

No need to apologize, this board is for learning.