Max Speed? 2.2i

OXO · Post by **OXO** » Wed 23 Mar, 2011 13:09

An odd thing I think.

Our new 2.2i 2001 has a low top speed.. seems to be due to gearing..?

2000 RPM in 5th I have 35MPH. This makes the top speed 105.

Both the speedo and the revcounter seem to be ok. I checked the speed against our GPS and it's accurate.

On the revcounter, I hit the hard cut rev limit at about 6750 indicated. This seems correct.

Is there any chance there is a different final drive fitted? Seems odd, but if there was, then wouldn't the speedo be wrong?

Z3cade · Post by **Z3cade** » Wed 23 Mar, 2011 13:35

Tut tut.....

In all honesty 105 does seem very low, have you got a z3 brochure? should state what top end should be in there..
But unless you do track days i wouldnt worry about top end

EDIT: Ive just checked my Brochure and it states
1.8 zed top speed 122mph
2.0 top speed 130mph
2.8 top speed 140mph
M 3.2 top speed 155mph

So looks like theres something not right there.....

Post by **Robert T** » Wed 23 Mar, 2011 13:42

2.2 is quoted as having a top speed of 224 km/h (~ 140 mph) according to the bmw_z3 belgacom site.

According to your figures, at 6750 rpm you will be doing 118 mph. To achieve 140 mph at 6750 rpm, you would need to be doing 41 mph at 2000 rpm. That's only 6 mph out, which could be down to speedo error or wrong size tyres - possibly even worn tyres (you lose about 1cm of diameter on worn tyres). Try measuring your speed with a satnav and try noting the rpm at some higher speeds which should reduce the error.

Cheers R.

nero · Post by **nero** » Wed 23 Mar, 2011 13:49

Top speed should be 139 mph (137 for auto)

See my page here - BMW Z3 2.2i SPORT ROADSTER (page also has dyno plots)

BimBeema · Post by **BimBeema** » Wed 23 Mar, 2011 14:02

For a moment I thought this thread was about members admitting what top speed they had reached with their Zeds!

Good god that it isn't! Wouldn't want to think what RobBruce would make of such a thread!

OXO · Post by **OXO** » Wed 23 Mar, 2011 17:22

Robert T wrote:2.2 is quoted as having a top speed of 224 km/h (~ 140 mph) according to the bmw_z3 belgacom site.

According to your figures, at 6750 rpm you will be doing 118 mph. To achieve 140 mph at 6750 rpm, you would need to be doing 41 mph at 2000 rpm. That's only 6 mph out, which could be down to speedo error or wrong size tyres - possibly even worn tyres (you lose about 1cm of diameter on worn tyres). Try measuring your speed with a satnav and try noting the rpm at some higher speeds which should reduce the error.

Cheers R.

As I said, I checked the speed with a GPS (satnav) and it's within a couple of mph at 70 mph, so it's not tyres.

What I don't understand is if there's a different final drive fitted, why isn't the speedometer wrong?

Post by **Robert T** » Wed 23 Mar, 2011 17:44

Ok, let me rephrase that... what RPM is indicated at a steady 70 mph as indicated by the GPS? The mathematical error will be less than trying to scale up a value from 35 mph.

It is also possible that the analogue rev counter gauge is out - you can put the odometer into self test mode and check that the indicated RPM matches what the car measures digitally. See this thread for details.

Cheers R.

nero · Post by **nero** » Wed 23 Mar, 2011 18:35

or ...

Why not use the system of cameras, conveniently set up at the side of some roads. You get a nice photograph and a letter to prove your speed

Unfortunately it costs a minimum of £60 for this service

spanwah · Post by **spanwah** » Wed 23 Mar, 2011 19:17

book speed 139mph! deos it really matter cruisings what its all about

OXO · Post by **OXO** » Wed 23 Mar, 2011 21:33

spanwah wrote:book speed 139mph! deos it really matter cruisings what its all about

Yes it does, because it means the car is much lower geared, and doing more rpm for a given cruising speed.. therefore worse fuel consumption.

spanwah · Post by **spanwah** » Thu 24 Mar, 2011 08:59

OXO wrote:
spanwah wrote:book speed 139mph! deos it really matter cruisings what its all about
Yes it does, because it means the car is much lower geared, and doing more rpm for a given cruising speed.. therefore worse fuel consumption.

ok keep your hair on!

you that worried get a diesel fiesta

devboy · Post by **devboy** » Mon 28 Mar, 2011 16:13

Nero wrote:or ...

Why not use the system of cameras, conveniently set up at the side of some roads. You get a nice photograph and a letter to prove your speed

Unfortunately it costs a minimum of £60 for this service

I've had another accident.