Why is the ZT 190 so slow on paper?
 

Hello forum,

My first thread here.

Just got a ZT-T 190, lovely car! Just wonder how it spec-wise could be so slow. My previous car, an E39 BMW 525i Touring, is 160kg heavier, has no more power, and is certainly quicker according to (saloon) specs :o

From Zeperfs:

ZT 190/525i E39:

Motor: 2.5 V6 24V | 2.5 I6 24V
Power: 190hp @ 6500 | 192hp @ 6000
Torque: 245Nm @ 4000 | 245Nm @ 3500
0-100 claimed: 8.2s | 8.1s (Touring 8.5s)
0-100 verified: 8.8s | 8.0s
0-180 verified: 32.6s | 26.5s
Top speed claimed: 225 | 238 kph (Touring 235 kph)
Top speed verified: 224 | 231 kph
Verified weight*: 1520/1680 kg

*My 2003 ZT-T 190 and 2002 525i Touring, full tank, 65 kg driver

So the E39 Touring is 160kg/350lbs heavier, and according to specs, quicker (Touring can't weigh 180 kg more if 0-100 is just 0.4 seconds slower).

Another example is 325Ci E46 (Zeperfs), also quicker, being a passenger heavier than the ZT.

I'm curious about this mystery. Given the huge weight difference to the charts, have someone done a Racelogic test or dyno'd a stock 190? What were your results?

Thank you,
Ahrle

Short of the ZT 260 V8 - the 1.8t which was limited by BMW/MGR to 160 bhp to prevent outshining the 190/BMW sports saloons when reset to its original 200 BHP is the speediest.

Am sure a 190/V6 owner will come onto explain.

Welcome to the club. :}

I expect one or both vis motors are kaput which can certainly make the car feel sluggish.

Don’t forget that the bmw is rear wheel drive, which is far superior in a standing race to x speed. That will likely be the reason for the quicker times. And as others have said, for the zt to not be reaching its stated times there is probably a vis motor dead. And finally, the tourer is heavier so you’d need to have the official specs for that, then compare. The extra weight of the bmw will help traction off the line

Thanks for the quick replies! :)

Thank you :) Seems understandable, as it would also compete with the more expensive sixes (although the predecessor 620ti already had 200hp).

Hm, my guessings too. Do bad VIS motors also affect performance at high revs (say, above 4k)?

Well, it could be, but the 0-100 kph difference is just 0.8 seconds. At 180 kph, the gap has increased to over 6 seconds. I feel, if anything, it should be the opposite. The ZT should perform more equal to a loaded 3 series (coupé, cabrio).

Although one car might not say too much; my 190 tourer weighs in at 1520kg with driver, full tank and no spare wheel mod (bless or blame previous owners). Just 35kg heavier than claimed weight of the saloon.

Yeah, thought of that. At Zeperfs, the ZT seems slower in 3rd, but quicker in 4th and 5th. ZT's top speed is lower too, so I guess it has lower gearing (may check in detail later).

ZT's 0-100 dilemma seems partly caused by the theoretical 2nd gear top speed of 98 kph, meanwhile the 525i hits 101. But the ZT still doesn't catch up on 3rd; that's when it's really getting behind.

Performance appears more equal to the 170hp 520i; also the Rover 75 2.5 will dust it at 180 kph.

Got a theoretical comparison of the ZT-T 2.5, 525i and 525i Touring, making the ZT-T justice as the dragstrip/0-140 kph winner.

Still curious why ZT-T has lower gearing/top speed, yet largely declining performance above 140 kph/80mph, though. Could it be the additional 500rpm needed for peak power?

And if you wish to test your VIS motors you could use the freeware programme Toaf which is very handy, covers most things, and is easy to use, or borrow a simple tester from me. I generally have a few reconditioned "Stocktake" VIS motors here in Gävle, superior to standard ones and sold at cost on an exchange basis.

Regards

Most welcome to say hello on here too ... https://www.facebook.com/groups/1800705170206717

The British horses are smaller ?:getmecoat: