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MG ZR ZS ZT Technical - Whats the difference ZT160/190

What are the differences between the ZT160 & 190 as its the same engine.

Is any of the running gear ie brakes differents and how easy would it be to buy the cheaper 160 and have the engine tweaked to 190BHP?
Michael

Well apart from 30bhp, the main difference I would suppose is Insurance clasification.

Mike
ProMGR

not sure how true but i heard the 160 is a detuned 190 and can be chipped to give 190bhp

rob
rob

Apart from the obvious 30ps power difference, the main change is to larger front brakes on the 190. (The 160 takes standard Rover 75 brakes).

Don't know whether the large brakes fit inside the ZT160 wheels or not! They certainly don't fit inside the optional steel spare on the 190. If you have a front wheel puncture, you have to move a rear wheel to the front, and then use the steel spare on the rear...
Dave

Its a good idea not to put a space saver spare on the front anyway.
An AA patrol recommended swopping a rear to the front if you have a front wheel puncture, then fitting the spare on the back last time I had a puncture.
I'd normally have changed the wheel myself, but anyone whoes ever tried getting an alloy wheel off a cast hub will know what a pain it is.
Tony

Same sh*t, different bucket.
Jonesy

Have they started doing performance chips for these cars yet and ifso whats the cost/results
Gary

Leave the chips in the paper with the fish! Chipping MEMS is notoriously difficult and even with replacement externally programmable ECUs the difference in power is less than you would see from a dirty air filter. Feel can be changed and fuel consumption worsened. That covers the 4 cylinder K series. With the 6 cylinder K series the Seimens engine managment control is a new one so I don't yet know of anyone who has looked into it. In any case the answer will be the same as for the 4 cyl K series.

Tinkering is waste of time, effort and money and engine mapping changes are only worth the effort when you have physically altered the volumetric efficiency of the engine. In other words improved the breathing of the engine so it is physically capable of taking in more air in the same time. More air and more oxygen can then make use of more fuel and produce stronger combustion pressures and hence torque, which is turned into power.

Now the differences between the 160 and the 190 spec engines are perhaps not as wide as may at first appear to be the case. Induction and exhaust differences are present to cap the higher rev power production of the 160, remembering the 190 has a modded inlet cam with 4 degrees extra duration. In reality I suspect the 160 will be making a little more than 160 whilst the 190 probably won't be making more than is claimed for it.

Add the 12% longer gearing of the 160 by using the standard 75 final drive, but the add the fact that the 225/45x18 tyres on the ZT range makes that gearing slightly longer still and you can see how to make a car not only go slower but actually make it feel worse than it is. Incidentally the two wheel designs of the ZT are both 7.5x18, Hairpins and Straights.

Rog
Roger Parker

So in pounds£££ terms what do you think the damage would be to change the cam and alter the other little bits to make it 190 spec. My thoughts are the 160 would surfice for now but maybe a year down the line be a bit boring.
Gary

I suggest that around 500 pounds could go quite some way to bridging the gap using external changes only. My experience of the induction system on the ZS180 and comparing it to that of the ZT190, plus the detailed tech info mentioning the changes to get to 190PS, indicates that there is a useful and quite large chunk of power to come from external induction changes.

I have been delayed for various reasons in getting to a rolling road to quantify changes, but if they confirm the seat of the pants feeling then this can certainly be transposed to the 160PS engine. I do actually believe that it may even give a small advantage to the 190 spec as this has to conform to very restrictive noise regs.

One thing to remember though is that the 160 gearing will always make the car noticeably slower and only a boost of some 25% or more in torque will overcome this deficiency.

Rog
Roger Parker

Gary,the V6 head design is very similar to the MGF VVC ports and valves,the obvious gains can be made by reworking the heads and modifying the valves, as proven on the MGF, with the addition of modified cams , induction and exhaust I would suggest over 200BHP would be easily achievable,providing the engine management can cope.
Mike.
mike

This thread was discussed between 10/03/2002 and 17/03/2002

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