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Discussion Starter #1
Because the R75 and ZS180 both put out 177bhp I always assumed it was the same engine running the same map, but I'm not so sure anymore.

I've only drive a R75 KV6 once, and can't really remember what the power delivery was like.

If anyone's driven both, how different are they?


Also, has anyone with a ZS got the ZT190 map applied? What difference does it make?
 

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I drive a 2.5 75 tourer and my wife's ZS 180 as well.To say that they are like chalk and cheese would be a good description.

The 75 is a relatively laid back car unless provoked, wheras the ZS is totally alive and alert. The power delivery is there without any effort and the whole car feels alive in your hands.

You would not think it was the same engine!! The throttle response is much sharper and there is real pull at all engine speeds in the ZS - the 75 is really lazy until you reach 3000 revs or so.

Also the gearing is different - the engine is spinning at higher revs per mph in the ZS and the gear ratios are much closer (different ratios compared to other ZS's as well).

I don't know about the engine mapping, but remember that the 190 has some additional mods, including bearings I believe.

Go and drive a ZS 180 - you'll be carrying a broad grin for at least a week afterwards!!
 

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I thought the 75 had the 160ps version of the V6, not sure of the differences are only with the map, the ZS180/ZT190 might also have different profile cams to the 75.

Steve
 

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Discussion Starter #4
Steve B said:
I thought the 75 had the 160ps version of the V6, not sure of the differences are only with the map, the ZS180/ZT190 might also have different profile cams to the 75.

Steve
No, the 75 has always had the 177bhp engine. The 160ps version was new to the ZT!

I don't think the engines have different cam profiles, the 180 and 190 certainly don't because a chap in Total MG who put a ZS180 engine in his MGF got the 190 map applied to it. However I think in the ZT190 the air intake was optimised.
 

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The map between the ZS and the ZT is different, hence the different output, cams will be the same in these two models, not sure about the 75 though.

Steve
 

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Your probably right John, just what I heard some time ago, I am not sure to be honest. It can only be the mapping then.

Steve
 

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Changing the subject slightly, does anyone know what is involved in changing the 177bhp 75 engine to the 187bhp ZT engine? I'd love a few extra horses!
 

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Discussion Starter #10
boxwellm said:
Changing the subject slightly, does anyone know what is involved in changing the 177bhp 75 engine to the 187bhp ZT engine? I'd love a few extra horses!
That in effect is what I was asking above. It's definitely possible, you need to find a very agreeable dealer though as I don't think it's something MGR would be very happy about.

As you've got the R75, you'd probably need to look into getting the ZT airbox fitted as I believe this is optimised - it certainly is over the 160ps KV6 in the ZT. Phew this is getting confusing!!
 

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There is going to be a big difference in the way that a ZS180 drives over a 2.5 litre Rover 75 - and a lot of that is going to be down to weight and gearbox, both of which are substantially different between the two cars...

Putting that aside though, yes, I gather that the difference between the '180' engine and the '190' is all in the induction and the ECU map.

Big further gains can be had with cams and a decent exhaust manifold - the design of the latter in particular is poor as standard. Not sure as to the options available at present? I seem to recall that a couple of specialists were working on suitable designs?
 

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Major Ingram said:
Camshafts are the same, it has to be down to intake and ECU mods.....
It's down to the mapping and nothing more.

If you want a few extra horses and you're out of warranty get a serial download done, should take you to about 200BHP.
 
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