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MG ZR ZS ZT Technical - ZR exhausts

HI
I have test driven a MG ZR 160 (hubbula hubbula), and I am thinking about getting a ZR 105. I was wandering if anyone knew if the ZR105 has the same / similar throaty exhaust note as the ZR160. May I point out that this will not affect my decision as whether to get the car, its just out of curiosity.

Many thanks,
Andy May
Andy May

Andy, the ZR160 has a special exhaust back section that routes exhaust gases around the baffles over a certain RPM point, this adds to the sound of the car, sadly the ZR105 doesn't have this and won't sound the same.

I haven't heard one, so I can't comment on what it actually sounds like.

Steve.
Steve Childs

Thus a question poses itself: will a ZR160 back box fit a ZR105...? :o)

Or any other Rover 200/25 for that matter ;o)
Rob Bell

I think the box should fit the 1.8 engined models, but not to sure about 1.6 and 1.4, I think the pipe o.d. is smaller.

Will phone dealer and find out.
David Harasym

HI.
Thanks for the info, I will have to drive round and go brummm myself.
I doubt the 1.8 back box would work on the smaller engines as to bypass the baffles a certain gas flow-rate would be needed. Due to the 1.4?s smaller capacity this flow rate would be achieved at only higher (higher than the 1.8) revs.. Rover will have to be persuaded to make a similar back box for the smaller engines..
Thanks again,
Andy May
Andy May

The rear box on both the ZR160 and ZT190 has this bypass system that is ECU controlled so there is no real point messing with the exhaust from the 160 as you will achieve similar results by way of te more common route for aftermarket exhausts. There are numerous 200 and 25s running with alternative exhausts such as Janspeed.

The base 105 model is a hoot to drive as the chassis provides all the exitement of the 160 yet the throttle can largely be left planted. It was a very entertaining car to drive on the winding A and B roads round Wales. In some ways the R65 gearbox was more precise than the PG1 of the 160 too.

I will just pose one thought and that is what can you imaging MG Sport will be retaining next year? (Remember the Special Tuning dept at Abingdon???)

Rog
Roger Parker

Andy,

I started work recently for a Rover Dealership ( god help me, one of the reasons was to get to drive the whole range without having to pay for the privilege. How sad.) and I drive a ZR105+ as a company car. It is nowhere near as raucous an exhaust note as the 160, but Rover have made an effort to get the feel and sound of the car well on the way - it's like the little brother to the 160 and certainly feels as if it wants to grow up double quick. I like it.
My personal opinion is that if Rover are aiming at under 25's for insurance, economy with performance, etc, then they've done a bloody good job. I would have liked to have seen the side skirts as standard on them though - they finish the car off and at £200 as optional extras, I don't see why they couldn't build them into the total price.
garry cutress

On the question of back pressure, not sure how much of a problem it would be to fit a 160 back box on a smaller engined cars- unfortunately there are plenty of other restrictions in a mass-produced exhaust manifold that isn't the optimum in terms of design, and there is also a catalyst- so tuning the exhaust to promote exhaust gas extraction is probably not too much of an issue. Rolling road testing would probably be needed to confirm the absence of power loss- I wouldn't expect a power gain!

The internal valving of the 160 back box is probably going to be THE stumbling block in more wide spread application of this clever system- IMO in terms of cost versus other back boxes available on the after-market. But there is an advantage too. Whilst it would be prohibitively expensive to put the valving under electronic control (unless one personally has experience of these kinds of control systems)- I can't think of a reason why one might not have a manual switch: quiet and loud! One would need to look at the control systems of the back box to determine the fesibility of this- but it may/should be possible?
Rob Bell

OK phoned my dealer today, the parts arn't yet out for the zeds so don't know how much the 160 back box is yet.
David Harasym

HI.
Thanks for all of the info. It has been most useful, i have decided to use the sale of my old car to fund an aftermarket exhaust..

Ta and thanks..
Andy
Andy May

You either have a very cheap old car, or want a very expensive new exhaust.
David Harasym

Its the car that's cheap!!
Andy May

I do not know how applicable this is, but many of these 'additions' to alter the exhaust note at certain positions are to 'fudge' the noise tests in the drive past test sequence. I can't recall the start point, but it with the car moving in a particular gear from which point full throttle is applied for the duration of the test.

Now with a test tat does such a limited test in a narrow speed band, then that will equate to a narrowish rev band too. Now having a compliant exhaust which has an internal bypass which comes in at revs that is beyond the test point means you pass the test and still have something of a sporty exhaust.

Now am being too cynical???

Rog
Roger Parker

Roger , alright mate i'm sorry to correct you but the ZT190 does not have an ECU controled valve it is only on the ZR160 core models.
Dave
dave mgf tech

Dave,

Thanks for that.

I read some official information that said the ZR and ZT had the internal valving. I saw the obvious on the ZR, but I couldn't see anything on the ZT exhaust so was left wondering. Another small glitch in the printed info!

Rog
Roger Parker

I love the idea of an exhaust/silencer system that cuts out the baffles over a certain rev point. For the forthcoming V8's they should have dead straigh pipes with 2 cherry bombs that are bypassed at 1500 rpm

ahhhh the music!

N
Neil

This thread was discussed between 01/10/2001 and 22/10/2001

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