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MG ZR ZS ZT Technical - Modified Induction system for ZS 180

Those Elise and MGF owners who have now expereinced the ITG Maxogen induction systems will appreciate the benefits, if not the cost, of such a system.

Now the ZS180 has in my opinion a restrictive air filter system. The standard air filter with the quick release and remove element is a long thin affair, but at it's base is a small bore plastic pipe that connects to a resonator which is behind the front nearside corner of the front panel. A similar system is used on MGF also, and the gains from modification are proven.

I also believe, but have yet to confirm than the ZS180 system is a carryover from the 45V6 Steptronic model rather than a purpose designed system for the MG. Certainly the general layout of the standard 75 seems to be more flow efficient. Indeed some of the ZT190's extra power comes from a larger bore air induction system, and this is from engineers!

Today I have taken the first step with ITG to develop a similar 'Maxogen' system for the ZS180 and subject to successful development and costing out it could easily be made available for everyone. The advantage of the Maxogen for those unfamiliar is to have a high flow completely sealed induction system feeding air at ambient temp, not engine bay temp to the throttle housing.

Additionally the design allows for conditions of positive pressure to be created within the filter housing that can increase airflow further. The average increase seen on the 1.8 K series applications is 9.5% increase at peak, with similar marked increases in the mid range too. Note that sound levels are only slightly above standard, certainly NOT anything like a clamp on cone filter!!

It would be of use to gauge the degree of interest that such a kit would attract - comments please???

Roger Parker

FWIW if I had a ZS180, I'd buy one!
Rob Bell


I've no idea what sort of money you might be talking about - how much is the MGF kit? - but I have to say that the thought of a ZS190 does appeal. Please keep us posted on developments.

Steve H

I dunno, I kind of like the noise from the K&N, but wish it added a bit more umph. I feel Rob's flubbadob (or whatever) mod coming on soon, with a few personal tweaks!

Would ultimately depend on the cost Roger, if its current ITG induction kit cost, forget it - its too expensive for me.

Steve Childs

Top Man

you just keep doing this stuff!

I am waiting for the V8 ZT I fancy it big time!!
when that arrives i am sure Mr Rog will be at them quick as you like


Yes go on Rog!
The thing i like about this is the fact it should be easy to fit. If you don't like it-remove it!
No having to have the engine stripped and rebuilt.

I would be VERY interested in what you could do for the ZR 160.

The ZS180 has some carry overs which does appear to have been done for convenience as the performance is on target for what was wanted. This does seem to leave the door open for the reasonable expectation of worthwile improvement. However in the world of tuning absolutely nothing is guaranteed except that it is easier to lose power than gain it. Hence a start will be made on a the design and build of a prototype system on 2nd November.

The same principles adopted for the MGF 1.8i have seen an average 9 to 9.5% increase in peak power on a standard engine. This difference is just one aspect and at some points the advanatage was as low as 2%, but in another area was as high as 18%. (The area where the standard engine has a mid range torque dip.) This is one change where the paper figures paint a two dimensional picture and the reality in three dimensions is a whole lot more. Naturally I hope that this will be reproduced for the V6, and looking at the ZT190's induction system I am hopeful.

The Trophy 160 engine spec is more difficult to improve upon. Simply because the factory has taken advanatge of the gains that a modified induction system offers and introduced a production version of their own. The system for the 4 cyl cars is already well advanced, without any input from me and should be available in the not too distance future. Testing on a Trophy 160 engine is yet to be done.

The costs are certainly going to be difficult issues, as can be seen from the costs of current ITG Maxogen kits. Oddly it is not the material costs that are the most difficut to control, so glass fibre is not so different from carbon fibre in cost terms.

On the ZT V8's I don't think there is much room for me to play! When the factory are talking about screwing 700plus bhp I don't think my inputs have much chance of competing!!

Roger Parker

I think its great that MG owners are willing to help each other. I came down the M6 the other day and spotted a broken down MGF on the other side of the motorway.

I picked up my stanless steel parts from the polisher and on the way back slowed down to see if i could be any help.

No need, another MGF plus a new blue ZS. I dont see too many BMW drivers doing that for each other!

Rog, does playing with the air filter system invalidate any warranty? On thing I like about MGR is the 3 year warranties, as I am not 100% convinced about total reliablility of the ZS. Anyway, I'm interested as I could do with some more power.

BTW, Nice story about the MGF on the M6. In 3000 miles of motoring in the last 4 weeks, I have not yet seen another ZS...

Alex Rogers


Warranty is an issue that is dealt with directly by the dealers. Experience of MGFs fitted with a variety of different air filters and exhausts has almost without exception shown no problems. However if the issue is one that is exacerbated by the change then this could certainly raiseis other issues.

As an example look at the MGFs with plastic throttle bodies, where overtightening of the aftermarket air filter replacement clamp between air filter connection tube, where it joins the throttle body, leads to distortion and a sticking throttle. Even here many issues have been dealt without problems.

If an engine suffered such wear that it was clear that there was massive amounts of dust inhalation then I would expect problems, however this is one of the main points of such a system and it is designed to pick up air at ambient temp away from debris tracks. In fact the air pick up should be from the same area as the current system. Fortunately UK environment is a low dust one so such a problem is unlikley even without a filter for long periods.

On balance this change, like fitting a different radio or different make of tyre, is unlikely to cause any problem to the warranty. We may even see such mods in MG Rover's MG Motorsport parts lists for other applications.

Roger Parker

This thread was discussed between 18/10/2001 and 21/10/2001

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