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

Some may recal my posting back in October under the same title.

Well profgress has been slow due to lots of toher things geting in the way and all the people that have to be involved not being available at the same times etc.

Anyway I have a prototype system fitted to the car and even though it is yet to be subjected to some back to back rolling road testing, the before and after fitting shows some very interesting and very promising changes.

The main thing is that the mid range has become very much stronger and traction is clearly more of a problem under wide throttle conditions. There is more of a step in power delivery so that a previously minor change at 3000rpm is now quite noticeable, with a further change at 4000 to 5500. Sound levels are unchanged at all throttle openings except full, and even then only at 4000 to 5500rpm is there an increase. Then the increase is a deeper V6 growl of little extra volume.

I did feel fuel consuption was apparently better, but not acording to the first fill after the fit!

Testing is sheduled to occur in the next 2 to 3 weeks but because of the way the systems (standard and ITG) fit swapping between the two takes some time. Therefore the rolling road will have to be free for a day to get all the testing done, which may add another delay. If the promising start is quantified to worthwile results (hopefully up to 10% bonus) then it is reasonable to expect a production version of the kit to be made. This may still take some months before hitting the shelves.

Another change I want to do is a mirror of the 4 cylinder K series. The 4 cyl has two different specs of throttle body with 48 and 52mm throttle sizes. Guess what the same dual approach is also applied to the V6. The ZT190 using a body with a larger throttle size to all other V6 engines. I fancy that a 190 throttle body and an ITG kit will be a superb road conversion and push beyond 190 and perhaps closer to 200PS. We shall see.

Roger Parker

Sounds like you're making good progress, Rog. Please keep us posted - I like the sound of a ZS200!

Steve H

Yes Rog
I remember your post,along long time ago, don't think i had even been baned back then. Love the posts please keep us posted!

I looked at the TB's from both a ZS180 and a ZT 190 today and the physical throttle bodies are the same.....the only discernable difference being the throttle ramp/cam mechanism. The ZT seems to have a much sharper/quicker/steeper throttle action. Both throttle bodies have the same casting number and the throttle butterflies are of the same diameter (approx 55mm)

How will MGR view warranty issues on modified cars? I know other manufacturers will stay well clear of doctored cars!
George Hunt

two words - They won't!!!

Any mods would be frowned upon as such....

Currently, there are no 'approved' mods :-(

Thank you for that info Dave.

I noted that the part numbers were different so needed to verify if there was any difference. I also noted that the original press info lists the power gains coming from an increase in induction pipe diameter from 70 to 80mm plus the 4 degree advance on thbe inlet cam profile.

Interestingly the average fuel consumption in the 600 plus miles since fitting is showing a clear improvement.

Roger Parker

I know this is a bit off-thread, but has anyone yet tried an aftermarket filter on a ZS120? Are improvements similar to those on the F possible?

David 'still toying with the idea of a ZS120' Bainbridge
David Bainbridge

So if engine mods invalidate the warranty, which makes sense. Where is the market place?
George Hunt

My owner has modified my induction system, so before I go in for my first 'dealer service' my owner will put me back into factory spec!!

My owners say there are lots of mods for my cousin, the MGF. ie. exhausts, cat bypass, filters, ignition systems. There is a healthy market for all these goodies!

Have a nice day


Just the attitude I expected Modified.

So when you walk into MY dealership with your damaged engine you expect MGR to pay?
George Hunt

George, out of interest have you ever seen a damaged engine that was definetly caused by adding a performance air filter onto the engine?

Steve Childs


That is not the point. You are altering the production spec of the engine and consequently invalidate your warranty as well as most insurance policies.

It's not a good idea bestowing the virtues of modified engines to MGR!
George Hunt

George, that is exactly the point! You'll find a number of dealerships out here that don't mind little modifications like a cone air filter or similar. Ask them to stick a super charger on it however and they will moan! Of course they insinst on doing the work themselves, but that's only fair - they are then warranting their own work.

btw, you don't invaliate the insurance as long as you tell them.

I for one have never heard of an engine being damaged because a performance air filter was used.

Steve Childs

George, most aftermaket sales companies would not survive if every go faster accessory they sold damaged the engine. Most carry out extensive testing of their products too

In the case of the ZS180 I think I am right is saying that the ecu is 'adaptive' It can work out to some extent what is going on!! The manufatures have also fitted a rev limiter, they know at what revs an engine will be damaged. There is quite a healthy saftey margin! The fitting of an filter on its own would not result in such a power increase as to damage the engine. IMHO.



To add to these points, although not really MGR related. There are a couple of SEAT dealers that do mods such as chips, exhausts and filters to mention a few that offer after market conversion. I didn't take the offer cos they charged way over the top compared to the same conversion using the same products elsewhere.

My chip is covered from the chip company, and they have already sorted a shudder problem I had. The dealer also knows of the chip, and are ok with it as long as you tell them.
This is on a TDi engine, raising power from 110bhp to 154bhp, and torque from 173lb/ft to 230ish.

Neil Turner

Kelvin, Neil

With respect.

Go to MGR tell them you have modified their engine and watch their response. "If there is any doubt there is no doubt"
George Hunt


With respect, also.

I dont think I said that I had modified my car, but I do support anyone who may wish to do so.

It may interest you to know that some of the tinkerings that go on by certain respected enthusiasts actully find their way back to MGR for appraisal.


A minor query, prompted by rumour/urban myth of an insurance company which declined to pay out due to a vehicle modification:

Since the ECU is adaptive, would Testbook show that the ECU was compensating for a high-flow air filter, even if the original filter was fitted at the time of servicing? If your engine were to 'blow up' (for whatever reason) could an MG-R technician use Testbook data to wriggle out of their warranty obligations?

I guess the onus would be on MG-R to prove that the testbook data indicated a performance air filter, and not just a malfunctioning ECU.

Paranoid? Me?


This thread was discussed between 13/02/2002 and 01/03/2002

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