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MG MGF Technical - Performance upgrades

Oh dear. I feel the darkside calling me.

I've just purchased second hand for an extremely reasonable price the following items:
Mongoose stainless steel quad axhaust
K&N induction kit
Cat bypass tube
Superchips Icon Race chip

The K&N and exhaust I'll definitely fit, however I'm undecided on the Icon Race chip and the Cat Bypass tube. My car is just over a year old (22K miles though) and I'm not sure that invalidating the warranty by fitting the chip kit is worth it. I've spoken to the dealer about the air filter and that isn't a problem as long as I don't knacker anything when I fit it.

Has anyone out there got any advice about this chip mod? Is the 6bhp gain that superchips advertise worth it? Cat bypass worth it? I'm not due for an MOT for nearly two years.

By the way, if you're wondering why I've bought something that I may not fit - I'm not mad, the exhaust and filter alone was worth the money I paid.

Any advice would be much appreciated.



If you fit the cat bypass pipe, then you'll need to re-attach a cat before your first MOT. As your car is only a year old this might not disuade you, just thought it worth mentioning.


You can only fit a bypass pipe up to late 2000MY cars, believe there is an extra sensor fitted to later cars.
Apparently power gains of only +/- 1bhp can be achieved anyway.
MS sells two types of exhaust, upto 2000 and 2000 onwards, not sure what the diffenrence is but you should check you have the right one!
If you have a TF I would reconsider fitting the K&N as you may accually loose power (standard system is pretty good) would make a nice sound though.
S White

My MG is a Y plate F, so I know that the air filter is definitely worth fitting. As for the exhaust, I don't know about compatibility yet and I won't for a few weeks as I'm going abroad with work and the kit got sent to my brother in laws. I'm hoping it'll be OK.

I'm not too bothered about the CAT bypass tube, but I may take the opportunity to change the studs on the CAT before they get too rotten when I fit the exhaust.

Anyone out there have a Superchips Icon race chip fitted?

Chat to Tim - he seems pretty happy with his. A very important thing to note however is that it is essential to get the ICON set up correctly on a Rolling Road after fitting.

The car will run even if you do not do this, but there is a very high risk of engine damage if you don't (look at Dirk's experiences on this site's archives).

I agree, the K&N is well worth fitting (make sure that you have the cool air ducts with the kit - if not, buy a pair - they are essential if you want the power, failure to fit them will result in LESS power than before).

The Mongoose exhaust is a nice looking system (we tried to get a system for our RR comparison, but sadly failed). Chances are that it is for a pre-2001 car. A section of pipe will need to be cut off to fit and a new flange welded on - a fiddly job!

The cat bypass I personally wouldn't bother with - for the reasons mentioned by Stephen above.
Rob Bell


Depending on whether you want to come down to South London you can certainly have a go in my car to see what the chip does. If you leaveit until you have your filter and exhaust fitted you'll get a pretty good idea, of before and after. Mind you, bear in mind I have an MPi not a VVC.

Drop me an email if you're interested.

tim woolcott

2001MY cars, which this could well be unless it was old stock when registered, will feature the new MEMS 3 spec engine managment that incorporates the twin lambda sensors, pre and post cat. This makes fitting of the pre 2001MY style exhaust impossible without interesting cutting and welding of the exhaust incorporating the flange which provides attachemnet to the cat discharge pipe.

The cat bypass is also a non starter for the same reason, and I would have to ask why as only noise is guaranteed to change. Power can be lost as well as gained with the cat removal, even then the difference is perhaps 2 bhp - not worth getting dirty for. Only if the cat has a basic problem will there be any additional gains and this is easily tested with a specific pressure gauge that fits into the boss in the manifold once the lambda is removed. This on it's own is a major issue as many a lambda is completely ruined as the thread breaks up on both the sensor and the boss, that is if you can actually move it!! (Often the reason that a new exhaust manifold is needed when the lambda is identified as being faulty.) It is possible that some greater changes may be seen with a specifically mapped ICON, however like the stock market the torque and power graphs achieved may gain in some areas and lose in others. Tuning is far from the simple game some would make out.

Roger Parker

Thanks for the info guys. The offer of a drive in your MG is very generous Tim and I may well take you up on it, but I'm going to be out of the country for 3 weeks or so, so it won't be in the near future.

Sounds like the exhaust could be a real pain as my car was straight off the production line (I had to wait long enough for it), so I imagine I have the twin lambda sensors.

I'm not bothered about the bypass pipe. It wasn't advertised as part of the deal. The guy just threw it in!

Hi There

I have a 97 VVC with 52mm throttle body, Motobuild performance exhaust, Piper cross viper cold air box filter and Superchip fitted in mine..

If you want to compare VVC's directly, you are welcome
to testdrive mine, I'll even meet you halfway if you like...


Can I test drive too? If you can just meet me... halfway.

Sorry studying for exams, going nuts.

I had Icon as well, but took it off. Did you get a dyno tune for that?
Hanah Kim

I didn't know you had an ICON.
What it is like on the VVC...?
Do you have the Rolling Road graph for the calibration....?

Hanah, I was thinking of driving down to Bombay next month if you're interested :o)

tim woolcott

Stu mentioned that his ICON was installed by Motorbuild. They don't have RR facilities in Hounslow.

Have you had your ICON RR tuned Stu? If not, I would really really recommend that you should. As Tim showed us with his power graphs, there are additional gains to be had, not to mention the engine safety aspects.
Rob Bell

Stu, Tim, Jodi,

Check out the M3D with VVC thread. Interested?


Guys, I don't have a VVC it's your bog standard 1.8 MPi. Sorry if I gave the wrong impression!


You have email. Hopefully, all will become clear. Check out the M3D with VVC thread anyway and you'll see what I mean.


Roger wrote...

>> This makes fitting of the pre 2001MY style exhaust impossible without interesting cutting and welding of the exhaust incorporating the flange which provides attachemnet to the cat discharge pipe. <<

True, but Mike Satur does an 'adapter pipe' which enables pre-MY2K rear silencers to be fitted to a post-MY2K car. You do need to tell him that your F is post-MY2K though as he will need to supply one with the hole for the additional sensor in it.

I have had an ICON for around 5 years now, but after hearing of Dirk's disasters, i decided not to fit it. To this day it languishes on a worktop gathering dust. Tim has had some good experiences with his though, and it appears that providing it is set up correctly it should be OK. I cannot stress this enough though, Dirk's ICON was implicated in his total engine meltdown a few years ago (scared the hell out of me, hence no fitment!) If you do go ahead, discuss it with Tim as he knows the pitfalls and can advise you on how to get it set up properly.

K+N 57i? Go for it! :-)

Cat bypass? 2 benefits, it prolongs the life of your catalyst and it roughly doubles the volume of the exhaust! :-) If it is possible to fit it to your F, then i recommend it. However, if your F does turn out to be MEMS3 spec, then it is not possible.

Welcome to the Dark Side! :-)


So as it stands my situation is:

I have a Y-plate July 2001 MGF 1.8 MPi which will undoubtedly be MEMS3 spec.

I have a lovely mongoose exhaust that currently won't fit. Damn!

But Mike Satur to the rescue with an adapter pipe that saves me having to cut and weld? Am I right?

If not :(

If so :)

K&N will fit :)

Cat bypass won't fit, but not bothered.

ICON chip, sounds scary :/

Better get in touch with Mike. Having already fitted his Boxer Hoops and windstop I have no doubts that any conversion pipe will work wonders.

Thanks for the info SF.


Mike's adapter pipe will only allow a post MY2001 exhaust to a Mk1 car - sadly not the other way round. :o(

Still worth a chat with him though. His Daytona exhaust is superb - and he may be able to find a buyer for you for the Mongoose ;o)
Rob Bell

Sorry to hear your exhaust won't fit - I was interested in buying it too, but the price went up too high for me.
You could always try re-advertising the exhaust back on ebay (with a reserve price) and see what interest you get.
Jason H
Jason H

Jodi, I saw the items on ebay.. you certainly got a for for your money : )

JasonH I agree the price he was quoting for the parts on ebay was high. You should have contacted him, he offered me the lot for 150.

Hmmm, I think Rob may be right. :-(

MY2K Fs and later have a catalyst with a 90 degree bend on the end, this means the bend on the intake pipe on the MY2K rear silencer box has been reduced by 90 degrees to compensate.

Pre-MY2K rear silencers have a longer, full 180 degree bend on this pipe making fitment to a MY2K catalyst impossable as a cat (with sensor) is necessary on a MY2K F.

Mike has adapted his exhaust system in line with the MY2K design and he supplies a 90 degree adapter pipe to enable fitment to earlier cars. Rob is right in this regard, it doesn't work the other way around. :-(

This leaves only 2 remaining options:

Heavily modify the rear silencer intake pipe. This involves sutting 90 degrees off of the length and re-welding the connection flange.


You could drill a hole in the 90 degree bend of the rear silencer for the exhaust sensor and use a pre-MY2K catalyst (would need to buy one).

The latter is the easiest, but could be a bit expensive (catalysts aren't cheap). The former is a lot more tricky. Hobson's choice IMO. :-(

Sorry for the false hope Jodi, an error on my part.


Don't let Jodi hear that - he paid double that!
Jason H
Jason H

How's about removing the cat completely and using the CAT bypass pipe with the exhaust does that combo fit a 2001 car or has the whole exhaust system from manifold back changed on a 2001 machine?

Ian 150? Did you not think that was a snip for a near pristine mongoose exhaust retail 375 a K&N induction kit (also pristine) 89, cat bypass tube a few quid ICON chip 165 and fuel pressure boost valve ? In total well in excess of 630!! To be honest I still think I got a bargain at 350 even if I do have to do a cut and weld job.

He offered me the exhaust for 150 and would chuck in the other bits, which on their oen arent worth much.

To be honest I didnt want the chip or the boost valve, its a lot a money for not a lot of marginal power. I looked at the extra power you get from the exhaust and its not a lot.

Jodi, I get offered loads of mod parts like this all the time, from salvage yards and when vehicles are returned from finance agreements and the parts have to removed for resale.

When you buy secondhand, things are not worth anywhere near their retail value, since this price includes packaging marketing costs .....


Yes, that will fit, but the engine management system (MEMS) on the MY2K cars is the third version (MEMS3) and this has a sensor to detect the presence of a catalyst. The later model cats have the 90 degree bend in the exit pipe to accomodate the sensor.


You're right Ian. In the second hand market something is only worth what someone is willing to pay for it. I'm still happy that I've saved myself a lot of money over what I would have had to pay retail.

SF, what does the engine management system do if it doesn't sense the presence of the CAT?

I have a contact who does stainless steel welding anyway so I think I'll end up doing the cut and weld option. It's not top of the priority list any how at the moment. The filter will go on first :)


>>what does the engine management system do if it doesn't sense the presence of the CAT?<<

The engine warning lamp lights up, and the MEMS switches the fuel/ignition map to 'safety.' If you had a VVC (and I note that you don't), then the extra cam profile would also be locked out...

Basically, don't do it.

If there is a way around this 'problem,' the Lotus Elise boys are the chaps to ask!
Rob Bell

... and to add to what Rob has said, I have had some feedback from those with access to all of the current range and a budget to explore!!! Essentially even if you were to replace the cat with a sportrs cat on the 2001MY on cars you still have the engine managment detecting what it considers a cat fault and doing exactly what Rob has described. So there is no room down that road, at least until someone comes up with a solution. I have one, but is would be very expensive and really not worth the effort for the gains.

Roger Parker

Thanks for all the info guys. Me and my brother in law will modify the exhaust. He has a contact who welds stainless steel so it hopefully shouldn't be too much of a pain.

Looking forward to the sound of my K&N and exhaust :)


This thread was discussed between 15/10/2002 and 22/10/2002

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