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MG MGF Technical - VVC Performance

Got my 2001 VVC with 1,000 miles about 9 months ago & have since covered 18,000 miles. The engine loosened up quite a lot over the first 10,000, but it still doesn't feel as fast as it should. In fact, it seems to accelerate about the same speed as a Vectra 2.2 (over 8 sec to 60 I believe) - judging by the way he was stuck to my rear bumper all the way up to 95 up a motorway slip road...

Anyone got any thoughts on this??


Wait till you get a BMW 330d on your bumper - these have amazing torque and can pull better than anything.

That's what it really comes down to - torque.
The VVC needs to be revved very hard to perform, it's only between 6000 and 7000 rpm that it's really effective - and you won't be at those revs for long.
The Vectra 2.2 has a pretty good spread of useable torque and it's that spread that allows it to stay with you.

Keep it above 6 !


I think you need your MEMS looking at if you don't notice the VVC mechanism kicking in before 6K. And those Vectras can shift, judging by the number that flew past me coming back from Plymouth yesterday.

Ed Clarke

Vectra, BMW fast yes, but are they fun to drive !!!

Boring Saloons/coupe's for reps and managers in suits..

Even the Audi TT doesnt feel as 'alive'

A bit to much comfort for my liking..

I prefer to 'drive' my car and enjoy it (its not just about speed is it !)

So let them pass, and feel good about themselves for a nano second...


Erm, had it nailed to 7,000 in every gear, so the bit about torque doesn't really wash if the VVC really does reach 60 in 7.5ish.

Not concerned about other people passing me as such, just worried that there's something wrong with the car. It does pull through to the redline smoothly enough, but I wouldn't say it takes off exactly...


The 0-60 second time is not important.
The Vectra almost certainly has problems getting off the line, even with traction control - it may well be faster 20-90 than the VVC.
You may well find that your car gets faster and faster till it gets 50k-60K on the clock (Golf GTis were well known for this - and the Vectra was probably well run in)

Why do you think you should out-drag the Vectra ?
The weights aren't so different, the Vectra's got another 400cc and can breathe better in the mid-range.
And torque is everything in this 'game'.

Why not take the car to (eg) Bruntingthorpe and find out what it really does ?

Bear in mind that on real roads so much is down to reaction times and exit speeds from the last corner.

eg. If you're rolling slowly at lights you can almost always beat any car away from them.

I suspect that that's gonna be more of an influence than 10bhp etc.

And most importantly... so what if he beats you down the sliproad onto a motorway!!! Your car is more than capable of whiping his proverbial on any fun twisty bit!! :-)

Paul Nothard

Sorry but you're missing the point. I'm well aware of the points you raise and I know the F is much more fun than your average repmobile.

BUT, if there IS a problem with the engine I want to get it sorted out - firstly so that I can enjoy it and secondly while it's still in warranty!!!

I would also note that the Vectra isn't the only car that's caused me to speculate. I drive the F fairly hard and there have been various other cars which are not exactly noted for their performance which certainly have not been far off...

Hence my concerns about the health of my engine!!


I do understand your point - and have noticed the same with my VVC - which I don't think is faulty; the latest one to surprise me was a BMW mini cooper (S?)
All you can do is test the engine in your car and make sure it's giving its best.
To be honest, I never expected the VVC to be a great performer, but it is adequate.


Cooper S 1600cc supercharged - 163bhp, 0-60 in 7 seconds.
You were surprised why exactly?

OK Steve, fair enough. Must admit though that I expected the VVC mechanism to give a better top end than it does. Guess the only answer is to query it with the local MG dealer - don't hold out much hope there though...



Chris - I sympathise with your point, I too often feel that my VVC does not perform as well on the road in comparison with other cars as the stats would suggest. I sometimes feel that I am struggling to keep pace with 1.6 family hatches, let alone some of the more powerful cars mentioned above.

I suspect like me you are questioning whether the engine is under-performing as spec'd, whilst not kidding yourself that you've bought a cheap TVR!

If you do pursue it with your dealer, please post the results (either way) as I was wondering whether to get mine looked at as well - it's a 97 with 34K, so should be well run-in by now.

... but the induction noise is sweeeeet with the K&N
Andy Gilhooley

I am not sure about this. The F is the first and only sports car I have ever had and I am far too old to be a boy racer. I have however had quarter of a century of company cars running through a Marina, Capris, Cortinas, Cavalier, Carltons and Rovers 800s. I also had access to many others by being nice to the people that ran the fleet.

I now have a 2.5 litre 75 Estate for rainy days.

I can say that the F is far and away the most lively of the lot. On the motorway it is perhaps less rewarding as so many cars can bomb along at 80-120 but in traffic and twisty roads their are not too many that can keep up.

My son thought the F was a bit of a tart's car until I took him out and completely wasted some boy racer in his Golf. He has now also got an F and does delight in the performance advantage over most of the tat on the road!

If you are struggling to keep up with 1600s then something is wrong! Only if it is over 2.5 litres do I have to struggle - and remember the my other car is a 2.5!

How about getting together with some other F drivers for a comparison or go on one the the track days to learn how to get the most out of the car.


Patrick Beet

>>Cooper S 1600cc supercharged - 163bhp, 0-60 in 7 seconds.
You were surprised why exactly?<<
I can't tell one mini from another - I just assumed it was the Cooper S (and I gave up at the speed limit)
As Paul said earlier, the driver makes a big difference.


As a point of interest at what RPM should the VVC kick in, and what does the oil temp need to be for it to kick in at all?

The VVC mechanism is variable, so doesn't neccesarily 'kick in'. That said, it certainly feels like it does - that may be down to the mapping of the process. Somewhere around 3.5 - 4K seems to be the point at which you really notice it, at least in my 96 car. Though I've never seen any real technical dtails of this - someone must have the info somewhere. Dieter?

My F will vary happily sit at 100mph for hours - obviously only where leal, officer - in fact it always seems better for the blast.

Ed Clarke


Fair point about your wanting to check what it's capable of.

If the car is feeling a bit lackluster then I'd suggest that you either:
- compare it with a friends VVC (eg. go to a natter)
- take it to a dealer and plug in the testbook.

The reason I suggest the latter is that the VVC mechanism will not fully kick in if there are perceived "problems" with the engine.
Specifically my VVC was feeling a bit slow and it turned out to be that the oil temperature sensor (there are two!!) was faulty.
The MEMS unit thought that the oil was always cold and stopped the VVC from kicking in.

As an aside... the Cooper S will always be very slow off the lights as it has a very long first gear. Once it gets going it will fly and will put up a serious fight against a well prepared 'F !!


ps. If you were in Germany you could test the top speed. Nailed the car should do 130mph easily. Usually more. That'll tell if you've got less power at the top end.
Paul Nothard

VVC Performance...hmmm.

I've had my VVC for 2 years now, and only now after, suspension mods, splitter, K&N etc am i starting to push it properly.

I've found the performance can vary greatly from day to day, however certain trends are appearing.

Some days it just feels slow to pick up, and even taking it up to the redline, doesn't seem to have the va va voom that it usually/can have.

Thought about various things, atmospheric pressure, humidity, climate, ley lines, what day of the week it is, but no trends.

However, I have found that a good thrashing, redlining a few times, and it comes alive again. Don't think its because the engine is now warm, as I only seem to have to thrash it a couple of times to "loosen" it up.
And also, without thrashing it, warm engine it can appear sluggish.

Another problem that i think may be associated, is occasionally (but only occasionally) i'll stop at lights and my revs won't drop. ie sat at lights, and you are idling at 2.5k revs.


Well I personally think it is most likely to be a sticky throttle body. maybe if it wasn't opening properly (in the case of sluggish-ness) and wasn't closing properly (in case of high rev idle).

Would this cause the symptoms i have?

I guess a nice new trophy alloy throttle body would sort me out?

Thoughts that it might not be the throttle body, is the fact that i still can redline it when sluggish, it just take a wee while longer to get up there.

Oh well, over to the techies, any ideas??


paul weatherill

Very interesteing points. How does one tell if the valve gear is operating on a VVC? Certainly our one does not have any noticable threshold when you know it is operating, unlike a Honda VVT. Can a dealer tell, ie: is there a printout detailing it's operation?
On the subject of Cooper "S" Vs VVC, a supercharged (or turbocharged) car is very likely to be faster due to the much greater torque available. The BHP figures do not tell the story.
T Green

If the throttle is not opening fully, then I don't think the pedal will go to the floor (assuming that it's adjusted OK - seems likely if this is just an occasional fault) - is there anything - carpet/mats - that could stop the pedal going to its limit ?

The failure to close the throttle fully could be a throttle body - can you move the butterfly by hand ?

I know what you mean by the performance variance.
Mine certainly benefits from a good thrash - especially when no-one can be bothered to drive it for more than a week (as is currently the case). I must try to use it before going to Kemble !


You could test if the trottle was opening fully by getting a friend to push the pedal to the floor and then seeing if you can turn the throttle from the boot any further (although I think this might turn out to be a red herring).
Will Munns

Thanks all,

Can't help but suspect that the VVC mechanism isn't operating properly - and can understand the points made that sometimes it seems quicker than others.

Looks like an appointment with the testbook, when I can afford to get near the dealer. Unfortunately, I've got a few financial comittments for the next couple of months (for wedding using wedding cars tonbridge, read skint), so it'll have to wait...

Will let you know of the outcome (of the testbook, not the wedding!!).



Re: revs sticking at 2.5k...
Almost certainly a sticky throttle...


If the revs are slow to die and/or they stick at around 1.3k then it is often the water temp sensor that is at fault.

If the either the water temp or the oil temp sensors are giving wrong results (may be 'wrong' as opposed to 'broken') then performance will be generally reduced.

Finally, these sort of problems can be caused by a faulty throttle position sensor too!

Cool! A choice of fixes! :o)

Either way, I strongly recommend that you use all this as an excuse to get the replacement throttle body anyway!!! <grin>

Paul Nothard

Thanks for help guys.

Pretty sure the accelerator pedal -> throttle ok.
not sure if the butterfly is opening completely,
will have to remove air filter, and find someone with a small head to fit in the engine bay, and have a look.

water temp/oil temp.
think these are ok, well if the cabin dials are anything to go by.

recently done an oil change (or rather paid ATS a 5 to do an oil change) and the average temp has crept up from 90 to about 110.

Faulty throttle position sensor, or maybe just dirty???
ok where is it? how do i clean it?

<grin> replacement throttle body </grin>
Paul, i think you're exactly right.
paul weatherill

Take the filter off the throttle body and check for 'gunk' impending the butterfly from closing.
That's most likely the cause... or the overtightened clip holding the tube on.
This is by far the most likely cause of your throttle problem Paul.
Both excuses to get another throttle body!!! :o)

(I suspect that Chris' is still a sensor problem)

Cabin dials are fed by a differemt sensor in both cases I believe. Easy test it to check with a voltmeter and a kettle - if possible... or to simply bung it on the testbook at the dealers.

Not sure about the increased oil temperature.
Others will know more about this than I.
Mine hit's 150 on every track day I go to and oft hits 110 during road use.

The TPS is at the far side of the throttle body. The other end of the shaft from the throttle cable.
I've had both a faulty sensor and a faulty cable/connector block. Had me flummoxed for weeks!

Paul Nothard

My F is VVC '96 with 67k on the clock, no mods. Very sweet and lively - if only for a better gear change.

The on ramp test for me is always 70 in second before changing into 3rd. Best sound and the best kick in the behind going.

More revs the better, between 4.5 to 6 .5 - though since going through a head gakset, 6k is more than adequate for UK speed limits.

I would be concerned about anything except a caterham or an elise riding your bumper on the on ramp - though it looks like i need to look out for that cooper s!

>>... is always 70 in second..<<
this equates to about 8300 RPM for a standard VVC.

There are many cars that can equal or better the VVCs performance especially above 30 MPH; however most british drivers appear to be frightened of using anything above 3000 RPM.

I agree that 6K is more than adequate for UK speed limits !


Just wanted to add my 1 years experience with a 2000 VVC which I drove everyday some 40km to work and back.

The car I had at the end of the year was very different to the one from brand new (DOH!).

I found that I could rev the car from standing to the limiter in 1st gear! Obviously I didn't do this too often but there were no cars that could evem match this. A couple of Audi S3 and various big engined BMW coupes endless golf variations and more maxed out other cars were more than surprised.

I had a K&N induction kit fitted and found that if you kept the revs between 5000rpm and 7000rpm thats where the real stonking performance was to be found.

I agree with another comment here that the VVC definetly had good and bad performance days. In the summer I tended to find the car a bit sluggish, but on cooler and colder days the car would performance much better.

But I also agree that at the end of the day its down to the driver. Thats why I am waiting for the loverly Swiss authorities to send me my months driving ban for speeding!

>>>good and bad performance days

Ideal MGF weather is dry, sunny and cold!
David Bainbridge

Chris, sorry missed this thread somehow...

>>The engine loosened up quite a lot over the first 10,000, but it still doesn't feel as fast as it should.<<

Two things to consider - first, the engine is still running in, and will feel faster still @ 20,000 miles! Second - check out the malifold alignment thread.

The VVC cast alloy inlet plenun, it appears, is subject to a surprisingly wide tolerance, to the extent that the throttle body may not align properly with it (causing a step and a restriction to air flow) and as Mike as just reported, between the plenum and the inlet ports on the cylinder head.

These problems can be sorted out. The first is an easy DIY inspection - remove the airfilter tube from the car and use a mirror to peer into the throttle body - open the throttle, and the next thing you should see is the inside of the plenum. You should not be able to see the casting face.

Is your car still covered by warranty? I suggest you get chummy with your MG technician, and see if they can arrange a swap for your plenum with one that better suits the TB and cylinder head ports.

If not, then drop Mike Satur a line.

Hope this helps!
Rob Bell

Rob,<between the plenum and the inlet ports on the cylinder head.>
Slight correction ,between the inlet manifold and the mating face of the head caused by material not milled from the face correctly ,the effect is to cause misalignment of the retaining studs and obviously then the ports. Hope that is a little clearer?

This thread was discussed between 14/08/2002 and 20/08/2002

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