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MG MGF Technical - Power Increase

Sometime ago someone listed the logical steps to increase the BHP relating to how much power increase the car would achieve and how much it would cost to do. Can anyone offer a recap?

The first step would be a K&N. An increase of 8 BHP on 1.8i and 15 BHP on the VVC. So what comes next?
Dave

I think I've mentioned something like this before Dave (worth checking the archives for the whole thread)> Basically it goes something like this- as a law of diminishing returns:

1. air filter. K&N is a good value item to a good bhp/£ ratio.
2. Upgrade the Throttle body- apparently PTP are the cheapest source of these (not sure how much power they release, but I'd predict 5+ bhp on the basis of what people are saying)
3. Exahust. Up to 5 bhp (Mike Satur's system represents best value for money on the bhp/£ scale.
4. Exhaust manifold. The standard item is extremely inefficient- best to replace with a decent 4-2-1 item (EBD seem to produce the best made and best performing manifold- although I'd recommend that you replace the cat with a flexi-tube for installation on the MGF) Cost 400 quid- power 5 ish bhp and a decent amount more of mid-range torque.
5. Fast road cam suitable for use with the hydraulic tappets- one of the best is the Piper 270 cams. About 300 notes? Plus fitting. May give useful power gains- especially at the top-end

That's it for bolt-on goodies that increase power. You might also consider a 'Power boost valve'- that increases the fuel line pressure. No extra power, but better throttle response, albeit with worse fuel economy).

This is also the threshold in terms of cost too- everything beyond this point starts to cost into 4-figures:

6. Gas flowed cylinder head- particularly worth while on 1.8i heads that have relatively small valves as standard. A decent high flow big valve head will equal much more power. You will definitely need a re-mapped ECU for many thing more than this...
7. Multiple throttle bodies (Luminition etc etc)
8. High lift cams, with solid lifters to replace the hydraulic tappets.
9. For high speed engine applications, get the bottom rebuilt and the crankshaft attended to!

An alternative to the high-engine speed approach (and similar power- 220+ bhp) you could go down the Turbo Techniques Supercharger route- if you are getting others to do the work for you, you could find the supercharger cost-effective, despite the 5.5k RRP!

Only a summary, not meant to be detailed, but hopefully provides a flavour of what can be done and for how much.
Rob Bell

I thought that someone (Dieter?) had commented that the standard exhaust was not a restriction on BHP up to about 150 BHP.

Or did I miss understand?
Stephen Ratledge

The catalyst is not a restriction to power output with a standard exhaust manifold (which is probably the most restrictive part of the exhaust system)
Rob Bell

oops, hit the carriage return by mistake.

As I was saying,


The catalyst is not a restriction to power output with a standard exhaust manifold (which is probably the most restrictive part of the exhaust system). We did not see any advantage in fitting a sports catalyst or fitting a bypass tube on either the 1.8i or the VVC we were testing at the time- suggesting that the standard catalyst represents no significant restriction to exhaust gas flow until power outputs significantly greater than 150 bhp (probably 170 is the limit, but without doing the tests, one cannot be sure).

The matter is slightly complicated by the condition of the catalyst- if in poor condition, it will generate significantly greater restriction to gas flow. Therefore removal will result in a far greater gain than we saw. Which makes the point- ensure that your catalyst is in good condition!
Rob Bell

That's a very intresting list. I'm looking into the various avenues but it's a sure pocket burner once past the first couple of stages.

Has anyone here fitted a Turbo or done any high end performance mods?
Dave

Given that a supercharger is around the £6000.00 mark and 'only' produces around 200 bhp. QED do a full race kit for £5295.00 which is claimed to put out a hefty 220 bhp. I would imagine that this sort of set up would be nigh on impossable to drive on a daily basis, but it is interesting to get the comparison.

SF
Scarlet Fever

Here is a very useful link that takes you through the power increase set up from the boys at moto-build.

http://www.moto-build.com/mgf-tuning.html

Matt

Thanks Rob, to have it all listed so clear. Wouldn't it be recommended to have a reprogrammable ECU fitted before touching the cams (point 5 of your list)?

To make it all more complete, I'll add Brodie Brittain Racing (BBR) to the list. Just like Moto-build, they do several kits to upgrade the performance of the F. They also do some (Garett) turbo conversions; up to a massive 300bhp. (http://www.bbrgti.demon.co.uk)

Or have a look at a page on my site (http://mgf.rulezz.com , Tuning, Engine: upgrade) to have it all listed on one page.

cheers;
Erik

with you on the changed ECU term, ... but moto-build ??
Not sure whether they are OEM though ;)

Dieter
Dieter Koennecke

YO Dieter!
I won Twat of the year award!
Almost as good as shoting down a 109!
Thanks for your help
Mega.
Ps
Are you going to get a TF or spend the rest of your life f*cking around with that sh*t heap! :)
Mega

Hi Erik,

good question regarding ECU + cams. The best thing to do at the point of fitting new cams probably would be to re-map the ECU to match fuelling and ignition maps the new cam profile- but with the Piper 270 road cams, this does not appear to be essential- the MEMS seems well able to cope with the cams in *isolation* or in conjunction with a cone air filter.

Ultimately, the decision will be coloured by what other mods have been performed to the car.
The point at which a new ECU does become essential is when you've got the engine 'breathing' with alternative intake systems, ported and flowed head and new cams.
Rob Bell

Don't forget NOS, £500 - up to 200BHP extra :D
Kingsley

Kingsley,
If you spend all weekend polishing the car, does the air flow quicker over it?
How many BHP can you gain in real world situations ;-)

Will
Will Munns

The other approach is to increase the percieved BHP. No engine mods, but you feel that you can go faster. Easy to do - get some decent tyres on! SO-3s are still the leaders I believe.....

N837 OGF
Hugh

Yep - it cuts through the air like a hot knife through butter (well better than that i hope)
realisticly gains are limited to 25-50 BHP before major mechanical work must be undertaken.

hmm, a christmass present idea for me

must stop wathcing fast and furious
Kingsley

Kingsley, personally I wouldn't go near the K Series with NOS. Sure, on a V6/V8 lump that is a bit stronger, but the K series is prone to problems on older cars as it is, add nos and you won't break your head gasket, you'll vaporise the poor thing! ;)

Steve.
Steve Childs

25 bhp just from Autoglym?
I must say that the car runs a lot 'cooler' when it is gleaming

Will
Will Munns

25-50 BHP from the NOS! :)
I reckon about 1-2 from the autoglym super resin, or 3-5 from super gloss :D
Kingsley

Dave - you don't say which engine you have at present? If it's a 1.8i, I have a complete race-prepared 1.8i engine for sale (MGF Trophy race car being upgraded to VVC for this year's championship). This engine is c.145 BHP and can be tried in the car before buying. If this is of interest, drop me an email at the above address.
Richard J.

Before you start tuning - make sure that the standard car is performing as well as it's able to.
It should be fully run-in.
Get it on a rolling road and make sure that it's producing the quoted torque over the whole rev-range - and then make sure that it's properly maintained.
None of this will impact your insurance (unless you blueprint).

Look at the engine speeds you use when you drive, and then tune for these engine speeds. What's the point of an extra 20BHP at 7000 rpm, when you drive at 4000 rpm?

Steve
Steve

This thread was discussed between 22/02/2002 and 28/02/2002

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.