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MG MGF Technical - FAO Rob Bell..........

Didnt want to Hijack the other threads but same(ish) questions if you could help?!.

As I am running out of places to stick shiny bits on my F, the next step is some go-faster mods so..........
If I fit 52mm body, Peformance exhaust,de-cat and induction kit what power gains can I expect(18mpi)?.
Also have you heard of "Falcon" performance exhausts?, and what does the cold air bracket do???.
Another one I was told was to fit trophy injectors is this right?!.

Cheers Rob in advance!.

Oh dear, stop faster, corner faster mods next! :o)

you're probebly expecting 135bhp ish as these are basicly the Mods rover do (they also put in slightly hotter cams)

Trophy injectos are the same as standard as far as I know, and no gain is to be had by changing the injectors unless you can remap the ECU
Will Munns

Thanks Will, I thought the same re-injectors, but was told they are bigger?!.

Hi Mark,

okay - I think I can answer most of those questions pretty directly:

>>If I fit 52mm body, Peformance exhaust,de-cat and induction kit what power gains can I expect(18mpi)?<<

52mm throttle body = 1 bhp (rather disappointing, but the throttle response is sooo much better that it is worth fitting it for this reason alone)

De-cat = 1 bhp - we found that cat bypasses really didn't benefit the performance, although it did increase noise! - see

Induction kit = 5-8 bhp depending on the kit you fit. Best are the enclosed airbox types, although very good results can be had retaining the standard airbox, installing a panel filter and fitting a short pipe from the airbox to the LHS air intake, bypassing all the other resonance boxes etc. A bit more information here:

>> Also have you heard of "Falcon" performance exhausts?, and what does the cold air bracket do??? <<

No direct experience with Falcon exhausts (do you have their URL handy?) - but our exhaust tests showed that even the best systems only gave 5bhp/ 5lb.ft torque. More here:

Cold air bracket - not sure - but perhaps a cold air intake for the standard airbox???

>> Another one I was told was to fit trophy injectors is this right?! <<

Sounds like cobblers I am afraid - the Trophy uses the same injectors as all the other MGFs - and on EURO2001 emission compliant cars, actually use a SMALLER injector (in common with all mgtfs and other MGs that use MEMS3 rather than MEMS1.9). Even if you use a larger fuel injector, over fuelling becomes a problem - and that is something that costs power. Thierry found this with his FSE Power Boost valve:

Mark, what kind of power are you searching for? And what kind of money are you prepared to spend?

In order of the things that I'd do to give a car with somewhere in the 140-150 bhp range:
1. air filter kit. Costs between 80 to 350 quid. Gives 5-8bhp.
2. Decent exhaust system. The old Mike Satur Daytona was best: 300 quid for 5 bhp.
3. 52mm throttle body - only 1 bhp on a standard car, but it's good for later modifications and really improves throttle response. 100 quid from eBay (see Neil's recent thread)
4. A decent 4-2-1 exhaust manifold: 3-400 quid. No independent power figures for the F yet, but should be good for about 5 bhp and a similar torque improvement
5. Cams - either retro fit TF135 cams (you'll also need a distributor drive - MEMS3 doesn't use a distributor) or purchase a pair of Piper cams - either BP270H or BP633. IIRC over 500 notes, but good for 15-20 bhp so long as they're timed correctly (use Vernier Pulleys)

* Beyond the 150 bhp threshold *

To breech the next threshold you'll need cylinder head work - check out Dave Andrews website for more info on this. If you want beyond 160 bhp, then you'll need multiple throttle bodies and a replacement ECU... don't waste your money on much of the above as it'll be junked.

Hope this helps (probably information overload! LOL)
Rob Bell

Thanks Rob.
Not planning on going to far but the induction kit looks like the best place to start!, then the 52mm Throttle body, then the...........................................OH DEAR Where will it all end!!!

Thanks again Rob. :o)

>> OH DEAR Where will it all end!!!

Mate, it never EVER does >:-)

On the plus side it's great fun.

My route was

Induction (K&N 57i)
Daytona exhaust
Throttle Body

This has put me within spitting distance of the 160 mark (VVC). Then I did some handling/braking mods. I have one last handling mod to do, then it's back to perfomance and it'll be the 4-2-1 manifold next. That should see me through the 160 barrier, after that, more braking improvements. So from my experience I'd say you are on the right (dark) path.

>> what does the cold air bracket do???

I would assume that this refers to Tom's superb bracket for K&N cold air pipes. Don't fit a K&N without them!!
Phil Brindley


>>This has put me within spitting distance of the 160 mark (VVC).

Are you going to come along to the Emerald Rolling Road day to find out :-) Feb 19th - see Rob's thread. How about bringing a contingent from the Midlands - nice cross country run to Norfolk!
Dave Livingstone

Still not sure TBH Dave, and nothing has changed since G-Force performance wise. I was hoping to get the 820 airbox mod on but that's not happened yet. Also as Lorna is 'doing' Stoneleigh I think I will have to do the 7am arrival and could probably do without a day over in Norfolk the day before. Not totally ruled it out yet though as I would really like to get over there and join in.
Phil Brindley

Remember that the Emerald RR will be much more accurate on run-down losses and give you a better feel for flywheel figures. Good to get a baseline for future mods ;-)

I'll be doing the Norfolk - Stoneleigh run too, but maybe not for 7 a.m. :-)
Dave Livingstone

Dave, does Emerald have a lambda probe (I think that's what you'll need) and be able to adjust certain valves for optimum performance? ;-)

Paul Nothard

Yes, I think so Paul :-) Quite apart from which it would be nice to hear about the VVC version of the M3D - even if I can only dream about one!
Dave Livingstone


Yes, Emerald do have a wide band Lambda, unfortunately it doesn't fit into the exhaust manifold but a probe up the exhaust tail pipes works almost as well.


This thread was discussed between 10/01/2005 and 11/01/2005

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