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MG MGF Technical - How many bhp?

If I were to fit a K&N replacement panel filter, a trophy throttle body and a trophy exhaust system approximately what gain would I get in bhp etc.

The K&N panel doesn't give you much power - the cones do much better, especially if you enclose them and give them a good cold air supply. A K&N 57i will give about 8bhp on a 1.8i and 15 on a VVC

Improved exhaust is probably ~5bhp

Throttle body: I don't believe this gives much power, just improves the torque curve somewhat.

All in all, you should be able to get around 160bhp at the flywheel from a VVC, maybe a little more (with a K&N cone).


what about on a 1.8i would about 12bhp be realistic?

To give you an idea.

I have an MPi with:
Trophy TB
Mike Satur exhaust
ICON chip.

The rolling road indicated 138BHP at the flywheel(est).
so take off say 8% for the chip. You may expect in the region of 128BHP if you had a cone filter. Bit of a guess though. I will defer to others..

tim woolcott

I reckon ICON is giving you around 3HP.
I had ICON chip on and off my car, didn't feel much difference.

your car:
K&N = 8hp
TB = 4-5hp (quote Roger Parker)
MS Exh = 5hp

Mpi = 118hp
so add all those = 135hp.
ICON add another 3 = 138hp.

Martin if you add all those (well CONE filter 57i kit) + other goodies -> you will see a definate improvement on your car. It would be nice to fit new spark plugs as well.

Hanah Kim

why fanny around guessing and estimating flywheel figures when you can measure the actual at-the- wheels figures and make a direct factual comparison?

Hanah, you're probably right about the ICON. It's difficult to Guestimate the performance of the chip. I only got the RR graph when I had the chip fitted :0(


The 'at wheels' figure is 115.6 the standard MPi figure is 102.

I only give the 'flywheel' (estimated) figure as this is a lot easier to compare to original Manufacturers figures...But you are right this can only be estimated. So my 'at wheels' figure shows a 13.6bhp performance gain with all the mods.

tim woolcott

thanks Tim, that's useful. Good base figure for comparison at the r/r day coming up too.

Tim hi, that's my guess as well! ;-) But sounds logical doesn't it?

The good thing about MGFs is that there is a very small loss in between the flywheel and rear wheels I reckon. Isn't it supposed to be like around 30%?

In this side of the earth, they like using Kw (kilo watts), which is HP / 1.34. Or kw -> HP takes kW times 1.34.

I would do RR testing of mine sometime in near future.
and will let you guys know.

Hanah Kim

hi all
i have the K+N, MS Exhaust,trophy tb and i just got the set of plug leads as well as new plugs Bosch Triple Fire good improvement
Luis Pereira

I dont know what the percentage loss is for an MGF but if theyre claiming its good, itd better be better than 30%. Thats getting into Automatic Honda territory

it looks like you loose about 20% through a PG1 box.

i got 218.6bhp at flywheel (estimate) and 176.4bhp at wheels.

and 233.9bhp at flywheel (estimate) 188.5bhp at wheels.

220 turbo with a few mods.


Drew Spalding

I have a VVC with a K&N panel filter and a Trophy TB. I have also modified the airbox to take cold air from the lhs intake. The difference is amazing, well worth it. If you are nearby then you are welcome to come and have a ride in the car.
Jason H
Jason H

This thread was discussed between 27/10/2002 and 04/11/2002

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