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MG MGF Technical - Dyno - MPi with toys fitted

Just been to the Dyno to have my Icon re-calibrated (yes, I'm very happy with it)

The car:
1996 MPi
Mike 'Imola' Exhaust
ICON race chip.

Book figures:
118 at the flywheel
102 at the wheels

Dyno Figure
135 at the flywheel
115.6 at the wheels

Sounds nice too but not quite up to RichieR level.

Just thought you folks might be interested.

tim woolcott

Did you perform the RR tests with the engine bay cover on Tim?

I only ask because if you did, engine bay heat build up will lead to an underestimate of engine output (you are probably looking at about a 5 bhp deficit).

Really interesting :o) According to two different RR, my car is putting out similar power (135-ish) with 'just' a K&N and a Trevor Taylor exhaust :o)

How did the RR chaps work out the transmission losses? Negative power run or by 'guestimating' it?
Rob Bell

Was it Richie who had his exhaust manifold reworked (in addition to the VVC which obviously has a massive impact)? Just wondering what we'd see on a dyno with an SP exhaust and a decent manifold.


I know that Andy G had his exhaust manifold bored out - not sure about Richie. No doubt he'll let us know!
Rob Bell


1. Boot left open during Dyno run.

2. Flywheel figure - guestimated

3. No 'Ram air' effect from plenum to K&N.

The chip has managed to smooth out a few of the peaks and troughs through out the power curve but in terms of out and out power increase it may makes less of an impact.

I have a previous RR graph at home which I must route out before the Exhaust and TB were fitted. I think it gave a very similar result. However, the pick with the new TB is superb and the 'breathing' with the MS exhaust allows much freer revving.

The guys doing the dyno did say I would benefit from a fuel boost valve. There's a lot more air getting in so could do with a bit of fuel too. Out of interest does the Trophy 160 have a different fuel valve thing?

tim woolcott

The number of rolling roads that accurately mimick air flow at speed can be counted on the fingers of one hand! ;o)

You'll probably find a bit more power if the engine cover is removed, as the opening of the boot lid alone is not enough to 'clear' all the hot air from the engine bay. So hey, good news is that you've got yourself a 140-ish bhp engine! ;o)

My understanding of 'Power boost valves' is that they maintain a higher fuel line pressure. There is no advantage to power under steady-state conditions - ie no more fuel is delivered under constant throttle openings. The advantage comes when you snap open the throttle, and suddenly there is a greater demand for fuel: the fuel line pressure drops, and as a consequence, there can be a modest deficit of fuel relative to air. Higher fuel line pressure means that more fuel can be supplied quickly. So great for acceleration! Not so noticeable in terms of absolute power.

Interesting question regarding the TF and Trophy 160 fuel pressure regulator: are they the same as the standard MGF?

Tim, could you send me a copy of your RR data? It would be interesting to compare with curves obtained from other MGF 1.8 MPis with standard ECUs :o)
Rob Bell

Just for interest how much does a rolling road cost (to do, not buy)? I'd like to get mine on one, ITG/daytona/TTB, so i can see before and after with future mods ;)
I assume these engine bay covering issues would not be present with the ITG or other closed induction systems?

Quotes really depend on where you go - can be about 50 quid per run.

Quite right about enclosed air intake systems Kingsley - they are much less sensitive to the effects of heat build up in the engine bay :o)
Rob Bell


I'm sending you todays dyno graph. Their coloured pens had dried up so on in black I'm afraid.

I'll scan the old graph for you when I get back from Le Mans.


The power run and Chip calibration cost me 30 quid, it was only half an hour.

tim woolcott

I will get my car dynoed, once Rob's exhaust arrives here!

But how come the loss from flywheel to wheels is so small on MGFs? Is it that efficient? Most cars are calculated to be around 25-30%.

But from Tim's it isn't. I can see that Rover's flywheel figure is 117hp. and Tim dynoed it to be 102hp at the wheels which is really damn efficient!

Can this be all true..

I think Tim's car is more powerful at the flywheel.. or should be.. because theoritically..

1) TTB = 5hp
2) K&N = 8HP
3) Exhaust= 5hP
4) ICON = 5-6HP

so shouldn't it be 140hp? Hey.. that means Rob's estimate is correct! +5

And still the wheels output is only 15% deduced from flywheel figure.. it's damn efficient isn't it!

Man what the hell am I talking about.. got an anatomy exam tomorrow..i must be going nuts.

Rob.. I want ur.... exhaust! :-)
then will get my car dynoed ASAP!


Hanah Kim

I thought it would be more than that, will have to start looking around for somewhere to do it.

Is there a cirtificate of calibration or somehting a place should have, or anywhere reputable i should try, as i heard results can vary a lot?

The problem is, when you know what your figures are, i bet you want more! :D


If we take the above assumption of 140 Bhp and we put into the mix a reworked Exhaust manifold and Mike stage one (plus) conversion what would we be looking at...

Mike figures, including one of his induction kits, for the conversion seem to show an improvement from 102 to 126 Bhp (at the wheels), so does it mean 160 could be hit from an MPi...?

Oh, any more ideas on that Trophy Pressure valve question....!?

tim woolcott

I would bet the Trophy has the same fuel pressure system as the standard F, performance can be gained in cheaper ways, also powerboost valves can hinder ecconomy figures.

I'm sure I'll be corrected, but IMHO I don't think 160bhp will be hit without bigger valves and higher lift cams. It's definately achievable, and has been done in other applications, though usually with more extensive internal engine mods.


Tim, thanks for the graphs. It looks as though you've got a nice flat torque curve there :o)

I'd agree with you Darren - probably 145 bhp is going to be the ceiling on 1.8i output (that'd be with a nice EBD 4-2-1 extractor manifold along with all the other bits and bobs).

Mike's stage one kit (which as we know, Scarlet is becoming very familiar with) is a simple gas flow and removal of excess casting marks. Sould take you comfortably up to the mid 150s I'd have thought.

To comfortably breach the 160/170 threshold, you'll want the head ported and larger valve areas - then depending on your rev limit, 180 - 220 bhp is quite possible with a 1.8 MPi (but at this point, you want a complete replacement ECU as the engine will be working well beyond MGR mapping parameters!!! ;o)

Actually Tim, you might want to start thinking of upgrading your MEMS/ICON combination to an Emerald to take advantage of the fuelling demands at the 2-3000 rpm raange.
Rob Bell

Engine Porting option is purely hypotetical at the moment.

Sure, porting the engine is all great fun but there are all of the knock on effects. If you're going quicker, ya need to stop quicker too. Add on 1K plus for the brake and suspension up-grades :o)

tim woolcott

I've done it the other way round,
breaks/suspension/gearshift first (it needed it realy)

Next it's big performance for the middle of summer/autumn replacement head (ptp 165? 190? :D ), CR Gearbox (&limited slip dif)(Rover BRM), tighter steering rack.
I think i'll be just about there then with my ultimate F :D

in between that lot i shal be robbing some banks to pay for it all!

>> Add on 1K plus for the brake and suspension up-grades :o) <<

Yup, that'd be right Tim - and then some depending on the parts you are keen to specify. But worth every penny IMO :o)

Have Techspeed suspension, Roversport discs, Mintex 1177 pads, braided hoses and servo support bracket :o)

Added a little more info to the suspension upgrade site last night, so for those who are interested: :o)
Rob Bell

This thread was discussed on 12/06/2002

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