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MG MGF Technical - Anyone tired of HGF!!!!!

take a look at these guys...
http://www.prototyperacing.com

so who's up for that mod then?

Drew
Drew Spalding

yes i would love to have a good engine in my mgf instead of a heap k series lump. i might sell the mgf as its falling apart even though it only has 45k on it
george

It's interesting to look at the Spec for the 2.0litre S2000 VTEC engine.
Maximum torque is 153 ft/lbs (at 7500 rpm)
Adjusting for the different engine size, this is roughly what we got on the rolling road for the VVCs
( ie (153 / 2000) * 1800 = 137 ft/lbs ).
Just goes to show that the S2000 gets its power by revving very, very hard. You can bet that maintenance on that engine is expensive - especially when it comes to setting valve clearances

Taking a look at bike engines with similar cylinder displacements - eg 1-litre V-twins, shows similar revlimits and similar torque, (max power is slightly up due to wilder cams).

So the VVC is in good company, I'd say.

Steve
Steve

9,000rpm and 260BHP.

I did a similar calculation based on a TF160 at 1.8L and 7000rpm.

Multiplying the 160 by the ratios of max rpm and engine size gives 228BHP so Honda must know something about engines

Brian

thats all good but i bet the honda engine can handle extra power and is alot more reliably than the mgf vvc engine
george

as far as I'm concerned the Honda VTEC engine in all it's guises is bullet-proof and the best thing since sliced bread etc. As some will know I've had a 1.8 VTiS civic for 3 years now and in 70k miles it has never missed a beat. I doubt a day has gone past without exceeding 8k revs, the limiter is set at 8400 in this model and once warm I change 2nd to 3rd just below it, cos it's fun and sounds nice. It has never needed other than the 'book servicing' which is only a couple of hours at most. My excellent dealer (Clover Leaf Ascot) once did the 18k service in 50 mins while I waited...
David

The issue is reliability, you can get 25%BHP+ from a K series and over 165ft/lb torque and at this spec it murders the VTEC for torque and BHP, *however* it is expensive to achieve and even when using properly prepared componentry is not bulletproof like the Honda will be.

However.. examine the driveshaft angle on the Honda conversion, if that doesnt give you kittens...

Dave
Dave Andrews

>>...from a K series and over 165ft/lb torque...<<
Is this close to the limit for this engine size on 95RON petrol and no forced induction / NOX ?
Looking at various engines, there appears to be a real limit of around 80 ft/lbs / litre on production engines (of all types)
Your figure of 165 ft/lb equates to around 90 ft/lb / litre - is this due to tuning of inlet & exhaust - and does this only happen in a very limited power band ?

And if you get your 80lb/ft / litre engine to produce that torque at around 6500 RPM then you get your oft-quoted 100BHP/litre ...

Steve
Steve

>> and does this only happen in a very limited power band ?<<

I guess that may depend on how you define a 'limited power band' Steve - but from the curves I've seen, DVA tuned engines run at standard-or-better torque from the bottom end, to massively more in the mid-top end of the rev-range. So you end up with a car that is as easy to drive as with a standard engine, but one with rather more of a ferocious appetite for the red-line!
Rob Bell

Thanks Rob...

93ft/lb per litre is about right for a fully prepped 4 valve race engine built on a production base. purpose built racing engines can make 96ft/lb a litre or more if tricks are played with induction pulses.

Peter Carmichaels 255BHP K series made 165 ft/lb torque at peak (6100-7200) and 255BHP at 8600, where its torque was 154ft/lb. It also had over 130ft/lb from 3900 to 9200 and over 110 ft/lb from 2500 upwards which is a pretty good torque spread. It used a 300 degree exhaust cam and 285 degrees inlet and a big valve head flowing 138CFM at 10" water. This is what enabled the torque to extend so far up the rev range. The output is qroundf 140BHP/litre.

Dave
Dave Andrews

This thread was discussed between 07/01/2003 and 10/01/2003

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