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MG MGF Technical - Can I get more torque?
|Although I love my F, and think that it's a joy to whiz around twisty country lanes; as an ex owner of a car with a turbo I am disappointed with the F's torque. |
What, if any, are the ways to increase my F's torque??
|K&N or some other filter is the cheap option.|
Head work and cams is the expensive route,
Que Dave Livingstone & Rob Bell with the results of the Emerald RR session in January.
|both of these will increese the BHP more than the torque- if you want torque then turbotechnics do a turbo, or wait a bit untill the Rover 1.8 turbo engine gets more mainstream.|
|'Kerching' That'll be £5000 please Sir!|
|Didn't say it would be cheap!|
Of course if you only want torque there was someone in here who planted a Diesil engine into a MGF- He left after we laughed at him!
|There was a Scubby wrx on ebay the other day for 5K and no HGF worries|
|I don't think that the K&N is the best modification for improved torque. I suspect that both the ITG Maxogen and Pipercross Viper will be an awful lot better! I base this observation on how well the Rover 820 airbox mod for the K&N 57i works, compared to Tom's ITG. Practically identical...|
I've now got in excess of 140 lb ft of low end torque, and the car really flies now :o)
'Trophy' 52mm throttle body
Mike Satur Daytona exhaust
K&N 57i in Rover 820 airbox
You don't say whether your car is an MPi or a VVC. Our rolling road experience seems to indicate that modifications to the K series seem to produce more gain in torque than bhp for the MPi and more gain in bhp than torque for the VVC.
The best we saw on an MPi was around 146ft/lbs at 4400 revs and on a VVC around 141 at 5000 revs.
We may find out more on the next rolling road day - 4th May in Thetford, Norfolk.
|The best we saw on an MPi was around 146ft/lbs at 4400|
I think that was mine wasn't it......! :0P
|I do believe it was Tim :-) It'll be fascinating to see what happens after the head work and of course to see the comparison between yours and Kingsley's - can't wait!|
|Ah - but Tim... remember the whole in your torque curve? It was larger than Tora Bora! ;o)|
Looking forward to seeing the results from the DVA modified cars - as Dave says, Tim's and Kingsley's should, in particular, be enlightening from the perspective of getting an idea of the difference that an Emerald ECU + multiple DTH throttle bodies makes on what should be pretty identical heads :o)
Tim, I presume you'll have the same cams as Kingsley?
|>Tim, I presume you'll have the same cams as Kingsley?< |
Haven't asked yet....
Kingsley.... 633 or 623's?
|BP285H s in mine i believe|
|Ooooh, those cams.....Hot hot hot. Would be a little lumpy in mine with MEMS and std throttle body I believe.|
It's a 97 VVC with a K&N 57i induction kit; Do I take it that the MPi is easier to modify then?
Tim, thanks for the scooby tip, a friend of mine owns one and whilst they are blisteringly quick and have loads of torque; two words spring to mind... pig and ugly.
|The MPi is a little simpler to modify, but you're starting from a higher point witht the VVC, so bolt on upgrades tend to make more of a difference.|
Tim, With the throttle bodies it barely runs on the MEMS, so the M3DK is essential realy. but cams are easy to thange as you perform further mods in the future;)
What's the position with changing cams in the vvc? i know you can replace the vvc mech with normal cams (i think piper do a kit?)
|146ft/lb seems unfeasibly high from an MPI with standard head, it represents around 87-90% volumetric efficiency which is extremely difficult to achieve even with careful head prep and very carefully timed cams with over 270 degree duration. Even with a VHPD head fully ported with appropriate induction it requires a lot of effort to make 150ft/lb, the best I have ever seen is 162ft/lb using extreme cams and very long induction. The stock head has poor airflow and the laws of physics apply to everyone. I dont wish to pee on the parade but if I saw a reading like that I would suspect that the RPM at 60 were wrongly set on the RR run which will inflate the torque.|
for waht its worth I'd expect Tims engine to make a true 138-140ft/lb on his choice of cams.
You have the graphs - they were from the RR day in Brixton last December. Take a look at Tim's results. The rpm setting was 3600, exactly the same as the other MPis. Tom Randell's MPi also recorded a peak of 145 ft/lbs and Rob Bell's 143 ft/lbs.
The VVCs were all lower, although we could never understand how Stu Dicken's car acheived 141 ft/lbs compared with the two cars with head porting - mine at 136 ft/lbs and Paul Nothard's at 133 ft/lbs.
Any ideas? We'll get a chance to re-test on 4th May as many of the same cars will be in Thetford although Tim's of course will be slightly different by then ;-) and all our eyes will be on Kingsley's!
It may well be that I am mistaken my RR results it was a couple of months ago! I do remember that of all the Mpi's tested mine did have the highest torque peak (not particularly flat, as Rob has already mentioned)
Still..... >for waht its worth I'd expect Tims engine to make a true 138-140ft/lb on his choice of cams.<
Seems pretty respectable to me and I suspect more useable too !
I don't have the graphs any more and can't get into the site, can you have a look for me to jog my memory.
I suspect a scaling problem.
The VVC can be converted to solid cams using a blanking kit and larger journaled inlet cam, but you will need an after market ECU such as an Emerald. I do two kits to upgrade the VVC, one retains the VVC mechs, the other does not, see www.dvapower.com. You can also freeze the VVC mech in a fixed modulated position and use a better exhaust cam with an after market ECU and TBs.
|boy, I must type slowly...... |
could atmospheric condition have an effect ie. results taken on a bloody cold day....?
|Looks as though we'll have to look at the rpm calibration again Dave (and Dave!)|
Should have checked this before Dave, but when we did the last set of filter tests, we saw a rather more creditable 120 lb ft torque with the 1.8i and VVC cars (see http://www.mgf.ultimatemg.com/vvc_mpi_cf_kn.jpg)
It may be possible to recalibrate the power curves we got at Emerald using this graph as a basis: both the MPi and VVC were pretty much standard cars. Note that the torque and power curves where they're supposed to ;o)
As already said here, getting much more torque out of the MGF engine is costly. Of course the other way to look at this is to reduce weight.
Swapping the MGF for an Elise will cut around 350 Kg, and give you a much stiffer bodyshell and is more able to handle a tuned engine.
I also own a '97 VVC and personally think the bodyshell has enough problems handling the power that's already there (the TF's supposedly better).
Why not join one of the rolling road sessions and see how your car compares ? (A VVC should certainly have no problems in twisty lanes) At least you'll see what works and (perhaps) at what cost.
I found the last session in Brixton very useful - it persuaded me to go no further with the F. I've said that before though haven't I :-)
You have valiantly defended the MPi against the VVC,
but as its a quiet Friday afternoon at work, thought I'd open up the debate a bit ;-).
When relating to Torque/Power etc and improving responses, we don't tend to be talking about cruising at 70 mph down the motorway.
We are talking about, tight corners, sharp braking, and hard acceleration.
In this case, which your familiar with with your hill climbing experience, where would you say your rev range would lie?
If you fitted shift lights, where would you set the shift up/shift down triggers?
Looking at the graph, I'd proably set the shift up (at rev limiter obviously ;-)), but what about the shift down?
Probably around 3.5k???
Giving the VVC range 3.5k to 7.2k.
and the MPi matching the range up to 4.5k.
Which has the more power???
Please note we're all driving the best loved british ports car, so this is purely academic, and not slating the MPi. (just opening an lively debate, on a boring Friday afternoon.)
|Interesting, so are we saying that even though fitting a turbo or supercharger will greatly increase the torque, the general makeup of the VVC is not really equiped to cope with it?|
I know that the general answer is that if you're after that sort of performance; go and buy a different car. But I quite like the looks of my F, and was just wondering if I could have my cake and eat it :-D
|>>Interesting, so are we saying that even though fitting a turbo or supercharger will greatly increase the torque, the general makeup of the VVC is not really equiped to cope with it?<<|
That's my opinion; the MGF is an excellent car for Britain's roads - but it's no match for (say) a Mitsubishi EVO or a VX220 Turbo. Just how illegal do you want to be :-)
Consider also why MG have never produced a forced induction F - they've certainly looked at doing so.
>>I know that the general answer is that if you're after that sort of performance; go and buy a different car. But I quite like the looks of my F, and was just wondering if I could have my cake and eat it :-D <<
Well, just about anything is possible if you are prepared to pay. You've got to spend your money on something (how about a motorbike?) !
hmm, intruiging question. The MGF Abingdon Cup has now completely shifted to VVCs, so I think that this answers your questions! ;o)
>>When relating to Torque/Power etc and improving responses, we don't tend to be talking about cruising at 70 mph down the motorway.<<
2.5-4.0k rpm range is also the most often used in town too... But not, as you say, on a circuit.
>>We are talking about, tight corners, sharp braking, and hard acceleration.
In this case, which your familiar with with your hill climbing experience, where would you say your rev range would lie?<<
Probably in the 4-6k rpm range (as an MPi there is no advantage in revving the engine any harder than 6k - in fact the power peak has already passed at this point, but changing up at lower rpm means that you drop too far down the power band.
>>If you fitted shift lights, where would you set the shift up/shift down triggers?<<
Shift up for an MPi would be 5.5-6k. On a VVC you could work the engine a little harder up to 7k.
Shift down? Too busy braking, lining the car up for the corner, turning etc to look at the rev counter! LOL But I guess 3.5k might be a good point if you were to fit a 'shift down light' (does such a thing exist?) trigger.
On the basis of circuit work, there is no doubt in my mind that a VVC would be better.
|<<you were to fit a 'shift down light' (does such a thing exist?)>>|
I have one, was debating fitting it on the F, but its a bit too large, and as i don't race my F also completely pointless.
Although, looking forward to my first ever track day on the 11th of April, who knows I may get hooked ;-)
The one i have is about 7" in diameter, and when you set your limits, the whole dial flashes.
Although i think you can can slightly more descrete ones.
|I'm going to fit a shift up light this weekend, it can be driven off the Emerald.|
With the mods on my car red line is above 7k and it could definatly do more, but forged pistons would be in order so v. expensive..
4-7k revs is best for power now.
|>>The one i have is about 7" in diameter, and when you set your limits, the whole dial flashes<<|
Wowzers! Most shift lights I've seen are LEDS...
What track day are you going to in April Paul? They are initially quite daunting, but absolutely MASSIVE fun once you get going :o) I'm sure you'll love it :o))
>>I'm going to fit a shift up light this weekend, it can be driven off the Emerald.<<
<Chuckle> I think I may have mentioned this to Tim a couple of times Kingsley ;o)) Are you going to put in an additional LED, or are you going to use one of the dashboard warning lights (I was thinking of using the seatbelt warning lamp)?
Why set the limit to 7k? The MPi has the same bottom end as the VVC, which has a limit of 7500... ;o)
Actually, thinking about it, for track days, perhaps you should set your limiter to 5k... ;o) ;o)
This one doesn't actually tie into anything.
Its just like an extra rev counter, with maunal limit settings.
It doesn't actually act as a rev limiter, it just flashes when you reach the set limit.
So if you set rev limit to 5000, you just get a less than subtle reminder to change gear, doesn't mean you have to.
Dreadnought Garage have arranged a TVR/MGF night at Knockhill on Friday the 11th.
A few people from the board are going, although, not sure who's going on the track though.
The VVC has a lower rev limit than 7500, I beleive its 7200 and it has better pistons..
|Sounds good Paul - have fun :o)|
David, thanks for that info - I knew that early MPis had different bottom ends to the VVC (which was later standardised - not sure exactly when) but the differences in the pistons I was unaware of!
BTW, will send that SAE to you soon! Cheers :o)
This thread was discussed between 27/03/2003 and 31/03/2003
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