donut
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| posted on 2/10/06 at 05:41 PM |
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Torque v's bhp
Whats the best way of getting torque? I would prefer torque rather than bhp and i'm guessing the cam profile will determin when the power comes
in.
I'll be building my engine soon and would like a torquey engine with the power coming in at about 1500 rpm which is where i'm estimating
i'll be using the power most.
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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DIY Si
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| posted on 2/10/06 at 05:43 PM |
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Is this for the mini? A series or something more modern? If A series, what sort of use will it see? Ie, do you want a high eving screamer, or a slower
slogger?
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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smart51
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| posted on 2/10/06 at 05:47 PM |
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Look at a rally cam rather than a race cam if you want low down pull rather than high rev power. Higher compression ratios are good. A longer stroke
rather than a fatter bore is better too.
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flak monkey
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| posted on 2/10/06 at 05:49 PM |
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When it comes to torque the more cc's the better IMHO.... torques a direct result of the force of the combustion pushing the piston down the
cylinder, the greater the piston area, the more force you get to turn the engine i.e. torque. Small engines i.e bike engines  lack torque as they
are of a small capacity.
Hence why V8s have ludicrous torque figures, but not necessarily high BHP as they dont rev very high.
High CR is also a good way to get torque, hence why deisels have very high torque figures.
David
[Edited on 2/10/06 by flak monkey]
Sera
http://www.motosera.com
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donut
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| posted on 2/10/06 at 05:49 PM |
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Yes it's for a Mini. I would like it to produce as much torque/power as poss low down for pulling away rather than screaming it's nuts off
at 6000 rpm.
It will be for the street, not the track.
ta
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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DIY Si
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| posted on 2/10/06 at 05:52 PM |
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What size is the engine? Is it A or A+, or is it an old cooper engine? Either way, a nice overbore and a crank re-grind to something like 1430cc will
give a nice torque figure. If the engine is to keep a standard bore/stroke, then head work and as said a rally rather than race cam. Also, what
options do you have as per induction?
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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donut
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| posted on 2/10/06 at 06:15 PM |
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It will probably be a 1330 and it's an MG Metro A+ motor. Induction is via an SU HIF 44 and a big bore zorst will sort the smelly stuff! Not
sure what to do about the head, depends on cost.
Andy
When I die, I want to go peacefully like my Grandfather did, in his sleep -- not screaming, like the passengers in his car.
http://www.flickr.com/photos/andywest1/
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stevec
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| posted on 2/10/06 at 06:38 PM |
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More torque Big flywheel perhaps.
Steve.
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Simon
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| posted on 2/10/06 at 07:12 PM |
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One way to get big torque from an A series, may be (once you've overbored it) is to supercharge it.
Might start making things expensive and complicated, but a s/c from a BMW mini might be just the ticket, and reasonably cheap.
ATB
Simon
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iank
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| posted on 2/10/06 at 07:45 PM |
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Go to WHSmiths and have a peek in this mag http://www.gr8website2.com/calverst/main.htm
One of the example engine specs is for a largish (well it is a mini engine ) torque engine (it's the 1360cc uses 73mm pistons rather than the
normal 73.5mm 1380 overbore).
[Edited on 2/10/06 by iank]
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rusty nuts
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| posted on 2/10/06 at 07:53 PM |
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Treat yourself to David Vizards book Tuning the A series . Tells you everything you need to know and more .
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UncleFista
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| posted on 2/10/06 at 08:10 PM |
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I read in a magazine (can't remember which) about an A series that had been fitted with a BMW bike cylinder head.
Seemed simple-ish and the power figures were impressive..
Tony Bond / UncleFista
Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...
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coozer
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| posted on 2/10/06 at 08:19 PM |
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The mini engine with bike head was in the PPC.
If you want more torque use a diesel engine. There are some mighty fine turbo diesel engines out there and I have seen a Westfooled with an Isuzu
1.5td from a Corsa.
Mates directly to a gearbox from some other RWD Isuzu badged car.
And I've just upped the boost on mine and its gone from a standard 66bhp to 95 with masses more torque. 130mph here we come!!
Psst, dont tell anyone but the new Mini has a turbo engine instead of supercharger. I've seen them in the repair area at Cowley. SHHH!!
Steve
[Edited on 2/10/06 by coozer]
1972 V8 Jago
1980 Z750
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MikeRJ
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| posted on 2/10/06 at 08:22 PM |
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Fit a 4.33:1 final drive. Voila, more torque at the wheels for the same bhp 
The Kent 266 cam is excellent for a road going mini, perfect idle and pulls like a train from low RPM.
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Danozeman
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| posted on 2/10/06 at 08:44 PM |
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quote:
Treat yourself to David Vizards book Tuning the A series . Tells you everything you need to know and more .
I have this book. Its a very good read and very helpfull. Unfortunatley i sold my mini before i got to have a play. Im keeping it with intent on
getting another one.
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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Hellfire
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| posted on 2/10/06 at 09:00 PM |
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quote:
Originally posted by flak monkey
When it comes to torque the more cc's the better IMHO.... Small engines i.e bike engines lack torque as they are of a small capacity.
David
Oh dear, oh dear.  There's loads of threads regarding this old chestnut that will dispell this myth. Just do a search.
Phil
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smart51
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| posted on 2/10/06 at 09:06 PM |
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Yamaha R1 998cc 108 Nm
Citroen TU 954cc 74Nm
Toyota K1-3fe 998cc 93Nm
Honda fireblade 998cc 114Nm
Bike engines have less torque?
They have a higher compression ratio = higher torque. Bike engine tuning merely means that it happens high up in the rev range. You could fit a
different cam and have it lower down but you'd lose the power, but if you want your torque low down...
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flak monkey
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| posted on 2/10/06 at 09:06 PM |
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I was waiting for you to comment. Perhaps i should have put  after it 
Lets face it bike engines are totally different to car engines. If they hit their rev limit at 6500rpm they would be pathetic and useless. But seeing
as they will easily rev to well over 11000rpm they do still have very good power outputs since power is related to rpm and torque combined as we all
know...
David
[Edited on 2/10/06 by flak monkey]
Sera
http://www.motosera.com
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ettore bugatti
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| posted on 2/10/06 at 09:12 PM |
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quote:
Originally posted by coozer
The mini engine with bike head was in the PPC.
Steve
[Edited on 2/10/06 by coozer]
Which number of PPC featured the twincam conversion? BTW the twincam conversion needs revs to work.
MG Turbo is quite strong on torque.
A stroked A-series (1420 etc.) is very expensive since you have to use Cooper S conrods.
A very good option is to use a 1330 or 1380 as a base with Swiftune SW5 cam (aka Cooper 997cc cam) or MG Metro cam.
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Catpuss
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| posted on 2/10/06 at 09:26 PM |
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quote:
Originally posted by Hellfire
quote:
Originally posted by flak monkey
When it comes to torque the more cc's the better IMHO.... Small engines i.e bike engines lack torque as they are of a small capacity.
David
Oh dear, oh dear. There's loads of threads regarding this old chestnut that will dispell this myth. Just do a search.
Phil
Yep having the right size carbs/throttle bodies helps. Also longer stroke.
Its bloody yamaha's fault with the R6 and its two stroke power delivery that gives the impression of no torque.
With bikes its more a problem with the spread of tourque rather than the max output. Car engines can produce a lot of tourque quite low in the rev
range. All sorts of factors some into it, not just longer stroke and smaller carbs/throttle bodies.
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DIY Si
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| posted on 2/10/06 at 10:55 PM |
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The first thing to do is to buy the Vizard book. It's the tuning bible for the A series.
If possible I'd bin the single HIF44 and get something better. Whilst I know the HIF's are good, I'd prefer a twin carb or single
webber set up (IMHO). If you want something a little different, a single downdraft IDA webber (as fitted to GT40's!!!) works really well! My
engine has a single 48 IDA webber, with lots of mods, and has 150/160bhp and a mere 1338cc! They are available in smaller sizes too. Also, the cam
choice will play a huge part in how the engine produces its power. I'm also a huge fan of the VP3C cam, which forms just a part of the APT range
of cams. These are all high lift, low(er) duration cams and are actually suited to the A series, as opposed to the higher duration/older cams which
are less good. for example, the VP3C in a 1400cc engine can produced 110lbft and 130 bhp. This cam also has a tame, if slightly lumpy idle and pulls
from low down too.
Also, Cooper rods and other bits aren't that expensive, but as with every thing it depends upon bugdet. Stroking a standard crank will mean
using the Cooper rods though, due to the now smaller journal diameter. Head work and camming will do wonders for the A series, and if money is tight,
can be done yourself and still produce very reasonable results.
[Edited on 2/10/06 by DIY Si]
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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NS Dev
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| posted on 3/10/06 at 07:27 AM |
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quote:
Originally posted by smart51
Yamaha R1 998cc 108 Nm
Citroen TU 954cc 74Nm
Toyota K1-3fe 998cc 93Nm
Honda fireblade 998cc 114Nm
Bike engines have less torque?
They have a higher compression ratio = higher torque. Bike engine tuning merely means that it happens high up in the rev range. You could fit a
different cam and have it lower down but you'd lose the power, but if you want your torque low down...
Higher compression ratio = higher torque.............
errrrr NO!
WRONG!
you can have all the compression in the world and make no torque at all, look at a diesel engine at tickover!!!
Torque IS closely related to BMEP (obviously via crank/rod geometry) but nothing whatsoever to do with static compression ratio.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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NS Dev
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| posted on 3/10/06 at 07:30 AM |
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PS in answer to the original question, one previous answer hit the nail on the head, stick a supercharger on it.
The A series (or A+) head will never breathe particularly well, but the supercharger will get neatly round that one and can be "pulleyed"
suitably to make enough torque to blow your head gasket at whatever revs you care to choose.
PS surely you want an HIF6 carb not HIF44?? (not that I know much about these things but that's what I used on a 1275 in my mini days!)
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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iank
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| posted on 3/10/06 at 07:52 AM |
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HIF44 is the metric version of the HIF6
The BMW bike cylinder head conversion featured in PPC is now available from Morspeed. http://www.morspeed.co.uk/latest-newspage.htm
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DaveFJ
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| posted on 3/10/06 at 07:57 AM |
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quote:
Originally posted by smart51
Yamaha R1 998cc 108 Nm
Citroen TU 954cc 74Nm
Toyota K1-3fe 998cc 93Nm
Honda fireblade 998cc 114Nm
Bike engines have less torque?
They have a higher compression ratio = higher torque. Bike engine tuning merely means that it happens high up in the rev range. You could fit a
different cam and have it lower down but you'd lose the power, but if you want your torque low down...
My Fiat tin top..... 2470cc 230Nm 
<sorry couldn't resist >
Dave
"In Support of Help the Heroes" - Always
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